J /_

THE LIBRARY

OF

THE UNIVERSITY
OF CALIFORNIA

PRESENTED BY

PROF. CHARLES A. KOFOID AND
MRS. PRUDENCE W. KOFOID

THE

MICROGRAPHIC DICTIONARY;

A GUIDE TO THE EXAMINATION AND INVESTIGATION

OF THE

STRUCTURE AND NATURE

OF

MICROSCOPIC OBJECTS.

BY

.1. W. GRIFFITH, M.D., F.L.S. &c.,

MEMBER OF THE ROYAL COLLEGE OF PHYSICIANS ;
AND

ARTHUR HENFREY, F.R.S., F.L.S. &c.,

PROFESSOR OF BOTANY IN KING'S COLLEGE, LONDON.
ILLUSTRATED BY FORTY-ONE PLATES AND EIGHT HUNDRED AND SIXTEEN WOODCUTS.

LONDON:
JOHN VAN VOORST, PATERNOSTER ROW.

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PRINTED BY TAYLOR AND FRANCIS,

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PREFACE.

UN arriving at the conclusion of their labours, the Authors feel that some
apology is, in the first place, due to the Subscribers, for the extent to which
the number of their pages has been increased beyond the original estimate.
They have, however, the pleasure of stating that no complaints have been
addressed to them on this head, but, on the contrary, strong injunctions, when
the work was somewhat advanced, to allow no considerations of arbitrary limits
to prevent equal justice being done to the subjects falling under the later
letters of the alphabet. They feel therefore that due allowance has been
made for the difficulty of calculating beforehand the extent of a work like the
present, and that the circumstance which has chiefly led to the enlargement of
the volume, namely, the revision of the articles at the latest moment before
committing them to press, has been duly taken into account.

Secondly, a few observations may be offered on the character, objects and
uses of the work. It was stated in the Prospectus, that the ' Micrographic
Dictionary ' was offered as an index to our knowledge of the structure and
properties of bodies revealed by the Microscope. The Authors venture to
hope that their work may possess many useful qualities beyond those strictly
implied in the above definition.

Few or none of the works hitherto published have dwelt upon the
manner in which observers might judge of the structure of objects from the
appearances presented under the microscope. There are works treating of the
construction of the mechanical and optical parts of the instrument, and the
manner of using them ; of the methods of preparing objects for examination ;
and to these are usually appended lists of objects presenting interesting appear-
ances. But there exists no work which will direct the Student how to vary the
methods of preparation of the objects examined, so as to elicit their true
structure.

r-=o/? o/i no

iv PREFACE.

An Introduction has been prefixed to the 'Dictionary/ affording instruc-
tions for the selection of a Microscope and the accessory apparatus, explaining
the manner of using these, and particularly the precautions requisite with the
less perfect, but more economical foreign glasses ; and lastly, entering minutely
into what may be called microscopical manipulation and the special education
of the eye. i-d aoiJBYi

Many valuable contributions to our knowledge of the structure or
functions of microscopic organisms are probably lost, through the inability of
microscopic observers to ascertain readily the name and position in Nature of
objects which fall under their notice. It is hoped that the very numerous
illustrations to this work will form a valuable guide in such cases, and render
the descriptions of microscopic animals and plants, of minute structures,
tissues, &c., which form the main body of the volume, a real Dictionary of
objects. At the same time it is not unreasonable to expect that much advan-
tage may be derived, from the attention that has been paid to directing
observers to subjects and disputed points on which • new information is
desirable.

To the lovers of Comparative Anatomy, Physiology, or of the Natural
History of the microscopic members of the Animal and Vegetable Kingdoms,
the Authors have endeavoured to furnish, without departing from the principal
purpose of the work, something more than a mere descriptive catalogue of
objects, and the means of examining them. Numerous articles on various
subjects have been written with a view to enable readers, by the help of the
system adopted, and references printed in SMALL CAPITALS, to acquire a general
knowledge of particular departments of science. Thus, taking a departure
from the article ANIMAL KINGDOM (or VEGETABLE KINGDOM), the reader may
proceed to the Classes and Orders there enumerated ; under the latter will be
found a general description of these (where the microscope is much required in
their investigation), followed by a reference to the Genera, under which is
given more or less extensive information on the Species, according to the state
of knowledge, or as the subject has seemed to require. Proceeding from the
article TISSUES, in like manner, the details may be gradually collected by
tracing them through the subdivisions by means of the references. Many
other general articles are given, with such headings as the names of well-
known organs or substances, of vital or other phenomena, &c., under which
could be conveniently collected references to a variety of miscellaneous infor-

PREFACE. v

mation scattered through the alphabetical arrangement. Those who use the
volume in this way will probably derive the greatest amount of advantage from
it ; they will, it is true, most clearly perceive the deficiencies inevitable in a
great measure to a work having such an extensive field, and at the same time
so limited a compass.

The results of a large amount of independent observation have been con-
signed to these pages, and, as the bibliographical references show, recourse
has been had, as far as possible, to original sources for trustworthy and reliable
information published at home and abroad. In connexion with this, some
account may be given of the Illustrations. In the Plates, a large number of
the figures are original, drawn from the objects either by the authors or by
Mr. TufFen West ; in many cases, however, figures of species have been design-
edly taken from original plates, especially when the verbal characters were
doubtful. The Authors feel bound to express their thanks to Mr. West for the
manner in which he has applied his well-known skill and accuracy to those en-
gravings which were entrusted to him ; many of them, indeed, appear at first
sight somewhat crowded and on a small scale ; but they will be found in most
cases to display very clearly the parts of objects on which systematic or structural
characters depend, the chief design of all the illustrations of this work. With
regard to the engravings in the text, a portion have been selected, after
comparison with the objects themselves, from the excellent illustrations of the
Mikroskopische Anatomie of Kolliker. Most of the woodcuts of plants are careful
reproductions of drawings contained in original works and memoirs by
Kiitzing, Corda, Tulasne, Bischoff, Bruch and Schimper, and others, prepared
for Payer's Botanique Cryptogamique, to which, as to almost every illustration in
this volume, the magnifying power used has been added. Had not these beau-
tiful woodcuts been accessible to the publisher, it would have been impossible
to have provided this work so richly with illustrations.

The Authors have much pleasure in acknowledging their obligations to the
Rev. M. J. Berkeley, Messrs. Westwood, W. S. Dallas, Sollitt, and Tuffen West,
for the loan of authentic specimens, or for information kindly afforded on various
subjects, and to Dr. William Francis, for constant advice and assistance during
the printing of the work.

•^i JOHN WILLIAM GRIFFITH.

ARTHUR HENFREY.

London, December 1855,^ R

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PLATE 41.— Various Objects.

Figure

1 . Chlorogonium euchlorum, E., undergoing oblique division.

2. Elements of the chyle, a, molecules ; b, free nuclei ; c, chyle-corpuscles ; </, one of the

same with processes.

3. Coccudina cost at a, D.

4. Erythrceus ruricola.

5. Bacilli and cones of the retina of animals. «, |3, from the pigeon. «, bacillus ; a, proper

bacillus ; b, its pale inner extremity ; c, line of demarcation at the boundary of the
bacillar layer ; d, corpuscle of the outer granular layer, ft, cone ; c. as above ; e,
bacillus of cone ; f, proper cone ; g, globule of fat in the same ; h, expansion of cone.
y, from the frog, letters as above ; d, from the perch, letters as above ; i, part at
which the cone usually breaks oif ; k, radial fibre; /, expansion of inner granular
layer, e, twin cones.

6. Frustulia-membranacea. a, valve ; b, front view of frustule.

7. Emydium testudo. 7 a, isolated style ; 7 b, claw of leg.

8. Macrobiotus Hufelandii. f ovary; 8 a, oesophageal bulb ; x its framework.

9. Milnesium tardigrada. 9 a, pharynx, with + internal buccal lobes ; and f styles ; 9 b,

right posterior leg, seen from beneath.

10. Eucampia zodiaca.

1 1 . Halteria grandinella, D., seen from above.

12. Halteria grandinella, D., side view.

13. Kerona polyporum, E.

14. Gyges granulum, E.

15. Lacinularia socialis, E.; 15 a, the same more magnified.

16. Mask (labium) of JEshna (LIBELLULID^E).

17. Spermatozoa of Triton cristatus.

18. Sarcoleimna of muscle, twisted.

19-24. Navicula amphirhynchus in conjugation. Fig. 19, side view of valve of parent-frus-
tule ; 20, frustules in an early state of conjugation ; 21, sporangial sheath ; 22, spo-
rangial sheath, with parent -frustules attached ; 23, sporangial frustule (front view),
with sheath and one parent-frustule ; 24, side view of sporangial frustule.

25. Spermatozoa, human.

26. Spermatozoa of rat (Mus rattus).

27- Spermatozoa of field-mouse (Arvicola (Hypudaus) arvalis).

28. Spermatozoa of rabbit (Lepus cuniculus}.

29. Spermatozoa of goldfinch (Fringilla (Carduelis] elegans).

30. Spermatozoa of blackbird (Turdus merula).

31. Spermatozoa of wood-shrike (Lanius rufus).

32. Spermatozoa of a Coleopterous Insect.

33. Spermatozoa of frog (Rana temporaria).

34. Spermatozoa of perch (Perca fluviatilis}.

35. Spermatic cyst of rabbit, with five globules, a, separate globule.

36. Spermatic cyst of rabbit, the globules containing each a spermatozoon, a, separate

globule.

37. Spermatic cyst of the common creeper (bird) (Certhia familiaris), containing a bundle

of spermatozoa.

38. a, b, c, Staurosira construens, E.

39. Biblarium crux (leptostauron), E.

40. Goniothecium gastridium, E.

41. Periptera chlamidophora, E.

42. Periptera chlamidophora, E.

43. Aulacodiscus crux, E.

44. Goniothecium odontella, E.

45. Actiniscus sirius, E.

46. Rhizoselenia americana, E.

47. Cheetoceras didymus, E.

ERRATA, ETC. IN TEXT.

Introduction, p. xxxviii, line 8 from bottom, dele carbonate of lime.

Page 16, col. 2, line 27 from top, for Mucorini (Physomycetous Fungi) read Triclio-

dermacei (Gasteromycetous Fungi).
18, — 1, — 11 from bottom, for 89 read 289.

— 19, — 1, — 18 from top, for p. xxii read p. xxxi.

— 23, — 1, — 17 from bottom, /or fig. 4 read fig. 3d.
_ 28, — 1, — 24 from bottom, for PI. 19 read PL 31.

— 28, — 2, — 23 from top and lines 17 and 19 from bottom, for PI. 19 read PI. 31.

— 30, — 1, — 12 from bottom, for two lateral longitudinal lines read a median longi-

tudinal line.

_ 31, _ 2, — 18 from top, /or PL 10 read PI. 12.

— 40, — 2, — 27 from top, for OBJECT-GLASSES read TEST-OBJECTS.

— 41, — 2, last line, for Anatifer read Anatifa.

— 45, --2, line 10 from bottom,/or (i. e. two claws) read (with two claws).

— 45, — 2, — 8 from bottom, for tarsi 1-jointed read tarsi 2-jointed with one claw.

— 45, — 2, — 5 from bottom, add with two claws... Liotheum.

— 45, — 2, — 4 from bottom, for tarsi 1-jointed read tarsi 2-jointed with one claw.

— 47, — 2, — 19 from bottom, for founed read found.

— 51, — 1, — 5 from top, for fig. 28e read fig. 2Se.

— 51, — 2, — 23 from top, dele the (?).

— 55, — 1, — 23 from bottom, for Aspidephara read Aspidephora.

— 58, — 1 , — 10 from top, for Hopophora read Hoplophora.

— 58, — I, — 23 from top, to the genera add Argas and Pteroptus.

— 58, — 1, — 22 from bottom, dele (abdomen IL any-jointed).

— 103, — 1, — 21 from top, for row of cilia read of larger cilia.

— 104, under article C^EOMACEI refer to UREDINEI.

— 108, col. 2, line 11 from top, for Cyprididae read Cypridae.

— 129, — 1, — 7 from bottom, after (processes) add one.

— 129, — 2, — 15 from bottom, for Cyclidisia read Cyclidina.

— 154, — 2, — 2 from bottom, for between read in.

— 157, — 1, — 3 from bottom, for Uroglena read Uroleptus.

— 170, — 2, top line, for PL 30, fig. 23, read p. 235, fig. 201.

— 171, — 1, line 3 from bottom, for serrated read sinuated.

— 200, — 2, — 23 from bottom, for divided read divides.

— 223, — 1, top line, for lines read finer.

— 223, — 1, lines 3 and 8 from bottom, for tendo-Achilles read tendo Achillis.

— 232, — 1, line 3 from top, the genera of Polyphemidae (omitted) are Polyphemus

and Evadne.

— 232, — 1, — 27 from top,/or ENTOPLYA read ENTOPYLA.

— 283, — 2, GAMASUS omitted, see PARASITES.

— 349, line 2 from top, for Astasiae read Astasiaea.

— 370, col. 1, — 3 from bottom,/or bone read dentine (TEETH).

— 378, — 1, — 26 from top, for anthers read authors.

— 381, — 2, — 8 from top, for Lecidinese read Parmeliaceae.

— 396, — 1, — 12 from top, for facets read pyramids.

— 425, — 2, under article MICROCYSTIS refer to POLYCYSTIS.

— 472, — 1, line 17 from top,/or Schutze read Schultze.

— 519, — 1, — 26 from top, for granular read tubercular.

— 546, — 1, PYXIDICULA omitted, see STEPHANOPYXIS.

ERRATA IN DESCRIPTIONS OF PLATES.

Plate 2, fig. 32, represents Tetranychus glaber.

— 2, — 35, represents Tetranychus cristatus.

— 6, — 19, represents nitrate of soda.

Plate 13, fig. 13, left hand fmstule Nitzschia tania.
13, — 19, for Rhipidoptera read Rhipido-
phora.

8, — 10; 0, from clothes-moth; b, from | 14, — 20, noticed under SPERMATOZOA.

stag-beetle (Lucanus cervus). — 14, — 31, for Peracantha ovata read P.
8, — 12 ; a, urate of ammonia, artificial, &c. truncata.

10, — 59, Spirottmia condemata. 25, — 11, Trinema acinus, D. (not E).

FINIS.

Printed by Taylor and Francis, Red Lion Court, Fleet Street.

INTRODUCTION.

I. USE OF THE MICROSCOPE AND EXAMINATION OF
MICROSCOPIC OBJECTS.

THE Microscope as a means of investigation might perhaps be thus defined : the microscope
is an optical instrument constructed in order to enable us to investigate the characters
and properties of those objects which we are unable to study with the unassisted eye, on
account of their minute size.

In using the microscope, exactly the same precautions must be adopted and just the
same course pursued, as when the object under examination is distinctly visible to the
unaided eye. We have thought it requisite to introduce this formal definition of the true
use of this valuable instrument, from a knowledge of the fact, that in this country at least,
the microscope has hitherto been used chiefly as a means of viewing minute objects, and
judging of their nature from the simple inspection of them under the conditions in which
they naturally or accidentally occur. Such means, the most careless observer must be well
aware, is never trusted alone in the examination of objects visible to the naked eye, being
almost sure to lead to erroneous conclusions. Consider the common course pursued in the
examination with the unaided sight, of a body for the first time presented to our notice !
The first point is the examination of its general appearance and colour ; the relative position
of the eye of the observer and the object is then changed, so that an idea of its solidity may
be obtained ; its weight is next perhaps determined by taking it in the hand ; it is presented
to the light in various ways, in order to judge or» its transparency, and of the optical pro-
perties of its surface. If the object be at a distance, its size is judged of by comparing its
apparent size with that of adjacent bodies, whose dimensions are approximatively known ;
and its luminousness is also taken into consideration, it being known generally that the
nearer bodies of the same size are to us, the more luminous they appear. The observer
then is either satisfied with the conclusions drawn from reasoning, upon the results thus
obtained, or he makes besides a chemical examination. When the microscope is called into
use, many of these modes of determination of the properties and nature of objects are still
applicable, yet mostly is the observer satisfied with simple inspection ; the object is then
perhaps "put up," and exhibited to an astonished multitude, probably as many opinions
being formed of its nature as there are observers present, and possibly all of these incorrect.

Another frequent source of erroneous judgment consists in forming an opinion upon the

b

x INTRODUCTION.

normal or abnormal state of an organic structure, without a previous knowledge of the
natural structure of organic tissues. And so imperfect is the system according to which
investigations are conducted, that we not unfrequently hear of a morbid structure having
been submitted to two or more observers, each of whom gives a different report, even as to
its morphological components.

Through such and other similar circumstances, the microscope has given rise to most
absurd errors, which might have been easily prevented by a slight knowledge of its proper
use ; thus, to take a few examples : the fruit of the mulberry has been mistaken for entozoa ;
calcareous corpuscles have been regarded by several observers as ova, and the appearance
arising from the presence of concentric laminae has been interpreted to be the coils of an
enclosed embryo ; similar corpuscles have also been regarded as nucleated cells, and again
as blood-corpuscles : minute fossils in chalk have been strung together with portions of
vegetable tissue and (perhaps) the spores of algae, to constitute different stages of a fungus :
minute hairs projecting from the surface of a membrane have been declared to be spicula
within subjacent cells ; and quite recently, one writer states that certain minute bodies which
he has examined are either blood-corpuscles or the spores of fungi, but which, is doubtful !
while another recounts, how by fortunate accident he discovered that corpuscles, which he
had regarded at first as consisting of fat, were afterwards found accidentally to consist of
calcareous salts ! Again, we read in physiological works of the yolk-cells and the coloured
oil-globules of the yolk, and a beautiful function of assimilation has been attributed to
them : but they exist only in the imagination of the authors, who have regarded the one as
cells simply because they are round, and the other as consisting of fat, because they are
highly refractive. Since the publication of Schleiden's cell-doctrine, almost 'everything
round has been regarded as a cell ; any single body within this, or where there are several,
the largest, has been regarded as a nucleus, and any spot within the nucleus has been viewed
as a nucleolus. Whereas many of the so-called cells are homogeneous spheres ; many of the
nuclei are vacuoles, and a true nucleolus is very rarely found except in the books.

Hence, the very utility of the microscope as a means of investigation has been called in
question. But it must be borne in mind, that all the known errors committed in the
application of this instrument have been corrected also by its use ; so that the fault cannot
be attributed to the instrument, but to the observer.

As error is almost invariably associated, at least temporarily, with improvement or advance
in knowledge, it might be urged that the above errors were unavoidable. A little reflection
and the perusal of the means given presently, will show, however, that they have arisen
from extreme carelessness, and from ignorance of the means of distinguishing appearances
from realities. And it may be remarked, for those who have but small means at their
command, and who are unable to procure a first-rate English microscope, the possession of
which is commonly regarded as all that is requisite, that perhaps nine-tenths of the facts
elicited by the use of this instrument have been determined by foreigners with far less
perfect instruments, and that a large part of the results obtained in this country with the
best microscopes, are either erroneous or have been published as original after having been
previously made known in foreign works.

We have alluded to these errors merely for the purpose of warning future observers, and
impressing upon them the importance of making themselves acquainted with the difficulties
attendant upon microscopic investigations, and with the best means of overcoming them.
In fact, it may be briefly stated, that the object of the present work is to guide the micro-
scopist in his researches, to give him a notion of the manner of making these researches,
also some account of the microscopic structure and properties of objects in general, and to
show how he may most easily arrive at satisfactory results. A knowledge of the structure

INTRODUCTION.

XI

and properties of objects in general is of more importance than may at first be apparent ;
for bodies as found in nature are generally of a mixed kind, and it too often happens that a
young observer, soon after having procured a microscope, takes up some particular line of
investigation, to which he may have been previously attracted; and without the least
knowledge of the structure of objects in general, of what has been done before or of the
proper method of using the instrument, he arrives at the conclusion that all is new and
satisfactory. The whole is then destined to encumber the pages of scientific works with
a load of imperfect and useless details.

But, independently of the disadvantages attendant upon the improper use of the micro-
scope, there are difficulties inherently connected with the examination of microscopic objects,
which are not encountered when objects are examined with the naked eye. One of these
is, that with flie ordinary microscope, objects are only viewed with one eye ; hence we lose
the direct power of distinguishing solidity, &c., and are compelled to resort to indirect
means for these purposes. This difficulty is however now being overcome, since stereoscopic
microscopes are being constructed, and although not yet brought to perfection, will
undoubtedly be so in a short time. The ordinary objects around us are also usually viewed
by reflected light, whilst with the microscope they are mostly viewed by transmitted light,
and we are consequently much less practised in judging from the appearances of objects
thus illuminated, and therefore liable to err.

Another, but a less important difficulty in microscopic investigations, or at least manipu-
lations, consists in the image of the objects being inverted. Erecting eyepieces, as they
are called, will obviate this difficulty ; but as they are expensive, they are seldom used.

Another very serious source of error lies in the tendency to reason from analogy, as to the
structure or nature of a body viewed under the microscope. Any one who pursues this
course, has his mind prejudiced by preconceived notions, and becomes in fact no observer
at all.

In regard, again, to the real utility of the microscope, the time has passed when this might
be called in question ; it must be universally acknowledged by those who are in search of
truth in regard to the subjects it is employed to investigate. It need, moreover, be merely
remarked, that the ordinary appearance of objects to the naked eye, depends in all cases
upon a molecular structure, which is generally microscopic, the ordinary appearance being
the optical result or expression of this structure, and since totally dissimilar microscopic
structures may present similar appearances to the unaided eye, judgment as to the nature
of the former founded upon the latter can be of but little value. The reader will remember
that the common capability of distinguishing objects or structures by their appearance,
has been derived from practice and experience of effects ; when we bear in mind that the
experience and practice in the study of the causes are attainable, the superiority of the latter
must be evident.

Above all, however, it must never be forgotten, that microscopic investigations require
more time and patience than perhaps any others, even in regard to the determination of
simple facts of structure and qualitative composition ; and although it is not very uncommon
still to hear those engaged in them sneered at as wasting their time over a very simple
plaything, this may be regarded as arising from one of those prejudices which will exist so
long as people will venture to express opinions upon matters with which they are unac-
quainted, and which are beyond their comprehension.

We have expressed our intention of not entering upon a description of the microscope as
an optical instrument, and this, because it would have been requisite to have trodden widely
the field of general optics, which our space would not permit. We would advise, then,
those who wish to become acquainted with the microscope as an optical instrument, first to

62

xii INTRODUCTION.

study the general laws of optics, which may be done through the medium of any of the
works or treatises on Natural Philosophy ; as the article * Optics ' by Herschel in the
Encycl. Metropolitan ;Brewster's 'Optics;' Biot's 'Manuel,' &c.; the ' Natural Philosophy '
of the Society for the Diffusion of Useful Knowledge ; Lardner's ' Natural Philosophy/ or
Mrs. Somerville's ' Connexion of the Physical Sciences.' Perhaps the second work is the best
for the general reader; it is quite recent (1853), but greatly behindhand in regard to the
application of the microscope. They may then proceed to the application of these laws to
the various optical parts of the microscope. This may be found to some extent in the useful
work of Quekett on the Microscope, in which the various kinds of microscopes and accessory-
apparatus are figured and their action described, with lists of objects of interesting appear-
ance, &c. ; Brewster's Treatise on the Microscope; art. 'Microscope' in the Penny
Cyclopaedia by Ross. There does not, however, exist a wrork in which this is satisfactorily
done. The ' Observateur,' &c. of Dujardin is an admirable work, in many respects the
best ever written ; the ' Micrographia ' of von Mohl is greatly esteemed in Germany.

We must not, however, omit a notice of the principles which should guide in the
selection of a microscope and the accessory apparatus ; because a large number of mi-
croscopes are at the present day sold, frequently at no mean cost, which, although well
calculated to afford amusement, are utterly valueless for the purpose of scientific investiga-
tion. To those to whom money is no consideration, we may recommend with safety as the
best which can possibly be procured, such as are manufactured by Smith and Beck, Ross,
or Powell, of London. These makers have a thorough knowledge of the instrument, and
a reputation at stake ; hence there is little occasion to test their instruments. But it may
happen that a person may not wish to expend so much money as the purchase of these
instruments requires, may wish to purchase a foreign instrument (and these are cheaper),
or may meet with one second-hand. A word or two may then be of service in guiding them
in their choice ; for a microscope may look very well and very handsome, yet be worth but
little. It must, however, be borne in mind that there is room for much opinion in these
matters, for according to what any one has been accustomed to, or according to prejudice
from what he may have heard a supposed authority say, so will an instrument or a piece of
apparatus be regarded as requisite or of importance, or not so. Our statements rest upon
our own experience in the long-continued use of the instrument, and as such they must be
taken.

First, it may be remarked that the microscope is usually regarded as composed of the
object-glass or glasses, and the stand, body, stage, eyepieces, &c. ; and the object-glasses are
generally sold separately, for by means of an "adapter" they can be applied to any
microscope.

In regard then to the stand, body, &c. : the stand should be firm, and so heavy and its
feet so arranged, that the instrument cannot be easily overturned.

The body should be about 8 or 10 inches in length ; in many of the foreign instruments
the body is short and the eyepieces are adapted accordingly, but this adaptation is decidedly
objectionable.

The microscope should be so constructed, that the body can be inclined at any angle
desired, so that the observer may examine objects while sitting. Many persons, however,
prefer to use the microscope with the body placed perpendicularly, and when chemical
reagents are to be applied this position is essential ; but when long-continued examination
of an object is required, it becomes very painful and fatiguing to keep the head in the
position which the perpendicular position of the body requires. Moreover, as in a microscope
with the joint or arrangement by which the body can be inclined, the body can always be
placed perpendicularly, the joint is decidedly advantageous. Again, it is almost essential

STAND-STAGE. xiii

when the camera lucida is used. A brass pin or some similar contrivance should be placed
near the joint so as to check the motion of the body of the microscope when it reaches the
horizontal position ; no microscope should be without this.

The microscope should have a coarse " rack and pinion " movement or " quick motion "
for adjusting the focus of the lower powers or object-glasses; and when used with an
object-glass of about half an inch focus, the image of the object examined whilst coming
in and going out of focus, must not appear to move from one side to the other of the field
when the body is raised or depressed by the coarse movement. Also when the milled head
of the coarse movement is rotated, the motion should feel smooth, not irregular, uneven,
or jerking. In some foreign microscopes, the effect of the coarse rack and pinion move-
ment is replaced by the sliding of one tube within the other, the body consisting of two
tubes working after the manner of those of a telescope. This arrangement is very objection-
able, although used by some very good observers, who probably have more tact than most
people, and who do not use such high powers as they ought ; for when the highest powers
are used it is perfectly intolerable. The objection is somewhat overcome in some micro-
scopes by the existence of a fine movement ; but we regard the rack and pinion coarse
adjustment as essential.

A " fine movement " or " slow motion " is indispensable, for with the higher powers
(one-eighth and one-twelfth) it is impossible to adjust the focus without it. When the
finger or fingers are applied to this in its use, no apparent motion of the object must take
place ; should this occur, the movement is worthless, unless, at all events, it is very slight,
and this when tested with the high powers.

When the milled head of the fine movement is turned backward and forward, as in use,
the motion should be perfectly even, and should be produced very easily, with slight
pressure only of the finger or fingers ; moreover, no difference should be distinguishable
between the two directions in which it turned, but it should move with equal ease in both.

The "field" or luminous disc on which the objects viewed through the microscope are
apparently delineated, should have its marginal line clear and black. If this line appear
coloured, the eyepiece is not as it should be.

The stage should not be too small (say less than 2£ inches in diameter). To the best
instruments a moveable stage is adapted ; but whether this is essential or not is considered
a matter of opinion. Undoubtedly with low powers, the moveable stage may be dispensed
with, and is not often used ; but with the higher powers its absence is felt greatly, and we
should say that it was essentially necessary. In most of the English microscopes, whether
provided with a moveable stage or not, there is a " sliding piece " for producing the backward
and forward motion of an object, the lateral motion being effected by direct application of the
fingers. If the body of the microscope is to be used in the inclined position, the sliding
piece or a moveable stage becomes essential.

If the moveable stage be present, the " milled heads " should be pretty large, so as to be
readily grasped, and a flat object should remain in focus whilst traversing the field by the
movement of the stage. The stage should also be very thin.

The mirror should have one plane or flat face and another concave. It should not be too
small, and its centre should coincide with the axis of the body of the microscope.

So long as the above conditions are fulfilled, the general form and arrangement of the stand
and its parts are of little consequence. It must also be remembered that the complication and
accuracy of the apparatus required, will vary according to the kind of investigations pursued ;
thus, the structure of the various tissues of animals and that of most plants can be satisfac-
torily studied with apparatus which is totally insufficient to display the structure of certain of

xiv INTRODUCTION.

the lower forms of vegetable life, as the Diatomacese, &c. But, on the other hand, it follows,
that if a peculiar structure can be shown to exist in any kind of objects by a complicated
apparatus, which cannot be demonstrated by a more simple or less perfect apparatus, the
study of the structure of any object not previously examined, must always be attended with
uncertainty, so long as it has not been tested by the more perfect kind of apparatus ;
provided the microscopist has not acquired the art of replacing the imperfection of his
apparatus by superior tact and management, which can be done to a great extent.

Object-glasses. — The goodness of the object-glasses depends mainly upon their freedom
from chromatic and spherical aberration, and upon the magnitude of their angular aperture.
The freedom from the former renders them good in defining power, i. e. in exhibiting clearly
the margins of objects, whilst large angular aperture renders them capable of penetration,
or of rendering visible or distinct, markings upon the surface of objects. At least this is
the ordinary statement made in regard to the relations of defining and penetrating power ;
but it is only partially true, and there are two kinds of penetrating power, as we shall show
in the article "TEST OBJECTS," where we have entered more fully upon this subject.

As in the case of the stand, &c. of microscopes, so in regard to the object-glasses, the
best are made in this country, and can be obtained of first-rate quality of the three makers
above mentioned. But when a glass of unknown value presents itself, it should be tried
upon the test objects.

The defining power may be tested by the examination of the objects figured in Plate 1 .
figs. 1 to 4.

The outlines of these objects must appear black, well defined and perfectly free from colour,
not misty and red or green ; they should retain this appearance when the higher eyepieces
are used, of course, some allowance being made in regard to this sharpness of outline,
which will appear slightly broader and less defined, but in nowise interfering with the
distinctness of the image of the object. The various parts of an object lying in the same
plane, as a transverse section of whalebone, should also be visible at the same focus ; the
lines upon a micrometer used as a slide will also serve to test this point. It is not, however,
of very great importance, especially with high powers ; but it is a character of a superior
object-glass.

If the definition of the glass be good and the power adequately high, it will also exhibit
the structure of the objects in Plate 1. figs. 5, 6, 10, 12, and 13, clearly and distinctly; it is
then of sufficiently good quality for nearly all the purposes required in the investigation of
animal and vegetable structures. Some German and French glasses will do this tolerably
well (although many of those sold are worthless) ; but they are not provided with a correcting
adjustment to compensate for the effects of the varying thicknesses of the layer of liquid
and the glass cover through which objects are generally seen, so that the best working of
these glasses can only be obtained by accident. Still many of them are quite fit for all
ordinary investigations, so long as these are carried on in a proper manner.

The exhibition of the objects illustrated by Plate 1. figs. 6, 7, 8, 9, 10, 11, 12, and 13,
requires the first kind of penetrating power, but it does not require large angular aperture.
The second kind of penetration, however, requires above all large angular aperture,
independently of any other superiority ; i. e. a glass maybe perfectly corrected as to defining
power, and exhibit the above objects well, yet when the valve of a Gyrosigma is subjected
to it, the markings cannot be distinguished without particular appliances, which produce
the same effect as an increase of angular aperture in the object-glass. As this property is
therefore principally dependent upon the angular aperture, this should be determined by
direct measurement; the method of doing which is described under the article "ANGULAR

OBJECT-GLASSES. xv

APERTURE," in which also is contained a list of the various apertures of the best glasses, so
that the approximation in the cases of any glass to these magnitudes, will afford an indi-
cation of its quality.

The following remarks may perhaps assist in guiding the judgment in regard to the
selection of an object-glass : —

1. Large angular aperture is of less importance in the case of a low than of a high power.

2. Large angular aperture is neither requisite nor advantageous in physiological and
medical investigations in general.

3. Whether a glass of larger aperture will exhibit any further structure than one of less
aperture has already done, can nearly always be predicted from other means.

4. Object-glasses of high power and large angular aperture require to be brought very
close to the objects viewed, which is a great disadvantage, rendering them useless for gene-
ral investigations.

5. In regard to objects requiring large angular aperture for exhibiting their structure,
much depends upon the management of the light -, so that a glass may fail in exhibiting
certain parts of structure in the hands of one of but little experience, whilst in the hands of
another it may show them distinctly. Hence the direct measurement of the angle is best
to determine what a glass is capable of exhibiting when properly used.

6. The markings on the Diatomaceae were discovered by the aid of foreign glasses of
small angular aperture.

7. Almost all the investigations which rendered the microscope an instrument of science,
have been made with foreign object-glasses of small aperture ; and where these have been
found faulty, the fault has arisen mainly either from judging of structure by simple inspection,
or substituting analogical reasoning for observation.

8. The English object-glasses are very expensive; but they are incomparably superior to
the foreign in every respect — in denning power, in penetrating power, in the centring of
the lenses, in the existence of an adjustment for varying thickness of glass, and in general
perfection of workmanship. These advantages tell principally in the higher powers. An
English glass when used with the highest eyepiece will still define better than nine-tenths
of the foreign glasses with the lowest eyepiece.

As a complete set of English object-glasses is very costly, many persons will perhaps
prefer having some English and others foreign. Under these circumstances, the higher
powers should be of English and the lower of foreign manufacture.

It might be objected, that the structure of many of the very minute and delicate
objects examined by our continental neighbours have been erroneously described ; and this
would be a fact. But this arises from unacquaintance with certain precautions essential to
the proper use of high powers ; and the same errors have been committed by our own
countrymen, from the same cause, even with the finest object-glasses which have been made.

The student may perhaps find himself perplexed by the conflicting statements made by
different renowned observers in respect to object-glasses. The well-known Schleiden says
that only a magnifying power of about 500 diameters is useful for scientific purposes ; that
with our present microscopes, we may see whatever we like with a power of 3000 j and that
only the amplification of an object to the extent of 280 or 300 diameters is produced by the
object-glass, all beyond this being effected by the eyepieces with an almost total loss of light.
Now these statements may be very true in regard to German object-glasses as used by the
Germans ; but they do not apply to the English object-glasses as used here. The highest
English object-glasses (the one-twelfth of Ross and the one-sixteenth of Powell) will show
minute objects with a power of 600 diameters with the lowest eyepiece, as clearly and well
defined as the German glasses of 1-inch focus will show larger objects ; and we feel convinced

XVI

INTRODUCTION.

that if Schleiden were to try to obtain a view of the hexagonal structure of the dots on the
valves of a Gyrosigma with his object-glasses, he would signally fail ; for the exhibition
of this structure requires a power of about 2000 diameters to render it distinct beyond
dispute, with the use of stops in the condenser unless the object-glass be of very large
angular aperture ; and yet it is clearly shown with the English glasses, and the fact of its
impressing its own image upon photographic paper, at once shows its reality, or that its
perception is not the result of the imagination. The origin of these results and statements
is explained above.

Diaphragm. — Most microscopes are provided with a diaphragm. It consists of a circular
blackened plate, placed parallel to and beneath the stage, and furnished with a revolving
plate having a series of circular apertures of different sizes, each of which can be brought
successively opposite to the axis of the body of the microscope. It serves to regulate the
quantity of light in examining transparent objects ; it also reduces the angle of the cone of
the reflected rays. It is seldom, however, used, nearly the same effect being produced by
the two different surfaces of the mirror.

Revolving Stage-plate. — One of the plates of which the moveable stage is composed, is so
constructed as to revolve in the same plane upon its axis, whereby an object may also be
made to revolve in the same manner. This apparatus has, however, greater disadvantages
than advantages, for it renders the stage heavy and increases its depth, and the desired effect
may easily be produced by rotating the slide with the fingers ; moreover it is exceeding
difficult to place the object in the centre of rotation.

Spring Clamping -piece is intended to fix the slides upon the stage. It is of no use pro-
vided the slides are of the proper length, which we have given ; if they are longer, the clamp
will prevent the accidental displacement of an object in changing the power, &c.

Forceps are essential for holding opake objects, such as insects, and viewing them in
different positions ; to allow of which, the handle of the forceps is made capable of revolving.

Dark Wells are metallic cups of various sizes, blackened inside, and serving to prevent
the reflexion of light upon opake objects from below. They are supported in a holder,
moveable in an arm, which is inserted into some part of the stand of the microscope. Their
purpose is equally well effected by a slide, upon which a piece of black velvet has been
fastened by marine glue.

Achromatic Condenser. — This consists of an achromatic object-glass or set of lenses, in
an inverted position beneath the stage, moveable in all directions in its own plane and in the
direction of its axis. It serves to condense the light reflected by the mirror to a focus upon
the object, and to exclude all extraneous light. It is essential in examining minute objects
with high powers ; in fact, the structure of many objects cannot be made out without it.
In its most improved form, a rotating diaphragm is placed behind the back glass of the com-
bination forming the object-glass, perforated with a series of apertures of various sizes, some
of them being circular whilst others are annular ; the former diminishing or increasing the
cone or pencil of 'rays reflected from the mirror by excluding the lateral rays, the latter
admitting only the lateral rays, the central ones being intercepted by the portion of the
diaphragm within the ring, so that the angular inclination of the transmitted rays may be
increased or diminished at will. The markings upon many of the Diatomaceae can only be
made out when examined by oblique light, as procured by intercepting the central rays,
which effect is produced by this modified achromatic condenser. The same effect may be
produced in one of the achromatic condensers of the old form, provided the compound
lenses of which the object-glass in the condenser consists are separable (which should
always be the case), by pasting or temporarily placing a circular disk or " stop " of black
paper exactly upon the centre of the plane face of the innermost combination. The diameter

ACHROMATIC CONDENSER. xvii

of the disk should amount to about two-thirds of that of the surface of the combination to
which it is applied. The combinations are then fitted together as they were at first. This
stop intercepts the central rays, thus diminishing the amount of light transmitted ; but this
difficulty is easily got over. It may be remarked that the higher object-glasses consist of
three combinations of a doubly convex and a plano-concave lens cemented together so as to
form apparently a single plano-convex lens ; the outermost and smallest combination some-
times consists even of three lenses. When the achromatic condenser is used, the flat surface
of the mirror should form the reflecting surface, and care should also be taken that the axis
of the condenser coincide with that of the object-glass. To ensure this, a small circular disk
of brass having a small circular aperture in its centre should be fitted to the lower part of the
tube in which the condensing lenses are situated. When the object-glass is properly adjusted
with regard to the condensing lenses, the field of the microscope will appear black, excepting
at a minute luminous spot. This spot must be made to occupy the centre of the field by
moving the laterally adjusting screws of the condenser, or the body of the microscope. As
soon as this has been effected, the brass disk must be removed.

In using the stop in the condenser, its position must also be accurately central. This
may be determined by placing a piece of tracing paper upon the upper surface of a slide
laid upon the stage, and, by the aid of the axial adjustment, bringing the condensing lenses
as near as possible to the lower surface of the slide. On suitably inclining the mirror, a
minute black disk surrounded by a luminous ring will be seen with the naked eye upon the
paper, and on depressing the condensing lenses, a brilliant luminous spot will occupy the po-
sition of the black disk. On next removing the tracing paper, and approximating the object-
glass connected with the body to the condensing lenses, and suitably inclining the mirror, the
black disk will be seen on looking through the microscope with the eyepiece removed. The
disk should then be made to occupy the centre of the field as nearly as possible. It cannot,
however, be accurately centred in this way. But this may be easily done by inserting the
eyepiece and approximating the object-glass to the condensing lenses until the black disk
becomes again visible on looking through the microscope. On then suitably inclining the
mirror and arranging the lateral adjustments^of the condenser, the disk may be placed exactly
centrally. If the black spot be visible in the examination of an object, elevating or depress-
ing the condensing lenses will cause it to disappear.

The paper stop may be very advantageously replaced by a blackened metallic stop placed
behind the first pair of lenses of the condenser, and screwed into the top of the condenser in
the place of the ordinary diaphragm. Neither of these kinds of stop equal in convenience
the new condenser as constructed by Ross, and Smith and Beck ; because with the latter,
the number of rays transmitted or intercepted, and the degree of their obliquity, can be
varied by the simple rotation of the diaphragm. Exactly the same effects can however be
produced with a little more trouble.

The central stop is generally used when objects are examined with the higher powers.
The power used in the condenser will vary greatly according to the kind of object under
examination. If a considerable amount of light be required without obliquity of the rays,
the condensing power should be lower than that of the object-glass. If great obliquity of
the rays be required, the higher the power of the condensing lenses, and the larger their
angular aperture, the better. When the achromatic condenser is properly arranged in regard
to centring, and the condensing object-glass or set of lenses is properly selected and adjusted,
the structure of minute objects is displayed in a manner with which those who regard the
condenser as useless must be utterly unacquainted. A very simple and inexpensive achromatic
condenser may be easily contrived by any one with ordinary ingenuity.

Extra Eyepieces. — Always one and sometimes two eyepieces are obtained with the micro-

xviii INTRODUCTION.

scope when purchased ; but the highest eyepiece which is made should always be pro-
cured : for although high eyepieces are so far objectionable, that they magnify the imper-
fections of the image formed by the object-glass as well as the image itself, yet they fre-
quently render parts of structure distinct which are perhaps only just perceptible with a lower
eyepiece.

Polarizing Apparatus. — This usually consists of either two plates of tourmaline, or of two
Nicol's prisms. The latter are generally used, and are preferable on account of their free-
dom from colour. They are composed each of two half-rhombs of calcareous spar cemented
together so as to transmit only one image. The prisms should appear perfectly clear and
colourless, and free from scratches and veins ; and when, on holding them to a light, the
uppermost is rotated so as to occupy a particular position with regard to the other, no light
should be transmitted through them.

The polarizing apparatus is useful in bringing to light certain peculiarities of structure
which cannot be detected in any other way. A substitute may be made of two crystals of
the iodo-disulphate of quinine, dried upon and cemented to circles of thin glass. In use,
one is placed beneath the object, and the other on the top of the eyepiece.

Side Condenser. — This consists of a large doubly convex or plano-convex lens, or bull's-
eye, of short focus, 2 or 3 inches, mounted upon a brass arm, which slides up and down a
rod placed perpendicularly in a stand. The arm should be capable of being lengthened, and
the stand should be so broad and heavy that there need be no fear of its being overturned.
Its use is to condense the light upon opake objects. When used, it is placed between the
object lying upon the slide under the microscope and the lamp or other source of light, the
plane surface of the lens being at right angles to the direction of the rays of light ; and the
lens must be brought so close to the object that the focus falls upon the latter. Sometimes
a small condensing lens is used to concentrate the light already transmitted through the large
condenser ; this is usually fixed to some part of the microscope, but it is rarely required.
A doubly convex lens of much longer focus than the bull's-eye lens, about 7 or 8 inches,
will be found very useful for condensing the light upon the mirror when the achromatic con-
denser, stops, &c. are used with the highest powers. It should be placed very near the lamp.
The arm of the bull's-eye lens may be adapted to hold either or both the lenses.

Amici's prism is sometimes useful for throwing very oblique light through a transparent
object. It consists of a very flat triangular glass prism, the two narrower sides of which are
convex. The third and broadest side forms the reflecting surface. The prism may be
attached to a separate stand, or to the stand of the microscope. It exerts a condensing as
well as reflecting action.

Lieberkuhn. — Some opake objects may be well illuminated by a lieberkuhn or silver
cup ; by which the light, first reflected by the mirror upon the concave surface of the cup,
is afterwards reflected upon the object. But this can only be used for small objects, and is
therefore not generally useful.

The discovery of the importance of excluding the central rays of light and using a central
stop for this purpose is due to Mr. F. H. Wenham, who has invented an apparatus in
which this principle is taken advantage of. It is known as

Wenham's Parabolic Reflector, and consists of a brass tube fitted beneath the stage in the
place of the ordinary achromatic condenser, terminated above by a hollow truncated cone,
the perpendicular section of which forms a parabola, with an internal polished silver reflecting
surface. At the base of the parabola is placed a disk of thin glass, in the centre of which is
cemented a dark well. In use, the central rays are stopped by the dark well, whilst the
lateral rays passing up the tube impinge upon the parabolic surface, from which they are
reflected upon the lower surface of the object. This apparatus has since been modified by

CAMERA LUCIDA.

Mr. Shadbolt, and is constructed of a solid cylinder of glass terminating above in a solid
cone, the surface of which has the form of a parabola, and replaces the silver reflecting
surface.

Brooke's Reflecting Apparatus. — The purpose of this is to illuminate objects by reflected
light, so that they can be examined with the highest powers. It consists of two parts ; the
first is essentially the same as the apparatus proposed by Mr. Wenham. The second
consists of a small, flat, circular metallic mirror (a flat lieberkuhn), perforated to admit the
lower end of the object-glass, upon which it slides, and so arranged that the reflecting surface
is in the same plane as the lower surface of the object-glass. When in use the light
is reflected by the parabolic surface upon the plane reflector, and thence upon the upper
surface of the qbject.

A number of points in regard to the colour of objects, distinction of pigment-granules
from minute air-bubbles, &c., may be easily decided by this apparatus. In questions of
elevations or depressions of surface, the light should only be admitted on one side of the
tube (for which there is a special contrivance), so that it may proceed to the object obliquely
from one side only ; and the conclusions must be based upon analysis of the formation and
arrangement of the shadows, and not upon the general appearance, because it is well known
that objects, or parts of them, usually appear larger and more prominent in proportion to the
amount of light reflected by them to the eye. Hence, for instance, little depressions, which
are in fact extensions of surface, by reflecting more light than the surrounding flat or nearly
flat surfaces, would appear very brilliant and luminous, and thus resemble elevations. If
this apparatus be used without due regard to these points, it will be worse than useless.

It has not, however, received the attention its importance deserves. It will probably form
a cheap substitute for an object-glass of large aperture, and to a great extent free us from the
fallacies connected with the examination of objects by transmitted light.

Camera Lucida, and steel disk or Mirror of Sommering. — One of these is requisite for
drawing from the microscope. The camera lucida resembles that commonly used in sketch-
ing landscapes, &c., but is provided with a fitting adapting it to the eyepiece. The mirror
of Sommering is a plane mirror of polished steel, less in diameter than the pupil of the eye,
supported opposite the focus of the eyepiece by a small steel arm, attached to a split ring
which grasps the eyepiece by its spring action. There is one disadvantage in regard to the
eyepiece of Sommering, viz. that it inverts the image of objects, which the camera does not.
When either of these is used, the body of the microscope must if possible be placed hori-
zontally, and the axis of vision be directed perpendicularly ; the image of the object will
then be seen upon the table, and may be traced with a pencil. If there be no joint to the
microscope, so that the body is fixed perpendicularly, the paper upon which the object is to
be sketched must be fixed to an upright drawing-board placed in front of the microscope ;
but this is a very inconvenient arrangement. A more advantageous method than the latter,
consists in placing a box or board upon which the paper is to be laid, close to and at a level
with the stage, on its right side ; on then looking at the object through the microscope with
the left eye and at the paper upon the box with the right simultaneously, the image of the
object may be traced as before ; here the camera is not requisite, but considerable practice
is required in applying this method, and it is not so satisfactory as that first described with
the camera. In using the camera, it must be remembered that the size of the object will
appear greater as the distance between the eyepiece and table is increased ; hence it is best
always to place the microscope in one and the same position when about to use it for drawing,
so that the extent to which the objects are magnified by the same power may always be the
same. The pin mentioned at page xiii is invaluable for this purpose.

In using either the camera or the mirror of Sommering, the eye must be kept exactly in

INTRODUCTION.

one position, otherwise the image of the object will move. Also the field and the paper
must be illuminated to nearly the same extent. One of the screens mentioned at page xxv
is very useful for excluding extraneous light.

Live-Box and Growing-Slide. — The live-box is an apparatus in which portions of liquid
containing infusoria and other small animals or plants, can be confined so as to prevent eva-
poration and allow of their being watched in a living state.

A better apparatus however for this purpose is the growing-slide. This consists of a
piece of stout plate-glass, 5 inches long and about 2 wide. A circular aperture, of about the
diameter of a test-tube, is made near one end of it. A little glass cup, formed of a portion
of a test-tube cut off three-fourths of an inch from the closed end, and slightly less in
diameter than the aperture, is then fitted into the latter, either by pieces of cork, or
by a rim consisting of a glass ring forming a neck to the cup, or in any other way. The cup
should project about one-fourth above the surface of the slide ; and at one portion of its
margin a little groove should be ground, in which two or three threads of a lamp-wick can
be placed. The cup should be covered with a circular plate of thin glass, larger than its
mouth, and prevented from falling off by a disk of cork fitting the mouth, and fastened to the
plate by marine glue ; or the cup may be closed with a common cork, the only objection
to this being that the mouth of the cup is apt to be split. The manner in which the slide
is used is this ; supposing we wish to follow the changes undergone by some minute alga
or infusorium which we have just detected in a drop of liquid. It is placed upon a slide
and covered with thin glass ; the slide is then laid upon the growing slide in such manner
that the longer dimensions of the two are in the same direction ; a little ledge consisting
of a strip of glass fastened by marine glue to the growing slide will serve to rest the slide
against and prevent its becoming displaced. Distilled water, mixed with a small proportion
of the water in which the organism was living before being transferred to the slide, is next
put into the cup, and a few threads of lamp-wick cotton, thoroughly moistened with
distilled water, are then so placed that one end is immersed in the cup whilst the other is
brought into contact with the edge of the liquid in which the object is immersed. Thus, as
the water evaporates from beneath the thin glass, the threads will afford a continuous supply,
and the threads will not become dry until the whole of the liquid in the cup has become
absorbed by them and evaporated. In this way we obtain the requisite conditions for the
continued growth of aquatic organisms. Care must be taken however that the thin glass
presses but slightly upon the object, and that the threads come as little as possible into con-
tact with the portions of the slide lying between the cup and the thin glass. If the thin
glass cover to the cup fit tightly, and the thread be passed through the notch in the cup, no
loss will take place by the direct evaporation of the liquid in the cup. If living organisms
are kept in this apparatus, they must have the influence of light.

Compressor, an instrument for the regulated compression of a minute object. The same
effect can be produced by a well-made live box ; or by pressure directly applied to the thin
glass covering an object by the handle of a mounted needle.

Cabinet. — A box or cabinet, containing a number of drawers, will be requisite for holding
the objects. Each drawer should be numbered or labelled to facilitate reference. The ob-
jects should lie flat in the drawers, so that each may be found when required without loss of
time. The cabinet should be furnished with two folding doors, so as to exclude dust as
much as possible. It should also be made of thoroughly seasoned wood, oak or mahogany
being the best ; if made of deal or cedar, the vapour of the volatile oil of the wood will in-
sinuate itself beneath the thin glass cover and the slide in those objects which are mounted
in the dry state, and condensing upon them and the objects, will obscure and spoil them.

It may be remarked here, that the names of objects should always be written upon labels

SLIDES, COVERS, ETC. xxi

pasted to the slides, not merely upon the slides with a diamond ; and that the colour of the
labels should be different for each kind of object ; or if the labels be composed of white paper,
they should be impressed by a coloured margin ; thus those of the Desmidiacese green, the
Diatomacese yellow, &c., so that the various slides when accidentally mixed, after compara-
tive examinations, can be readily replaced in their respective drawers.

Bell-glasses. — The microscope when in use, either constant or occasional, should always
be kept under a large bell-glass, the base of which fits into an annular groove made in a
circular, flat wooden stand. In this way it is kept from dust, and the trouble and wear
and tear consequent upon putting it into a box is saved. Moreover, as thus protected, an
object under examination can be left without fear of injury or disturbance, and be also pre-
served from dust.

Several smaller bell-glasses of various sizes should also be kept at hand, under which any
objects which it may not be convenient to mount for a time, or the examination of which
may not be completed, can be protected.

Slides. — These are ordinarily made of glass about the thickness of common window-glass ;
then- length should be 2£ inches, and their breadth 1 inch. If longer than this, the ends
are liable to project beyond the sides of the stage, and may be displaced accidentally by
passing the hand to the mirror, or condenser, and they occupy more space in a cabinet than
when of the above size ; moreover, there is no possible advantage to counterbalance these
disadvantages. Where the objects are very large, the slide must be proportionately large,
and its thickness greater than usual. The slides should be made of colourless glass, so as
not to interfere with the appreciation of the colour of an object ; and they should be flat,
otherwise the parts of the object will lie in different planes, and every motion of the slide
will require new adjustment of the focus. The edges are best ground somewhat, to prevent
injury to the fingers. Very delicate structures require to be examined and mounted upon
thin glass. The slides may then be frequently made of wood, sheet-zinc, tin-plate, or card-
board, with a circular aperture in the middle, upon which a piece of thin glass is cemented.

Covers. — Comparatively few objects can be viewed in the dry state ; hence they are most
frequently immersed in some kind of liquid. To prevent the evaporation and condensation
of this upon the object-glass, and to reduce the thickness of the layer of liquid to a minimum,
the object is usually covered with a piece of thin glass. The form of this cover is either
square or circular ; and the thickness from about the -^ih to the ^ndth of an inch,
or even less. These covers are usually kept already cut by the microscope-makers and those
who sell objects. Before use, they are best allowed to remain immersed in water for
some time. Care is required in wiping this thin glass. It is usually effected by holding
the cover at two opposite points of the margin between the finger and the thumb of the
right hand, and rubbing the surfaces with a fold of a cloth, leather, or silk handkerchief
covering the same parts of the left hand. But the thinnest glass cannot be wiped in this
way without being broken. This requires to be held at the edge by the finger and thumb
of the right hand applied to the flat surfaces, and to be drawn slowly through the fold of the
cloth in the left hand as above.

Dipping-tubes. — These are glass tubes varying in length from about 5 inches to a foot,
and in calibre from ^ to i an inch. They are cut of the proper length by a three-square file,
and the ends gently fused in the flame of a spirit-lamp. One end is then coated outside
with sealing-wax and spirit, or some other coloured liquid, so that the same end may always
be used for the same purpose. They are of use for removing objects from water or other
liquids in which they may be contained. Suppose, for instance, it is required to examine
some deposit lying at the bottom of a liquid, or an object suspended, the fore-finger of the
hand in which the tube is held is placed upon the upper end of the tube so as to close it ;

xxii INTRODUCTION.

the other end is then immersed in the liquid and brought into contact with, or as near as
possible to the object, and the finger removed from the upper end. Hydrostatic pressure
then forces the liquid, and with it the object, into the lower part of the tube, and it can
be transferred to a slide. When a tube of narrow calibre is used, the liquid and object are
retained within the tube by capillary attraction ; they must then be removed by gently
blowing at the upper end, the lower end being placed upon the slide. The use of colouring
one end of the tubes is, that the idea of applying the mouth to the end of the tube which
has been immersed in some offensive liquid, as foetid water, &c., may be set aside.

These tubes should be kept in a glass of distilled water, with the coloured ends of course
uppermost.

When a large tube is used, as in removing the larva of an insect, a tadpole, &c., the
quantity of liquid removed is also large, and will be more than is required on the slide.
The tube should then be emptied into a watch-glass, and the object placed upon the slide
or in the live-box, by a camel's hah* pencil.

Forceps are in constant requisition for taking hold of minute objects, dissecting, &c.
Those used for medical purposes — common steel dissecting or surgical forceps — are best.
There are three points to be attended to in the selection of them. They should not be
too short, i. e. less than 4 inches in length at least ; the spring- (separating-) action shonld
be very feeble ; and the points should be perfectly flat and smooth where they come into
contact. If forceps are shorter than the above length, they are not easily held steadily ; if
the spring-action be strong, on holding an object, as in dissection, with the forceps, the at-
tention being perhaps directed to the scalpel, needle-points, &c., the blades of the
forceps separate, and the object escapes from their grasp. If the forceps have teeth or are
grooved, perhaps after laying an object out upon a slide under water, or elsewhere, a portion
of it becomes entangled in the teeth, and the whole displaced. Surgical " tenaculum-
forceps" are very useful occasionally in injecting. These forceps lock by their own spring-
action. Supposing, then, the injection is escaping from the orifice of some vessel which has
been overlooked and no assistant is at hand, on including the open end of the vessel be-
tween the ends of these forceps, which may then be left hanging, it is firmly fixed, and the
operator has both hands disengaged to tie it ; in fact, these forceps are indispensable to the
injector. They should be short and not heavy, otherwise the vessel may be torn by their
weight. ,

Surgical " dressing forceps " are also frequently of use ; and long " oesophagus forceps "
with scissor handles are serviceable for removing portions of plants, &c. from large jars or
glass vessels. •

Needles. — For separating the parts of minute objects, fine points are requisite ; these are
found in common needles of moderate size fixed by one end into the handle of a water-
colour brush. These are easily prepared : the needle is cut in half by cutting pliers ; the
blunt end is then forced into the stick, about half an inch in length being left projecting.
Surgeons' " cataract needles " ground down are elegant instruments of this kind, but they
require to be shortened. For minute dissection of plants, all needles require pointing on a
hone.

A stout sable-hair or fine bristle, inserted into a slender wooden handle, is frequently of
use in isolating minute bodies, as Diatomaceae, which would be broken by any other instru-
ment. It is used thus : suppose we have a number of Naviculae, or the like, in a bottle,
mixed with other bodies, and we wish to isolate one for preservation. A small quantity of
the deposit is taken up with a dipping-tube, and allowed to escape upon a slide in such
manner as to form a narrow stripe upon it. This is then examined with the lowest power
with which the object can be distinguished, and one near the margin of the liquid stripe is

KNIVES, ETC.— TEST-BOX. xxiii

selected, and may easily be removed with the mounted bristle (under the microscope) be-
yond the margin of the liquid. The remainder of the liquid is then wiped away with a
cloth, a little distilled water added to the small quantity of liquid left containing the object,
and the latter moved with the bristle into the middle of the slide. The liquid is then driven
off by heat, and the object is left on the slide ready for mounting. Or, when the matter is
dried upon the slide, any one of the minute objects being lightly touched with the bristle
will adhere to it, and by gently pressing or rotating the bristle upon the middle of a new
slide, the object will readily adhere to it. The Diatomacea3 may be easily isolated in this
way.

Knives. — Ordinary dissecting knives or scalpels. The handles should be sufficiently large
to allow of being firmly held.

A particular and most useful kind of knife for producing thin sections of soft bodies is
that known as "Valentin's knife." It consists of two blades with their flat surfaces
parallel, set in a handle. The blades can be fixed at any distance apart, according to the
thickness of the section required. It is drawn across and through the substance, from heel
to point ; the section remains between the blades, and is then removed, either with forceps,
or the blades of the knife are opened under water, and the section floated upon a slide, also
immersed in the liquid. In the latter case, the action of the water upon the tissue must
not be overlooked. Valentin's knife is absolutely indispensable in the examination of
animal bodies. Some sections, especially of vegetables, are best made with a razor.
• Black and white disk. — A disk 3 or 4 inches in diameter, made of seasoned wood, and
upon one face of which a piece of white paper or card-board has been fastened by paste or
glue. One half of the paper or card-board is coloured black, the other is left white. This
is very useful in dissecting or separating minute portions of tissues ; if these are white, they
become much more easily distinguished than usual, when placed (on a slide) over the black
part of the disk ; if they are dark, over the white portion.

Leaded cork. — Some structures require to be dissected under water, as, e. g. those of in-
sects, &c. These should be fixed with pins upon a piece of cork, to which a plate of lead,
corresponding in size, has been fastened. In many cases it is advantageous to dissect these
tissues under the simple microscope. An aperture may then be made in the lead and cork,
and the tissue or structure stretched across the aperture, so that the light may pass through
it ; or it may be illuminated as an opake object by the aid of the bull's-eye.

A trough, composed of five pieces of glass cemented together with marine glue, will
serve to hold the water and the loaded cork.

Evaporating Dish or Saucer. — It is advisable to keep one of these, with a flat bottom,
always at hand filled with distilled water, in which slides and covers that have been used
may be immersed. The remains of objects which have been examined are thus easily sepa-
rated from the glasses, and there is but little trouble in wiping the latter clean. If held
under a gentle current of water, all remains of tissues or test-liquids may be washed away ;
the glasses, from their gravity, remaining at the bottom.

Test-box. — A wooden box, holding from six to a dozen or more test-bottles, is indispen-
sably requisite. The box must be divided into partitions corresponding to the size of the
bottles, and the latter must be wedged between these partitions so that the stopper can
be removed without fear of disturbing the bottles. The box should be covered with a lid
furnished with hinges, so that no room may be required to place the lid when the box is
opened. The bottles will vary in size according to option, but they should be of at least
1 -ounce capacity. Each should have a stopper so prolonged as nearly to reach the bottom
of the bottle, its form being conical or rather fusiform. The advantages of this form of
stopper are, that a mere trace or several ordinary drops of the reagent may be applied to

xxiv INTRODUCTION.

the object as required. If a very minute quantity be desired, the lower part of the stopper
is allowed to touch the inside of the neck of the bottle when it is withdrawn, and if a larger
quantity be required this proceeding may be avoided. Each bottle should be labelled, and
a label should also be placed upon the upper end of the side or partition of the box near to
the bottle, so that the nature of the contents of each bottle may be ascertained without re-
moving it from the box. The general advantages of this apparatus are, that the quantity
of reagent required can be obtained to the greatest nicety, and it can be added to the exact
spot required with one hand only, so that the other can be employed to hold the slide and
object, &c. Mr. Ferguson, of Giltspur Street, supplies these at a small cost, after our
pattern.

Reagents or test liquids. — Some of these should be kept in the test-bottles -, but larger
quantities should also be kept in other stoppered bottles. We give a list here of those test
reagents which are most frequently required ; the method of preparing each, the strength,
&c., will be found under the respective heads.

1 Sulphuric acid. 2. Nitric acid. 3. Acetic acid. 4. Caustic potash. 5. Chloride of
calcium. 6. Aqueous solution of iodine. 7- Oil of turpentine. 8. Syrup. 9. Acid
nitrate of mercury (Millon's test liquid). 10. Distilled water.

^Ether and alcohol should also be kept at hand. Chromic acid should be preserved in a
wide-mouthed stoppered bottle, and its solution prepared when requisite, as it easily be-
comes decomposed by dust, &c.

Troughs — are flat, oblong, glass boxes, without lids. They are made of pieces of glass
cemented together by marine glue, and are used in examining the larger aquatic plants or
animals in a living state ; also in mounting objects.

Divided Scale. — A metallic or ivory scale divided into lOOdths, &c. of an inch, is indis-
pensable in micrometric admeasurements (see MEASUREMENT). The metal or ivory should
extend beyond the graduated portion.

Micrometer. — A glass slide with fine lines scratched upon it with a diamond, these being
ToV^th of an inch apart, is absolutely requisite. Another, with coarser divisions, is also
required to be placed in the eyepiece, for making measurements (see MEASUREMENT).

A piece of tin plate, or sheet iron, 5 or 6 inches square, is requisite. This is supported
upon one of the rings of a retort stand, a tripod, or some equivalent, and heated by a spirit-
lamp placed beneath. It is of use in macerating objects upon slides in chemical reagents,
oil of turpentine, or Canada balsam. An elegant substitute is found in the brass table
made by Messrs. Smith and Beck.

Ring-Net. —A very useful piece of apparatus for collecting Desmidiaceae, Diatomaceae, &c.,
where entangled amongst Confervas, &c., or forming crusts or films upon other aquatic
plants, consists of a wooden ring about 4 inches in diameter, furnished with a groove all
round its circumference, in which also a radial aperture exists, through which the end of a
stick may pass. A piece of very fine muslin, rather larger than the ring, is then laid over
it, and the margins of the muslin fixed in the groove by means of a vulcanized Indian-rubber
ring. Thus we have a kind of strainer, and by using several pieces of previously wetted
muslin in succession, a large number of the minute organisms may be separated from the
water. The pieces of muslin may be brought home, folded up, in wide-mouthed bottles,
separately, or several in one, according as the organisms are obtained from one or several
waters. In this way wre save carrying a large quantity of water. The pieces of muslin are
afterwards opened and placed in jars of filtered river-water, and exposed to the light, when
the organisms will become detached.

A single microscope, or some apparatus which will allow of dissection with the aid of
lenses, is essential, provided an erecting eyepiece, or the erector of Messrs. Smith and Beck

ILLUMINATION.

XXV

be not at hand. It is of little consequence which be selected, provided a large and firm
sloping arm-rest be furnished on each side of the stage. Either doublets or the lower
powers may be used. We have a very convenient simple microscope made by Mr. Varley.

Leather Case and Collecting Bottles. — The Diatomaceae, Desmidiaceae, and other smaller
Algae, as also the Infusoria, require to be collected and brought home in bottles. These should
be of about 1 or 2 ounces capacity ; and for portability without risk of being broken, they
should be packed in a case made of stout leather, with a separate space for each bottle.
The whole will pack up in the form of a book. These are manufactured by Mr. Ferguson
of Giltspur Street.

Having given a sketch of the most important pieces of apparatus, we will say a few words
upon the illumination.

Illumination. — The best light in general for microscopic purposes is undoubtedly day-
light, or that of the sun reflected from the clouds ; and this is certainly the light which can
be borne for the greatest length of time without injury to the sight. The position of the
observer is of importance ; it should be such that the window is on his left hand, or even
the back slightly turned towards the window'. The advantages of this position are great,
for then but little light will enter the eyes directly from the window, and it is of the greatest
importance, during a microscopic examination, that the least possible amount of light should
be admitted to the eye, from any source, besides that transmitted through or reflected
from the object. In drawing also with the Camera lucida this position should be strictly
observed, for all extraneous light which would interfere with the distinctness of the
ipaage is thus excluded, and the shadow of the pencil and hand does not interfere with or
obscure the sketch in progress, which would be the case if the observer's right hand were
towards the window. But in daylight, the light entering the eye from the window, even
in the position above mentioned, will interfere with the observation, unless a preventive be
employed, which is to place a screen, either supported upon a stand or fixed to the upper part
of the body of the microscope, between the eye and the eyepiece of the microscope and the
light. This screen may be made of card-board or thin wood, covered with black velvet. If
it be fixed to a moveable arm, like the lens of the side-condenser, it may be easily placed in
any convenient position. If to be fitted on the microscope, it may be constructed thus :
a piece of stout card-board, of about the size and shape of one of the plates of this work,
should have the corners rounded off, and should be bent at a right angle at about the lower
one-fourth ; a hole being cut in the middle of the smaller portion, of a size just to fit the top
of the body of the microscope, a short tube of card-board is then made by sewing or pasting,
and this being fastened in the same way to the circular aperture serves to keep the screen in
position. The whole is then covered with black velvet. When used, the long flap should
be placed towards the left side ; it then shelters the eye and upper part of the eyepiece
from the light. A screen of this kind should always be kept upon the microscope, for it
is of the greatest service. A tube made of a roll of card-board, fastened to the inside of
the angle of the screen described above, will serve to fix it to the stem of the side-con-
denser ; it may then be made to slide upon this axis or stem at pleasure. It is hardly
possible to use the high powers of the microscope by daylight without a screen of this kind.

But few persons have the opportunity of using daylight for microscopic researches,
hence artificial light of some kind is called into requisition, and the most common source
of this is an Argand lamp with oil. For ordinary purposes nothing can be better
than this. In a well-trimmed Argand lamp, the light is strong and perfectly steady — two
essential requisites ; moreover, there is no great difficulty in obtaining sufficient light with
it when a power of three thousand diameters is used. A most intense light may be obtained
from the elegant little Camphine lamp of Messrs. Smith and Beck, and this is very advan-

xxvi INTRODUCTION.

tageous when the most difficult valves of the Diatomaceae, &c. are examined with stops and
very high powers and eyepieces, whereby a large amount of light is intercepted.

Much of the success with which the structure of an object is displayed, will depend upon
the manner in which the light is thrown upon or transmitted through it. In general the
more light that can be condensed upon opake objects the better ; and when the various
parts of such objects are of different colours, the more direct the light and the greater the
angular aperture of the object-glass, the more clearly will the parts be distinguishable,
whilst in certain opake objects which present questionable elevations or depressions on
their surface, great obliquity of the incident light is essential. With transparent objects it
is sometimes desirable to dimmish the amount of light more or less ; which may be done,
either by means of the diaphragm, by using the flat instead of the concave face of the mirror,
or by inclining the mirror to one side. It must not be forgotten, in determining the cause
of the better display of an object by the substitution of a less amount of oblique light for a
larger amount of direct light, that it need not necessarily arise from the obliquity ; for in
many instances the cause is simply the diminution of light, whether direct or oblique being a
matter of indifference. When the mirror has only one reflecting surface, the amount of light
may be diminished by removing the lamp to a greater distance from the mirror. But the
difficulty usually found consists in the amount of light being too small instead of too great.
This arises from bad management, and may be overcome by attention to the following circum-
stances : the mirror must be placed as near the lamp as possible ; if it cannot be brought
within a few inches of the lamp, the shallow bull's-eye condenser must be used : with the
object-glasses of high powers the achromatic condenser must be used, and the lower the power
of the condensing lenses the greater will be the amount of light transmitted. The lined ap-
pearances presented by many objects, require for their exhibition very oblique light, which
may be obtained by first raising the mirror as near as possible to the plane of the stage, and
then bringing it as much to one side or the other of the stage as can be done : Amici's prism
is very useful for producing the same effect in a greater degree ; large angular aperture in the
object-glass is also very advantageous under these circumstances, because it will allow of
the admission of rays of such degree of obliquity as could not enter one of smaller aperture.
In cases where still more light is required than can be obtained in any way by reflexion
from the mirror, this must be turned aside, and the direct light of the lamp used.

Eleven years ago one of the editors* suggested a method of remedying the defects of
artificial light, or that ordinarily used to replace daylight. The well-known glare attending
lamp or candle light, and the predominance of a yellow colour, so visible when compared
with daylight, render it very unfavourable for microscopic purposes. It was proposed to
mix some substance with the combustible which during its combustion evolved a light of the
colour complementary to (or forming white light with) that predominant in the artificial light,
or to pass the light in its passage from the artificial luminary through a piece of glass, of
such colour as to intercept or check the objectionable rays. As these rays are of a yellow
or reddish-yellow colour, the colour of the glass must be blue, or purplish blue, but the
exact shade must be ascertained by experiment. Thus : the lamp, or whatever source of
artificial light it may be, is lighted in the daytime and the light transmitted through the
microscope by reflexion in the ordinary way, when its intensely yellowish colour is very
obvious. Pieces of glass of different colours are then separately placed at right angles to the
path of the rays from the lamp to the mirror, either close to the flame (in the form of an
ordinary lamp glass), upon the face of the mirror itself, beneath the stage, or hi an extra
head of the side-condenser. If the glass be of the proper tint, and be placed at the proper
distance from the light, and in the proper situation, the field will appear as white as the
* J. W. Griffith, M.D., Med. Gaz Nov. 13, 1843, and Tulk and Henfrey's Anatomical Manipulation, p. 184.

GENERAL METHOD. xxvii

light of the clouds, which may be easily proved by altering the inclination of the mirror so
as to reflect the light of the clouds and the lamp alternately.

It has been denied that this can be done, but it is as easily done as described. It may
be remarked, that the nearer the coloured glass is placed to the flame the less apparent effect
will be produced, i. e. the more will the yellow colour be perceptible, and vice versa. If the
field still appear yellow, the glass is not of sufficiently deep colour ; if it appear blue, the
colour of the glass is too deep. The first method, or that of mixing some substance with
the combustible (oil, tallow, &c.) capable of evolving a light of the requisite tint to form
white with the yellow of the artificial light, would be far preferable to the latter method,
but we are not aware that the subject has been taken up by any one, or that any experiments
have been made to cariy out the idea. It would have two great advantages, viz. that there
would be no diminution of light, and that the entire apartment would be illuminated by a
light equivalent to that of ordinary day. The second method has one objection, which
is, that it intercepts a large quantity of the light, so that in the examination of those objects
with high powers which require intense illumination, or where much of the light is arrested
by stops, it is decidedly objectionable. The advantages which the use of the blue glass
possesses are, that it softens the light very much, and that it enables the observer to discri-
minate between colours as in ordinary daylight.

A few years after the publication of the above method, a patent was taken out for the
construction of lamp-glasses of a blue colour ; but they are of little service, merely slightly
softening the light, or intercepting a small proportion of the yellow rays.

The proper way would be to " flash " the properly tinted blue glass upon one side of a pale
blue lamp-glass, so that by simply turning the glass round, the light might be transmitted
through either of the differently coloured portions.

II.— GENERAL METHOD OF DETERMINING THE STRUCTURE OF MICRO-
SCOPIC OBJECTS FROM THE APPEARANCES WHICH THEY PRESENT
UNDER VARIOUS CONDITIONS.

Microscopic and Jiistoloyical appearance, structure and analysis. — Before proceedingto this,
let us define what is to be meant by the structure of a microscopic object. If we take a
piece of the free end of the finger nail, and examine thin transverse sections of it under the
microscope, we find them to present numerous shorter or longer dark and somewhat irre-
gular lines running nearly parallel to the surfaces. These appearances do not vary essentially
whether it be examined in the dry state, or immersed in water or oil of turpentine.

But when it is moistened with solution of potash, and allowed to remain so for some time,
or the slide is gently heated, it becomes entirely resolved into a number of nucleated
cells ; and by watching the gradual action of the potash, it is easily seen that the cells were
originally flattened and arranged in layers, which layers produced the lined appearance
mentioned above (see the article NAILS). Now which is to be considered as repre-
senting the structure of the nail, the first or the second of the above results ? Undoubtedly
the second. The expressions microscopic structure and histological structure are used very
indefinitely, and often synonymously ; but the former may very conveniently be restricted
to signify the apparent structure as determined with the aid of ordinary mechanical means ;
whilst the latter may designate the true structure in relation to development. It may at
first sight appear very unnecessary to make any distinction between the two ; but it is
really very important, because most of the descriptions of the structure of bodies, at least
as given by English writers, refer only to their microscopic structure, nay, often to their
microscopic appearance only. These occupy but' little time, and readily afford the basis of

c2

xxviii INTRODUCTION.

extensive analogical reasoning ; a few sections and a glance, — all the parts which appear
round are cells, the elongated parts, fibres, or tubes, &c.,— a hasty comparison of these appear-
ances with others observed in other organisms, with a little analogical reasoning, will yield a
clear and lucid physiological explanation, and perhaps develope a beautiful homology. The
whole may be done in a few minutes, or at the most a few hours !

It is very different, however, with the determination of the histological or true structure.
Frequently a week or a month must be devoted to the determination of a single point.
Take the instance of a hard structure — a piece of the skeleton of one of the Invertebrata.
A few sections made by an artisan will exhibit cells, laminae or fibres, according to the pre-
conceived notions of the observer ; whilst the histologist will not express an opinion until
the inorganic matters have been removed by long maceration in acid, the calcareous salts
thoroughly washed away, and attempts been made to resolve the organic basis into its
histological elements by appropriate means. This may be the work of months, and may
require very many experiments to be made, and no mean knowledge of particular branches
of science for guidance in the selection of appropriate agents requisite for their performance.
Yet the two kinds of observations make equal show upon paper. We shall have frequent
occasion to use the above words in the restricted sense ; hence this should not be forgotten.
The word analysis will have the same meaning as that generally attributed to it, the ultimate
products being morphological.

A general method for determining the structure of objects can hardly be laid down ; it
must vary so greatly according to the nature of the objects and their size. The first point
is to render them transparent, if not already so. This may frequently be done by immersion
or maceration, if dry, in water or oil of turpentine ; sometimes the aid of heat is necessary,
and they may even require to be boiled in these liquids, either upon a slide placed upon the
tin plate over the flame of a spirit-lamp, or in a small tube. Sometimes sections require to
be made, and these treated in the same manner. If soft, their elements may be separated
by the aid of needles ; sometimes pressure will answer the same purpose.

When the object is very minute, it will frequently be desirable to examine both sides of
it with high powers. Hence it must not be placed upon an ordinary slide, on account of
the thickness of the latter, but must be supported upon, and covered by thin glass. The
best plan is to keep a number of slides, made of tolerably stout card or card-board, each
having a piece cut out of the middle. A piece of thin glass, rather larger than the
aperture, should then be cemented by marine glue or Canada balsam to one side of the
card, and a slide is thus prepared ; the thin glass cover is then applied as usual.

A great advantage of this method of temporarily or permanently mounting objects is, that
the card-board being flexible, there is no fear of injuring the object-glass, even if it should
come into contact with the glass cover. If the object be very small and its structure
very delicate, it must be crushed, so that some of the fragments may lie perfectly flat upon
the slide. See also the article PREPARATION.

But the points to be determined in regard to the different parts of an object, may be best
treated separately.

The examination of a microscopic object must comprise, — a, the microscopic analysis,
including, — 1, the form; 2, the colour; 3, the structure of the surface; and 4, the internal
structure : b, the histological analysis, in the sense already explained : c, the qualitative
chemical composition ; and d, the measurement.

A. MICROSCOPIC ANALYSIS.

1. The Form.— a. This is usually judged of from the outline, as seen by transmitted
light, and often erroneously. Where a low power is used, the upper surface of an object

,

MICROSCOPIC ANALYSIS. COLOUR. xxix

and its sides are mostly simultaneously visible ; but under a high power, only those parts
lying within a very limited vertical range, or in the same plane, are visible at one focus ; and
the parts lying in planes above or below this can only be brought into view by altering
the focus ; hence the views of objects under high powers correspond to views of transverse
sections of the same objects made through various horizontal planes j and as the margins
of objects are usually more distinct by transmitted light than the upper surface, spherical or
rounded bodies frequently appear flattened. When several bodies of the same kind are
visible in the field of the microscope, some will almost always be found lying upon their
sides ; and even when the objects are greatly flattened, some will mostly be found lying on
edge, presenting the side view.

b. But as there may be uncertainty in regard to the relation of these bodies to each other,
the only safe method in forming a conclusion is to cause them to revolve or roll over, so that
all their aspects may be distinguished. This is in general easily accomplished ; if the object
be already immersed in liquid, the inclination of the stage will answer the purpose ; or a little
aether, chloroform, naphtha, alcohol, or some other volatile liquid in which they are insoluble,
must be added. The currents produced by the evaporation of these will cause the objects,
especially such as are near the edges of the liquid, to move in all directions, and their true
form may be discerned. Sometimes moving the thin glass cover sidewise, the object being
kept in view, W7ill answer the same end.

c. In figures of microscopic objects, the side view should always be exhibited if possible ;
and if not, it should certainly be described.

d. In the case of crystalline bodies, or such as present angular edges, their angles should
be measured with the goniometer, if their chemical composition be unknown.

2. The Colour. — The colour of objects should always be carefully described, and its cause
accurately determined. It most commonly arises from, — 1, partial absorption ; 2, the pre-
sence of pigment, or other colouring matter ; 3, from iridescence ; 4, from polarization, &c.

1 . The most common cause is a peculiar property by which a portion of the coloured
rays composing the white light, which falls upon or is transmitted through an object, is
absorbed, the remainder being reflected or refracted so as to reach the eye. On examining
bodies thus coloured, with whatever powers, their substance is found uniformly coloured,
and this colour is unchanged by their immersion in water or oil of turpentine, and is the
same in transparent bodies by both transmitted and reflected light. This is commonly
regarded as the proper colour of an object. Example : a crystal of blue vitriol.

2. — a. In many cases, however, although an object may appear to the naked eye uniformly
coloured, on examining it with a high power, the colour, which in fact arises from the above
cause, is seen to be confined to certain molecules or granules, whilst the general substance
is colourless. These granules may consist of vegetable or animal colouring matters, metallic
oxides, &c. The nature of these matters should always be determined, if possible, either by
microscopic chemistry — micro-chemical analysis, as it has been called, — or by ordinary che-
mical analysis. When the colouring matter is of organic nature, and when its composition
cannot be determined, or it has no definite name, it is called pigment. Objects coloured by
pigment, metallic oxides, or other colouring matters, are best examined by direct (not
oblique) transmitted light, and when immersed in either water or oil of turpentine. These
liquids do not change the colour, nor destroy it unless the pigment be soluble in them ; but
by rendering the general substance of the object more transparent, they cause the granules
to become more distinct. The colour is the same both by transmitted and reflected light.
Example : a brown or black hair of an animal.

b. Sometimes bodies coloured by pigment or other colouring matters appeal' under the
microscope uniformly dyed, although the colouring matter consists of an insoluble molecular

xxx INTRODUCTION.

or granular powder ; as a white animal hair first macerated in solution of ferrocyanide of
potassium and then in solution of perchloride of iron. Chemical means will alone distin-
guish this cause of colour from the first, by removing the colouring matter from the colour-
less basis.

3. The colours of many objects vary according to the direction of the light transmitted
through them, or are only visible by oblique light, and the colours are different by direct
and oblique light. These arise from decomposition of white light by either interference or
refraction. For the sake of brevity, these may be designated colours from iridescence, be-
cause they mostly exhibit the brilliancy and transparency of the colours of the rainbow. The
interference or refraction upon which they depend is ordinarily produced by irregularities of
structure, frequently depressions or grooves, and sometimes cavities containing air, &c. Ob-
jects exhibiting these colours, which are most brilliant by very oblique light and under low
powers, when examined with a moderately high power by transmitted direct or but slightly
oblique light, frequently appear more dull and less brilliant, often dark or black in parts ;
and when immersed in oil of turpentine or some liquid approaching in refractive power the
substance of which they are composed, so that their irregularities become filled with it, the
colours vanish. Hence colour, when arising from iridescence, can readily be distinguished
from that arising from general absorption or from the presence of pigment ; and when the
colour of an object obeys the above law, it may be predicted that structural irregularities
sufficient to account for its production will be found if properly sought for. Moreover these
colours are not the same by reflected and refracted light, and they vanish under very high
powers. They may be studied in the species of Gyrosigma ; and those observers whose
microscopes do not magnify sufficiently, or whose object-glasses have not sufficient angular
aperture to admit of the detection of the markings upon some of the Diatomacese or other
bodies of similar structure, may be sure that they are present when these phenomena have
been observed. We were thus led to search for them upon the valves of Melosira varians,
and Borreri, species of Nitzschia, &c., where they had not been previously detected, and there
they are present. Again, the colours of the dried valves of the Diatomacea3, many of which have
a brown tinge, have been supposed to depend upon the presence of the peroxide of iron ; but
as this colour vanishes when the valves are immersed in oil of turpentine, independently of
the fact, that the valves do not present the same brown colour by reflected and transmitted
light, and by direct and oblique light, which we have stated to be characteristic of the pre-
sence of colouring matter, the colour cannot arise from this cause.

An example of iridescent colour arising from the presence of fibres, is found in the tape-
turn. Certain cases, referable to this head, require special notice. Thus it sometimes be-
comes a question whether a very minute red spot, visible in an Infusorium, Alga, &c., is the
optical expression of a minute vacuole, or a little depression filled with water, air, or other
fluid of less highly refractive power than the substance of which the organism consists ; or
whether it arises from the presence of pigment. The point is easily decided : a practised
eye will recognize the transparency of the colour where not arising from pigment, and its
granular appearance where the pigment is present. If the substance of the object be soft,
compression will frequently destroy the appearance when pigment is absent. Drying the
object and then immersing it in oil of turpentine or other highly refractive liquid will do
the same, whilst pigment will become even more distinct if present. Moreover, on altering
the focus of the object-glass, the colour will be found to change, when not arising from
pigment.

The colours of thin plates may be mentioned here ; but they are so rare in microscopic
objects, that we must refer to works upon optics for an account of them. They occur in
the crystals found upon the under surface of the scales of various fishes.

_

MICROSCOPIC ANALYSIS. SURFACE. xxxi

4. The colour arising from polarized light is noticed under ANALYTIC CRYSTALS,
DICHROISM, and POLARIZATION.

The colours of objects examined by transmitted light are frequently rendered much darker,
and colourless or coloured objects may appear dark or even quite black, from refraction or
reflexion of the light out of the field of the microscope. Thus, powdered vermilion appears
almost black ; air-bubbles appear black at the margins or entirely black, &c. ; hence the
importance of comparing observations made by both reflected and transmitted light, for
neglect of this precaution caused the air in the hairs of animals to be mistaken for pigment.
Milk-white opacity mostly arises from the presence of numerous molecules, granules, thin
layers of liquid or other surfaces which reflect a large quantity of the light incident upon
them, as in milk, where the reflecting bodies consist of the globules of fatty matter (butter),
in white paper, the two varieties of tubercle, &c.

3. Structure c/ the Surface. — a. When an object is of comparatively large size, the struc-
ture of the outer surface is in general easily determined by examining it with reflected light,

1. e. as an opake object, illuminated by the side-condeuser; but when the objects are small,
sufficient light cannot be thrown upon them with ordinary condensers ; recourse must then
be had to Dr. Brooke's reflector (p. xi); and this, because it enables us to examine the most
minute objects under the conditions in which we can most easily judge of their structure
from their appearance.

b. When this apparatus is not at hand, our judgment must depend upon the appearances
presented under the action of transmitted light. And here we meet with a difficult task, in
accomplishing which, the following questions are constantly presenting themselves : Do cer-
tain spots, hues or other markings visible upon the surface, represent elevations or depres-
sions? Are they cavities in the outer portion or layer of the object? Are they foramina or
holes ? Are they granules of pigment, or rows of them ? Do the lines represent a true lined
structure, or are they optical illusions ? Is the surface smooth and free from markings ?
The methods of answering these questions must vary so greatly, according to the nature of
the object, its size, &c., that it would be almost impossible to lay them down by rule. The
following considerations are, however, of most importance.

c. In many cases where structural appearances are visible at the surface of an object, their
true situation above or beneath the surface may be determined by raising the object-glass
above the focus of the surface. On then carefully and gradually depressing the object-glass
with the fine movement, the structure first brought into focus is the uppermost. Thus, the
inner surface of the under membrane of the elytrum of the stag-beetle (Lucanus cervus), is
covered with very minute hairs projecting from the surface (PI. 27. fig. 2). On placing
this with the inner side uppermost and adjusting the object-glass as just described, the hairs
are distinctly brought into focus before the surface of the membrane. Hence they are
situated upon the surface ; whereas, had the surface of the membrane been brought into
view before the hairs, it must have been concluded that the latter were situated on a plane
below this. It may be stated, that the surface of a membrane is recognized to be in focus
by certain irregular granules, molecules or wrinkles, mostly visible upon it.

d. Frequently, when hairs or filaments project from a surface, their relative position may
be easily determined by examining the margin of the object if it be rounded, or the margin
of a fold if it be flat and membranous ; as in the case of ciliated bodies, Infusoria, &c.

e. Cilia upon the surface of an object are sometimes so minute and transparent as to be
with difficulty detected ; they can however always be made evident, when present, by the
following means : — 1 . Drying the object ; they then become much darker from refraction.

2. Dyeing the object with solution of iodine; drying the object after the addition of the
latter solution is sometimes advantageous. 3. Mixing coloured insoluble particles with the

xxxii INTRODUCTION.

water in which the objects are contained j of course this is only of use if the objects be
living ; the particles will then be set in motion, and their motion may be distinguished from
molecular motion by the definite direction in which the particles move.

/. The nature of many markings, spots, &c. is best determined by comparing the effects of
the refraction of the transmitted light at different foci produced by the markings themselves,
and the substances in which they are situated ; and these phenomena may be conveniently
illustrated by their occurrence in known objects. If a drop of oil of turpentine, which has
been digested with alkanet root so as to become coloured, be placed upon a slide, a drop of
water added to it, a thin glass cover applied, and the cover be moved backwards and for-
wards upon the slide with the finger covered with a cloth, the drop of oil will be subdivided
into globules of various sizes, some of which will enclose globules of water j thus we shall
have globules of the oil surrounded simply by water, globules of water enclosed in globules
of oil, and some of these globules will contain within them globules of the other kind again ;
the globules of oil being readily distinguished by their red colour. On examining the slide
with a tolerably high power, all the globules will appear bounded by a black circle, and pre-
sent a luminous point in the centre, when viewed separately, and the focus suitably ad-
justed for each. But when they are examined in comparison and together, they will be
found to exhibit characteristic appearances according to the variation of the focus. Thus,
of the simple globules, when their margin is most distinctly brought into focus, some will
become more luminous as the object-glass is depressed (PI. 40. fig. 1 a), these are globules
of water surrounded by oil ; others will become darker under the same circumstances (PI. 40.
fig. 1 6), and very luminous as the object-glass is raised (PL 40. fig. 1 c), these are globules
of oil ; and the nature of the components of the compound globules may easily be deter-
mined by the occurrence of the same phenomena. The globules of oil, being more highly
refractive than the water, act like little convex lenses ; whilst the globules of water sur-
rounded by the oil, exerting a lower refractive power than the latter, act like concave lenses,
and their centre appears luminous, because the rays which traverse them diverge as they
ascend, as if they emanated from a virtual focus situated beneath the globules, or on the same
side of them as the mirror.

The same phenomena may be observed in air-bubbles immersed in water ; these corre-
spond with the globules of water surrounded by the oil. It need scarcely be remarked, that
the object in colouring the oil is to allow of the control of the conclusions arrived at.

g. In the globules of sarcode and many cells, the vacuoles are easily shown, by the same
method, to be filled with a material of less refractive power than the general substance of which
they are composed ; these vacuoles are frequently mistaken for nuclei and nucleoli, but they
are readily distinguished from them, by the dark appearance they present when the object-
glass is raised above the focus of their margins.

h. The above principles are applicable to the determination of numerous cases where the
elevation or depression of a spot or marking upon a surface is called in question ; for ele-
vations on a surface will produce the general effect of convex lenses, whilst depressions
will produce that of concave lenses. In the above experiment, plano-convex lenses of both
oil and water are frequently seen, and readily distinguished by the above means.

Take also the instance of a Paramecium Aurelia, either dried or immersed in water. The
surface is beautifully marked with pretty regular dots, which appear luminous as the object-
glass is depressed (PI. 25. fig. 1 a), and dark as it is elevated (PI. 25. fig. 1 b) ; hence they con-
sist of depressions upon the surface. Had they been elevations or little tubercles, they
would have become more luminous as the object-glass was raised, and vice versa.

When an isolated granule of pigment or of any opake substance is brought into focus, on
raising the object-glass, a luminous spot appears to occupy its place ; hence it agrees so far

MICROSCOPIC ANALYSIS. SURFACE. xxxiii

with a highly refractive granule. The appearance, however, arises from diffraction, and
may be distinguished from that produced by refraction, by the luminous spot equalling or
exceeding the granule in size, whilst in the latter it is smaller and more brilliant.

i. In all these experiments, the less oblique the light the more certain will be the results.
But this method is inapplicable to decide whether the less refractive portions are simply
depressions or cells. This may often be determined by examining the margin of the object,
where possible (as in Paramecium), and observing whether there are depressions upon it
corresponding to the parts at which the dots are situated, and whether these depressions are
continuous with the dots (PI. 25. fig. 1 6). When the substance of the object is somewhat
firm, drying it, if moist, will cause the dots to become filled with air ; they will then, if cells,
appear infinitely blacker than if simply depressions, and visible as readily by direct as by
oblique light; and after the object has been moistened with water or oil of turpentine, if it
be immediately examined, the blackness of the dots will appear still greater, and they will
be distinctly visible by direct light ; whilst depressions are much more easily filled with
liquid, and then, if minute, will only be visible by oblique light.

k. If it can be shown that the parts corresponding to the dots are depressed below the gene-
ral surface, and the dots or depressions present an angular outline, these dots cannot possi-
bly represent cells ; because, if the angularity of the outlines of cell structures arose from
the pressure of surrounding or adjacent cells, this pressure would necessarily be exerted also
upon the free or external portion of each cell, so as to render it convex, or at any rate, not
concave. The firmness of the substance of the object must be attended to ; because where
it is absent, as the cells part with the liquid portion of their contents, the outer portion of
the cell-wall may become approximated to the inner, and thus no space be left for the air
to enter ; as in the exuviae of a Triton for instance.

/. In brittle objects, as the siliceous valves of the Diatomacese, the examination of the mar-
gins of the fractured portions is important and sometimes conclusive, for it may be found,
as in Isthmia, &c., that the depression of the object-glass requisite to bring into focus the
margins of the thin depressed portion, is much greater than that required for the intermediate
thicker parts. In the valves of the more delicate Diatomacese (Gyrosigma, &c.), in which
this observation is difficult to be made, the point is important that the line of fracture of the
broken valves passes through the rows of dots or the dark lines corresponding to them, show-
ing that they are thinner and weaker than the rest of the substance ; had these dots
represented elevations, the valves would have been stronger at these parts. The nature
of the markings upon the siliceous valves of the Diatomacese, especially the species of
Gyrosigma, has long formed a much-disputed point. The continental microscopists take
little or no notice of them ; in fact, they are not generally acquainted with them, because
they do not comprehend the importance of the use of either the condenser with its stops, the
adjustment for the thickness of the glass cover, or the methods of compensating for the defi-
ciency of angular aperture which their glasses possess; and without attention to these circum-
stances they cannot be seen. If we take a flat fragment of an Isthmia, and examine it by
the aid of the condenser with a central stop and an object-glass of low power, care being taken
that the condenser and stop are perfectly central, it will exhibit a series of angular dark or black
dots bounded by luminous lines separating them (PI. 11. fig.47); and this, when all parts of the
object are best in focus, for when the object-glass is elevated or depressed, the whole becomes
indistinct. The black dots in this instance clearly coincide with the depressed portions of
the surface of the valve. On examining a fragment of the valves of a Gyrosigma strigosum
or angulatum, &c., exactly the same phaenomena'are witnessed when the parts of the object in
view appear at their most distinct focus, the black dots being bounded by angular short con-
tinuous lines, giving them the appearance of being distinctly hexagonal. On inclining the

xxxiv INTRODUCTION.

mirror somewhat, so as to render the light transmitted through the object unequally oblique,
the appearances will be reversed, a number of luminous dots being visible, bounded by dark
lines. In PI. 11. fig. 41, is a diagram of a portion of a valve of Gyrosigma angulatum,
magnified to the enormous extent of 15,000 diameters, taken from a photograph lent us by
Mr. F. H. Wenham (the lights and shades being, however, reversed) ; and PL 11. fig. 48
represents a portion of a valve of Gyrosigma s£n<70SMW,magnified4700 diameters, as seen under
our own microscope. The black hexagonal dots in the latter figure correspond to the black
dots seen in Isthmia, and represent the depressed portions of the valves. The article DIA-
TOMACE^E must be consulted for further details in regard to the structure of these valves,
and the article ANGULAR APERTURE in regard to the changes produced in the appearances
of objects by variation of the angular aperture of the object-glass, and of the degree of obli-
quity of the transmitted light. But we may remark here, that these dots must not be com-
pared to cells, but to the depressions found upon the seeds of the white poppy, Parame-
cium, &c., in which forms resembling those resulting from the mutual pressure of adjacent
cells are present, but do not arise, so far as we know, from this cause.

m. No special remarks are required in regard to furrows, as these are only elongated
depressions.

n. When ridges are present, these are frequently left projecting at the margin of a frag-
ment ; sometimes they project naturally : and it may readily be known that they are thicker
portions of structure, by their blacker margins and their exhibiting the characters of elon-
gated convex or plano-convex lenses.

In some cases, the position assumed by confined portions of air, when the object is im-
mersed in liquid, will denote the existence of ridges. Thus we have seen portions of air,
accidentally confined between the surface of a scale of Lepisma saccharina and the thin
glass covering it, assume an elongated form, being limited laterally by the ridges upon the
scale (PI. 27. fig. 3).

o. Foramina or holes are in general readily distinguished by their dark and defined margins,
and the absence of colour when they exist in coloured structures ; when existing in transpa-
rent colourless objects, the latter mostly exhibit minute irregularities, by which the presence
of some kind of matter is indicated, whilst these are absent in the foramina. Where there
is difficulty in deciding, the structure should be broken, if possible, and the margins ex-
amined. Sometimes the polariscope is of use; the general substance may polarize light, but
the foramina will not do so of course. Charring the structure, or colouring it with re-
agents, if organic, will sometimes afford decisive proof.

Foramina cannot be mistaken for elevations on the surface, because they do not become
more luminous as the object-glass is raised, after their margin has been brought most
distinctly into focus ; in fact the reverse occurs : hence they so far agree with depressions ;
but they differ from these in their luminous appearance with high powers, and their not
being rendered more distinct by oblique light, but the reverse.

p. When the structure in which they are situated is somewhat thick, and they form rather
tubes than foramina, as the axes of these can hardly coincide with the direction of the
transmitted light, their orifices will appear dark or black ; hence they might be mistaken for
granules of pigment : immersion or maceration of the structure in oil of turpentine will,
however, fill them, and cause the dark appearance to vanish, whilst pigment would still be
visible. Examination by reflected light will also readily distinguish the one case from the
other. Also where this tubular structure is present, perpendicular sections will exhibit
furrows, which may be recognized as directed above. In distinguishing foramina, the higher
the power employed the less is the difficulty.

q. It has sometimes to be decided, whether certain dark lines visible at the surface of objects,

MICROSCOPIC ANALYSIS. INTERNAL STRUCTURE. xxxv

represent ridges or grooves, or whether they are illusory shadows arising from the passage
of light through a structure furnished with depressions, granules of pigment, &c. This must
be done by examining the object when illuminated by reflected light, or a hollow cone of
oblique rays, such as is obtained on using the achromatic condenser with the central stop; when
thus illuminated, the lined appearance will vanish and the true structure will become visible.

r. It often happens that objects, especially highly refractive bodies, appear surrounded or
covered by a number of black lines, rings or annular lines, arising from diffraction, and it
becomes an important question whether these lines represent cell-walls, &c. When they
arise from diffraction, they vary in number according to the obliquity of the incident light
and the angular aperture of the object-glass ; and when the condenser is used, they vary
according to its adjustment, and at a particular adjustment they will sometimes disappear
entirely. Hence in these cases the condenser should always be used, and the results
obtained controlled by the effects of immersion in highly refractive liquids, and the means
mentioned below.

s. A very ingenious method has been proposed and adopted successfully by Mr. Wenham,
for exhibiting the form of certain very minute markings upon objects. A negative photo-
graphic impression of the object is first taken on collodion in the ordinary way, with the
highest power of the microscope that can be used. After this has been properly fixed, it is
placed in the sliding frame of an ordinary camera, and the frame end of the latter adjusted
into an opening cut in the shutter of a perfectly dark room. Parallel rays of sunlight are
then thrown through the picture by means of a flat piece of looking-glass fixed outside the
shutter in such a manner as to catch and reflect the rays through the camera. A screen
standing in the room, opposite the lens of the camera, will now receive an image, exactly as
from a magic lantern, and the size of the image will be proportionate to the distance. On
this screen is placed a sheet of photogenic paper intended to receive the magnified picture.
For further particulars see PHOTOGRAPHY.

A portion of a valve magnified in this manner is represented at PI. 11. fig. 41.

4. Internal structure. — We must be understood here as referring to the general structure
of an object, i. e. whether it is solid or cellular, &c. ; and where an object is composed of an
aggregation of similar parts, our remarks must be applied to these individually.

The first question arising is whether a transparent object is solid or semisolid and homo-
geneous, or whether it represents a cell, i. e. has an outer membrane or cell-wall and con-
tents of a different nature. When objects possess an outer coat, its two margins are some-
times easily distinguishable on examination by transmitted light, especially when its thick-
ness is considerable. But when the outer coat is thin, these are difficult to distinguish ; re-
course must then be had to other means than simple inspection ; and these will vary accord-
ing to the nature of the object, and especially the softness of its cell-wall. Sometimes
crushing it may show clearly that the contents consist of a liquid with numerous molecules
and granules, and that the cell-wall is thin and membranous, for the subsequent addition of
water may separate and render both distinct. The most valuable test-method however is
the production of endosmosis or exosmosis. If we take a cell with a soft and thin wall, and
add distilled water to it, it will imbibe a certain quantity of it and become distended, and
often the contents will become distinctly separated and visible within ; whilst if a saturated
solution of some salt, as chloride of calcium, be added, it will become wrinkled and col-
lapsed. On treating a solid or homogeneous body with water, it remains unaltered, or per-
haps swells slightly ; but on treating it with the solution of chloride of calcium, no wrinkling
or contraction occurs, and its appearance is unchanged. If the outer coat be firm and re-
sisting, the chloride will not cause it to contract and wrinkle.

If there be two coats, the outer being firmer than the inner, the latter will be wrinkled and

xxxvi INTRODUCTION.

collapsed, whilst the former retains its shape ; this is the ordinary occurrence in young vege-
table cells. The exosmotic effects of the chloride of calcium should be looked for soon after
its addition to the object, particular care being taken that it conies into contact with the
object ; for when solid or semisolid bodies are macerated for a long time in the saline solu-
tion, they will become contracted, and globules of sarcode will escape from them ; but we
believe that in all these cases there really exists a cell-wall, or a structure corresponding to
it ; hence by solid or semisolid bodies, we must be understood to mean those which differ
from cells according to the characteristic action of exosmose.

It must be remembered that solution of chloride of calcium is a highly refractive liquid ;
hence it frequently renders globules so transparent, that they are almost or completely in-
visible, and thus apparently dissolves them ; sometimes also it really dissolves them. More-
over, many so-called unicellular vegetable organisms exhibit the contraction of the internal
cell-wall or primordial utricle, from long maceration in water only, as is so frequently seen
in the Desmidiaceae " mounted " in water. An aqueous solution of iodine is also frequently
useful in bringing to light the existence of an inner cell-wall, especially in vegetable struc-
tures, causing it to become wrinkled and collapsed.

Cells have not the tendency to fuse together or adhere to each other, which globules of
sarcode or other glutinous solid or semisolid substances have.

If the object be brittle, crushing it will sometimes show its internal structure, by allowing
the examination of the margins of the fragments.

Spherical or rounded solid bodies, when immersed in water or other liquids of low re-
fractive power, generally present a much less distinct black margin than cellular bodies, or
those with membranous walls.

The determination of the contents of an object furnished with an outer coat, must be
made according to the foregoing indications. The contents often consist of liquid in which
are suspended molecules and granules. If these exhibit molecular motion, the material in
which they are suspended must be liquid. It sometimes becomes a question, whether a
body enclosed within another is central or lateral. This is readily determined by causing
the body to revolve by inclining the stage of the microscope, when, if central and fixed, the
enclosed body will retain this position j and if it be less than the cavity of the enclosing
structure, positive indication will be afforded that the latter is solid, or at least that it does
not consist simply of an outer coat with liquid contents and the enclosed body. But if it
be attached to the inner wall of the enclosing structure, the eccentricity of its motion whilst
revolving will be evident.

The contents of microscopic bodies are frequently rendered distinct by the addition of
reagents, and in some cases can alone be distinguished by their use ; thus the nuclei of ani-
mal cells are at once made evident by the addition of acetic acid, &c.

We frequently have to decide whether the interior of an object is solid or tubular. If it
consist of a firm substance,, drying it, if in liquid, will cause the evaporation of the liquid or
other contents, and the entrance of air. A section of it will also show whether it is solid or
hollow. The effects of crushing it should also be observed.

B. HlSTOLOGICAL ANALYSIS.

This consists in the resolution of the object into its component morphological elements,
and is usually effected by subjecting it to the action of various chemical reagents, continued
maceration, &c. It must never be attempted if inorganic matters be present in quantity,
until these have been previously removed. The reagent used should be one which
exerts a solvent action upon the substance of which the object is composed, the action
being interrupted at a certain stage by the addition of water, &c. In regard to those

CHEMICAL REACTIONS. xxxvii

objects whose morphological elements have become altered by individual growth, &c.,
histological analysis is of course useless ; and the manner in which these have acquired their
existing structure, can only be determined by tracing the gradual changes which their mor-
phological constituents undergo, from the earliest period of their existence to that at which
they form the object in question. This constitutes the study of development, or it might be
termed Histological synthesis. It can rarely be followed directly ; but can often be carried
out indirectly, by examining a number of the objects in all stages of then* development, and
comparing the changes undergone by their constituents. It requires special care in con-
troling the identity of the objects.

C. CHEMICAL REACTIONS.

We cannot too strongly insist upon the necessity of investigating these in the case of
all objects submitted to examination, the nature of which is at all doubtful; and this,
because in many instances the form or general appearance will afford no criterion by
which the nature may be determined. Judgment founded simply upon the form, or
upon the mere inspection of an object, therefore, will illustrate the abuse and not the
proper use of the microscope. The quantitative and ultimate analysis of substances cannot
be made in any manner by the aid of microscopic manipulation, but the qualitative
analysis, or the study of the action of chemical reagents upon the object or substance by the
aid of the microscope, or the micro-chemical analysis, as the Germans style it (and the
term is very convenient), may be undertaken with the prospect of almost certain success, in
most cases at least, in ascertaining the proximate chemical composition.

The characteristic reactions or tests for the various proximate principles are given in this
work under the respective heads of those substances, and we can only give here a brief
sketch of the manner in which the micro-chemical analysis of a substance may be con-
ducted, and without which its microscopic investigation must be imperfect, and of little or
no value.

The first point to be attended to is, to ensure, as far as possible, the freedom of the
object from foreign admixtures. Thus if it should have been found in an animal or vege-
table liquid, it must be carefully washed, either in a watch-glass, or upon a slide whilst
covered with thin glass. The former is readily accomplished ; the substance being placed
in a watch-glass, water or other solvent of foreign matters is added ; the whole is then set
aside, to allow of the subsidence of the substance, and the supernatant liquid removed by a
pipette. If the body or the particles be very minute, it or they must be placed upon a glass
slide, and covered with thin glass ; the latter should then be pressed, so far as is possible
without crushing the particles, but sufficiently to fix them, and a small piece of coarse white
blotting-paper placed upon the upper surface of the slide, so as to touch the edge of the
liquid. Capillary attraction will cause the liquid to be absorbed by the paper. Small quan-
tities of water, or other proper solvent, are then added by small portions from the end of a
glass rod to the opposite edge of the liquid confined by the thin glass. Thus a current will
be set up, and the newly added liquid will be absorbed by the blotting-paper, washing in its
course the particles confined between the two glasses. The current will be regulated by the
quantity of liquid added, and the facility with which the paper absorbs it.

When the body has been washed, the effects of the various reagents may be examined,
by the addition of them in small quantities from the conical stoppers of the test-bottles (see
Test-bottles). The test-liquid being applied to the edge of the liquid in which the body is
immersed, gradually mixes with it, and the effects produced may be watched step by step.
If a solvent or other action is seen to take place, the result is decisive ; but if no action be
evident, it must be remembered that the reagent added may not have reached the object

xxxviii INTRODUCTION.

under examination, perhaps from an insufficient lapse of time for the occurrence of diffusion
in the two liquids. To be positive, therefore, that the reagent has no action upon the object
when none is at first apparent, as much as possible of the liquid in which it is immersed
should be removed by blotting-paper ; or the liquid be gently driven off by evaporation ; or,
if the object be of sufficient size to ensure its not being lost, the thin glass should be removed,
and the whole, or as much as possible, of the liquid removed either by the blotting-paper
or evaporation. On then covering the object with the thin glass, and adding the re-
agent to the edge of the latter, there can be no doubt of its coming into contact with the
body ; and the result may be considered as decisive.

Where the combined effects of a reagent and heat are required to be observed, the former
may be added as usual, and the slide placed upon the tin plate mentioned at p.xvi. until the
liquid boils, or the requisite amount of heat has been applied ; the object, of course, being
covered by thin glass. The slide must then be allowed to become perfectly cold before
being placed under the microscope, otherwise the heat might melt the balsam with which
the lenses of the object-glass are cemented together. The cooling is much facilitated by
placing the slide upon a plate or surface of metal ; we generally use the foot, or a part of
the stand of the microscope, for this purpose.

The effect of a red heat is sometimes very desirable to be tested. This may be accom-
plished by exposing the object, placed upon a strip of platinum foil, a piece of thin glass or
of mica, to the flame of a spirit-lamp. The odour evolved should be noticed. If this be
ammoniacal, or resemble that of burnt horn, the body, if not crystalline, is probably of
animal nature, and certainly contains nitrogen.

If the body consist solely of inorganic matter, or of oxalates, it will not be blackened by
the heat. If it consist partly of inorganic and partly of organic origin, it will be blackened,
and the inorganic matter will be left in the form of an ash. The alteration produced in the
form of the object by the heat should also be noted.

In applying a red heat to substances upon thin glass, the whole of its moisture must first
be expelled by evaporation, otherwise the glass will certainly crack, and the experiment be
spoiled. The strip of platinum may be held by forceps ; and the thin glass or mica, upon
a curved piece of iron wire. We can add here a few only of the reagents, the action of
which it may be most desirable to obtain in determining the nature of a doubtful body.
Further particulars will be given under the heads of the various reagents, principles and
tissues, in the body of the work.

1. Solution of caustic potash (especially when heated). — The cell- walls of plants are not
greatly affected ; they retain their primitive form, only becoming somewhat swollen, whilst
animal substances are mostly dissolved; chitine, however, is unaltered. The solution also
possesses a remarkable power of separating many animal structures into their component
cells, &c. When cold, it separates all proteine compounds from fatty matters, &c. It also
removes the foreign compounds with which the cellulose of the epidermal structures of
plants is often imbued.

2. Solution of iodine (in water) dyes most animal and vegetable substances brown ; ren-
ders also carbonate of lime brown ; colours starch, certain cell-walls of vegetables, amyloid,
the amylaceous bodies of the human brain, &c., blue.

3. Sulphuric acid, when added to the external coat or cell- wall of plants (cellulose) dyed
with iodine, renders it blue or purple. In a few instances, however, where cellulose exists
in animal tissues, the same blue colour is produced ; but in these there is real animal matter
also, recognizable by its appropriate tests. When added to bile or proteine compounds
mixed with solution of sugar, it renders them red (Pettenkofer's test). If the body contain
lime (except already as sulphate), the acicular crystals of the sulphate are produced.

MEASUREMENT. xxxix

4. Muriatic acid with heat colours the proteine compounds. (See PROTEINE COM-
POUNDS.)

5. Acetic acid brings into view the nuclei of animal cells and tissues ; dissolves many
salts, &c.

6. Dilute nitric acid (20 per cent.) coagulates albumen, renders unstriped muscular fibre-
cells very distinct, &c. Strong acid by boiling removes all but the cellulose from woody
fibre.

7. Millon's test-liquid for proteine compounds. (See MILLON'S TEST.)

8. dEther dissolves fatty and resinous matters, &c.

These are perhaps the most common reagents which the experimenter will be called upon
to use. A general plan for the qualitative analysis of substances must be obtained from works
upon chemical analysis. It may be remarked, however, that the qualitative analysis of
portions of a substance too minute to be more than barely discerned by the naked eye, may
be effected by the aid of the microscope. The use of the microscope in strictly chemical
investigations also, cannot be too highly recommended ; for it will frequently throw great
light upon the distinction of chemical precipitates of closely approximative chemical pro-
perties.

D. MEASUREMENT.

A knowledge of the size of objects is of the utmost importance, and is frequently of great
assistance in the distinction of one object from another ; for many objects of totally dis-
similar nature present exactly or nearly the same appearances when examined with different
powers. The dimensions should invariably be added to the description of microscopic
bodies, and when figures are given, the number expressing the linear amplification of the
objects should be placed near them.

A striking instance of the careless manner in which conclusions are formed from micro-
scopic appearances, and of the importance of attending to the size of objects, occurred a few
years ago, and a sketch of it may serve to impress this importance upon the mind. A
diligent microscopic observer discovered a few rounded bodies, the nature of which was
unknown, in some human secretions. Another microscopic observer, apparently not
acquainted with the method of determining their nature, examined various substances used
as food, and in bread detected some of the spores of a fungus, somewhat resembling the
former in appearance, although but slightly. The conclusion was at once formed that
the two kinds of bodies were of identical nature, and the result was laid before a Society
which ought to have been learned in these matters, but no one detected the error. On sub-
sequent examination, however, it turned out that the former bodies were about twelve times
the size of the latter, and as the smaller bodies were known to be in the mature state, the size
alone would have afforded sufficient evidence of their distinct nature. It might, perhaps,
be truly stated, that nine-tenths at least of the figures of objects which are published, are
of no real use, because their size is not expressed ; hence an observer is incapable of com-
paring the appearance presented by any object before him with the figures, or of comparing
the results of his investigations with those of others.

Directions for determining the measurement of objects are given under the head
MEASUREMENT. It must always be expressed in fractions of an English inch.

In conclusion, we must remark, that the observations given in this Introduction are not
offered as by any means complete. They will, we hope, however, serve to show those who
have not kept their eye for many years upon subjects connected with microscopy, that
numerous means are at their command for determining the structure of objects, to indicate
the nature of these means, and that microscopic researches should be carried out upon some-

xl INTRODUCTION.

thing like a definite plan. They may also serve to refresh the memory of those who are
aware that such means exist, but who do not take advantage of them.

The following list of incongruous materials, forming an analysis of the second part of the
Introduction, may serve to recal to the observer the most important points to be looked for,
and the means of discovering them.

MICROSCOPIC ANALYSIS. Form: — a, outline; b, rolling over; c, side view ; d, end
view ; e, angles, goniometer.

Colour : — 1, General colour, true colour ; 2, pigment ; a, partial from pigment ; b, general
colour from pigment ; 3, iridescence, thin plates ; air-bubbles, &c., immersion in highly re-
fractive liquids, action of transmitted and reflected light ; compression ; 4, polarization, &c.

Surface : — Reflected light (Brooke's apparatus} ; projections ; cilia, margin, iodine, desicca-
tion, flne particles ; hairs, crystals, upon or beneath the surface ; tubercles, ridges, folds,
side view ; effects of altered focus ; fracture ; foramina, polariscope ; illusory lines, dif-
fraction; depressions, circular, angular; furrows; tubules; cells; oblique light, stops in
condenser.

Internal structure and contents: — Homogeneous; cell- wall, endosmosis, exosmosis, chlo-
ride of calcium ; adherence ; margin, crushing, molecular motion ; granules ; nucleus,
central, excentric ; reagents, acetic acid ; nucleolus, vacuoles.

HISTOLOGICAL ANALYSIS. — Reagents; maceration, development.

MICRO-CHEMICAL ANALYSIS. — Washing; heat j red heat, odour, ash j reagents, con-
tact with reagents ; potash, iodine, sulphuric, muriatic, nitric, acetic acids • Millon's test ;
sulphuric acid and syrup ; sulphuric acid and iodine ,• cether, fyc.

MEASUREMENT. — In fractions of an English inch (not line nor foreign measures).

BIBLIOGRAPHY. — OPTICS. Herschel, ' Optics,9 Encyc. Metropolitana; Brewster, Optics;
Biot, Manuel, fyc. ; Art. ' Optical Instruments ' in Natural Philosophy of the Society for the
Diffusion of Useful Knowledge ; Lardner, Natural Philosophy, &c. &c.

MICROSCOPES, APPARATUS, and OBSERVATION. Quekett on the Microscope, 2nd ed.,
1853 ; Brewster, Treatise on the Microscope; Ross, Art. 'Microscope ' in the Penny Cyclo-
pcedia; Dujardin, Observateur ; Mandl, Traite pratique du Microscope, Paris, 1839;
Chevalier, Traite' des Microscopes, fyc., Paris; Tulk and Henfrey, Anatomical Manipulation;
Von Mohl, Micrographia (German) ; H. Schacht, Das Microscop (German, translated by
Currie, 1853) ; Harting, Het Mikroskoop (Dutch ; extracts in Edinburgh Monthly Journal of
Medical Science, 1852) ; Carpenter, article ' Microscope ' in the Cyclopaedia of Anatomy
and Physiology ; Transactions of the Microscopical Society of London, and Quarterly
Journal of Microscopical Science (passim), &c. &c.

MICROGRAPHIC DICTIONARY.

.— Aclass in the Animal King-
dom, commonly known as Sea-nettles, on
account of their producing a sensation of
indication when touched, or Jelly-fishes, from
their gelatinous consistence.

They are transparent, floating and free,
discoid or spheroid, and vary in size from
an almost invisible speck to a yard in dia-
meter. Then* organs are arranged in a ra-
diate manner around a central point and lon-
gitudinal axis, which are occupied by the
digestive apparatus. The disposition of the
parts is generally quaternary.

The body is usually composed of a trans-
parent gelatinous substance, closely resem-
bling the vitreous humour of the eye in the
Vertebrata, and consisting of delicate and
transparent polyhedral cells of various sizes
filled with colourless liquid ; these are some-
times nucleated, at others not.

The cutaneous surface of the body is co-
vered with a very delicate epidermis (PL 40.
fig. 2). Cilia exist on various parts of the
body, especially the arms, tentacles, cirrhi,
&c. ; upon which also peculiar stinging organs
and organs of adhesion occur. In those spe-
cies which are notorious for their stinging
powers, these stinging organs are also situ-
ated in aggregations beneath the epidermis
of the body. The stinging organs usually
form oval capsules, in which a spirally coiled
filament is enclosed (PL 40. fig. 3 a, b) ;
this flies out on the slightest touch, with the
capsule to which it is attached, from the
irritated part of the skin (PL 40. fig. 3c,d).
In some Acalephse, these stinging organs are
replaced by oval capsules from which a rigid
bristle projects (PL 40. fig. 4). These do
not produce urtication, but enable the animal
to adhere to other bodies. It would be of
great interest to determine whether these
stinging organs give indications of the pre-
sence of formic acid, as they much resemble

in appearance similar organs occurring in
Hydra, in which we have met with such in-
dications. Near the surface of the body and
between the cells composing its substance,
pigment-cells frequently occur, some of
which are isolated, others aggregated into
groups. The paler and more delicate co-
lours are said to arise in some instances
from pigment uniformly dissolved in the sub-
stance of the body; it is most probable,
however, that they arise from iridescence.

A distinct muscular system is present, in
the form of long, thin, reticular muscular
fibres and bundles, almost everywhere per-
vading the contractile substance of the body.
These muscles appear to be transversely stri-
ated.

The floating and locomotion of these ani-
mals is aided by larger or smaller cavities
filled with air.

The nervous system consists of a ring with
eight ganglia surrounding the oesophagus,
with delicate filaments issuing from them,
and a single ganglion at the opposite end of
the body; and in the Medusae there are
ganglia at the bases of the tentacles.

The organs of sense consist of tubercular
or spathulate bodies situated at the margin
and end of the body, and connected with ad-
joining ganglia. These were regarded as
organs of vision ; and consist essentially of a
membranous capsule containing a clear liquid
with crystals of carbonate of lime, and some-
times a red pigment (PL 40. fig. 5). But
as many of them contain no pigment, they
have been considered as of auditory function,
and the crystalline bodies as otolithes.

The digestive cavity is lined with ciliated
epithelium and furnished with distinct walls,
which are directly continuous with the gene-
ral parenchyma of the body, so that there is
no abdominal cavity. The mouth is either
single and central, or multiple. In the former

ACALEPELE.

ACANTHODIUM.

case, it is situated in the middle of the under
side and leads into a stomach, which is fre-
quently furnished with caecal appendages.
When several oral apertures are present,
either several cesophageal canals conduct the
nutriment through the arms, in which the
oral apertures are placed, to a central sto-
mach, or each separate mouth is connected
with a distinct tubular stomach. A distinct
hepatic organ has not yet been found.

The respiratory system consists of vessel-
like canals traversing the body, filled with
water, and either terminating in the gastric
cavity or opening externally. These are lined
internally with cilia, and represent a water-
vessel system.

The blood-vessel system consists of a set of
closed vessels with very delicate walls, ac-
companying and enclosing the water-vessels,
and containing a coloured liquid with co-
loured globules, representing the blood. But
there is no regular circulation; the indivi-
dual parts of the vascular system contract
here and there irregularly, whence the blood-
corpuscles become moved very slowly and in
no definite direction. Neither are the blood-
vessels lined with cilia.

The Acalephae are propagated by the for-
mation of ova, and according to the plan of
alternation of generation. They are either
hermaphrodite or unisexual.

The reproductive organs of the two sexes
frequently so closely resemble each other in
colour, external form and arrangement, that
they might easily be mistaken for each other,
without examination of their contents. They
form either utricular or strap-shaped stripes,
placed at various parts of the body. In the
former case, the spermatic fluid and the ova
are evacuated through distinct excretory ducts;
in the latter, the spermatozoa and ova escaping
from the strap-shaped testis or ovary, pass
directly outwards, or into capacious cavities,
opening externally by wide orifices. The
ova are round, and surrounded by a single
very delicate capsule, and the germinal ve-
sicle with its simple germinal spot is visible
through the whitish, violet or yellow yolks.
The spermatozoa move rapidly in, and are
unaffected by water ; they are sometimes li-
near, at others one end is rounded, the other
prolonged into a capillary appendage (PL

The developmental metamorphosis of the
Acalephae (Medusae} is very remarkable.
When the ordinary process of segmentation
of the entire yolk is completed, the ova be-
come converted into ovate infusoria-like em-

bryos (PL 40. fig. 6), which revolve upon
their longitudinal axis by means of ciliated
epidermis, and swim about like species of
Leucophrys or Bursaria. After a time, they
become fixed at the anterior extremity to some
body; arms then shoot out from the unat-
tached extremity, between which the mouth
of the polype-like animal is developed
(PL 40. figs. 7 & 8). At this stage of de-
velopment the larvae multiply by the forma-
tion of gemmae (PL 40. fig. 9 a), and off-
sets or stolons (PL 40. fig. 9 b) ; and ulti-
mately undergo transverse division, which
takes place as follows : — the larvae grow in
length, and the body becomes constricted into
several segments, from each of which eight
bipartite processes shoot out in a whorl
(PL 40. fig. 10). The segments of the body
then separate from each other seriatim, from
before backwards, swim about with eight rays,
and at last become gradually developed into
perfect Medusae. Many of the Medusae are
phosphorescent, and render the sea luminous.

BIBLIOGRAPHY. Eschscholtz, System der
Acalephen, Berlin, 1829; Will, Horce Ter-
gestince, fyc., 1844 ; Ehrenberg, Abhandl. der
Berl. Akad. 1835; Art. Acalepha, Todd's
Cycl. Anat. andPhys. (R. Jones); Art. Ovum,
id. (A. Thomson) ; Siebold, Lehr. d. Vergl.
Anat. ; Owen, Lectures on Comparative Ana-
tomy, Huxley, Phil Trans. 1849; Leuckart,
Siebold and Kolliker's Zeitschrift fur Wiss.
Zool Bd. 3, 1851 ; Lesson, Suites a Buffon
(Zoophytes Acalephes}; Wagner, Icones Zoo-
tomicce.

ACANTHACE^.— The seeds of many
genera of this family are clothed with hairs
composed of hygroscopic cells, containing
unreliable spiral fibres or detached rings.
Among these me,Acanthodium spicatum, De-
lile, Blepliaris, and Ruellia formosa. Other
species and genera have the hygroscopic cells
destitute of internal fibre, as Ruellia litto-
ralis, PJiaylopsis glutinosa, Barleria nocti-
fiora, Lepidagathis, &c. Further particu-
lars respecting the hygroscopic cells will be
found under CELL-MEMBRANE and SPIRAL
STRUCTURES. See also ACANTHODIUM and
RUELLIA, and for a similar phaenomenon in
other families, COLLOMIA,COB^EA,SALVIA.

BIBL. Kippist, On the existence of Spiral
Cells in the seeds of Acanthacea. Linnean
Transactions, vol. xix. p. 65.

ACANTHODIUM. (Flowering Plants,
fam. Acanthacecs). — Mr. Kippist thus de-
scribes the appearances presented by the hairs
upon the seed of Acanthodium spicatum, De-
lile. The entire surface of the seed is clothed

ACAREA.

ACARUS.

with hairs of whitish colour, appressed and
closely adherent in the dry state, being ap-
parently glued together at their extremities.
When placed in water the hairs are set free
and spread out on all sides; they are then
seen to consist of clusters of from five to
twenty spiral cells firmly coherent below, but
free above and separating from the cluster
at different heights, expanding in all direc-
tions like plumes, and forming a very beau-
tiful microscopic object. The free portions
of the cells elongate so as to separate the
coils of one, two, or occasionally three in-
ternal spiral fibres, which are sometimes
branched and not unfrequently broken up
into rings ; «,t the lower part of the cells the
turns of the spiral are connected by perpen-
dicular processes so as to convert the spiral
into a reticulated structure. See SPIRAL
STRUCTURES of plants.

BIBL. Linnean Transactions, xix. 65.
ACAREA. — A family of Arachnidous ani-
mals belonging to the (3rd) Order, Acarina
(see ARACHNIDA).

ACARINA. — An order of ARACHNIDA.
ACARUS (Tyroglyphus}.—K genus of
Arachnidous animals, belonging to the order
Acarina and family Acarea.

Char. The body presents a transverse fur-
row between the 2nd and 3rd pairs of legs ;
legs nearly equal, entire, and terminated by
an acetabulum.

These animals are commonly called mites,
and every one is familiar with them as occur-
ring in cheese, sugar, and flour, &c. The
parts of the mouth, and basal joints of the
legs, &c. of the Acari can be best made out by
crushing the animals upon a slide with a thin
glass cover ; then washing away the exuding
substance with water, as directed in the
Article PREPARATION; sometimes hot so-
lution of potash is requisite, with the subse-
quent addition of acetic acid and further
washing. When subsequently dried, and
then immersed in Canada balsam, the vari-
ous parts become beautifully distinct and
may be permanently preserved.

1. Ac. domesticus (PI. 2. fig. 1), the
common Cheese-mite. Body oval, soft,
whitish, turgid and furnished with long fea-
thery hairs (6). The transverse furrow (c)
occurs at about the anterior fourth of the
body, and another is seen between the head
and the part corresponding to the thorax.
The head is susceptible of elevation and de-
pression. In its natural state it appears
conical (d], and is furnished with two large
mandibles ; these consist of a soft retractile

basal joint (e), and a second dilated, non-re-
tractile joint (/) resembling the fixed claw
of a lobster, and a moveable piece (/) work-
ing against the latter. The two last pieces
are toothed where in contact with each other.
These mandibles can be advanced separately
or together, and be separated or approxi-
mated. When in a state of repose, they form
as it were a roof above the labium. The
labium(^) is quadrilateral, elongated, notched
at the end, thin anteriorly and in the middle,
and consolidated laterally with the palpi,
which are 4 or 5-jomted (JiTi). The legs are
reddish, inserted in two separate groups, but
not very far distant as in Sar copies. The
anterior pair of legs are remarkable for their
size in the male, which is smaller and more
active than the female ; the third pair are the
shortest and smallest; the third joint or
femur is larger and longer than those next it ;
the sixth joint is long and thin ; the seventh
joint is furnished with a cordiform membra-
nous caruncle, and a single simple claw or
hook ; rostrum and legs reddish.

This species is viviparous and oviparous,
and the eggs very numerous.

These mites are very abundant upon old
cheese, the powder of which entirely consists
of them, with their eggs and excrement.

2. Ac. longior. Body oblongo-ovate.
Found upon Gruyere and Dutch cheese (PI.
2. fig. 2)f

3. Ac. bicaudatus. Abdomen furnished
with two pediform tubercles, beneath the
base of each of which is a stigma. Found
upon the feathers of an ostrich.

4. Ac. farina. Found in bad flour.
DeGeer, Mem. vii. p. 97. pi. 15. fig. 15.

5. Ac. destructor. Somewhat resembles
Ac. domesticus, but said to differ in not having
the rostrum and the reddish legs, and in
having long black hairs. It feeds upon the
contents of entomological cabinets, especially
butterflies. Schrank, Enum. Ins. Austria,
sp. 1057 ; Lyonet, Mem. Mus. xviii. p. 284.
pi. 12. fig. 10-12.

There is another Acarus which well de-
serves the name of destructor, from its de-
structive effects upon dried insects ; it differs
from the Ac. domesticus only in having a more
strongly marked furrow, in the legs being
shorter, and the two foremost pairs being
somewhat more widely separated at their
origin ; the sixth joint is particularly short.

6. Ac. lactis. Found upon preserved
cream. Fabricius, Spec. Ins., ii. 490.

7. Ac. Dy sentence. Nyander, Am&nit.
Acad. v. p. 97 ; Linn. Gmel. p. 2929. Found

B2

ACARUS.

ACEPHALOCYSTS.

in the dejections of dysentery; also in old
casks.

8. Ac. passerinus. Found upon young
birds. DeGeer, vol. vii. 139. Ac. ckelopus,
Herm. Mem. Apterol. p. 82. pi. 3. fig. 7.

9. Ac. passularum. With two very long
buccal bristles ; it lives upon dried figs, and
other saccharine fruits. Bering, Nova Acta
Nat. Curios, xviii. p. 618. pi. 45. f. 14-15.

10. Acarus plumiger, Koch, Deutschl.
Crust., &c. fasc. 5. pi. 15, is said to have
feathery hairs ; but this is probably the case
in all the Acari, and certainly in many of
them (PI. 2. fig. 1 b). Probably in Ac. plu-
miger this supposed peculiarity is distinguish-
able with a low power, under which these ani-
mals have been usually examined.

Some other species have been formed into
new genera, which may find place here.

a. Glyciphaous (Hering). Body soft, not
divided into two parts by a transverse line or
furrow ', legs entire, with acetabula.

11. A. (Gl.) prunorum. Found on dried
plums. Hering, Nova Acta Nat. Curios, xviii.
p. 619. pi. 45. f. 16-17.

12. A. (Gl.) hippopodos. Body as broad
as long, very acute anteriorly, entirely co-
vered with short hairs ; a minute projection
at the end of the abdomen. Found upon the
crusts of ulcers on horses' feet. Hering,
Nov. Act. Nat. Curios, xviii. 607. An unde-
scribed Acarus has also been mentioned as
occurring upon the feet of sheep affected
with the canker. Grognier, Zool. veter.y.233.

13. A. (Gl.) cursor. Found in the feathers
of the owl and in the cavities of the bones
of skeletons. The hairs are jointed. Gervais,
Ann. Sc. Nat. 2 ser. xv. p. 18. pi. 2. f. 5 a.

14. A. (Gl.) (Sarcoptes)palumbinus. On
the pigeon. Koch, 1. c. fasc. 5. pi. 12.

Some other species have been insufficiently
examined.

15. Ac. avicularum, DeGeer, Mem. vii.
106. pi. 6. fig. 9. Louse of the grouse.
Lyonet, Mem. Mus. xviii. 281. pi. 15. f. J6.

16. Ac. marilce, Gervais, Diet. Sc. Nat.
Suppl. i. 45.

17- Ac.favorum. Found in old honey-
combs. Herm. Mem. Apterol. p. 86.

18. Ac. fungi, Herm. I. c.

b. Myobia (Heyden). Body elongate,
many-lobed; legs entire, the posterior ones
largest. The type of this genus is

19. A. pediculus musculinus, Schranck,
p. 501. pi. 1. f. 5. Sarcoptes musculinus,
Koch, Deutsch. Crust, fyc. fasc. 5. pi. 13.

c. Hypopus. See HYPOPUS.

BIBL. Duges, Ann. d. Sc. Nat. 2 ser. ii.

p. 40; Koch, Deutschl. Crust. ; Walekenaer,
Apteres, 3.

ACAULON, C.Miiller.— A genus of Phas-
caceae (Acrocarpous Mosses), including cer-
tain species of Phascum of Schreber, &c.

1. A. muticum, C. Mull.=Phascum mu-
ticum, Schreb.

2. A. triquetrum, C. Mull.=P^. trique-
trum, Spruce.

ACEPHALOCYSTS.— A term used to
denote certain simple sacs filled with a trans-
parent liquid, found in the bodies of animals,
and usually known as Hydatids by patholo-
gists. They were formerly regarded as para-
sitic animals, or entozoa, but recent observa-
tions have tended to show that they consist of
the cysts of Echinococci, from which the ani-
mals have disappeared by death and dissolu-
tion, or in which the entozoa have not been
formed, or in which they have been overlooked.
The cysts in which many hydatids are deve-
loped, contain at first only an amorphous sub-
stance or a liquid. At a later period their real
nature is determined by the presence of the
included entozoa. But it appears that in
some of them the entozoa are never formed.
The sacs or vesicles are described as oval or
somewhat spherical; developing smaller
cysts between the laminae of the parent,
which are discharged from its inner or outer
surface. They vary in size from a pin's to
a child's head. The walls of the sacs vary
in thickness and transparence. They pre-
sent no appearance of either head or body.
In the larger cysts the walls are distinctly
laminated. They exhibit no fibrous struc-
ture, but appear composed of a homogeneous
substance closely resembling albumen in
properties. Regarding these bodies as ani-
mals, two species have been distinguished : —

A . endogena (socialisvel prolifera], the pill-
box hydatid of Hunter. This is met with
in the liver, kidney, ovary, testis, and cavity
of the abdomen. When developed in the
substance of an organ, it is always enveloped
by areolar tissue. The secondary cysts are
detached from the inner surface of the pa-
rent.

A. exogena : in this, the progeny is deve-
loped from the outer surface. It is said to
be found in the ox and other domestic
animals.

The cysts found attached to the choroid
plexus of the human brain, have been denied
to be hydatids by pathologists, and con-
sidered merely to arise from accidental dis-
tension of the coats of the veins. Dr. Bel-
lingham however has found that they develop

ACETIC ACID.

J

ACHLYA.

granules which are detached from the inner
surface of the parent cyst. In the examination
of cysts supposed to be hydatids, careful
search should be made for the hooks ofEchi-
nococcus, which can frequently be found
when no further remains of the body are di-
stinguishable. These hooks are figured in
PI. 16. fig. 1 b. See ENTOZOA and ECHI-

NOCOCCUS.

ACETIC ACID. This is the well-known
acid of vinegar.

It occurs in the juice of the flesh of ani-
mals ; sometimes in the stomach in indiges-
tion ; also in the human blood after the use of
alcoholic liquids, and in that of animals whose
food has been soaked in spirit. It is also a
common product of the decomposition of
vegetable substances, both by fermentation
and in distillation, as well as a component of
the natural plants, mostly combined with
lime or potash ; it is also a rare constituent
of some mineral waters.

The only salts of this acid requiring men-
tion, are the acetate of copper (neutral),
which is made by dissolving common verdi-
gris in excess of dilute acetic acid, filtering and
crystallizing upon the slides. The crystals,
when mounted in Canada balsam, exhibit
well the phenomena of dichroism. PI. 31.
fig. 2.

Acetic acid is one of the most common
and valuable micro-chemical reagents. It
is particularly useful on account of its action
upon animal cells in general, rendering the
cell-walls transparent and the nuclei more
distinct. The ordinary strong acid (sp. gr.
1048) should be used.

ACHETA.—A genus of Orthopterous in-
sects, one species of which, A.domestica, the
house-cricket, is familiar to everyone. The
general structure of this insect agrees so
closely with that of Blatta orientdlis, the
common cockroach or black beetle, which is
described at some length, that it requires no
special notice here. (See BLATTA.) Some
parts of the internal structure of the cricket
are very beautiful, as the tongue (PI. 26.
fig. 23) and the gizzard (PI. 27. fig.l). These,
as also the curious mechanism by which the
chirping noise of the male is produced, are
described under INSECTS.

ACHLYA, Nees (Saprolegnia, Kiitzing).
— A genus of Siphoneee (Confervoideae). Re-
markable microscopic plants, here referred
to the Algae, but by some accounted as Fungi.
They are found growing parasitically upon
the bodies of dead flies lying in water, also
upon fish, frogs, &c., and in some cases upon

decaying plants. To the naked eye they ap-
pear like colourless minutely filamentous
tufts adherent to such objects, forming a kind
of gelatinous cloud more or less enveloping
them. When placed beneath the microscope
the tufts are seen to consist of long, colour-
less, tubular filaments, spreading out in all
directions, with or without lateral branches ;
these erect filaments arise from a kind of my-
celium of ramified filaments lying upon the
object upon which the plant grows. The
erect filaments are devoid of septa, narrowed
upwards, and vary in thickness, being usually
of smallest diameter in those cases where
they are closely crowded ; the ordinary thick-
ness varies from 1-1000 to 1-350 of an inch.
The tubes contain a colourless, slightly gra-
nular protoplasm, which is denser on the
walls, and these sometimes exhibit an irre-
gular spiral arrangement of the granules;
the granules are seen to move slowly in ana-
stomosing currents running in various direc-
tions, exhibiting, that is, the well-known
phenomenon of the circulation of cell-con-
tents, such as is met with in the hairs of Tra-
descantia, &c. The walls of the tubes are
coloured blue by iodine and sulphuric acid,
therefore consist of cellulose ; the contents
are nitrogenous, taking a bright yellowish
brown with iodine ; no trace of starch or of
chlorophyll can be detected in the cell-con-
tents in this stage, whence these plants are
regarded by some authors as Fungi ; but, as
mentioned hereafter, Pringsheim states that
their ripe spores do contain starch.

Kiitzing describes a number of species of
this genus, under the name of Saprolegnia,
while a recent observer, Pringsheim, regards
them all as forms produced by varying ex-
ternal conditions. The latest writer on this
subject, A. de Bary, separates Achlya proli-
fera, Nees, from Saprolegnia ferax, Kiitzing,
referring to the former the Saprolegnia fe-
rax of Carus and the Saprolegnia capituli-
fera of Alex. Braun, to the latter the Achlya
prolifera of Carus, and, doubtfully, the "S.
molluscorum of Nees and Gruithuisen. The
distinction between these lies in the details
of the formation and emission of the active
gonidia or zoospores. The following is a
description of the phenomena as presented
by two of the forms :

1. Achlya prolifera, Nees (Saprolegnia
capitulifera, Al. Braun). — In about thirty-six
hours after the appearance of a specimen on
any body, the apices of the erect filaments
exhibit remarkable changes. The granular
protoplasm, which at first was equally dif-

ACHLYA.

ACHLYA.

fused throughout the tube, only densest
where it lies on the wall, increases in quan-
tity and "travels up" into the end of the
tube, becoming accumulated there, giving
it a brownish colour and at the same time
causing its distension, so that the upper part
of the tube acquires a clavate form, rounded
off above. At this time the dense mass of
contents thins off gradually below into the
protoplasm of the lower part of the tube,
but a sharp line of demarcation is soon
formed, by the division of the primordial
utricle, followed by the production of a sep-
tum, which shuts off this clavate joint as the
sporange. Simultaneously with the for-
mation of the septum, a little projecting
pouch or beak is developed at the summit,
or sometimes a little below this, on one side;
and the contents, becoming still more con-
densed, again apply themselves as a thick in-
vestment on the wall, leaving a lighter space
in the middle of the cavity. Inequalities, or
nodular protuberances, are soon observable
in this layer, and it speedily becomes broken
up into numerous little isolated portions, the
individualization of these commencing at the
summit of the sporange and becoming com-
pleted gradually from above downwards. The
end-cell is now a clavate sporange filled with
numerous polyhedral or globular new " pri-
mordial cells," in the development of which
from the contents of the general mother-cell
no trace of nuclei or " special-mother-cells "
can be detected; their size is about 1-2700
of an inch. These primordial cells, the
mother-cells of the gonidia, have clearly-
defined outlines, but are still connected to-
gether by a gelatinous substance, in which
they are completely imbedded, and which
seems to have been secreted by themselves,
as the entire protoplasm of the sporangial
parent-cell has been previously converted
into daughter-cells. These daughter-cells
then become retracted from the walls, and
accumulate in a dense, rather confused-look-
ing mass in the centre of the sporange ; en-
dosmose of water through the now bare cel-
lulose wall of the sporange seems to exert
a pressure upon them, and also on the wall
itself, which finally bursts at the process or
beak mentioned above, and the daughter-
cells nearest the opening are shot out with
some force, the rest following, but gradually
more quietly. There is no independent
motion of the contents, or jerking of the
daughter-cells, before this emission of the
latter; on the contrary, while in the spo-
range, they adhere so closely that their shape

is scarcely distinguishable, and it is only
when the greater portion have escaped, that
it is perceived that the pressure had caused
them to assume a spindle-shape. As the
emission of the daughter-cells goes on, those
escaping first are only removed so far as to
make room for their successors, and the
whole remain adherent together as a glo-
bular mass or " capitule" seated on the apex
of the sporange; they re-assume, more or
less completely, the spherical form, by de-
grees, after they have escaped from the spo-
range; those which can expand freely be-
come globular, those pressed upon by their
fellows become polyhedral. At the time
of emission, these daughter-cells exhibit a
double line at the circumference, which
seems to indicate the thickness of the 'pri-
mordial utricle/ Soon after the expulsion
another delicate line is detected external to
these, and this indicates a newly produced
envelope, which becomes thicker with age,
and after a certain time can be coloured blue
by sulphuric acid and iodine, which demon-
strates its composition of cellulose. Appli-
cation of a strong acid is necessary for this
purpose.

The globular head of daughter-cells re-
mains for two or three hours attached upon
the summit of the empty, colourless spo-
range. Then these minute cells emit their
contents by a lateral orifice, giving birth,
each of them, to a zoospore or active goni-
dium. Neither the motion nor the appear-
ance of the cilia follows the expulsion imme-
diately, but takes place after the gonidia have
increased somewhat in size and acquired an
ovate form. The duration of the motion
lasts from a few seconds to a few minutes,
after which the spore sinks to rest and begins
to germinate. The gonidia possess no cellu-
lose membrane while in motion, but acquire
one when they come to rest and germinate.
The cilia are two in number, and arise from
the point which first emerged from the pa-
rent vesicle, and which at all periods exhi-
bited a lighter tint, indicating a vacuole in
the protoplasmic mass. If the expulsion of
the gonidia is prevented, as occurs some-
times when the plant is kept under the
pressure of a glass slide, in too little water,
in microscopic investigation of it, the go-
nidia germinate within their cell-membranes,
which, instead of discharging active zoo-
spores, emit germinating prolongations, just
like those issuing from the single germina-
ting gonidia. These spread out here in all
directions from the globular capitulum, still

ACHLYA.

ACHNANTHES.

seated on the end of the sporange. During
the formation of these sporanges and the go-
nidia, after the septum has been completed,
the tube sends out lateral branches from just
below it, which sometimes equal the spo-
range in length by the time the latter dis-
charges its contents ; then this branch be-
comes developed as a sporange, either at its
summit or in its whole length, or, when the
branch is very short, the portion of the main
tube below the first septum becomes a spo-
range. Sporanges of a third rank may suc-
ceed to those of the second rank, and so on,
until the plant has exhausted the supply of
food at its service.

Achlya prolifera also produces, though
more rarely, globular or spindle-shaped spo-
ranges, borne on special, short, lateral branch-
es, in which are developed resting spores,
characterized by a larger size, double cell-
membrane, and by the absence of the cilia
and consequent motion. The mode of their
development is similar to that of the active
gonidia, but they are much fewer in number,
sometimes as many as twenty, sometimes
only four, three, two, or even one being pre-
sent in a sporange. When a number occur
in a spindle-shaped sporange, they are ranged
in two rows, alternately, so that each is par-
tially interposed between its two opposite
neighbours. Their diameter varies from
1 - 1250 to 1 -750 of an inch, the colour brown-
ish, displaying numerous oil-drops in the
granular contents when mature. The spo-
ranges producing them display a number of
round orifices when the spores are ripe, but
the spores appear to escape by the decay of
the walls. These resting spores may remain
unchanged in water for a long time when no
suitable nidus exists, and then will quickly
germinate if a dead insect or similar object
is thrown in.

2. Achlya prolifera of Pringsheim, Unger,
Carus and others (Saprolegnia ferax, Kiitz-
ing), differs from the true A. prolifera in two
important points : — 1. The sporanges do not
produce the capitules, by the accumulation of
the daughter-cells giving birth to the active
gonidia at their summits, but the active go-
nidia are produced directly from the contents
of the sporange, and begin to move even
before they escape from this. 2. The later
sporanges are not formed by lateral branches,
but the septum forming the bottom of the
first sporange grows up into the empty
cavity of this and swells into a new spo-
range within the old one, which remains as a
second, outer coat. In other respects there

is no difference in the general mode of deve-
lopment. S. ferax is ordinarily of smaller
diameter ; it produces globular cases of rest-
ing-spores in a similar manner; and these
occur mostly after the gonidial sporanges,
generally at the ends, but occasionally in the
middle of the tubes. The resting-spores are
from 1 to 40 here, while the active gonidia
are from 5 to 150, the number depending in
each case on the size of the sporange, not
upon the size of the spores or gonidia, which
is tolerably regular. Pringsheim states that
starch occurs in the contents of the resting-
spores of S. ferax.

BIBL. A description of the supposed spe-
cies will be found in Kiitzing's Species Alga-
rum, p. 159. For further information on the
development, see Al. Braun's Rejuvenescence
in Nature, translated for Ray Society, 1853,
pp. 188,268; Pringsheim, Nova Acta, xxiii.
pt. 1. p. 397-460, 1851; Anton, de Bary, Bo-
tanische Zeituno, x. p. 473, 1 852. Also Un-
ger, in the Linncea for 1843, p. 129 (trans-
lated in Ann. des Sc. nat. 3me ser. tome ii. p. 5.
pi. 1. 1844); M.eyen,Pflanzenphysiologie,m.
457 ; Nageli, Zeitschrift fur fViss. Botanik,
heft 1. p. 102, heft 3,4. p. 28 (Ray Society's
Reports, 1845, p. 278, 1849; p. 101); Thu-
ret, Ann. des Sc. nat. 3me ser. t. xiv. p. 20.
p. xxii. 1851; Ch. Robin, Hist oire des Vege-
taux Parasites, 2nd edit. 1853, p. 372. A list
of all the writers who had treated of Achlya
before 1843, is subjoined to Unger's Essay
in the Linncea.

ACHNANTHES, Bory.— A genus of Dia-
tomaceae.

Char. Frustules either single, in pairs, or
united into a straight filament, frustules
curved in front view, without septa; a punc-
tum (orifice) at the middle of the lower mar-
gin of the undermost valves.

The individual frustule, when single, or
the lowermost when they are united, is in
some species furnished with a stipes or stalk,
arising from one end of the lower margin,
in others this is absent ; and the latter have
been separated from the former to make a
distinct genus, Achnanthidium, principally by
this character. Side view of frustules ellip-
tical, oblong or linear, sometimes slightly
constricted in the middle ; markings of upper
and lower valves different, the upper (PI. 12.
fig. 2) exhibiting transverse rows of dots
(appearing like striae under a low power) in-
terrupted by a longitudinal line, the lower
(PL 12. fig. 3) being also furnished with
transverse rows of dots, interrupted by a stau-
ros, as also by a longitudinal line which in

ACHNANTHIDIUM. [

some has a nodule at each end. The valves
being much compressed, the transverse rows
of dots appear also in the front view. The
hoops exhibit faint longitudinal and some-
times transverse striae.

Achnanthes resembles Striatella in its
stalked flag-like filaments, but may be known
from it by the absence of internal siliceous
plates.

Mr. Ralfs distinguishes five species thus :

fFluviatile, striae (wanting? or) indi-

J stinct 2

*'] Marine or submarine; lateral striae

L evident 3

rStipes much longer than the frustule;

J lateral surfaces subacute exilis*.

] Stipes not longer than the frustule ;

L lateral surfaces obtuse minutissima.

f Stipes longer than the frustule longipes^.

\ Stipes shorter than the frustule 4

f Lateral view lanceolate, with acute
4.4 ends brevipes.

[ Lateral view elliptic, with obtuse ends subsessilis.

* PL 12. f. 4. t K. 12. f. 1.

Kiitzing enumerates 14 species of Ach-
nanthes, and 4 of Achnanthidium', Achn.
microcephalum, pi. 12. f. 5, Achn. delicatu-
lum, pi. 12. f. 6, Achn. Jlexellum (Cocconeis
Thwaitesii, Smith), and Achn. lanceolatum.

ACHNANTHIDIUM. See ACHNAN-
THES.

ACHORION, Link and Remak.— The
generic name applied to one of the vegetables
occurring in Favus, and characteristic of
that disease of the skin (also called Porrigo
or Tinea favosa) . The structure of the plant,
Achorion SchoBnleinii, bears much resem-
blance to that of the genus Torula, but it
occurs in definitely bounded patches having
a special arrangement of the microscopic ele-
ments of which it is constituted. The fol-
lowing is the botanical character given by
Link and Remak.

Achorion. Orbicular, yellow, coriaceous,
immersed in the human skin, especially of
the head.

Mycelium soft, pellucid, floccose, filaments
very slender, not jointed, very much branched,
mostly fixed in a granular stroma. Recep-
tacle formed of thicker filaments composed
of elongated cells, somewhat branched, di-
stinctly articulated, joints unequal, irregular,
terminating in a sporidium. Sporidia round,
oval or irregular, germinating at one or seve-
ral points. Allied to Oidium.

Achorion Schcenleinii, Remak. Character
the same as the genus.

Ch. Robin gives a very full history of this
plant, but it will suffice to abstract the prin-
cipal points touching on the microscopic

] ACHORION.

structure, previously to presenting some re-
marks tending to alter the opinion commonly
entertained as to the nature of the so-called
Achorion. The plant is found upon the
human skin, either in the hair-follicles or in
depressions of the surface. With regard
to the former situation, it appears to be a
secondary seat, as it were, since only the
" spores" or moniliform filaments composed
of rows of "spores" occur therein, adhering
firmly to the hair and forming a kind of
sheath around it. When it occurs upon the
ordinary surface of the skin, it forms a little
mass, like a little cup, the favus, which is at
first developed beneath the epidermis, and
laid bare afterwards by desquamation. The
favus is somewhat hemispherical in general
form, and varies from 1-25 to 3-5ths of an
inch in diameter, its depth or thickness being
from 1 -25th to l-6th or l-5th of an inch. The
upper, free side is concave, the lower convex,
the colour is pale sulphur yellow, sometimes
a little browned by the presence of foreign
bodies. The cup-like depression existing at
first becomes filled up with advancing growth,
and when the /aw have acquired a consider-
able size, concentric lines are perceived upon
the upper surface. The circumference of the
free upper surface adheres to the epidermis,
and the mass is generally traversed by one
or two hairs, passing completely through it
from below. When a vertical section is made
of a favus dissected out of its seat, it is found
to be composed of the following elements.
The periphery consists of a granular crust,
about 1-150 of an inch in diameter, the
stroma, apparently a hardened exudation
from the surrounding parts ; this is lined by
the mycelium passing in from it, composed
of flexuose, branched, inarticulate filaments,
uniform in thickness (at most 1-8000 of an
inch). Next the mycelium, proceeding in-
wards, come the receptacles or 'sporophores,'
consisting of tubes analogous to those of the
mycelium, less flexuose, the fertile being
more or less straight, terminating in strings
of spores. These receptacles are from 1-500
to 1-125 of an inch long, and from 1-25000 to
1-5000 of an inch in diameter. The spores
are round or oval, the smallest 1-8000 to
1-6000 inch, the largest 1-5000 to 1-4000
inch in diameter, the oval are as much as
1-3500 to 1-2500 in length; the spherical
sometimes 1-3500 in diameter. Their mem-
brane is well-defined, water and acetic acid
do not affect them. Their contents are
strongly refractive and homogeneous, ex-
cepting from the presence of a veiy fine

ACHORION.

ACINETA.

powder of molecular granules in the centre,
which exhibit the ' molecular ' movement
very actively when the spores are in water
under the microscope. Spores of irregular
forms are also met with.

Much has been written by medical authors
regarding these bodies, but we shall not
enter into this part of the subject here,
further than to state that the presence of
this vegetable structure seems to be essen-
tial and causative in the disease of the skin
to which we have alluded. Remak wras un-
able to make any of the spores germinate in
or on animal substances; some however
emitted prolongations when placed upon an
apple, but the surface then decayed and
turned brown within the week, and became
covered with mildew (Penicillium glaucum).
One of the entire corpuscles kept upon the
arm for several days, fell off without leaving
any mark, but a fortnight after afavus began
to be developed. Gruby states that he inocu-
lated various parts of the body with it, and
even caused it to grow upon wood (?). Ben-
nett ultimately confirmed the statements of
Gruby as to the inoculation. Other authors
are mentioned at the end of this article.

Looking at the structural characters of
this body, and remembering the fact of the
occurrence of a true Puccinia in Favus (Puc-
cinia Favi, Ardsten), it seems very probable
that we have not to do with a distinct generic
or specific form in Achorion, but that these
bodies which we have described under this
name are neither more nor less than the fore-
runners of the Puccinia, the spermagonia of
that plant, such as occur in the Puccinai, Cceo-
macei and allied tribes of plants. Should
this surmise be correct, the so-called recep-
tacle of Achorion would represent the sterig-
mata, while the " spores" would be the sper-
matia, and therefore probably not reproduc-
tive bodies. The fact of inoculation does not
militate against this view, as fragments of the
mycelium would suffice ; while the abortive
germination described by Remak as occurring
so strangely only upon a vegetable structure,
is open to doubt. The characters of the
spermagonia of the Puccinai will be found
under the head of PUCCINIUM, where also
the other fungus of Favus is described. JEci-
dium presents analogous organizations as
forerunners of the true spore-fruits.

BIBL. Ch. Robin, Vegetaux parasites,
Paris, 1853 (with plates, 2nd edit.) ; Bennett,
On the Vegetable nature of Tinea favosa
(Porrigo lupinosa of Bateman),4*c. ; Monthly
Journal of Medical Sciences, 1850 (with

figures) ; and Trans. Royal Society of Edin-
burgh, 1842, xv. pp. 227-294 ; Gruby, Me-
moire sur la Teigne, fyc., Comptes Rendus,
1841, xiii. p. 72; Sur les Mycodermes, fyc.,
ibid., 309; Ueber Tinea favosa, Miiller's
Archiv, 1842, p. 22; Hannover, Muller's
Archiv, 1842, p. 281-95. pi. 15. figs. 7-9 ;
Miiller and Retzius, Muller's Archiv, 1842,
p. 192, pi. 8 and 9; Lebert, Physiologie Pa-
thologique, t. ii. p. 477, Paris, 1845 ; Remak,
Diagnostische und Pathogenische Unters.
Berlin, 1845, p. 193-215; Bazin, Rech. sur
les Teignes, Paris, 1853, 8vo (plates).

ACINERIA, Duj.— A genus of Infusoria,
of the family Trichodinia.

Char. Body oblong or lanceolate, de-
pressed, the fore-part somewhat obliquely
recurved like the blade of a sabre ; a row of
cilia, directed forwards, arising from one
side.

Differs from Trachelius, Duj., in the ar-
rangement of the cilia and in the anterior
curvature ; devoid of a mouth, like Trache-
lius, which especially distinguishes the pre-
sent genus from Pelecida. 2 species :

1. A. curvata (P1.23.fig.l); marine, colour-
less; length 1-577 inch.

2. A. acuta (PI. 23. fig. 2), found in fresh
water; length 1-576 inch.

Dujardin remarks that the latter species
appears to have cilia only on the convex mar-
gin, whilst he figures cilia upon both margins,
those on one side being directed forwards,
and those on the other backwards !

These species probably belong to the ge-
nus Trichoda of Ehrenberg.

ACINETA, Ehr.— A genus of Infusoria,
belonging to the family Acinetina of Ehren-
berg.

Char. — Body stalked; carapace simple,
membranous; tentacles radiant, numerous,
not vibrating. 4 species : —

1. A. Lyngbyei, marine ; body spherical,
very pale yellow, stalk thick; length, in-
cluding stalk, 1-100 to 1-170 in.

2. A. tuberosa (PI. 23. fig. 4), in salt or
brackish water; body colourless or yellow-
ish-brown, triangular when expanded, 1-100
to 1-410.

3. A. mystacina, fresh water; body yel-
lowish-brown, rounded, tentacles in two
bundles, 1-120 to 1-860.

4. A. ferrum-equinum, fresh water; body
ovate, colourless, nucleus horseshoe-shaped,
1-240.

Dujardin places this genus in his family
Actinophryina, with the following characters :
— Body globular or compressed, immoveable,

ACINETINA.

ACROSTICHE^E.

emitting variable, very slowly contractile ex-
pansions, which are frequently dilated at the
ends, supported upon a simple pedicle, the
membranous envelope of which is more or
less prolonged over the body.

The researches of MM. Pineau and Stein
tend to render the existence of the species of
Acineta doubtful, by showing that similar
organisms form intermediate stages of deve-
lopment of Vorticella, Vaginicola and Epi-
stylis. The organisms described by Mr.
Brightwell and Mr. Alder are probably re-
ferable to the same category.

Compare also DENDROSOMA and ACTI-
NOPHRYS.

BIBL. Pineau, Ann. d. Sc. nat. 3 ser.
Zool. iii. and ix.; Stein, Archiv f. Naturg.
1849; Alder, Ann. Nat. Hist.vii.', Brightwell,
Fauna In/us. Norfolk ; and Pritchard, Inf.
Anim.; Ehr. Infus.-, Duj. Infus.

ACINETINA, Ehr.— A family of Infuso-
ria, including the genera Acineta, Actino-
phrys, Trichodiscus, Podophrya, and Den-
drosoma of the same author. It corresponds
to the family Actinophryina, Duj., which see.

ACMOSPORIUM, Corda.— A genus of
Mucorini (Physomycetous Fungi). No Bri-
tish species yet recorded.

ACOMIA, Duj. — A genus of Infusoria,
of the family Enchelia.

Char. Body oblong-ovate or irregular, co-
lourless or granular, turbid, composed of a
glutinous homogeneous substance containing
irregular granules, and ciliated only or prin-
cipally at one end. 7 species : —

1. A. cyclidium, marine, length 1-650.

2. A. ovata, aquatic (fresh water), length
1-1250.

3. A. vitrea (PI. 23. fig. 3), aquatic, 1-868.

4. A. ovulum, aquatic, 1-300.

5. A. vorticella, aquatic, 1-1000.

6. A. costata, marine, 1-500 to 1-650.

7. A. varians, aquatic, 1-450 to 1-1000.
ACREMONIUM, Link.— A genus of Mu-

cedines (Hyphomycetous Fungi), filamen-
tous Fungi. The plants consist of micro-

Fig. 1.

^

Acremonium fuscum (highly magnified).

scopic septate filaments, bearing very slender
lateral branchlets, each terminating in a ve-
sicular spore. British species : —

1. A. verticillatum, Link, On dead wood,
trunks of trees.

2. A. alternatum, Link. On decaying
leaves.

3. A. fuscum, Schmidt (fig. 1). On dead
wood and sticks.

BIBL. English Flora, v. pt. 2. p. 347;
Greville, Scott. Cryptogam. Flora, t. 124.
figs. 1 and 2.

ACROCARPI.— An artificial division of
Mosses (see MOSSES).

ACROPERUS.— A genus of Entomo-
straca, of the family Lynceidae (Baird).

Char. Shell somewhat harp-shaped, the
anterior inferior margin projecting and ob-
tusely angular, inferior antennae long ; beak
blunt, very slightly curved downwards ; shell
striated with longitudinal ribs directed ob-
liquely downwards and forwards ; colourless.
2 species : —

1. A. harpee (PI. 14. fig. 1) ; each branch
of inferior antennae with 3 long setae from
the extremity of the last joint only.

2. A. nanus (PI. 14. fig. 2), much smaller
than the last; anterior branch of inferior
antennae with 4 setae, 1 arising from the
second, and 3 from the end of the last joint.

BIBL. Baird, Ann. Nat. Hist. xi. 91 ; and
Nat. Hist. Brit. Entomos. 129.

This genus is scarcely distinct from Camp-
to cercus.

ACROSPERMUM, Tode.— A genus of
Sphaeronemei (Coniomycetous Fungi), con-
sisting of minute, somewhat cartilaginous,
epiphytic bodies, a few lines high, discharging
stick-shaped, simple, microscopic spores from
a terminal pore or ostiole. British species : —

1 . A. compressum, Tode. On dry stalks of
herbaceous plants.

2. A.cornutum, Fries. On the gills of black-
ened Agarics (not uncommon).

BIBL. English Flora, v. pt. 2. p. 221 ;
Grev. Sc. Crypt. Flora, t. 182.

ACROSPORIUM, Nees. — A generic
name, formerly applied to certain species of
Oidium (see OIDIUM).

ACROSTICHE^.— A sub-tribe of Poly-
podaeous Ferns, with naked sori, containing
the following genera : —

i. ACROSTICHUM. Sori seated on all the
veins, venules and parenchyma ; veins very
much branched, and anastomosing in more
or less regular meshes.

ii. CAMPIUM. Sori on all the veins, ve-
nules and the parenchyma ; veins very much

ACROSTALAGMUS.

ACTINOCOCCUS.

branched, and anastomosing in more or less
regular meshes, with free venules,

iii. POLYBOTRYA. Sori on all the veins,
venules and the parenchyma ; veins pinnate,
scarcely anastomosing.

ACROSTALAGMUS,
Corda. — A genus of Mu-
corini (Physomycetous
Fungi), of great beauty.
No British species as yet
recorded (?). The accom-
panyingfigurerepresents
a continental species, A.
parasitans (fig. 2), occur-
ring upon jCephalospo-
rium Acremonium. The
globular heads at the ex-
tremities of the branches
are vesicles or peridia,
like those ofAspergillus.
The end of the branch
projects into the interior

and produces Spores Acrostalagmus parasitans

which become detached (highly magnified).
in the peridium ; this finally vanishes, and
the very minute spores are set free. A. cin-
nabarinus grows in large patches on rotten
potatoes : spores 1-5000".

ACROSTICHUM, L.— A genus of Acro-
sticheae (Polypodaeous Ferns), with naked
sori seated on all parts of the leaf. See
HAIRS.

ACTINIA.— A genus of Polypes (Zoo-
phytes).

Char. Body conical or cylindrical, ad-
hering by a broad discoidal base ; mouth
simple, superior, surrounded by one or more
uninterrupted series of conical, undivided,
tubular tentacula, which are entirely retrac-
tile; marine.

Dr. Johnston describes 20 British species.
They are commonly known as sea-anemones,
and are found on the sea-coast adhering to
rocks and stones. A. mesembryantJiemum
(1-H in. diam., with numerous azure-blue
tubercles surrounding the margin of its oral
disc) is very common on the British coast.

The body is formed of a thick coat, the
inner layer of which consists of longitudinal
and transverse muscular fibres. The tenta-
cles are hollow. The space between the sto-
mach and the skin is divided into cellular
spaces by perpendicular partitions ; the ova-
ries are situated in these spaces, and the
spermatic convoluted tubes lie beneath the
partitions.

The fibro-areolar tissue, of which the
parenchyma of the body consists, is com-

posed of numerous fibres, cells, and interme-
diate stages, of extreme delicacy (PL 33.
fig. 1), and somewhat resembling the fibro-
plastic tissue met with abnormally in the
human body. Dispersed throughout it are
numerous spindle-shaped, flexible, organic
spicula (PL 33. figs. 1 a and 2), many of
them curiously marked by interrupted trans-
verse markings (fig. 2).

In reproductive power they almost equal
the Hydrse ; when cut across, new tentacles
form in a few weeks on the lower half, and
each piece becomes a new animal. They are
usually propagated by ova, which pass from
the ovaries into the stomach, where they are
developed. The young have fewer tentacles
than the adults. Many of the species exhi-
bit the most splendid iridescent colours.

BIBL. Johnston, Hist, of British Zoo-
phytes, 1847.

ACTINISCUS, Ehrenberg.— A genus of
Diatomacea?, provided with siliceous shells
bearing radiating spines.

Char. Individuals microscopic, solid, ra-
diate, resembling a star ; marine.

These organisms, which are found both
recent and fossil, are ill understood at pre-
sent. They are especially remarkable for
their valves being frequently found perfo-
rated. Species : —

1. A. Tetrasterias, Ehr. Stellate, with 4
free rays ; diam. 1-1000". Virginia.

2. A. Pentasterias, Ehr. Rays 5 ; diara.
1-1200". Recent on the shore of Norway ;
fossil in the chalk-marl of Greece.

3. A. quinarius, Ehr. Stellate, rays 5,
free ; diam. 1-3000". ^Egina.

4. A. Sirius, Ehr. Rays 6, acute, winged
at the base ; diam. 1-1200". Shore of Nor-
way, recent.

5. A. Discus, Ehr. Disc-shaped, centre
smooth, 8 marginal rings not exserted ; diam.
1-2000". Oran.

6. A. Rota, Ehr. Disc-shaped, centre
smooth, 10 marginal rays exserted; diam.
1-1900". Oran.

7. A.Lancearius, Ehr. Body stellate, with
8 marginal lanceolate rays, and some central
shorter, enlarged at one side, single, deci-
duous; diam. 1-240". Antarctic Ocean.

BIBL. Ehrenberg, Leb. Kreidethierchen,
1840, p. 69; Monatsbericht, 1844,p. 76, &c.;
Kutzing,Kieselschal.Bacillarien,\S44,p.l39't
Species Alg arum, 1849, p. 141.

ACTINOCLADIUM, Ehr.— A genus of
Mucorini (Physomycetous Fungi). No
British species yet recorded.

ACTINOCOCCUS, Kiitzing.— A genus

ACTINOCYCLUS.

[ 12 ]

ACTINOPHRYS.

of exotic Algae (marine), referred to Rivu-
laria by Suhr (Kiitz. Tab. Phyc. 31. fig. 2).

ACTINOCYCLUS.— A genus of Diato-
maceae.

Char. Frustules solitary, free or adherent
to other bodies ; disk-shaped ; valves circu-
lar, exhibiting apparently cellular markings,
with rays or bands radiating from the centre,
which is free from the cellular appearance ;
no internal septa ; marine.

The cellular appearance arises from the
existence of depressions upon the surface.
The radiant bands arise from undulations of
the surface, which are best seen in the front
view (PI. 18. fig. 43 b).

Only 1 British species, A. undulatus
(PL 18. fig. 43 a); rays 6, diam. 1-250 to
1-1100".

Kiitzing enumerates 34 species ; some are
found fossil.

BIBL. Ehrenberg, Leb. Kreidethierchen,
1840, p. 57 ; Monatsbericht, 1844 ; Kiitzing,
Kieselschaligen Bacillar. 1844; Species Al-
garum, 1849.

ACTINOGONIUM, Ehr.-A genus of
Diatomacese.

Char. Prismatic, frustules not forming a
filament, sub-spherical, with 7 or more angles.

A. septenarium. With 7 angles. Found
fossil in Barbadoes earth, with Polycystina.

Not British.

BIBL. Ehr . Monatsber. d.Berl. Akad.l 847;
Ann. Nat. Hist. vol. xx. p. 127.

ACTINOPHRYINA, Duj.— A family of
Infusoria.

Char. Animals without appreciable or-
ganization; immoveable or fixed; provided
with variable, very slowly contractile, always
simple expansions, the ends of which by con-
traction frequently become globular.

This family corresponds with Ehrenberg's
Acinetina, and includes 5 genera : Podo-
phrya, Actinophrys, Acineta, Trichodiscus
and Dendrosoma.

ACTINOPHRYS.— A genus of Infusoria,
of the family Acinetina, E. ( Actinophryina, D.)

Char. Body without vibratile cilia, having
numerous setaceous tentacles radiating on all
sides (mouth abruptly truncated), E.

Dujardin says, body spherical or discoid-
al, surrounded with radiating, filiform, very
delicate and slowly contractile expansions.
Species : —

A. sol, E. and D. (PI. 23. fig. 7b). Sphe-
rical, whitish tentacles radiating from all
parts of the body, once or twice as long as
its diameter, D. (rather less than once, E.);
diam. 1-430 to 1-1200"; aquatic.

ft (?) A. Eichornii, E. Diam. 1-100" (PI. 23.
fig.7a).

y marina, D. Colourless, contractility of
tentacles greater, marine.

A. digitata,D. Colourless, body depressed,
rays flexible, thickened at the base, and when
contracted forming finger-like prolongations;
diam. 1-770; aquatic.

A. discus, D. (Trichodiscus sol, E.), PI.
25. fig. 8. Hyaline or yellowish ; body dis-
coidal, depressed, a ring of radiating taper
tentacles arising from one portion of the
body only; diam. 1-210 to 1-430"; aquatic.

A. difformis, E. and D. Colourless ; body
irregularly lobed ; rays variable, taper ;
diam. 1-280 to 1-570"; aquatic.

A. pedicellata, D. (Podophrya fixa, E.),
PI. 23. fig. 5 a. Body spherical, whitish,
exhibiting a cellular appearance, from the
presence of numerous vacuoles (?), furnished
with a peduncle ; tentacles capitate, as long
as the body is broad ; diam. 1-430" ; aquatic.

ft salsa, E. Tentacles not capitate ; ma-
rine.

A. viridis, E. and D. (PL 23. fig. 6). Body
spherical, greenish; rays numerous, taper,
shorter than the body ; diam. 1-280 to
1-620"; aquatic.

A. granata, D. Spherical, opake in the
centre ; rays taper, shorter than the body.

Different opinions are held as to the man-
ner in which these animals are nourished.
M. Stein says that no foreign particles ever
enter the body. M. Ehrenberg admits the
existence of a mouth and an anus at opposite
ends of the body. Mr. Brightwell says that an
infusorium, when entangled by the tentacles
(expansions), is absorbed into the body of
the animal by its surface, or by the thicker
expansions of the body. The most recent
writer upon Actinophrys (sol) ?, M. Kolliker,
considers the body to be composed of a ho-
mogeneous substance with granules and va-
cuoles, some of the latter, which give it a
cellular appearance near the centre, contain-
ing nucleated cells. He states that an in-
fusorium, or a minute alga, coming into
contact with one of the tentacles, generally
becomes adherent. The tentacle with the
prey then slowly shortens, and the surround-
ing tentacles apply themselves upon it, bend-
ing their points around the captive, so that
it gradually becomes enclosed on all sides. In
this way the prey is gradually brought to the
surface of the body. The spot at the surface

is lying slowly retracts, and forms at first a
shallow depression, which gradually becomes

ACTINOPTYCHUS.

ADULTERATIONS.

deeper and deeper, in which the organism is
finally lodged. As the depression becomes
still deeper, its edges coalesce, and thus a
cavity closed on all sides is formed, in which
it remains for a certain time and becomes
digested. If there be any indigestible resi-
due, a passage for its exit is formed, and it
is expelled by further contractions of the
substance of the body, and in the same or a
different direction from that at which it en-
tered, the canal and the aperture entirely
disappearing. M. Kolliker also noticed the
remarkable fact, that two perfectly distinct
individuals became gradually fused so as to
form a large single animal. The results of
this conjugation were not traced.

BIBL. Kolliker, Zeitschr. f. Wissensch.
Zoologie, Bd. i. (Qt. Journ. of Micr. Science,
vol. i.) ; Stein, Archiv. f. Naturgeschichte,
1849; Brightwell, Fauna Infusoria of Nor-
folk ; Pritchard, Inf. Animate .

ACTINOPTYCHUS, Ehr.— A genus of
Diatomaceae.

Char. Frustules solitary, free, disk-shaped,
with rays and internal radiating septa ; valves
apparently cellular (areolar), except opposite
the rays.

Kiitzing enumerates 16 species, distin-
guished principally by the number of septa
and rays: A. ternarius, septa 3; A. quater-
narius, septa 4; A. senarius, rays 6 (PI.
18. fig. 45), &c. Another species, A. hex-
apterus, has 6 thick, solid conical rays ; the
margin of the disc thick, undulate, and
toothed within. Many of the species are fos-
sil, none British.

ACTINOTHYRIUM, Kunze.— A genus
of Sphaeronemei (Coniomycetous Fungi),
forming minute, round, p- 3

flat, black spots, with a
central boss of close,
radiating, fibrous struc-
ture. British species : —

A. graminis, Kunze.
On leaves and stalks of

Grasses in Spring (fig. Actinothyriuin graminis
3). (highly magnified).

The innate, radiately fibrous, shield-like
perithecium finally dissolves at the apex.
The spores, which are spindle-shaped, are
formed beneath the disk ; their development
and mode of attachment do not seem to
have been made out.

BIBL. Greville, Scott. Crypt. Flora, t.218.

ACTINURUS.— A genus of Rotatoria, of
the family Philodinsea, Ehr.

Char. Eye-spots two, frontal (red) ; tail-
like foot with 2 lateral horny processes and

3 terminal toes. (Rotifer with 5 points to
the foot.)

Agrees with Rotifer in general structure ;
teeth 2 in each jaw (PI. 34. fig. 2).

1 species, A. Neptunius (PI. 34. fig. 1).
Colourless, body attenuated ; length 1-18 to
1-36". Very common, aquatic.

ADIANTUM, Linn. A genus of Asple-
nieae (Polypodaeous Ferns), with one elegant
indigenous, and many exotic species.

Fig. 4.

Adiantum (pinnule with sori covered by indusia) : 5 diam.

ADULTERATIONS.— A very important
use to which the microscope is applicable,
consists in the detection of various adultera-
tions of articles of food, drugs, and products
of the arts and manufactures. We have no
space here to enter into the details of this
question as regards the individual substances
liable to be adulterated, or used as adulte-
rating ingredients, but must confine our-
selves to a few general remarks. Further
particulars will be found under the special
heads of articles of food, &c., such as
COFFEE, TEA, STARCH, &c.

The first point in a question of adultera-
tion, is to determine, by microscopic and
micro-chemical analysis, the structure and
composition of the pure substance; and if
the Table given at pajge xl of the Introduc-
tion be kept in view in this proceeding, but
few points will probably be overlooked. On
then comparing these results with those ob-
tained by a similar mode of proceeding in
regard to a suspected substance, there will
in general be found little difficulty in deter-
mining'whether it be pure or not. If im-
purities or adulterating ingredients are pre-
sent, the next point will be to determine
their nature. To do this with certainty,
would require that the structure and compo-

^ECIDIUM.

JECIDIUM.

sition of every kind of substance, either
natural or artificial, should be known, which
would imply an amount of knowledge pos-
sessed by no one. But the question is sim-
plified in practice, because substances used
in adulteration must be cheap, and either
grown or manufactured in quantities at home,
or imported from abroad. Hence they are
generally common, and it is pretty well
known of what they will probably consist.
When the adulteration consists of a chemical
substance as it might be called, i. e. a salt,
metallic oxide, proximate principle, &c., its
nature is readily determined by chemical
analysis ; but when it consists of a vegetable
tissue, which has been perhaps subject to a
partly chemical process of manufacture, the
judgment must be based upon the form of
the various parts, their size, relative position,
and other particulars holding a place in the
Table already alluded to.

BIBL. Ure, Dictionary of Arts and Ma-
nufactures; Mitchell, Adulterations of Food;
Normandy, Handbook of Commercial Ana-
lysis ; Reports from the Select Committees
of the House of Commons ; various papers
in the last five volumes of the Lancet, and
the last two volumes of the Medical Times
and Gazette, (the best on record) ; Pereira,
Materia Medica; Aikin, Arts and Manu-
factures.

jECIDIUM, Persoon.— A genus of Cseo-
macei (Coniomycetous Fungi), consisting of
numerous parasitic fungi infesting leaves and
herbaceous stems, appearing in their full-
grown condition as little cups filled with a
reddish or brownish powder (spores), formed
by a raising-up and bursting of the epidermis
by the parasite developed within. Many may
be detected in earlier stages by the deformi-
ties they produce in the growing structure
of the plants infested, or by pale or reddish
spots on the green surface, arising from the
presence of the imperfect fungus underneath.
These plants are commonly known under the
name of blight, brand, &c. Their history
has recently received much elucidation at the
hands of Tulasne, De Bary and others, and
they are found to exhibit a more complicated
organization than was formerly imagined.
The organs of fructification are produced in
two kinds, bearing great resemblance to the
conditions lately ascertained to exist gene-
rally in the Lichens. A brief account of the
natural history of certain of the species, de-
rived from De Bary, will give a general idea
of the character of this genus.

The nascent JEcidia are observed as mi-

nute spots upon the herbaceous parts of the
plants which they infest. When sections are
made of these and placed under the micro-
scope, it is found that the parenchyma of the
plant is deformed, irregular, and interrupted
by large intercellular passages, among which
ramify the filaments of the mycelium of the
fungus; these are delicate, much-branched
and septate, about 1-3600 of an inch in dia-
meter. At certain points these filaments are
crowded and interwoven into hollow globular
conceptacles, about 1-180 of an inch in dia-
meter, immediately beneath the epidermis,
the interior of which conceptacle is lined
with delicate filaments (about 1-12000 of an
inch in diameter) arising at all parts and con-
verging toward the centre, except at the
upper part, (which is open, and only shut
from the external air by the persistent epi-
dermis of the ' nurse-plant,') where they are
directed upwards. A granular mass occupies
the centre of the conceptacle, separating the
converging filaments from each other. By
the growth of the upper filaments and the in-
crease of the central granular mass, the whole
structure increases in size, so as to push the
epidermis up above the surrounding surface,
finally bursting it, when the upper filaments
(paraphyses)grow out through the orifice and
form a little funnel-shaped tuft on the sum-
mit of the protuberance, through the middle
of which the granular mass formed below
makes its escape. These bodies may be
found commonly on the Spurges (^E. Eu-
phorbia), the Berberry (d£. Berberidis),
nettles (JE. Urticte], Composite (jE. Compo-
sitarum), &c., early in the season ; later, they
may frequently be recognized in a dried-up
condition, being forerunners of the true spo-
riferous bodies (PI. 20. fig. 1). The name
applied to these organs is spermagonia. The
filaments converging into the centre of this,
termeds£eri#ma£a(P1.20.figs. 2,3, st), are the
important parts of the structure ; they termi-
nate in rows of minute bodies of oval form,
about 1-6000 of an inch long and 1-12000
in diameter (ibid, sp], which become de-
tached and separated, falling loose into the
cavity, where, by a continued growth and
shedding of similar bodies from the con-
verging filaments, they accumulate to form
the granular mass above spoken of as exist-
ing in that situation. The number ultimately
becomes enormous, and a gelatinous sub-
stance is secreted, glueing them into a mass.
When placed in water under the microscope,
or when wetted by rain in its natural po-
sition, the ripe mass swells and is protruded

jECIDIUM.

[ 15 ]

^CIDIUM.

through the orifice of the spermagonium on
the surface of the leaf. By a longer action
of moisture the jelly dissolves, and the mi-
nute bodies (spermatia) spread about in the
water exhibiting " an oscillatory motion, as
of a body attached at one extremity." De
Bary states that he found iodine arrest this
motion, while it persisted for some time in
solution of chloride of calcium. No cilia can
be detected. Fresh spermatia were coloured
bright purple red by sugar and sulphuric
acid, but at the same time were so acted on
that it could not be made out whether they
possessed a membrane free from nitrogenous
matter. Sortition of potass renders invisible
the outlines, not only of the spermatia, but
of the sterigmata and paraphyses. The re-
semblance of these bodies to the spermatia
of the Lichens (see LICHENS), is too evi-
dent to be mistaken ; hence the same terms
are applied to the corresponding organs.

Following the history of the spermagonia
in the plant : after the emptying of the
cavity, the ordinarily bright yellow or reddish
colour becomes dulled, all parts shrivel up
and form a dirty brown mass, in which only
the outline of the spermagonium can be recog-
nized, the paraphyses become glued together
or fall off. The spermatia are likewise decom-
posed; the tough jelly spread around the
spermagonia preserves them for a time, but
they gradually vanish, until only a multitude
of actively moving molecules of extremely
small size can be detected. This mass finally
dries up, and when a number of spermagonia
were grouped together, a thin crust, often
brown, is formed over the epidermis sur-
rounding them.

The spermagonia occur either in regular
groups or scattered just like the peritkecia ;
when the latter are on the same surface of a
leaf, they often form a circle round the
former. Frequently they burst through on
opposite sides of a leaf, and then the sper-
magonia are oftenest on the upper, theperi-
thecia on the lower face (PI. 20. fig. 1, sp).

After a number of spermagonia have been
successively developed and discharged their
spermatia, the mycelium, from which they
originated, produces a new globular body
formed of densely interwoven filaments,
usually in the interior of the substance of
the leaf or stem, not immediately beneath
the epidermis, and ordinarily colourless. In-
creasing in size in all directions, this
globular body, the perithecium, soon pre-
sents at its base, i. e. the point furthest
from the nearest epidermal surface, another

body, composed of very numerous free-
ended filaments enclosed in a cellular mem-
brane, which body rapidly grows up within
the perithecium, in the direction of the sur-
face of the leaf or stem. The filaments, at
first very delicate, are crowded very closely
together, and each exhibits in its interior a
row of short, colourless, roundish cellules,
the uppermost of which is always the largest
and the most advanced in development.
These cellules are the spores, and the fila-
ments in which they are found are the spo-
rangia or thecce. The membrane enclosing
the sporangia, the peridium of Persoon,

^Ecidium Compositarum, Mart.
Fig. 5.

Peridia in various stages of growth on the surface of a leaf :
30 diam.

Fig. 6.

Perpendicular section through a burst peridium, showing
the sporanges contained in it : 100 diam.

grows pari passu with them, and is com-
posed likewise of rows of cells, which stand in
a circle around the sporanges, but are firmly
connected together side by side by an intercel-
lular substance; this membrane closes in like
a bell or vault over the sporanges. By the re-
ciprocal pressure of all parts, the cells of this
membrane, at first spherical or ovate, become

.ECIDIUM.

AERIAL ROOTS.

polygonal. At a certain stage the apex of
the perithecium gives way, so that it forms a
kind of cup around the membrane enclosing
the mass of sporanges arising from the base.
The whole structure has by this time come
immediately up to the under side of the epi-
dermis, which is next ruptured, and the peri-
thecium with the sporanges are protruded,
more or less according to the habit of the
species (PL 20. fig. 1, p, p). The upper
portions of the rows of cells composing the
peridial membrane then separate more or
less from each other, splitting into lobes, so
as to set the sporanges free, and form a kind
of cup with toothed margins seated in the ex-
panded perithecium (Woodcuts, figs. 5 82 6).

The spores, which are at first delicate cel-
lules, subsequently acquire a tough mem-
brane, increasing considerably in size, so as
to distend the parent utricle or sporange,
which is ultimately only recognizable where
it connects the spores together in a monili-
form series. The spores in most cases now
acquire a deep yellow (except in JE. leucoco-
nium) colour, owing to contents chiefly ac-
cumulated in the centre. Their membrane
is colourless, their form finally irregularly
polygonal, and the diameter varies much,
even in ripe spores of one and the same spe-
cies, from 1-1000 to 1-1800 of an inch. The
upper spores are often ripe at an epoch when
young spores are still in course of produc-
tion at the lower end of the sporanges,
finally, however, the development ceases be-
low and the tube elongates a little beneath
the lowest spore, forming a kind of pedicle
or basidium to the row. The ripe spores
either soon fall apart and fill the cup as a
loose powder along with short incomplete
sporanges, or the rows persist even after they
mature, held together probably by a firmer
sporangial membrane. The cells of the pe-
ridial membrane undergo changes also, con-
temporaneously with the ripening of the
spores, becoming thickened by internal de-
posits and acquiring a rough cuticle, giving
them a papillose or spiny aspect. This
cuticle, like that of the spore, is dissolved by
solution of potass; the cell-membrane which
it invests is coloured brown-yellow by sul-
phuric acid and iodine. Information regard-
ing the mode in which the ^Ecidia probably
become implanted in the vegetables they in-
fest, is contained under the head of PARA-
SITIC FUNGI.

The British species of ^Ecidium are nume-
rous; more than thirty are described by
Berkeley in the British Flora, many of which

are common, especially those of the Mints,
the Composite, such as the Coltsfoot, &c., the
Berberry, theGooseberry, Buckthorn, Spurge,
Nettle, &c.(jE.Compositarum, Menthce, Ber-
beridis, Grossularice, crassum, Euphorbia,
Urticce, $•<?.)•

The species occurring upon Pomaceae are
separated by Fries, and form the genus
Roestelia, Rebentisch ; among these are Me.
(R.) cornutum, on the Mountain ash, and
cancellatum occasionally occurring in great
abundance on Pear-leaves. See ROESTELIA.

BIBL. For Species : — British Flora, ii. pt.
2. p. 369 : Greville, Sc. Crypt. Flora,pl$. 7,
62, 97, 180, 209.

For Anatomy and Physiology : — Unger,
Die Exantheme, pp. 297, 300, t/3. f. 18, 19,
t. 4. ; Meyen, Pflanzenpathologie, pp. 143,
148-50; Tulasne, Comptes Rendus, March
24 and 31, 1851 ; Ann. des Sc. nat., ser. 3.
t. xv.; ibid. ser. 3. t. vii. p. 45; Leveille,
Rech. sur le dev. des Uredinees ; Ann. des
Sc. nat. ser. 2. t. xi. ; Corda, Icones Fun-
gorum, iii. t. 3. f. 45 ; Anton, de Bary, Die
Brandpilze, Berlin, 1853, p. 55 et seq. pi. 5,
6 and 7-

^EGERITA, Persoon.— A genus of Mu-
corini (Physomycetous Fungi). ^E. Candida,
Persoon, occurs upon damp decaying wood,
forming a white mealy coat.

BIBL. Greville, -Sc. Crypt. Flora, pi. 268.
fig.l.

^NGSTRCEMIA, Br. and Sch.— A ge-
nus of Leptotrichaceous Mosses, including
certain Dicrana and Weissia, &c. of authors.

1. jEngstrcemia cerviculata, C. Miill. =
Dicr. cerviculatum, Hedw.

2. M. heteromalla, C. Miill. =Dicr. hete-
romallum, Hedw.

3. JE. subulata, C. Mull.=D«cr. subula-
tum, Hedw.

4. jE.curvata, C. Miill. =Z)zcr. curvatum,
Hedw.

5. M. varia, C. Miill. = Dicr. varium,
Hedw.

6. M. rufescens, C. Miill. =Dicr. rufes-
cens, Turn.

7. jE . squarrosa, C. Miill. =Dicr. squar-
rosum, Schrad.

8. M. Grevilliana,C. MiiU.=D«cr. Schre-
berianum, Hook.

9. M. crispa, C. Mull.=Dicr. crispum,
Hedw.

10. M. cylindrica, C. M.\d\.=Didymodon
cylindricum, Hook.

AERIAL ROOTS.— A very large pro-
portion of the exotic Orchids are epiphytic
plants and produce aerial roots, which ab-

L 17 ]

AGATE.

sorb moisture from the atmosphere. These
aerial roots attach themselves to the cracked
bark of trees by fine hairs. The hairs con-
sist of cells in which a delicate spiral fibre is
rolled up in close convolutions. These were
first pointed out by Meyen, but he appears
to have overlooked the primary cell-wall, and
regarded the spiral-fibre as the sole consti-
tuent of the structure. The external coat of
the root is likewise composed of cells con-
taining a spiral fibre.

BIBL. Meyen, Pflanzenphysiologie, i. p. 19.
t. 4. fig. 14 ; Link, Ann. Nat. Hist. ser. 2.
v. p. 40.

^THALTUM, Link.— A genus of Myxo-
gastres (Gasteromycetous Fungi). The com-
mon jEthalium, dE. septicum, L. (flavum,
Grev.), occurs frequently on tan in hot-
houses, where it is very injurious, from the
rapidity of its growth and the abundance of
its spores. The ordinary form is yellow,
but violet and reddish brown varieties have
been met with. It grows also on mosses in
woods.

BIBL. Greville, Sc. Crypt. Flora, t.272;
Sowerby's Fungi, t. 399. fig. 1 (as Reticularia
hortensis, Bull.), figs. 3 & 4 (as R. carnosa
and R. cerea) ; Bolton, Brit. Fungi, 1. 134 (as
Mucor septicus, L.).

AGARICINI.— A family of Hymenomy-
cetous Fungi, characterized by bearing their
basidiospores on thin fleshy lamellae or gills,
arranged vertically on the under side of a
stalked cap, as in the common Mushroom.
The basidia are elliptical or elongated cells
growing out from the surface of the lamellae,
with four slender stalk-like processes at the
upper end, each bearing a single spore, which
becomes detached when ripe. These basi-
diospores are observed by means of cross
sections of the lamellae ; the sections must
be very thin, and require a high power for
satisfactory observation. The sections keep
tolerably well put up in chloride of calcium,
and are most instructive when taken from a
series of specimens of different ages. See
AGARICUS, BASIDIOSPORES and HYME-

NOMYCETES.

BIBL. Berkeley on the Fructification of
Hymenomyc. Fungi, Ann. Nat. Hist. vol. i.
81 ; Leveille, Sur VHymenium des Cham-
pignons, Ann. des Sci. nat. 2 ser. viii. 321.

AGARICUS, Linn.— A genus of Agari-
cini (Hymenomycetous Fungi), of which the
common Mushroom, Agaricus campestris, is
the most familiar example. The spawn of
mushrooms consists of the flocculent myce-
lium, or vegetative structure, from which the

fruits arise, and its nature can only be de-
tected by the microscope, which shows it
to be composed of a multitude of branched,
densely interwoven filaments with colourless
contents.

The fructification of the Agarics consists
of basidiospores, arising from the sides of
the gills or vertical plates under the cap ;
they may be seen by making exceedingly
delicate cross-slices of the gills, and exami-
ning them under a high power. An eighth
objective is requisite to get a satisfactory
view. For the characters of the BASIDIO-
SPORES, see under that head.

AGATE. This well-known mineral is an
aggregate of other mineral substances, as
chalcedony, jasper, amethyst, and other va-
rieties of quartz. It consists, chemically,
almost entirely of silica, coloured by metallic
oxides. Its interest in relation to the micro-
scope depends upon the supposed organic
remains found in it. The animal remains have
been especially examined by Mr. Bowerbank
in agates, principally moss-agates, and other
siliceous bodies, as jasper, the flints of the
chalk and greensand, &c., which he very
ingeniously supposes to have originated in
the continued attraction and solidification by
sponges, of silex dissolved in the water of the
ancient ocean; these sponges formerly ex-
isting at the bottom of the sea in as great
abundance as their recent types are now
found in the ocean, both in tropical and
temperate climates. The spicula of sponges
are commonly found; also very frequently
the fibres, sometimes in a perfect state of
preservation, but usually presenting the
appearance of having suffered to a great
extent from maceration and disruption of
their component parts previous to fossiliza-
tion. Generally the fibres adhere together
in confused masses, with here and there one
or two in a better state of preservation, and
occasionally, near the outer surface of the
mass, small portions of the tissue are found
quite perfect; in other parts all the inter-
mediate states between perfect preservation
and nearly complete decomposition may be
observed. The siliceous matter in which
these remains are imbedded, usually presents
a clear and frequently a crystalline aspect,
while the remains of the organized mass are
strongly tinted with colours, — bright red,
brown and ochre-yellow prevail, but occa-
sionally the fibres are milk-white or bright
green. Sometimes the interior of the tubular
fibre only is filled with colouring matter,
whilst the sides are semipellucid or of a

AGAVE.

AIR.

milky-white, in others the whole of the fibres
are impregnated with it. PI. 19, fig. 14 re-
presents sections of a piece of agate, show-
ing the silicified fibres of sponge, a; the
gemmules are seen at b ; a separate fibre at
c, and spicula at d.

There are two distinct points connected
with the presence of these supposed organic
remains in agate; one is, whether they really
are organic remains, and the other is whether
they are related to the formation of the
agate, or merely accidentally present. The
first point is a very difficult one ; we have
only the microscopic appearance of the
bodies under one set of conditions to judge
from : this is always very unsatisfactory ;
many of the appearances most peculiar to
organic bodies, especially when the latter are
not connected so as to form a tissue, can be
closely imitated by crystallization. Still the
mass of evidence is decidedly in favour of
the appearances really representing portions
of sponges.

In regard to the second point, we believe
that the necessary connexion of the presence
of the sponges with the formation of agate
cannot be maintained; but with this ques-
tion we have nothing to do.

The supposed vegetable structures of
agates, described by Turpin, Miiller and
many others, have been clearly shown by
Prof. Goppert to be entirely inorganic pro-
ducts, chiefly dendritic deposits of oxide of
iron. His essay contains an elaborate history
of the strange notions which have at various
times been propounded concerning these
objects. Sometimes agate contains crystals
of quartz, carbonate of lime, or other mineral
matters imbedded in its substance. Those
paler varieties of quartz, which consist of
concentric layers of radiately grouped cry-
stalline needles, frequently polarize light very
beautifully.

BIBL. Bowerbank, Trans. Geol Soc.1840,
(Ann. Nat. Hist. vol. vii. 1841 ; vol. x. p. 9
and 84) ; Toulmin Smith's objections (but
they refer rather to flint), Ann. Nat. Hist.
vol. xix. p. 1 and 89 ; Goppert, On the
plant-like bodies enclosed in Chalcedony,
Ratisbon Flora, 1848, p. 57. See FLINT.

AGAVE.— See FIBRES, Vegetable.

AGRION. — A genus of Neuropterous
Insects. See LIBELLULIDJE.

AINACTIS, Kiitzing.— A genus of Oscil-
latorieous plants growing on stones in water.
The two known species have been found in
Britain.

1. A. granulifera. Fronds from 1-12 to

1-2" in diameter, often confluent, formed of
repeatedly dichotomous filaments, dark olive
green, containing separate particles of car-
bonate of lime. Rivularia granulifera, Carm.
Hassall, Brit. Fr. Algte, Ixv. 1.4; Ainactis
alpina, Kiitz. Tab. Phyc. vol. ii. pi. 63. 1.

2. A.calcarea, Kiitz. Fronds 1-4 to 1-2"
in diameter, orbicular, convex, ultimately
confluent, sometimes greenish, often dark
chestnut, composed of dichotomous filaments,
at length incrusted continuously with car-
bonate of lime. Kiitzing, I. c. pi. 63. ii. ;
Rivularia calcarea, Carmichael ; Lithonema
calcarea, Hassall, I. c. tab. Ixv. fig. 2.

Kiitzing states that the gelatinous sheath of
the filaments of A. alpina have a spiral fibrous
structure. See SPIRAL STRUCTURES.

AIR. It need scarcely be remarked that
the air consists essentially of a mixture of
two gases, oxygen and nitrogen, in the pro-
portion by volume of about 21 parts of the
former to 79 of the latter, with variable
quantities of gaseous carbonic acid (about
l~2000th) and aqueous vapour. Now as the
component molecules of gases are invisible
with any powers of the microscope, the air
possesses no microscopic characters. In two
respects, however, the study of the ah' in its
relations to the microscope is of great im-
portance : — 1st, in regard to the optical
appearances produced by the passage of
light through it when contained in bodies
submitted to microscopic examination ; and
2ndly, in regard to the particles which are
always, in greater or less numbers, suspended
in it.

In microscopic investigations we meet with
air either existing in cells or cavities in various
tissues, or in the form of bubbles, confined
by the liquid in which the objects are usually
immersed. When surrounded and confined
by liquid, it mostly assumes a spherical
form, in accordance with the law of hydro-
statics, that the pressure of fluids is equal in
all directions ; sometimes the spherical form
is exchanged for that of a compressed or
oblong spheroid, the result of the pressure
of the glass slip covering the object. When
confined in cells or cavities, it assumes the
form of these. It is in general easily recog-
nized by transmitted light, from the smooth
and even darkness or shading given to its
margins, whilst in the centre it appears
luminous and clear. Sometimes the dark
margins of air-bubbles have a pale purplish-
yellow, blue or greenish tinge. By reflected
light, of course no darkness is produced, but
it then appears vitreous and shining, in con-

AIR.

[ 19 J

AIR.

sequence of the reflexion taking place from
its surface. So long as air-bubbles or con-
fined portions of air are large, the optical
appearances above described are sufficiently
characteristic; although should any doubt
exist as to the nature of a supposed accumu-
lation of air, the latter must be displaced,
either by pressure between two slips of glass,
or by immersing the object in which it exists
in some liquid and applying heat. When,
however, air is confined within very minute
cavities, especially when these possess defi-
nite forms, the clear centre is frequently no
longer to be detected, the whole appearing
perfectly black and solid, and grave errors
have arisen from inattention to this circum-
stance, as explained in the Introduction
(p. xxii).

The corpuscles of dried bone were thus
formerly considered as solid bodies, as their
name implies, and as consisting of calcareous
matter, until it was found that they could be
filled with a liquid. In all cases, then, where
absolute certainty is required of the nature
of an apparent air-bubble or accumulation of
air, attempts should be made to displace the
mass, either by pressure, or prolonged im-
mersion in a liquid, especially with the aid
of gentle heat.

The appearance presented by air contained
in tissues, is easily studied in a dry section
of any kind of pith or other vegetable struc-
ture, such as elder-pith, rice-paper or cork.
(Cork is really heavier than water, and owes
its lightness to the air it contains : see CORK.)
On immersing these in water, this liquid
soon enters the lateral cells, but long diges-
tion is required before the internal cells
become filled with it and the whole of the
air is displaced.

Gases of whatever kind present the same
appearances under the microscope as air,
excepting those which are coloured ; but as
these are not naturally met with, they
require no notice.

The determination of the actual nature, as
regards chemical composition, of air confined
in tissues, is a matter of difficulty, where the
quantities are microscopic. The nitrogen
can only be detected by its negative proper-
ties to reagents; the presence of oxygen
might be determined by moistening a sec-
tion of any structure with recently boiled
distilled water, and then placing it in a cell
containing a solution of protosulphate of
iron, and immediately sealing the cell with
varnish and allowing the action to continue
for some time.

For the detection of CARBONIC ACID, see
that article.

There is yet a source of fallacy in the
detection of air imprisoned in structures
where these are of a hard resisting nature,
as in mineral bodies. An illustration of this,
with the method of its avoidance, is given
under TOPAZ.

In regard to the solid particles present in,
or subsiding from the air, and forming dust,
these consist principally of the spores of
fungi, lichens, algae and mosses, the detritus
of the soil, fine fragments of vegetable and
animal fabrics accidentally separated and
diffused during the ordinary operations of
every-day life, the dried, but not dead
bodies of infusoria, and the ova of the lower
members of the animal kingdom. The kind
of bodies present in the air varies according
to the locality ; thus in cities, the dust con-
sists mostly of fragments of products of
manufactures, with the spores of fungi,
mixed with particles of carbon or soot, the
ova of the lower animal forms being compa-
ratively few, and belonging to a limited
number of species ; whilst in open places in
the country, a more ready diffusion of the
spores of plants and the ova of animals takes
place, and the sources from which fragments
of textile fabrics are derived, are less nume-
rous.

The inorganic particles deposited from the
air, consist of fine grains of sand, wafted
from the soil by winds, and rarely fall other-
wise than near the currents by which they
are borne. They are easily recognized by
their angular forms, then* resistance to com-
pression, and their not being destroyed or
decomposed by exposure to a red heat.
Certainty as to their composition can only be
obtained by chemical analysis. See SAND.

The animal forms deposited from the air
formerly gave rise to much perplexity. It
has long been known that when solutions of
various organic substances, or liquids con-
taining these matters, undergoing sponta-
neous decomposition, were exposed to the
air, the liquids were soon found to teem
with life ; infusoria of various kinds, accord-
ing to the nature of the decomposing
matter, being discovered in them in abun-
dance. It seemed very natural to conclude
that these derived their origin from the sub-
stances undergoing decay, and it is not to be
wondered at, that the fact should have given
rise to the conclusion that here was evidence
of the spontaneous or equivocal generation
of animals.

c2

AIR.

[ 20 ]

AIR.

This theory has now ceased to be acknow-
ledged; and a common source of fallacious
reasoning lies in overlooking the fact, that
the air contains the germs of numerous
animal forms, still capable of resuming their
active vitality when they meet with the
requisite conditions. Of this we have con-
vincing proof. For, if the liquid containing
the decomposing matters be heated to ebul-
lition for some time in a bottle or other
vessel, into the cork closing which two bent
tubes are inserted, and after the air has been
completely displaced by the vapour, the fresh
air admitted be previously passed through
red-hot tubes, which we have no reason to
believe exerts any action upon it, animalcules
cease to be met with, and the decomposition
of the substance and growth of the organisms
no longer take place, even for an indefinite
period. That the liquid in these cases does not
experience alteration rendering it incapable
of supporting the life of the animal forms
introduced, is shown by subsequently admit-
ting air which has not been heated to red-
ness, when the animalcules appear as rapidly
as in fresh liquids.

In the infusoria, which are the forms most
frequently met with in infusions of decaying
substances, and the increase of which takes
place in a threefold manner, by subdivision,
gemmation, and the formation of ova, we
cannot wonder that these reproductive parts
are not frequently recognizable, when we
recollect that the perfect organisms them-
selves, in many cases, are barely within the
reach of the highest powers of our micro-
scopes.

A list of the animalcules most commonly
existing in, or conveyed by the air, will be
given under the head of those liquids in
which we find them living: see also the
articles INFUSIONS, SOLUTIONS, FERMEN-
TATION, and PUTREFACTION.

Vegetable forms are constantly met with
as deposited from the air. In them, the
spores are probably alone the bodies by means
of which the diffusion of the lower plants by
the agency of the air is effected. Minute
fungi are frequently found, like the animal-
cules above alluded to, in various vegetable
and animal liquids undergoing fermentation
and decomposition. The question of the
relation of these fungi to the processes, will be
found discussed under FERMENTATION and
PUTREFACTION; and the various genera and
species found in different kinds of liquids
are treated of under the heads of these
liquids. Fungi and algse are also met with

as parasites and entophytes upon and in
living animals ; for an account of these, see
PARASITES and ENTOPHYTES.

The lower forms of fungi are frequently
found growing upon surfaces from which
they can derive no nourishment, as upon
slips of glass, window-panes, &c. In these
cases they must derive their nourishment
from the atmosphere. When found in these
situations, however, they soon cease to grow
by subdivision of cells or gemmation, but
speedily form spores. The most common
ones in these situations are the sugar fungus,
Penicillium glaucum and Aspergittus penicil-
latus, Mucors, &c.

The method of distinguishing whether any
minute particle deposited from the air is, of
animal or vegetable nature, is described
under TISSUES, ANIMAL and VEGETABLE.

Organic bodies derived from the air are
sometimes met with in snow and hail.
These are alluded to in the articles SNOW
and HAIL.

The air has frequently been examined in
regard to the presence of animal or vegetable
organisms, which might account for the pro-
duction of epidemic and infectious diseases.
In none of these cases have any bodies ever
been found which could in any way be inter-
preted as the origin of the diseases — nothing
more has been met with than common infu-
soria and such other bodies as may at all
times be found in air, from whatever source.
As these experiments cannot, however, be
too frequently repeated, it may be well to
point out the method of making them. The
best plan is to connect a glass tube, twice
bent at right angles, with an aspirator ; the
free end of the tube should be drawn to a
fine point, and just above this, the tube
should be blown into a bulb. The point is
then immersed in a small quantity of pure
water, and the water allowed to run very
slowly from the aspirator. The water is then
slowly drawn into the tube and the air is
washed as it passes by the water in the bulb.
When a large quantity of air has been
washed by the water, the latter is shaken
briskly and allowed to run into a clean glass
for examination.

Another method consists in closing, by
fusion, the end of a glass funnel, filling
this with ice, and collecting the drops of
water condensed from the air in a receptacle
placed beneath.

The appearances presented by air as exist-
ing in cell-cavities is represented in PI. 38.
fig. 23 a ; as confined in spiral vessels in

AIR-BLADDER.

ALARIA.

PL 37. fig. 20 ; in the delicate cavities of a
hair in PL 22. fig. 1 ; and the lower part of
the same figure represents a portion from
which the air has been displaced by liquid.

AIR-BLADDER of Fishes. See SWIM-
MING BLADDER.
AIR-BUBBLES. See AIR.
AIR-CELLS of animals.— These are dila-
tations or expansions of the air-passages; but
a distinction must be made between them
and the lungs, which might be regarded also
as air-cells. See LUNGS.

The proper air-cells or air-sacs, as met
with in birds, are membranous cavities com-
municating' with the lungs and distributed
through the chest and abdomen. These
air-sacs, or prolongations of them, extend
over almost all parts of the body, around the
joints of the extremities, into the bones, the
quills and the feathers, and even between
the skin and subjacent muscles. During
inspiration, the air enters all these cavities.

In insects the air-cells or sacs consist of
dilatations of the tracheae. See TRACHEAE.
Their obvious use is either to diminish
the specific gravity of the body, or to act as
reservoirs of air during the impeded respira-
tion connected with flight.

BIBL. Siebold and Stannius, Lehrb. d.
vergleich. Anat.; Owen, Hunterian Lectures;
Carpenter, Man. of Compar. Anat.

AIR-PASSAGES in plants are large
intercellular passages, occurring especially
in the stems of Monocotyledons and in the
leaves and stems of aquatic plants. Their
form and arrangement are sometimes very
regular and elegant, especially when they
depend upon a certain regular peculiarity of
shape in the cells which form the walls of the
passages. Thus cross sections of the com-
mon rush are pleasing microscopic objects,
exhibiting regular stellate cells, the rays of
which are separated by large air-passages,
giving the spongy texture to the structure.
In the Nymph&acece (Water-lily family) the
large air-passages in the floating leaves and
the stem have peculiarly developed star-like
cells projecting fully into these cavities;
these cells are filled with a granular substance
very unlike the contents of the large cells of
the general parenchyma of the leaf. Their
nature and office are yetunknown. They occur
in the common water-lilies andintheF«c£or«a.
The stems of the Equiseta, or Horse-tails,
present a very regular arrangement of per-
pendicular air-passages in the thin walls of
their hollow stems, seen well in cross sections.
See EQUISETACE.E.

AIR-SACS in plants. — The genus
Utricularia, or Bladder-wort, takes its name
from a peculiar structure of its leaves. The
common species, U. vulgaris, L., may be
often found swimming just below the surface
of the water, in quiet streams, and sending
up a little yellow blossom above the water
in autumn. It is provided with a curious
floating apparatus, formed by modification
of portions of the feathery leaves, consisting
of small membranous sacs or pouches, closed
by a valve. The opening of the pouch is
somewhat funnel-shaped, and the mouth,
as also the internal walls of the cavity, are
furnished with curious microscopic glandular
hairs. Certain of the cells contain a blue
colouring matter distinct in its nature from
chlorophyll. The valve of the pouch appears
to be capable of opening inwards only ; so
that while it is turgid with sap, in the vi-
gorous periods of life, it is kept closed by the
pressure of the air apparently secreted within
the pouch ; afterwards the tissue loses its
tension and the air makes its way out, allow-
ing water to enter, and thus putting an end
to the performance of the function of the
air-sac.

BIBL. Meyen, Secretions-organe der
Pflanzen, Berlin, 1837, p. 12. t. v. figs. 1-6 ;
Goppert, Botanische Zeitung, 1847, p. 721 ;
Benjamin, Bot.Zeit. 1848, 1 et seq.; Schlei-
den, Principles of Botany, English trans-
lation, pp. 77-2/9.

AIR-TUBES of Insects.— These are horny
tubes found in some insects which live in
water, as the larvae of many Diptera and
some water-bugs (Nepa, Ranatra). They
are placed either at the first or last abdominal
segment. See NEPA, CULEX, INSECTS.

AIR-VESSELS in Insects, see TRACHEAE.
In plants, see SPIRAL VESSELS.

ALARIA, Greville.— A genus of Fucoid-
eous sea-weeds belonging to the family
Laminariaceae, distinguished by their superfi-
cial fructification, in Alaria arranged in
definite patches on the surface of special
fronds, something like the sori of Ferns. The
patches consist of sporaiiges resembling the
thecae of lichens, crowded together and inter-
posed between perpendicular epidermal cells.
The sporanges are described by most authors
as pyriform spores enclosed in a perispore,
but they are probably oosporangia producing
biciliated zoospores like those of Laminaria.
See LAMINARIA.

One British species is known, a common
sea-weed having a large flat and narrow leaf-
like frond, with a thick midrib, a prolonga-

ALBERTIA.

ALBUMEN.

tion of the stalk by which it is attached to
the rocks. It grows from 4 to 12 feet long.

Alaria esculent a, Grev.

ALBERTIA.— A genus of Rotatoria. See
ALBERTINA.

ALBERTINA.— A family of Rotatoria
(Duj.).

Char. Body cylindrical, vermiform,
rounded in front, with an oblique orifice,
from which the ciliated organ, scarcely
broader than the body, projects, terminated
behind by a short conical tail. Jaws forceps-
like, simple or unidentate.

This family contains only a single genus,
and this a single species, A. vermiculus
(PI. 34. fig. 4), which lives parasitically in the
intestines of worms (Lumbrici) and slugs
(Limaces). Length 1-47 to 1-79".

Within the body are seen ova and foetus
in various stages of development. The cili-
ated apparatus in front of the mouth is sur-
mounted by a hood-like appendage.

ALBUMEN (Chemical).— A proximate
principle of animal and vegetable bodies,
with which we are familiar as occurring in
the white of egg. It exists in two states,
uncoagulated and coagulated. At a tempe-
rature of 160° F., provided no free alkali is
present, it is reduced from the former into
the latter condition. Its chemical relations
to other proteine compounds are not very
firmly established. It is reddened by Millon's
test ; is insoluble in acetic acid ; is rendered
purple by Pettenkofer's test, but the reaction
requires some time for its production. In
the coagulated state it is distinguished from
fibrine by the action of acetic acid, and by
its insolubility under prolonged digestion at
a heat of 110° F. with solution of nitrate of
potash. When heated with strong muriatic
acid, it is coloured purple.

Albumen possesses no microscopic charac-
ters ; when coagulated, it appears to consist
of extremely fine amorphous granules. See
PROTEINE.

BIBL. See works on Chemistry; Brande's
Chemistry ; Lehmann's PhysioL Chemie.

ALBUMEN (of seeds). — Thisis a technical
term used in Botany to denote the cellular
structure which exists in greater or less
quantity in all seeds where the development
of the embryo is not accompanied by the
entire absorption of the nucleus of the ovule.
When the embryo does so displace the
nucleus, it becomes immediately invested by
the seed-coats; in other cases it is found
imbedded in a mass of cellular tissue of
varying structure, which is the ' albumen.'

The structure of albumen corresponds to that
of the cotyledons of seeds devoid of albumen,
both serving the same office, namely, that of
reservoir of nutriment for the germinating
seed. This nutriment may be laid up in
different conditions, namely, in the state of
starch, of oil, or of cellulose, and in the last
case in a soft and fleshy, or a hard and horny
condition. Combined conditions are often
met with in the same structure, as when a
fleshy tissue contains starch or oil in the
cavities of its cells, &c.

Starchy, mealy or farinaceous albumen
constitutes the chief part of the seeds of
many plants, especially of those of the Grass-
tribe, and is that portion of the corn-grains
whence white flour is obtained. Here the
cellular tissue is composed of membranous
cells densely filled with starch-grains (PI. 36.
fig. 1 c). The edible portion of the cocoa-nut
is the corresponding region of that seed, and
affords us a good example of an oily albu-
men, composed of tolerably thick-walled
cells filled with a viscid mucilage, in which
abundance of oil-globules are suspended.
The stone of the Date, the nut of the Areca
Palm (PI. 38. fig. 21), are good examples of
a horny albumen, the cells possessing walls
of extreme thickness, traversed by pores and
formed, like wood-cells, by the deposition of
successive layers. In the ripe seed the
structure of this horny albumen is generally
much disguised, and a section exhibits the
appearance of a homogeneous horny sub-
stance excavated in irregular cavities. By
applying dilute sulphuric acid, the true
boundaries of the cells may generally be di-
stinguished, and often even the lamination of
the walls (PI. 38. fig. 22). The substance
called Vegetable Ivory is the albumen of the
seed of the Phytelephas Palm, and is an
instance of an extreme degree of develop-
ment of the cellulose albumen, vicing with
the hardest woods in the solidity of its cell-
walls. A fine section of this albumen, espe-
cially if treated with acid, at once reveals the
cellular structure of this dense substance
(PI. 38. fig. 23). The cotyledons of many
seeds are, as above stated, formed of element-
ary structures resembling those of albumen.
We find them farinaceous, fleshy, or oily,
but rarely attaining to a very great degree of
solidity in the horny form. The cotyledons
of beans are composed of a fleshy cellular
tissue with thick, porous walls, coloured
blue by iodine alone (amyloid), while the
cavities of the cells are filled with starch-
grains (PI. 36. fig. 20). The cotyledons of

ALCYONELLA.

[ 23 ]

ALG.E.

the almond, nut, &c., are examples of fleshy
cells containing abundance of oil-globules.

The albumen of seeds may be formed by
the development of the tissue of the nucleus
of the ovule, in which case it is distinguished
by some botanists as the episperm; some-
times it is formed from the cells inside the
embryo-sac, the latter expanding to displace
the nucleus which becomes absorbed; such
albumen is called endosperm. Some seeds,
such as those of the Nymphaeacese, Ranun-
culaceae and others, have both endosperm
and episperm., i. e. albumen formed inside
and outside the embryo-sac. The term
perisperm is often (advantageously) substi-
tuted for albumen, which has quite a different
signification in physiological chemistry.

The albumen of seeds is examined by
means of fine sections. In the horny or bony
seeds, the application of solution of potash
or nitric acid is very serviceable in ascertain-
ing the true cellular structure.

BIBL. Schleiden and Vogel, Ueber Albu-
men, Nova Acta, 1838, xix. p. 52 (with
plates).

ALCYONELLA.— A genus of freshwater
Zoophytes or Polypes, belonging to the
order Bryozoa (Polyzoa).

Char. Polypidom fixed, incrusting or
floating in the form of an irregular sponge-
like mass composed of vertical aggregated
membranous tubes opening on the surface.
Polypes ascidian, the mouth encircled with
a single series of filiform tentacles, depressed
or incomplete on one side : eggs coriaceous,
smooth.

1 species, Al. stagnorum, PI. 33. fig. 3., found
in autumn in stagnant waters, especially those
tinctured with iron in solution ; the polypi-
dom forms large, blackish-green, amorphous
masses. The tentacles are sometimes disposed
circularly. The ova are figured in PI. 33. fig. 4.

BIBL. Johnston, Brit. Zoophytes, 1847.

ALCYONIUM.— A genus of marine Po-
lypes or Zoophytes, belonging to the order
Anthozoa and family Alcyonidae.

Char. Polype-mass lobed or incrusting,
spongious, the skin coriaceous, marked with
stellate pores ; interior gelatinous, netted
with tubular fibres and perforated with lon-
gitudinal canals terminating in the polype-
cells, which are subcutaneous and scattered.
Polypes exsertile. 2 species : —

A . diyitatum. Form of polypidom variable,
greyish-white or orange-coloured, skin some-
what wrinkled, studded over with stellate
pores, even with the surface.

Very common, so that on many parts of

the coast scarce a shell or stone can be
dredged from the deep that does not serve
as a support to one or more specimens.

A. glomeratum. Colour deep red ; rare.

BIBL. Johnston, "Brit. Zoophytes.

ALDERIA. — A name proposed by Mr.
Pritchard to designate a new genus of animals
discovered by Mr. Alder.

The body of one species (P1.40. fig. 13) con-
sisted of a vase- or cup-form, expanded at the
top and furnished with numerous pointed
tentacles, abruptly thickened towards the
base and forming more than one row : they
had very little motion, but were occasionally
bent forwards, and the whole were sometimes
slowly retracted. The body was attached to
a Sertularia by a tolerably stout stem.

A second species (P1.40. fig. 14) was rather
smaller, the body of an ovate form with a
very slender and shortish stem; the tentacles
were capitate, not so numerous as in the first
species, and placed in a single row round a
narrow disc.

This species was also found on a Sertularia.

A third (PI. 40. fig. 15) was found in fresh
water. Its body was pear-shaped, or rather
bell-shaped, with a distinct rim round the
top and a single row of delicate capitate
retractile tentacles ; the stem was long and
slender. Mr. Alder remarks that they come
nearest to the genus Acineta of Ehrenberg ;
the third species somewhat resembles Ac.
mystacina, E., yet differs from it in the latter
appearing of a more simple form, and the
tentacles arising irregularly from different
parts of the body.

Mr. Alder remarks that they form a more
perfect link between the Infusoria and the
Campanularian Zoophytes than any hitherto
known.

Should these animals be again met with,
it would be very desirable to keep them
alive and ascertain whether they do not
represent an immature condition of some
Zoophytes. They appear to us to have but
little affinity with those species of Acineta,
the existence of which as mature organisms
has not been called in question.

BIBL. Trans, of Tyneside Naturalists'
Field Club, i. p. 365 ; Ann. Nat. Hist. vii.
p. 426 ; Pritchard's Inf. Anim. p. 558.

ALECTORIA, Acharius.— A genus of
Parmeliaceous Lichens, in eluding two British
species, A. jubata and A. sarmentosa, the
fructification of which is rarely met with.

ALG^E, Sea-weeds, ^c.— This class of the
Thallophytes includes the Sea-weeds and the
multifarious green vegetable forms of simple

ALGJE.

ALG^E.

cellular structure, met with in all streams,
ditches, ponds, or even the smallest accumu-
lations of fresh water standing for any length
of time in the open air, and commonly on
walls or the ground in all permanently damp
situations. The great variety of conditions
of organization, all variations as it were on
the theme of the simple vegetable cell, pro-
duced by change of form, number and
arrangement of this simple element, renders
the Algse peculiarly interesting as objects of
microscopical research, even in regard to
morphological conditions alone.

This simple condition of the .structures is
here, as in other cases^ accompanied by a
delegation of the physiological functions
more completely and fully to the individual
cells, that is to say, the marked difference of
purpose seen in the leaves, stamens, seeds,
&c. of the flowering plants is absent here,
and the structures carrying on the operations
of nutrition and those of reproduction are so
commingled, conjoined, and, in some cases,
identified, that a knowledge of the micro-
scopic anatomy is indispensable, even to the
roughest conception of the natural history of
these plants. Added to this, we find these
plants of such simple structure that we can
see through and through them while living
in a natural condition, and by means of the
microscope penetrate to mysteries of organ-
ization, either altogether inaccessible, or only
to be attained by disturbing and destructive
dissection, in the higher forms of vegetation.

This Class comprehends a vast variety of
plants, exhibiting a wonderful multiplicity
of forms, colours, sizes and degrees of com-
plexity of structure, but the subdivision of
them into three groups, characterized by
striking external characters, which are
adopted in the classifications of some of the
leading Algologists, facilitates the cursory
consideration to which we are confined here.
These three Orders are the Red-spored Algce
(RHODOSPORE.E or FLORIDE^E), the Dark-
spared Algce (MELANOSPORE^E or Fu-
coiDE^5)andthe Green-spored Algce (CHLO-

ROSPORE^30rCoNFERVOIDE^E),thefirsttwO

consisting almost exclusively of Sea-weeds,
the last of marine and more especially (ac-
cording to our present knowledge) of fresh-
water plants, the majority of which are
microscopic when viewed singly.

Orderl. RHODOSPERME.E orFLORiDE^E.
Almost all marine plants, rose-red or purple,
rarely brown-red or greenish red. Fructifi-
cation not yet well understood, appearing in
three forms : — 1 . spores, contained in external

or immersed conceptacles (ceramidia), or
densely aggregated and dispersed in masses
through the substance; 2. tetraspores, red
or purple, either external or immersed in the
frond, rarely contained in proper conceptacles
(stichidia), each enveloped in a transparent
membranous sac, separating, when ripe, into
four sporules ; 3. antheridia, pellucid sacs
filled with yellow corpuscles (ciliated accord-
ing to Nageli). See FLORIDE^E.

Order 2. MELANOSPORE^EorFucoiDE^.
Marine plants of an olive-green or brown
colour. Fructification consisting of: — 1.
simple sporangia, 2. oosporangia, and 3.
trichosporangia (antheridia?). 1. The first are
membranous sacs (perispores] containing
dark-coloured spores, either single or in
groups, arranged in masses of definite form.
The spores are sometimes divided into two,
four, or more sporules before germination.
Those of Fucus are ciliated all over. 2. The
oosporangia resemble the spore-sacs or peri-
spores, butproducelarge numbers of biciliated
zoospores or active gonidia. 3. The tricho-
sporangia, which are apparently to be re-
garded as antheridia, consist of tubular sacs
or minute jointed filaments, producing very
minute biciliated corpuscles. SeeFucoiDE^E.

Order 3. CHLOROSPORE^E or CONFER-
VOIDE^E. Plants green, rarely red or livid
purple. Fructification occurring in all cells
of the frond, the entire cell-contents being
capable of conversion into reproductive
bodies, viz.'— 1. Spores, cells formed singly
within parent cells, with or without conju-
gation, passing through a stage of rest before
germination; 2. Gonidia or zoospores. Active
2-, 4-, or multi-ciliate bodies, formed singly
or in twos, fours, or vast numbers, from the
contents of the vegetative cells, escaping
from the parent-cell before acquiring a
membrane, moving actively for a time, then
settling down and germinating. Marine
or more commonly, aquatic, in ponds,
streams, ditches, or on damp surfaces. Most
of the forms microscopic, some (included
among Infusorial Animalcules by Ehrenberg)
retaining their cilia and active movement
throughout life. See CONFERVOIDE^E.

Excluded families of Algae : —

CRYPTOCOCCE.E, Kg., containing the
genera Cryptococcus, Kg., Ulvina, Kg., and
Sphcerotilus, Kg.

LEPTOMITE^, Kg., containing the genera
Hygrocrocis, Ag., Sirocrocis, Kg., Leptomi-
tus, Ag., Arthromitus, Leidy, Cladophytum,
Leidy, Mycothamnion, Kg., Erebonema,
Ro'mer, Chamcenema, Kg., Nematococcus,

ALKALOIDS.

ALKALOIDS.

Kg., Chioniphe, Thienemann, Moulinea, Ch.
Robin, Enterobryus, Leidy, Eccrina, Leidy.

PH^EONEME^;, containing the genera
Stereonema, Kg., Phceonema, Kg., Phceosi-
phonia, Kg.

All these are byssoid or mucoid products
occurring in organic liquids undergoing fer-
mentation, vinous, acetous or putrefactive,
or in solutions of mineral salts, which are
likewise decomposed by them. They are
probably mycelia of various Fungi and not
independent organisms.

BIBL. Harvey, Manual of British Algce,
2nd ed. 1849 ; Phycologia Britannica ;
C. Agardh, ' Sy sterna Algarum; 3. Agardh,
Species, Genera et Or dines Algarum ; Kiitzing,
Phycologia generalis; Species Algarum ; Ico-
nes PhycologictB ; Phycologia Germanica ;
Lyngbye, Hydrophytologia Danica; Greville,
Alga Britannica.

ALKALOIDS.— The utility of the micro-
scope in distinguishing the more common
alkaloids from each other, has been shown
in an able paper by Dr. Anderson. The
characters consist in the crystalline form of
the alkaloids themselves, and in that of their
sulphocyanides.

The method employed consisted in dis-
solving the alkaloids in dilute hydrochloric
acid, and mixing the dilute solution, on a
glass plate, with solution of ammonia of
moderate strength if the alkaloid itself is to
be examined, or with a strong solution of
the sulphocyanide of potassium if the sulpho-
cyanide is required, and at once placing it
under the microscope. The only precaution
requisite is to avoid having the solution too
concentrated, as the crystals are then less
well-defined than if a dilute solution is em-
ployed.

The power employed should be 250 dia-
meters ; for if a very high power is used, the
form of the crystals is not so readily distin-
guished.

Atr opine is precipitated in the amorphous
state by ammonia, and not at all by the
sulphocyanide of potassium.

Brucia. A salt of brucia in a sufficiently
dilute state, mixed with ammonia, does not
give an immediate precipitate; but in the
course of a very short time, irregular star-
like groups of pointed crystals are observed,
as in PI. 7- fig- 1 • Solution of sulphocya-
nide of potassium produces a precipitate in
tufts of extremely thin and feathery crystals,
which either radiate from a centre, or present
a sheaf- like appearance. The latter form is,
however, much better marked in the crystals

deposited after some hours from a dilute
solution, which are still microscopic, although
somewhat larger than those represented in
the figure.

Cinchonine is obtained by precipitation
with ammonia in the form of minute granular
masses, made up of more or less distinctly
acicular crystals, radiating from a centre. It
is, however, somewhat difficult to obtain
them well-marked, and they not unfrequently
appear as a confused mass of granules, in
which the radiated structure is very imper-
fectly seen. They form best when the solu-
tions are rapidly mixed (PI. 7- fig- 2). With
sulphocyanide of potassium, cinchonine gives
a precipitate consisting of six-sided plates,
together with a variety of irregular crystal-
line masses, and a few rectangular plates
(PI. 7. fig. 3). When formed by mixing
in a test-tube with agitation, and allowing it
to stand for some time, the crystals are still
microscopic, but much more definite, and
sometimes consist almost entirely of isolated
six-sided tables, of great regularity. The pre-
cipitate dissolves readily in hot water, and is
deposited as the solution cools, in irregular
plates.

Narcotine is precipitated by ammonia in
branched groups of pointed crystals (PI. 7.
fig. 4). In concentrated solutions a preci-
pitate is thrown down by sulphocyanide of
potassium, which dissolves readily in hot
water, and is again deposited on cooling.
Under the microscope it is perfectly amor-
phous.

Strychnine. The hydrochlorate, treated
with ammonia, gives an immediate precipi-
tate, consisting of minute prismatic crystals,
all nearly of the same size and very well
defined. Most of them are isolated, but
some cross each other at an angle of about
60°. When lying in one position, they
exhibit more or less an appearance of a
St. Andrew's cross, arising from a peculiar
arrangement of some of then' facets (PI. 7.
fig. 5). The sulphocyanide consists of flat-
tened needles, sometimes single, but generally
in irregular groups, as in PL 7. fig- 6. They
are terminated by either a blunt acumination,
or are truncated. Those precipitated on the
large scale present the latter forms.

Morphia. Ammonia does not produce an
immediate precipitate in solutions of morphia;
but in the course of a longer or shorter
period, according to the degree of dilution,
crystals form, which gradually increase in
size, and possess the form represented in
PI. 7- fig- /• Salts of morphia are not pre-

ALLANTOIN.

r

ALTERNATION.

cipitated by sulphocyanide of potassium,
unless the solution is highly concentrated.

Quinine. A solution of this alkaloid gives
with ammonia a perfectly amorphous preci-
pitate; with sulphocyanide of potassium it
gives small irregular groups of acicular
crystals, resembling those produced by
strychnia, but longer and more irregular
(PI. 7. fig. 8). When the precipitate is
produced in a test-tube, arid with a concen-
trated solution, it falls immediately as a white
powder composed of extremely minute
needles ; but when the solution is dilute, it is
deposited after the lapse of twenty-four hours,
in crystals from 1-4 to l-3rd of an inch in
length.

BIBL. Anderson (T.), Edinburgh Monthly
Journal, viii.

ALLANTOIN. —A crystalline organic
substance found in the liquid of the allantois,
and in the renal secretion of the calf. As
artificially prepared, it is one of the products
of oxidation of uric acid.

Its crystals form transparent colourless
needles and four-sided prisms, with mostly
dihedral unequal summits, PI. 6. fig. 1. They
are not very soluble in either cold or boiling
water ; more soluble in alcohol, but not at
all in aether.

BIBL. See CHEMISTRY.

ALLANTOIS. — An oblong or pyriform
sac developed during a very early period of
embryonic life from near the end of the in-
testine. Its function is that of a temporary
embryonic respiratory organ. The capillaries
in the allantois of the chick are distributed
closely like those of the lungs of the Batra-
chia.

BIBL. Wagner, Elements of Physiology,
translated by Willis.

ALLICULARIA, Corda.—
A genus of leafy Liverworts(see
JUNGERMANNIE.E), contain-
ing one British species, common
on hedge-banks.

A . scalaris = Jungermannia
scalaris, Schrad., J. lanceo-
lata, Eng. Bot. (fig. 7).

Jungermannia compressa,
Hook., which has stipules only
on the innovations, is included AiHcularia scala-

Fig. 7.

inthisgenusbyFriesandothers. ris- Imn?ature

T» TT 1 TI -j.' 7 T sporange m the

BlBL. Hooker, British Jun- opened perigone

germannifs, pi. 61 ; Sowerby, (magnified).
EngL Botany, pi. 605.

ALONA. — A genus of Entomostraca, be-
longing to the order Cladocera and family
Lynceidae.

Char. Shell quadrangular or roundish
obovate, striated or grooved longitudinally,
or reticulate ; inferior antenna short ; beak
blunt, directed forwards and upwards. Three
British species, freshwater.

f Shell reticulated .............. reticulata*.

' \ Shell striated or grooved ...... 2.

("Anterior margin of shell nearly
2 J straight, shell brown ........ quadrangular is f .

1 ^ Anterior margin of shell convex,

L shell colourless .............. ovata.

* PI. 14. fig. 4.

t PL H. %• 5.

Alsophila excelsa.
Pinnule with sori.

Fig. 9.

BIBL. Raird, British Entomostraca, p. 121
et seq. pi. 16.

ALSOPHILA, R. Fig. 8.

Brown. — A genus of
Cyatheaeous Ferns.
Exotic (fig. 8). Al-
most all the Alsophila
are tree-ferns. Sec-
tions of their petioles
exhibit fine scalari-
form ducts, the slits
between the fibres
forming many perpen-
dicular rows.

ALTERNANTHERA, Forskal.— A genus
of Amaranthacese (Flowering Plants), pos-
sessing remarkable branched hairs upon the
leaves. See HAIRS, of plants.

ALTERNARIA, Nees. — A
genus of Torulacei (Coniomyce-
tous Fungi). Microscopic fila-
mentous fungi, remarkable for
their flask-shaped, cellular
spores, produced in chains which
ultimately break up into the
single links (fig. 9). No British
representatives of this genus
appear to have been recorded
hitherto.

A. tennis grows parasitically
upon other filamentous Fungi,
and it is common about Berlin,
Prague and other places. Corda
made the ripe spores germinate
on Cladosporium herbarum kept
moist. They usually first pro- .

11 ^i i .«_ Ai_ i Alternaria te-

truded a filament from the neck,

or attenuated projection, and

afterwards others from the cells

at the sides and opposite end of nified).

the spore. These filaments became branched.

BIBL. Corda, Icones Fung. in. p. 5. pi. 1.
fig. 16; Prachtfl. Europaisch. Schimmelbild.
p. 13.

ALTERNATION OF GENERATIONS.
See GENERATION.

nuis. Fertile
spore -bear-

ALTEUTHA.

AMBER.

ALTEUTHA, Baird.— A genus of Ento-
mostraca, of the order Copepoda, and family
Cyclopidse.

'Char. Body depressed; foot-jaws two
pairs, small and simple ; two strong falciform
appendages arising from the fifth segment of
the body.

One species, A. depressa (PI. 14. fig. 3).
Eye red. Found in Berwick Bay, but not
common.

BIBL. Baird, Ann. Nat. Hi$t. xvii. p. 416 ;
and Brit. Entomostr. p. 216.

ALTICA. See HALTICA.

ALUCITA. — A genus of Lepidopterous
insects, of the family Alucitidse.

The species are remarkable from having
the wings divided into six lobes or rays
which are fringed with long narrow scales,
resembling hairs, giving them a beautiful
feathery appearance. They are not uncom-
mon in gardens, and sometimes enter out-
houses.

The species of Pterophorus exhibit the
same structure, excepting that the anterior
wings have two, and the posterior three lobes.

BIBL. See INSECTS (Wings).

ALUM. — This well-known substance con-
sists chemically of potash and alumina, with
sulphuric acid and water. Its crystals belong
to the regular cubic or tesseral system, and
usually assume the octohedral form. When
dissolved in boiling water with slaked lime,
it crystallizes in cubes. The term alum has
recently been extended to those compounds
in which the potash is replaced by other
bases; thus we have soda-alum, chrome-
alum, &c. The crystals exert no influence
upon polarized light. Common alum pos-
sesses but little microscopic interest. Its solu-
tion is usedin some of the preservative liquids.

ALYSCUM, Duj.— A genus of Infusoria,
of the family Enchelia, Duj.

Char. Body ovoid-oblong, irregular ; sur-
rounded with radiating cilia, provided also
with a lateral bundle of long recurved con-
tractile cilia, by means of which it leaps
suddenly from one place to another. One
species.

Alsaltans (P1.23. fig.8). Colourless, with
faint longitudinal furrows ; length 1-1260 to
1-1000".

Found in infusion of hay, and river-water,
which have been kept.

Dujardin remarks that it differs from
Enchelys nodulosa, Duj. (Pantotrichum En-
chelys, Ehr.) only in the presence of the
contractile cilia.

BIBL. Dujardin, Infus. p. 391.

ALYSSUM, Linn.— A genus of Crucifera
(Flowering Plants), possessing elegant stel-
late hairs. See HAIRS, of plants.

AMBER. — This substance, found as a
mineral, but strongly resembling in appear-
ance various gum-resins, is the fossil resin of
one or more Coniferous trees belonging to a
vegetation now extinct. It is found in drops,
lamellae and stick-shaped pieces, the form
and condition depending probably on the
mode and situation of its exudation from the
trees. In many instances the fragments of
amber contain well-preserved remains of the
animals and plants which lived at the period
of its formation, these having been enclosed
by the fluid resin as it escaped from the tree,
in a manner which may be exactly compared
with our mode of preserving microscopic
objects in Canada balsam. Numerous insects,
Arachnida and other animals, with leaves,
twigs, fruits, even flowers of plants, have
been described and referred satisfactorily to
their systematic position, and the aid of the
microscope has been largely called in for this
purpose, since the elementary structures are
in many cases perfectly preserved. The
tissue of the fragments of Coniferous wood,
the stomates of leaves, glandular and other
hairs have been recognized ; and besides the
larger Cryptogams, Mosses, Jungermanniae,
&c., peculiar microscopic Fungi and Diato-
macese have been preserved in a perfectly
distinct condition.

The structure of the wood of the Amber-
fir, Pinites succinifer, Goppert, approaches
closely that of our Pinus Abies and P. Picea,
differing scarcely in any respect but in the
smaller number of the bordered pores,
which are of slightly different form.

Three microscopic Fungi preserved in
amber have been described and figured by
Mr. Berkeley : — 1. Penicillium curtipes ;
2. Brachycladium Thomasinum, and 3.
Streptothrix spiralis, all from the Baltic
coast.

Ehrenberg has detected a number of fossil
Infusoria in amber, namely, Amphora gracilis,
Cocconeis borealis, Cocconema Cistula, Fra-
gilaria Capurina, Navicula afnis, N.
Amphioxys, N. Bacillum, Pinnularia capitata,
P. Gastrum.

BIBL. Goppert and l&erendt, Die Bernstein,
Sfc., Berlin, 1845; analysis of ditto in Reg ens-
burg Flora, vol. xxviii. p. 545, 1845; Ehren-
berg, Bericht. Berlin. Acad. 1848. p. 17;
Berkeley, on Moulds detected in Amber,
Annals of Nat. Hist. 2nd ser. vol. ii. p. 380.
tab. xi., xii.

AMBLYODON.

AMMONIA.

AMBLYODON, Pal. de Beauv.— A genus
of Funariacese (Acrocarpous Mosses), to
which is referred a Eryum and Meesia of
other authors.

A. dealbatus, P. de Beauv. =Bryum deal-
batum, Dicks.

AMBLYOPHIS, Ehr.— A genus of Infu-
soria, of the family Astasisea.

Char. Unattached; a single (red) eye-
speck; a simple flagelliform filament, no
tail. One species.

A. viridis (PI. 23. fig. 55). Green; length
1-210 to 1-240".

The anterior end of the body is colourless,
and cleft so as to represent a two-lipped
mouth. Near the middle of the body is a
kind of nucleus (?).

Dujardin regards this animal a,$a,Eufflena.

AMIBA, Duj. See AMCEBA.

AMMONIA, HYDROCHLORATE OR MU-

RIATE OF. — This salt crystallizes in cubes,
octohedra and trapezohedra. When crystal-
lized rapidly it forms curious feathery con-
gregations (PI. 7- fig. 9). The crystals do
not polarize light.

AMMONIA, OXALATE OF. — This salt is
readily prepared by neutralizing a solution of
oxalic acid with ammonia or its carbonate,
and evaporating.

It crystallizes in long slender needles,
belonging to the right rhombic prismatic
system. When mounted in Canada balsam,
these form a very beautiful object for the
polariscope (PL 19. fig. 7).

AMMONIA, OXALURATE OF ; formerly
known as the lithoxanthate of ammonia.

This salt may be prepared by mixing
1 part of uric acid with 32 parts of water and
heating the mixture in a porcelain capsule
until it acquires a boiling temperature . Strong
nitric acid, previously diluted with 2 parts
of water, is next added in small quantities at
a time, until nearly the whole of the uric
acid is dissolved. The liquid is then boiled,
filtered, mixed with excess of solution of
ammonia, and concentrated by evaporation.
As it cools, the salt is deposited in needles
or warty groups of crystals. These are freed
from the mother-liquor by pressure between
blotting-paper, dissolved in warm water and
a little solution of ammonia added. On
evaporation the pure salt separates.

The oxalurate of ammonia forms one of
the most beautiful and interesting substances
that can be examined by the polarizing
microscope. When a small quantity of its
aqueous solution is slowly evaporated on a

slide, some of it usually crystallizes in circular
disks or very flat spheres, consisting of
minute needles radiating from a centre and
in an intimate state of mechanical adhesion ;
sometimes the extremities of the needles are
seen projecting beyond the circumference of
the disks. The latter appear colourless or
yellowish by reflected light; pale or dark
brown, or even black by transmitted light,
according to their size and thickness. When
immersed in Canada balsam, they become
transparent, often nothing more being di-
stinguishable than radiating lines, indicating
the needles of which they are composed.
But if examined by polarized light and with
the analyser, when these are so arranged
that the plane of polarization of the analyser
is at right angles to that of the polarizer (the
field being black), the disks present the
appearance of beautiful little stars, sometimes
almost white, at others splendidly coloured,
each being also traversed by a black rectan-
gular cross (PL 19. fig. 11).

On rotating the slide, no change is pro-
duced. But on rotating the analyser or
polarizer 90°, the arms of the cross appear
to rotate, which, as there are no fixed points
visible in the disks, gives rise to the appear-
ance of the disks themselves rotating. When
the analyser has been rotated a quarter of a
revolution, the former position of the black
cross is occupied by a white one, and the
colours of the intermediate parts become
complementary to (forming white light with)
those which they at first possessed; these
appearances being alternately reproduced at
each quarter revolution.

If a plate of selenite is placed beneath
the slide, the beauty of the objects is much
augmented (PL 19. fig. 12). On some parts
of the slide dendritic aggregations of the
needles are seen (PL 19. fig. 11 a).

Sometimes the colours are disposed in
concentric rings; when these are well-defined,
a concentric arrangement of the groups of
needles is distinguishable on examining the
disks by common light.

A simple experiment will show the origin
of the cross and the colours. If eight crystals
of any doubly refracting salt be arranged
upon a slide in the directions of equidistant
radii of a circle, they may be regarded as
forming two crosses, alternating in position.
If the slide be placed under the microscope,
with the plane of polarization of the polarizer
and analyser at right angles, and the crystals
be simultaneously rotated and kept in the same
relative position, a point will be reached at

AMMONIA.

[ 29 ]

AMPHILEPTUS.

which each alternate crystal will become
black, the intermediate ones appearing
coloured; and on continuing the rotation,
the crystals which were at first black will
appear coloured, those which were coloured
appearing black.

The blackness of the crystals arises from
the plane of primitive polarization of the
light transmitted by the polarizer being
parallel with the optic or neutral axis of the
crystals, consequently there is no double
refraction and no interference to produce
colour ; whilst in the coloured crystals, the
optic axis of .which does not coincide with
the plane of polarization, double refraction
and interference ensue, by which the colours
are produced. The tint of colour varies
according to the thickness of the disks.

See CIRCULAR CRYSTALS and POLARI-
ZATION.

AMMONIA, PURPURATE OF; also called
Murexide. — Is an artificial product of the
decomposition of uric acid. It may be pre-
pared by dissolving uric acid in dilute nitric
acid, as directed under AMMONIA, OXALU-
RATE OF. The solution is evaporated
until it acquires a tile-red colour ; then
cooled to exactly 158° Fahr., and dilute so-
lution of ammonia added to it, until it is
neutralized. Half its bulk of water is then
added, and the mixture deposits the salt in
crystals as it cools.

The crystals form short, flattened, four-
sided prisms (PI. 7- fig- 10) ; they are ruby-
red by transmitted light, and the two broad
surfaces are emerald-green by reflected light.
They are also analytic.

BIBL. See CHEMISTRY.

AMMONIA, URATE OF. See URATES.

AMMONIO-CHLORIDE OF PLATI-
NUM. See PLATINUM.

AMCEBA, Ehr. (Amiba, Duj.).— A genus
of Infusoria, of the family Amcebaea.

Char. The same as that of the family.

Ehrenberg admits four species ; to these
Dujardin has added ten; but the characters
cannot be depended upon.

They are found in almost all infusions
which have not become putrid ; also in the
slimy debris covering bodies immersed in
fresh or salt water.

Their size varies from 1-70 to 1-2800".

Amoeba diffluens (aquatic) is represented
in the expanded state by PI. 23. fig. 9 a; and
when contracted, by fig. 9 b.

AMCEBA A, Ehr. and Duj.— A family of
Infusoria.

Char. Animals composed of a glutinous

substance, without integument or internal
structure, constantly changing form by the
protrusion or retraction of parts of the body,
whence result variable expansions; move-
ment slowr.

These curious organisms apparently con-
stitute the simplest forms of organic beings,
for they consist of a single kind of matter, a
simple mass of sarcode. When first placed
upon a slide, they represent minute rounded
semitransparent masses; but soon one or
more rounded or pointed lobes, or transparent
expansions, are seen to shoot out from the
margin. These move almost imperceptibly
along the slide, and becoming fixed to it,
slowly draw the mass towards the fixed
point. They are usually found to contain
within them other Infusoria, Diatomaceae,
Desmidiacese or other minute Algae serving as
food; these bodies being involved in the same
manner as occurs in thecaseof ACTINOPHRYS,
atemporary digestive cavity beingthus formed.
Sometimes also vacuoles are seen within them,
containing simply the surrounding liquid;
these contract occasionally and disappear.

They are propagated by spontaneous
fission. When cut or torn, each segment
contracts upon itself and forms a new being.

One genus, AMCEBA. See RHIZOPODA.

AMPELOMYCES, Ces. See OIDIUM.

AMPHIBLISTRA, Presl.— A genus of
Pterideae (Polypodaeous Ferns). Exotic.

AMPHILEPTUS.— A genus of Infusoria,
of the family Colpodea (Ehr,).

Char. Eye-spot wanting ; no tongue-like
process ; proboscis and tail present.

The so-called proboscis resembles in ap-
pearance a neck.

Dujardin gives the following characters,
placing the genus among his Paramecia.
Body elongated, fusiform or lanceolate, nar-
rowed at each end, or at least at the anterior
extremity, and furnished with an oblique
lateral mouth.

These animals are usually found in clear
marsh water, and in streams, between aquatic
plants. They are all furnished with cilia but
one ; in some these are arranged in longitu-
dinal rows. Species : —

1. Amphileptus anser, E. (Dileptus anser,
D.). Colourless; length 1-120".

2. A. margaritifer, E. and D. Colour-
less; 1-72".

3. A. moniliger, E. and D. Colourless ;
1-72 to 1-96".

4. A. viridis, E. and D. Green ; 1-120 to
1-4G".

5. A. fasciola, E. and D. Colourless;

AMPHIMONAS.

AMPHIPRORA.

1-720 to 1-144" (PI. 23. f. 10 a, from above;
b, side view).

6. A. meleagris (Loxophyttum meleagris,
D.). Colourless; 1-72" (PI. 24. f. 42 a;
b, anterior portion in side view).

7. A. longicollis, E. Colourless ; 1-120 to
1-96".

8. A. papillosus, E. Yellowish-brown;
1-600 to 1-430".

9. A. 'borax, D. (Trachelius vorax, E.).
Colourless*

10. A. ovum, D. (Trachelius ovum, E.).
Colourless.

BIBL. Ehr. Infusionsth., p. 354; Dujardin,
In/us., p. 483.

AMPHIMONAS.— A genus of Infusoria,
of the family Monadina (Duj.).

Char. Of irregular and variable form,
having at least two filaments, one anterior
the other lateral, arising from a narrowing of
the body, or both lateral, with or without a
tail-like prolongation.

Found in kept saline solutions and marsh
water. Species : —

1. A. dispar. Colourless; length 1-3860
to 1-2700" (PL 23. fig. 1 1).

2. A. caudata (Bodo saltans?, Ehr.).
Colourless; 1-2180 to 1-1270".

3. A. brachiata. Colourless.

BIBL. Dujardin, Infus., p. 292.

AMPHIPENTAS, Ehr.— A doubtful or-
ganism, regarded by Ehrenberg as a genus
of Diatomacese.

Char. Unattached ; frustules solitary, bi-
valve, pentagonal and siliceous. Species : —

1. A. pentacrinus ', diam. 1-240 .

2. A. alternans (PL 19. fig. 11).

Both are fossil. Ehrenberg questions
whether the latter does not consist of calca-
reous particles of an Echinoderm !

BIBL. Ehrenb. Eericht.d. Eerl. Ak. 1840
and 1843, Abhl 1841; Kutzm&Bacill. p. 136.

AMPHIPLEURA, Kiitz.— A genus of
Diatomaceae.

Char. Frustules free, straight or slightly
sigmoid; valves lanceolate or linear-lanceo-
late, each with two lateral longitudinal lines.

Ehrenberg regards the lines as corre-
sponding to ridges. We have only had
an opportunity of examining the frustules of
one species, A.pellucida (PL 12. fig. 7 a, side
view of frustule ; b, of valve). In this, the
frustules are very much flattened, so that the
front view can only be seen as they are
rolling over. The valves are furnished with
a median line, which is thickened and ex-
panded longitudinally at each end. There
is no median nodule.

The valves appear to resemble those c
Nitzschia in their inequality ; but they ar
compressed in the opposite direction to thos
of that genus, and thus the median lines c
both valves are visible at once. That th
lines seen upon the frustules are the same a
the median lines of the separated valves, i
evident from their exhibiting the termim
expansions. This view is confirmed by th
sides of the frustules being half as broad agai:
as the separate valves. British species : —

1. A.pellucida (Navicula acus of Mr. Sol
litt and the Hull naturalists, but not th
Nov. acus of Ehrenberg, which is the Synedr
subtilis of Kiitzing) (PL 12. fig. 7, a,b). Aqua
tic, valves linear-laneeolate ; length '0044'
The valves are furnished with longitudina
and transverse striae (rows of depressions ?
of extreme delicacy, requiring the very bes
object-glasses of the largest aperture, and th
most oblique light to render them visible
Mr. Sollitt estimates them at 125 to 130 i:
1 - 1 000". These valves form the most difficul
test-objects at present known, for angula
aperture and obliquity of light; but those o
some species of other genera are probabl
much more difficult.

2. A. rigida. Marine ; valves narrow!
linear-lanceolate, slightly sigmoid; lengtl
•0067" (PL 12. fig. 7 c, side view).

3. A.Danica. Valves lanceolate, truncate
length -0025"; found on the shores of Den
mark.

4. A.inflexa. Marine ; linear,lunate,slightl;
attenuate at ends, obtuse ; length *0030''.

BIBL. Kiitzing, Bacillar., p. 103; Spec
Alg. p. 88 ; Smith, Brit. Diat. i. p. 45.

AMPHIPRORA, Ehr.— A genus of Dia
tomaceae.

Char. Frustules free, solitary, constricte<
in the middle ; valves convex, having a me
dian keel, with a nodule at each end, am
either a nodule or stauros in the middle.

Marine, or inhabitants of brackish water.

The frustules are sometimes much twisted
occasionally resembling a violin in form
from one-half of the frustule being on a Ion
gitudinal plane almost at right angles to tha
of the other. The surface of the valves i:
more or less distinctly marked with trans
verse striae, which under high powers am
proper manipulation are resolvable into dot
or minute depressions, arranged as in PL 1 1
fig.8. SeeDiATOMACE^;. British species :—

1. A. alata, E. Common (PL 12. fig. 8
a, side view; b, front view).

2. A. constricta, E.

3. A. didyma, Sm.

AMPHISTOMA.

AMYLOID.

4. A. Kutzingii, Breb. (Vitrea^}, Sm.)

5. A. paludosa, Sm.

BIBL. Ehr. Abhandl. d. Berl. Akad. 1841,
p. 333 ; Kutzing, Bacill. p. 107 ; Spec. Alg.
p. 93 ; Smith, Brit. Diat. i. p. 43.

AMPHISTOMA (Holostomum, Diplodis-
eus). — A genus of Entozoa of the family
Trematoda.

Char. Body soft, oval, cylindrical or co-
nical; two pores, one anterior, the other
posterior.

Rudolphi enumerates 21 species, of which
3 are doubtful. They are most common in
birds, but sometimes occur in mammalia,
reptiles and fi3hes ; generally inhabiting the
alimentary canal ; length from l-10th to
4-5ths of an inch.

BIBL. See ENTOZOA.

AMPHITETRAS, Ehr.— A genus of Dia-
tomaceae.

Char. Frustules cubiform, connected with
each other by one of the angles, and thus
forming a chain or filament ; filament at-
tached by a short stipes ; marine. Side view
of the frustules rectangular, the angles some-
times produced ; valves covered with de-
pressions, which are readily seen under a low
power.

This genus approaches Isthmia and Bid-
dulphia, from which it differs in its rectan-
gular and not compressed figure. Species : —

1. A. antediluviana (PI. 12. fig. 9). Lateral
surfaces of the frustules with concentric ra-
diating depressions, their sides concave ;
British : a, frustules united ; b, side view ;
c, front view ; d, perspective view.

2. A. adriatica. Depressions concentric
and radiating; angles of the frustules ob-
tuse; lateral surfaces of frustules with
straight sides ; Adriatic sea.

3. A.parallela. Depressions parallel ; in
Greek marl.

BIBL. Ralfs, Ann. Nat. Hist. 1843, xii.
p. 275 ; Kutzing, Bacill. p. 135 ; Sp. Alg.
p. 133; Ehrenberg, Abh. d. Berl. Akad.
1839, pp. 122, 142; Ber. d. Berl. Akad. 1840,
p. 62.

AMPHORA, Ehr.— A genus of Diato-
rnaceae.

Char. Frustules solitary, free or adherent;
valves with a nodule (aperture ?) or a stauros,
at the middle of the margin on one side.

The nodules exist on the flat side of the
frustules; the frustules are plano-convex;
PI. 12. fig. 10 a represents a transverse sec-
tion ; the side view of the frustules can only
be seen when these are made to roll over, by
sliding the glass cover upon the slide with

the mounted needle. (INTRODUCTION, p.
xxii.)

The valves are furnished with transverse
striae, resolvable into dots, but in some spe-
cies they are excessively minute.

The species are both marine and aquatic.
British species : —

1. A. ovalis, K. Aquatic; frustules turgid,
oval, ends rounded or truncate ; length
1-400"; common (PI. 12. fig. 10, front
view; 10 a represents a transverse section).

2. A. minutissima, S. Aquatic, adherent
to other Diatomacese ; valves with a stauros ;
length 1-1200".

3. A. costata, S. Marine; ends beaked;
valves longitudinally ribbed ; length 1-500".

4. A. lineolata, Ehr. and K.

5. A. membranacea, S. (PI. 10. fig. 11).

6. A. coffeaformis, K.

7. A. affinis, K.

8. A. hyalina, K.

Kutzing enumerates 13 other foreign spe-
cies : — A. libyca, veneta, elliptica, aponina,
gracilis, ostrearia, quadrata, navicularis,
acutiuscula, borealis, carinata, crystallina,
and fas data.

BIBL. Kiitz. Bacill. p. 107; Spec. Alg.
p. 93 ; Smith, Brit. Diat. i. p. 19.

AMYLIDE CELL, of Kutzing. See
PRIMORDIAL UTRICLE.

AMYLOID. — The name was given by
Schleiden and Vogel to a peculiar modifica-
tion of vegetable substance met with in the
thickening layers of the cell- walls, in the coty-
ledons of certain Leguminosse, viz. Schotia
speciosa, S. latifolia, Hymencea Courbaril,
Mucuna urens, M.gigantea, and the tamarind
(Tamarindus indica) ; also of the common
white Haricot bean. When in a dry condi-
tion, it is of a soft horny consistence ; when
wetted, it softens, becomes gelatinous and
transparent; it is soluble in boiling water,
strong acids, and in solution of potash, but
not in alcohol or aether. It is coloured blue
by iodine, like starch, the compound being
soluble in water with change to a yellow co-
lour. The ' amorphous starch,' described by
Schleiden, in the seeds of Cardamomum mi-
nus, in the rhizomes of Carex arenaria and
Sarsaparilla, seems scarcely distinct from
amyloid ; it forms a thick viscous layer
lining the cells. Amyloid forms a trans-
itional substance between starch and bassorin
and cellulose, and probably presents modifi-
cations approaching more nearly to one or
other of them in different plants.

When cellulose is treated with a mixture
of 4 parts of sulphuric acid and 1 of water,

AMYLUM.

[ 32 ]

ANALYTIC CRYSTALS.

it swells into a clear jelly, which is at first
stiff, but gradually acquires liquidity ; alco-
hol or water throws down from it white flakes
of amyloid, which are coloured blue like
starch by iodine. It differs however from
starch, in the circumstance that the iodine
can be washed out of it, and the blue colour
made to disappear by the action of water,
which is not the case with starch.

The production of this substance forms a
valuable test of the presence of cellulose
in the higher plants. In applying the test,
the tissue to be examined is first dyed with
aqueous solution of iodine, the excess is then
removed by a piece of sponge, and a drop of
strong sulphuric acid added, and the mixture
set aside. The time required for the pro-
duction of the colour will vary ; sometimes
it appears immediately, at others some hours
may elapse. In some cases it can only be
produced when the substance has been pre-
viously treated with solution of potash or
strong nitric acid. Care must be taken, in
making this experiment, that the slide be
perfectly clean; it should be wiped with a
silk handkerchief or piece of wash-leather,
and not a linen or cotton cloth, because these
consist of cellulose ; also, blotting-paper
should not be used to absorb the excess of
the solution of iodine, for the same reason.
It frequently happens that the sulphuric acid
precipitates the iodine from the solution in
the form of exceedingly minute crystals,
which in mass have a purplish-blue tint.
This should not be forgotten as a source of
fallacy. See CELLULOSE.

AMYLUM. See STARCH.

ANABAINA, Bory. See TRICHORMUS.

ANACALYPTA, Rohl. (Musci). See

POTTIA.

ANACYSTIS, Kiitz. (Alga Palmellacea).
— Probably a resting form of Euglena. See
EUGLENA.

AN^CTANGIUM, Hedw.— A genus of
Mosses. See PILOTRICHUM.

ANALYTIC CRYSTALS. — This term
was proposed by Mr. Fox Talbot, in 1837,
to designate those crystals which possess the
power of analysing polarized light, like the
tourmaline. The substances in which this
property is best exhibited are the nitrate of
potash, the sulphate of chrome and potash
dissolved in tartaric acid by heat, boracic
acid, the oxalate of chromium and potash,
allantoin, hippuric acid, urea, oxalate of urea,
uric acid, &c. They must be immersed in
Canada balsam. The crystalline compound
of disulphate of quinine with iodine is infe-

rior to none in this power. The phaenomen
scarcely need description, since analytic cry
stals merely play the part of a thick plate c
tourmaline, or a Nicol's prism, i. e. if polar
ized light be transmitted through them (
polarizer alone being used)., in one positioi
they suffer it to pass freely, while if they ar
rotated 90° they arrest or absorb it entirety
or to a greater or less extent ; and if a plat
of selenite, or other depolarizer, be place*
beneath the slide upon which the crystal
are situated (without the analyser), th
lateral surfaces are seen to be coloured, th
complementary tints appearing at each quar
ter rotation.

Of course these crystals will act equally a
polarizers and analysers. Mr. Talbot gives th
following explanation of the cause of the phse
nomena in the crystals which he examined
When a beam of polarized light is transmitte<
very obliquely through a small prism of nitre
its outline generally exhibits two colours in
stead of one ; for while the edge of the prism
which is on that side from whence the ray o
light comes, is, for instance, red, the opposit
edge will appear green. On reversing thi
polarization of the light, these colours are ex
changed. This observationshows why the phse
nomenon only occurs in crystals possessinj
strong double refraction, like nitre, in whicl
the refractive indices of the two rays are mate
rially different. When a ray of common ligh
is incident upon such a crystal, and therefon
is divided into two rays oppositely polarized
both rays are transmitted through the cen
tral parts of the crystal, which are bounde<
by parallel planes, or by planes approachin{
to parallelism. But when the boundinj
planes of the crystal are much inclined t<
each other, and therefore refract the light ii
the manner of a prism, the refractive indice
of the rays may differ so much, that whiL
one passes freely through such a prism, thi
other cannot pass at all, but suffers total in
ternal reflexion, and is thereby dispersed
just as if the prism had a larger refracting
angle with respect to that ray than to thi
other. Therefore if two oppositely polarize*
rays are presented to such a crystal as in ou
experiment, one will be transmitted and thi
other not. That this is the true explanatioi
appears from this, that when the obliqui
planes are well-formed and clearly defined b;
the microscope, the colour also is accuratel1
limited by the same boundary ; so that whiL
this part analyses the tints of a plate of sul
phate of lime, the rest of the crystal is in
active.

ANANAS.

ANDILEACE.E.

That internal reflexion, however, is not
the cause of the separation of the coloured
rays, is shown by the fact that those lateral
surfaces of crystals which, when viewed
through the microscope (with the polarizer
and plate of selenite alone), appear of a cer-
tain colour, say green, exhibit the comple-
mentary tint, red, when viewed with the
naked eye from the side of the stage ; hence
the two coloured rays are separated merely
by refraction.

The margins of cavities containing air and
air-bubbles, which sometimes exist in the
crystals, exhibit the colours in the same
manner and from the same cause as the
lateral oblique surfaces of the crystals.

Nothing can surpass the curious and beau-
tiful appearance presented by analytic cry-
stals ; the delicacy and brilliant transparency
of their coloured margins giving them the
aspect of figures drawn with coloured ink.

PI. 7- fig. 11 a, b, represent two crystals
of nitre, viewed with the polarizer but nei-
ther the analyser nor the plate of selenite ;
fig. 12, a, b, represent two crystals as seen
when the polarizer and plate of selenite are
used, exhibiting the complementary colours;
fig. 12 c, represents an air-bubble enclosed in
the crystal. See DICHROISM and POLAR-
IZATION.

BIBL. Brewster, Phil Trans. 1835; Fox
Talbot, I.e. 1837.

ANANAS. See BROMELIACE.E.

ANAULUS, Ehr.— A genus of Diato-
maceae.

Char. Frustules single, compressed, sub-
quadrate, not furnished with either tubular
processes, nodules or apertures, but having
lateral constrictions.

In the latter character it resembles Bid-
dulpJiia.

Kiitzing admits one species : —

A. scalaris, Ehr. Valves turgid in the
young state, very broad and flat when ma-
ture ; having 4, 6, 8, or 14 lateral constric-
tions, which give the front view a ladder-
like appearance ; marine ; diameter 1-470 to
1-175'C

Found in the Antarctic Ocean.

A. indicus, Ehr. = Terpsinoe indica, Kiitz.

BIBL. Ehrenberg, Bericht. derBerl. Akad.
1844, p. 197 ; 1845, p. 361 ; Kiitzing, Spec.
Alg.-pp. 119, 120.

ANCHORELLA,Cuv.— A genus of Crus-
tacea, of the order Siphonostoma.

Char. Body short, produced in front into
a kind of neck, which is transversely rugose ;
arms two, furnished with a sucker or adhe-

sive disk at the end, and confluent through-
out their length.

Two British species : —

1. A. uncinata (PL 14. fig. 7), milk-
white ; found on the gills and gill-covers of
the cod, haddock and whiting ; length about

2. A rugosa, found on a species of cod ;
length about 1-3".

The above characters refer to the female.

BIBL. Baird, Brit. Entomostraca, p. 336.

ANCYRIUM, Werneck.— A genus of Po-
lygastric Infusoria, according to the system
of Ehrenberg.

Char. That of an Enterodelous Bodo, with
a moveable setaceous foot.

6 (?) species.

BIBL. Werneck, Bericht. d. Berlin. Akad.
1841, p. 377.

ANDILEA, Ehrh.— A genus of Mosses.
See ANDR^EACE^E.

ANDR.EACE.E.— A family of inopercu-
late Acrocarpous (terminal-fruited) Mosses,

Fig. 10.

Fig. 11.

Andrea rupestris.
Fig. 10, A sporange not yet open.

Fig, 11. A sporange burst into four valres, united at their
points. Magnified 20 diameters.

characterized especially by the peculiar mode
of splitting of the fruit, somewhat analogous
to that which is found in Jungermannia, the
urn-shaped capsule dividing perpendicularly
when ripe into four or eight valves, which
remain attached together at their points
(figs. 10 and 11). Many of the species have
the leaves of a dull brownish colour. The
cells of tissue of the leaves are parenchyma-
tous, with their walls thickened, and they
are somewhat papillose on the surface. The
calyptra at first covers the capsule entirely,
then splits off horizontally as a mitre-shaped
or bell-shaped cup, which is very fugacious.
The archegonia and antheridia are either on
the same or distinct plants (monoecious or
dioecious), and the latter terminal on distinct
branches. The few British species are na-
tives of rocky, usually alpine districts, and
constitute the only genus, Andraa.

D

ANEIMIA.

C 34 ]

ANGUILLULA.

Fig. 12.

ANEIMIA,
Swartz. — A
genus of Schi-
zaeous Ferns.
Exotic (fig.
12).

The fertile
fronds, bear-
ing the spo-
rangia, are re-

r!nr>prl fn rnprp Aneimia mandioccana.

duced to mere Group of sporanges bursting to dis-

riDS. charge the spores. Magnified.

ANELLIDA. See ANNULATA.

ANEURA, Du-

mortier. — A genus
of frondose Liver-
worts (see Pellieae),
growing in wet
places, containing
three British spe-
cies :

1. A. pinguis,
L. Frond irregu-
larly branched,
margins sinuate,
calyptra smooth,
whole plant brown-
ish - green. = J.
pinguis, Hooker,
Br. Jungerm. t.
46 (fig. 13).

Fig. 13.

Aneura pinguis.

2. A. multifida, Bursting sporanges. Nat. size.
L. Frond bipinnately divided, calyptra tu-
berculate. = J. multifida, Hooker, Br. Jun-
germ. t. 45 (figs. 14 and 15).

Fig. 14.

Fig. 15.

Aneura multifida.

Fig. 14. Portion of a frond with young perichsetes, mag-
nified 20 diameters.

Fig. 15. A perichsete, more magnified, cut open to show
the archegonia.

3. A. palmata, Nees. — Frond palmate,
calyptra tuberculate. = J. multifida, var.
palmata, Hooker.

BIBL. Hooker, Brit. Jungermannia.

ANGIOPTERIS, Hoffmann.— A genus of
Marattiaceous Ferns. Exotic.

ANGUILLULA, Miiller (Rhabditis,

Duj.). — A genus of animals, formerly placed
among the Infusoria, but arranged in the order
Nematoidea of the class Entozoa by modern
zoologists. The popularly known " eels "
in vinegar and paste, belong to this genus.

Char. Body filiform, narrowed at the
ends ; mouth terminal, round, naked ; anus
subterminal ; tail of the male either naked
or furnished with a membrane (winged) ; a
double spiculum ; tail of the female conical,
acute. The mouth is succeeded by an oblong
cavity (pharynx), which is furnished with
two or three longitudinal bacilli and is distinct
from the oesophagus, which is muscular and
fusiform or cylindrical ; stomach top-shaped
or spherical, furnished with a kind of dental
armature. The tail of the female is frequently
prolonged into a fine point. The uterus is
bifid, and the vulva situated near the poste-
rior third of the body.

These animals are especially remarkable
and interesting on account of their great
tenacity of life ; resembling in this respect
the Tardigrada and Rotatoria.

Thus, Aug. fluviatilis, when existing in
places exposed to the heat of the sun, will
dry up and become hard and brittle. But
as soon as remoistened by rain, it revives,
swells up, becomes soft, takes food and
exercises its reproductive functions as before.
The same faculty is possessed to an extra-
ordinary degree by Ang. tritici, which will
revive after having been kept in a dry state
for more than five years. Nor are they
destroyed by being frozen.

Dujardin admits three species : —

1. Ang. Jluviatilis (?) (Ang. terrestris,
Duj.) (P1.16.fig>.4). White,about fifteen times
as long as broad ; oesophagus fusiform,
expanded posteriorly so as to become conti-
nuous with the much larger stomach; length
of male 1-50 to 1-J2".

Found in wet moss and moist earth,
whence it gets washed into rivers and
ditches; sometimes also in the intestinal canal
of snails, frogs, fishes, worms and insects.

2. Ang. aceti (PI. 16. fig. 5). From 30 to
45 times as long as broad, narrowed poste-
riorly and terminated by a drawn-out point ;
oesophagus cylindrical; tail conical, pointed;
length 1-30 to 1-17".

This species was formerly very common in
vinegar, and the "eels in vinegar" were
favourite popular microscopic objects. To
the freedom of our vinegar from mucilage,
and the addition of oil of vitriol (sulphuric
acid) allowed by law, must be attributed
their absence in the present day.

ANGULAR APERTURE. [ 35 ] ANGULAR APERTURE.

3. Aug. tritici (PL 16. fig. 6). 20 times as
long as broad in the adult state; length 1-42
to 1-4".

Found in blighted wheat.

4. Ang.glutinis(¥\. 16. fig. 7). About 20
times as long as broad, terminating posteri-
orly in a fine elongated point; length 1-15".

Found in sour paste.

Other Anguillulce are found in the same
situations as A.fluviatilis; but whether they
are distinct species, or merely varieties, has
not been determined.

It is almost impossible to dissect these
minute beings in the ordinary manner ; the
best method of proceeding is to wound the
body, and gently press out the contents
under water.

BIBL. Duges, Ann. d. Sc. Nat. 1826, ix. ;
Bauer, Phil. Trans. 1823 ; Ehrenberg, Sym-
bol(B Physica (Phyt. Polypi) ; Dujardin,
Hist. d. Helminthes.

ANGULAR APERTURE.— The angular
aperture of an object-glass is the angle
measured by the arc of a circle, the centre of
which is formed by the focal point of the
object-glass, the radii being formed by the
most extreme lateral rays which the object-
glass admits.

Thus let fig. 16 represent a perpendicular
section of the lowest combination of an ob-
ject-glass of small aperture ;

Fig. 16.

Fig. 17.

a is the angle of aperture, and /, e the most
oblique rays which the object-glass will
admit ; the angle is measured by the dotted
arc b. In the object-glass of larger aperture,
fig. 17, the arc b which measures the angle
is much larger, and the radii representing
the extreme lateral rays are much more
oblique. Hence it is evident that the object-
glass of larger aperture admits all those rays
admitted by that of less aperture and a
certain number of other rays, these being
more oblique.

Measurement of the angle of aperture. — It
is of the utmost importance to know the
angle of aperture of the object-glasses used
in investigations; because the appearances
presented by objects frequently vary accord-
ing to the magnitude of this angle, and this
variation must always be taken into account
in determining the structure of an object
from its appearance. A particular piece of
Fig. 18.

E.ratus is requisite for this purpose
18), which may easily be constructed as
ws. A rectangular piece of board must
be procured, the shortest sides of which are
about 2 inches longer than the body of the
microscope, and the longer sides twice this
length. A small hole must then be made
opposite the middle of one of the long sides,
at about half an inch from its margin, and
from this, as a centre, a semicircle must be
traced upon the board, and the semicircular
line divided into 180°; the portions outside
the semicircle being cut away. The wooden
plate of this form is shown in perspective
in the woodcut. A flat thin piece of
wood (a) rather broader than the body of the
microscope, a little longer than the radius of
the semicircle and pointed at one end, is
then placed upon the board in such manner
that the pointed end corresponds with the
graduated margin, whilst the other end is
transfixed by a pin (b) which below is driven
into the board. Thus we have a rotating
arm or radius of the semicircle, which may
be compared to the hand of a watch or clock,
the pin forming the centre of rotation. To
the upper surface of this arm are glued two
thin pieces of wood, excavated in the middle,
so as to form supports for the body of the
microscope; the excavations should be tri-
angular, the apex being directed downwards.
When used, the object-glass to be tested
is screwed to the end of the body next the
pin, and so adjusted that its focal point is as
nearly as possible perpendicularly over the
pin. A lamp is placed 2 or 3 yards from the

D 2

ANGULAR APERTURE. [ 36 ] ANGULAR APERTURE.

board and upon exactly the same level as
the axis of the body of the microscope, the
straight side of the board being next the
lamp, and when the arm has been so adjusted
that the pointed end is opposite 90°, the
lamp is so placed that the flame is seen
through the body of the microscope. The
eyepiece is next put into the other end.
The arm supporting the body of the micro-
scope is then moved on one side, the body
looked through in the usual manner, until
the field is seen to be divided into two parts,
a dark and a luminous half; the degree
which the pointed end of the arm coincides
with is then noted, and the arm is moved in
the other direction until the division of the
field is again seen ; the number of degrees
included in the arc, thus traversed, measures
the angle of aperture.

It has been objected, that this method does
not afford an exact estimate of the angle of
aperture. But it is questionable whether
the objection made to it is real ; for it is a
fact that an object-glass, which, according
to the above method, is of larger aperture
than another, will display markings which
the one of less aperture will not.

As an object-glass of large aperture admits
a greater number of oblique rays than one of
less aperture, the central rays being in
nowise interfered with, so the total number
of rays admitted is greater, and objects will
thereby be more brilliantly illuminated. This
is one of the advantages gained by the use of
an object-glass of large aperture; and the
explanation applies especially to its use in
the examination of opake objects, in regard
to which it can be readily understood that a
greater number of the rays reflected from all
parts of an object being admitted, will render
it more luminous and distinct. In this case
the same effect would be produced by con-
densing an additional amount of light upon
the object.

But strictly speaking, large angular aper-
ture in an object-glass used in the examina-
tion of opake objects is disadvantageous; for
although objects thus viewed appear very
luminous, brilliant and beautiful, yet a
number of the rays which cannot enter an
object-glass of small aperture from their
obliquity, and which thus map out as it were
the form and structural appearances of the
object, are admitted by an object-glass of
large aperture, and thus the contrast by which
the various parts are rendered visible will be
destroyed. This applies especially to un-
coloured objects; for those which are

coloured are best seen under a glass of larger
aperture, the difference between the tints of
colour reflected being sufficient to render
each part distinct.

There is, however, another far more im-
portant use of large angular aperture in an
object-glass. It was first found by Dr. Go-
ring that longitudinal and transverse lines
upon the scales of Lepidopterous and other
insects could be seen under certain object-
glasses, but not under others ; and that the
power of displaying these, or the penetrating
power of the object-glass, as it is called,
depended upon the magnitude of the an-
gular aperture. The same has since been
found the case with the markings upon the
valves of the Diatomaceae.

1. If the prepared valve of a Gyrosigma
be examined under an object-glass of 1-4 or
1-8 of an inch focus, and an angular aperture
of 60° or 70°, as illuminated by the ordinary
light of the mirror, nothing more is seen
than the more or less coloured valve with a
distinct outline, the central line and the
nodules ; and no change is produced in the
appearances, however intensely the object
may be illuminated. But if an object-glass
of larger angular aperture be used, a number
of fine dark parallel lines are seen traversing
the valve. Hence the object-glass of larger
aperture possesses a particular power of ren-
dering indications of structure evident, wrhich
is not possessed by the one of less aperture.

2. If, in the same experiment, the mirror
be brought towards one side of the stage,
and the light be then thrown upon the object,
the lines will become more distinct if pre-
viously visible, and frequently visible when
not so before.

3. Placing a central stop in the object-
glass will also, to a certain extent, produce
the same effect as using the object-glass of
larger aperture.

4. Placing a stop in the condensing lenses
of the achromatic condenser will increase the
distinctness with which the markings are
seen, if already visible, and will frequently
render them visible when not so before.

These experiments show, that using an
object-glass of large aperture in the exami-
nation of an object, bringing the mirror to
one side, and placing a central stop in the
object-glass and the condenser, or in both,
produce the same effect, viz. that of render-
ing the markings upon an object visible when
not so previously, or of rendering them more
distinct if previously visible. And it is
evident that the alterations of the conditions

ANGULAR APERTURE. [

under which the object is examined in the
above experiments, involve simply the view-
ing of the object when illuminated entirely
or more completely by oblique light. For
an object-glass of large aperture admits more
oblique rays than one of less aperture, the
central rays being in nowise interfered with ;
inclining the mirror to one side, causes all the
rays which are reflected from it to become
oblique; and the use of central stops excludes
all the central rays, so that only the oblique
rays are admitted. Hence the visibility or
greater distinctness of the markings upon an
object depends upon its illumination by
oblique light.

Experiment also shows us, that the degree
of obliquity of the light requisite, varies with
the delicacy or fineness of the markings,
being greater as these are more delicate ; so
that the most delicate markings require the
most oblique light which can possibly be
obtained, to render them evident, and the
angular aperture of the object-glass must
necessarily be proportionatelylarge, otherwise
none of these oblique rays could enter it.

It has never yet been satisfactorily ex-
plained why transparent objects, which require
penetrating power in an object-glass, are best
shown, or can only be shown under the
microscope by oblique light.

In entering upon this question, we may
take the opportunity of examining somewhat
minutely the reason why objects become
visible to us under various circumstances.

The ordinary cause of objects becoming
visible to us under the microscope, is that a
certain number of the rays of light trans-
mitted through or incident upon them or
their parts, either become absorbed, refracted
or reflected. Thus the parts at which these
phenomena occur, may become either co-
loured or dark, whilst the parts which
transmit or reflect the light, become lumi-
nous. We shall leave the cases of absorption
and reflexion out of the question at present,
and consider only those of refraction.

If the parts which refract the light are
large in proportion to the power of the object-
glass and of irregular form, they will refract
a certain number of rays so that these cannot
enter the object-glass, and they will hence
become dark, and will map out, as it were,
in the image formed of the object, the
structural peculiarities of the object. But if
the parts are minute, of a curved form and
approximatively symmetrical, they will act
upon the light transmitted through them in
the manner of lenses, and their luminous or

] ANGULAR APERTURE.

dark appearance will vary according to the
relation of the foci of these to that of the
object-glass. Thus, the parts of an object
may appear dark and defined, from the
refraction of the light from the field of the
microscope ; also, from the concentration or
dispersion of portions of the light by these
parts, all the rays being admitted by the
object-glass, or entering the field. In speak-
ing of the parts being small or large, it must
be understood that the refractive powers of
the objects are assumed to be the same ; for
if the object be large and the substance of
which it is composed have a low refractive
power, the same effect may be produced as
if the object were small and of high refractive
power, the form being also the same.

Another condition, rather physiological
than optical, is concerned in the question of
the distinctness with which an object is seen,
nay, even of its absolute visibility. It con-
sists in the relation which the luminousness
or darkness of an object bears to that of the
field or back-ground upon which it is appa-
rently situated; and all objects, even those
seen with the naked eye, may be regarded as
viewed upon a back-ground or field, compa-
rably to an object viewed in the field of the
microscope. The familiar instance of the
visibility of the stars by day from the bottom
of a coal-pit, whilst invisible from the surface
of the earth, may serve to illustrate this
point. The same phenomenon is constantly
met with in microscopic investigations; thus
it is well known that parts of structure which
are visible most clearly by the light of a lamp
in a dark room, cannot be distinguished
when the room is illuminated by ordinary
daylight; and luminous objects are best seen
on a black ground, and dark objects on a
light ground.

The refraction of the light out of the field
of the microscope or beyond the angle of
aperture of the object-glass, is the ordinary
cause of the outlines of objects becoming
visible; and in these cases an increase of the
angular aperture of the object-glass will
impair their distinctness, because it will allow
of the admission of those rays which would
otherwise have been refracted from the field,
and the margins will become more luminous
and less contrasted with the luminous field.
All that is required here is that the object-
glass shall be achromatic, and that the mar-
ginal rays shall not be decomposed, so that
any of the coloured rays should enter the
field; in which case, the margins of the
objects would appear coloured instead of

ANGULAR APERTURE. [

black, and thus the contrast requisite for
distinctness would be lost.

The cause of the distinctness of an object
by refraction, all or nearly all the rays enter-
ing the field of the microscope, may be inves-
tigated in a drop of oil immersed in water,
or in a drop of milk, as illuminated by light
reflected from an ordinary mirror. The
refractive power of the globules is so great
and their form such, that each exerts the
action of a minute spherical lens; and the
parts within the margin will appear light or
dark according to the relation of the focus of
the little lens to that of the object-glass.
Under an object-glass of small aperture and
moderate power, the outline will always
appear black, because the marginal rays do
not enter the object-glass. If the object-
glass be of sufficient aperture to admit these
marginal rays, the black margin will disappear,
and the little lens will only be distinguish-
able by the above focal relation. Its appear-
ance under oblique light (thrown from all
sides, as when the condenser and a central
stop are used) will vary; but taking the case
of extreme obliquity of the rays, the lens will
only be visible by a luminous margin from
reflexion, giving it a very beautiful annular ap-
pearance. Hence it is more distinct by direct,
or slightly oblique, than by very oblique light.

But in certain objects, the irregularities of
structure are of such extreme minuteness, or
the difference of the refractive power of the
various portions of the structure is so slight,
that the course of the rays is but little
altered by refraction on passing through
them; and under ordinary illumination, all
the rays will enter the object-glass ; neither
are the rays accumulated into little cones or
parcels, of sufficient intensity to map out the
little light or dark spots in the field of
the microscope according to the relation of
their foci with that of the object-glass.

Let us take the instance
of an object with minute
depressions on the surface,
as the valve of a Gyro-
sigma. These are so mi-
nute, that when the light
reflected from the ordi-
nary mirror is used, the
rays passing through the
depressed and the unde-
pressed portions are not
sufficiently refracted to
cause either set to be ex-
cluded from the object-
glass, consequently both

Fig. 19.

] ANGULAR APERTURE.

sets will enter it. This may be supposed
to be represented in fig. 19, where the
slightly oblique and converging rays passing
through a portion of the valve become sepa-
rated into two sets, one passing through the
thinner depressed portions, the other through
the thicker and undepressed portions ; both
sets enter the object-glass. But on trans-

mitting oblique light through the object, as
represented in fig. 20, one set of the rays
will be refracted so as not to enter the object-
glass, whilst the other set will gain admis-
sion ; thus the two parts, which have differ-
ently refracted the rays, will become distinct.
If the markings were more delicate, or the
difference between the refractive power of
the two portions of the valve were less than
that represented in fig. 20, both sets would
enter the object-glass. But on rendering
the light still more oblique, one set would
be again excluded, from being refracted out
of the field. Hence it is evident why the
angular aperture of the object-glass must be
larger, as the markings are finer, or the
difference between the refractive power of
the two portions of tissue is less ; because
the obliquity of the light requisite to cause
the exclusion of one set of the rays will be
very great, and the other set will be too
oblique to enter the object-glass, unless it be
of correspondingly large aperture.

This is the simple explanation of the
necessity for oblique light to render evident
the markings upon objects.

No explanation of any peculiar agency by
which objects become more distinctly visible
when illuminated by oblique than direct
light is requisite, because it is not a fact that
such exists. The distinctness with which
objects or their parts are seen, always varies
according to the contrast they form with the
ground upon which they are viewed ; and in

ANGULAR APERTURE.

ANGULAR APERTURE.

the illumination of objects by oblique light
under the microscope, the manner in which
the rays are refracted or reflected by their
various parts, will always afford a satisfactory
explanation of the appearances they present
in accordance with the laws of refraction or
reflexion.

The most difficult point to explain, has been
how it is that an object-glass of large angular
aperture will render markings evident which
were not visible under an object-glass of
smaller aperture ; because it would naturally
be imagined that the larger aperture would
admit both sets of rays (fig. 20), one of which
was excluded by the object-glass of smaller
aperture. "The difficulty vanishes when it is
recollected that the additional rays admitted
by the object-glass of larger aperture are
more oblique; hence one set of these rays
will be refracted from the field of the micro-
scope, whilst the other set will enter the
object-glass and will illuminate the more
highly refractive parts of the object; thus
the two kinds of differently refractive struc-
ture become distinctly separated, one appear-
ing dark, the other luminous ; and thus we
illuminate one part of the object, whilst the
illumination of the other is not increased.
Or, to simplify this very important point, the
object may be regarded as illuminated by
two sets of rays, one corresponding to those
admitted by the object-glass of small aper-
ture ; the other set corresponding to these
plus those admitted by the excess of angular
aperture of the second object-glass over the
first; the first set of rays not being suffi-
ciently oblique to allow of a portion of them
being refracted beyond the angular aperture
of the first object-glass, whilst the second set
are so. Hence under the object-glass of
larger aperture, the distinctness of the mark-
ings is impaired by the admission of the first
set of rays. Now this always occurs when
objects are examined under an object-glass
of large aperture; although the more oblique
rays render the markings visible, by their
illuminating one part of the object and not
the other, the less obhque rays render them
indistinct by illuminating both parts, unless
the central stop be used, which totally inter-
cepts all but the very oblique rays, and allows
the markings to be seen in perfection, as
illuminated by the more oblique rays alone.
Refraction of the rays of fight has alone
been considered thus far; the action of
oblique light and angular aperture in relation
to colour and reflexion has been neglected.
The question of colour is easily answered.

Neither oblique light nor large angular aper-
ture possesses any power of rendering co-
loured transparent objects more distinct; and
markings, when arising from the presence of
pigment, are perfectly visible under an object-
glass of small aperture, and the ordinary
light of the mirror.

It has been assumed that the oblique
light requisite for the display of the markings
upon objects is separated into two sets of
rays by refraction; but it might be ques-
tioned whether these are not separated by
reflexion. There can be no doubt that the
latter is not generally the case ; perhaps the
most important reason which maybe assigned
for this is, the considerable comparative
breadth of the luminous portions, of the
valve of the Gyrosigma for instance. On
transmitting unilateral light obliquely
through the valve of an Isthmia, in which the
depressions are very large, in such manner
that part of it is reflected by portions of
them, it is easily seen how small the amount
of reflected light is; and this because the
surface of the depressions is curved, and thus
the portions inclined at the requisite angle
for reflexion are also very small. As the
amount of light reflected is so small in this
case, it would be inappreciable in that of the
Gyrosigma, in which the depressions are so
exceedingly minute. In fact, attention to
this point affords a ready means of distin-
guishing whether an object is illuminated by
reflexion or refraction. The illumination of
the sides of globules of oil by reflexion, has
been already noticed at p. 38. The same
phenomenon may be seen in the instance of
minute globules of metallic mercury. It
might be questioned whether the luminous
ring surrounding the globules in both cases
did not arise from diflraction. It is, however,
far too defined for this ; and it cannot arise
from refraction in the latter case, because
the globules of mercury are opake.

It has been shown, that the efficacy of
large angular aperture depends upon the
illumination of the objects by oblique light ;
and that the action of oblique light depends
upon one set of rays being refracted from
the field. Let us now attempt to trace the
relation of the penetrating power of an
object-glass to its defining power. It has
been stated, that penetrating power depends
upon angular aperture ; and as angular
aperture owes its efficacy to oblique tight,
the relation of oblique light to penetration is
evident. Is there any essential difference
between penetrating and defining power?

ANGULAR APERTURE.

ANIMAL KINGDOM.

This question will be best answered by ex-
periment. If we take a fragment of the
valve of an Isthmia, and examine it under a
high power of small aperture, all the parts
are very distinctly seen by the ordinary light
of the mirror ; and the various depths of
shadow of the different parts of the depres-
sions and the undepressed portions render
these also clearly distinguishable (PL 13.
fig.2c); and when an object-glass of very large
aperture is used, the distinctness is rather
impaired than improved. But if we examine
a fragment of the valve of a Gyrosigma, and
this requires an object-glass of large aperture
to render the markings visible, no distinction
of the various parts of the depressions and
the undepressed portions is visible ; all we
see is, that the depressions, as a whole, are
dark and the undepressed portions are lumi-
nous (PL 11. figs. 39, 40, 48). Hence the
Isthmia requires defining power, whilst the
Gyrosiyma requires penetrating power and
large angle of aperture, to exhibit the mark-
ings ; yet the structures differ only in size.
And there can be no doubt that if we could
examine the valve of the Gyrosigma under a
power as high relatively to the size of the
depressions, as that under which we can
examine the Isthmia, the same relations
being preserved between the angle of aper-
ture of the object-glass and the angular in-
clination of the refracted rays, the various
parts of the depressions and the undepressed
portions would be equally recognizable in
both cases.

The same relation applies to fine lines
scratched or etched upon glass. It was
noticed by Dr. Goring, that although the
lines on the scales of insects required an
object-glass of comparatively large aperture
to show them, yet those existing upon glass
micrometers did not so. But this statement
is only partially correct; for although the
coarser lines upon micrometers are well seen
under an object-glass of small aperture with
good defining power and direct light, yet the
finest lines upon Nobert's test-slide require
penetrating power in the object-glass, and
oblique light.

Hence it is evident that large angular
aperture or penetrating power in an object-
glass is a substitute, and a very imperfect
one, for defining power. This most import-
ant point has not hitherto been noticed; and
it is to be hoped that our object-glass
makers will direct their earnest attention to
it, and endeavour to supply those who are
engaged in microscopic researches with that,

to the production of a very imperfect substi-
tute for which, all their energy appears at
present devoted.

In conclusion, it may be noticed that these
remarks have been principally confined to one
class of objects requiring penetrating power,
viz. the valves of the Diatomacea3. This has
been done advisedly, because the scales of
Insects, which may be regarded as forming
the type of the other class, involve consi-
derations of a mixed kind, which would have
tended to confuse the subject. The longi-
tudinal ridges upon the scales of Insects, in
regard to their relation to penetration, may
be viewed in the same light as the unde-
pressed portions of the valves of the Diato-
macese; and the same explanation will apply
to the visibility of the one as to the other,
under the various conditions.

The transverse lines seen upon the scales
of insects, will be noticed under SCALES OF
INSECTS. The structure of the valves of
the DIATOMACE^E is discussed under that
head; see also INTRODUCTION, p. 33, /.

We have thought it better to refer the
angular apertures of the various object-
glasses to the article OBJECT-GLASSES.

The above article consists principally of
an abstract from a paper read before the
Royal Society of London on the 1 1th May,

BIBL. Wenham, Trans. Micr. Soc. iii.
p. 83, April 1850 and April 1854; Rainey,
ibid., Oct. 1853 and Jan. 1854; Gillett,
Proceedings of Royal Society, vii. 16.
March 1854; Lister, Phil. Trans, cxxi.;
Goring, Micrographia ; Select Works ; Jour-
nal of the Royal Institution, xxii. ; Pritchard,
Microscopic Cabinet ; Griffith, Proceedings
of Royal Society, vii. 60. May 1854.

ANIMAL. The definition of an animal
in reference to the distinction from vege-
tables is discussed in the article VEGE-
TABLES.

ANIMALCULE. — A little animal ; a
term usually applied to the species of Infu-
soria, Rotatoria, &c. It was formerly applied
also to many of the lower Algae. The Latin
term animalculum (with the plural animal-
cula) is frequently met with.

ANIMAL KINGDOM.— In accordance
with our plan, as laid down in the Preface,
we give here a tabular view of the animal
kingdom, so that the position of the various
classes and orders alluded to in various parts
of this work, may be readily found. Those
classes, orders, families and genera to which
particular interest is attached, in relation to

ANIMAL KINGDOM.

ANIMAL KINGDOM.

structure or other qualities, which the micro-
scope is required to investigate, are specially
treated of under their respective heads.

Kingdom. ANIMALIA.
Subkingdom. VERTEBRATA.
Class I. MAMMALIA.

Order 1. BIMANA.
Homo, man.

Order 2. QUADRUMANA.

Simla, ape ; Cercopithecus, common
monkey; Semnopithecus, Indian mon-
key.

Order 3. CHEIROPTERA.
Vespertilio, bat.

Order 4. INSECTIVORA.
Erinaceus, hedgehog ; Talpa, mole.

Order 5. CARNIVORA.

Canis, dog and wolf; Ursus, bear;
Felis, lion ; Phoca, seal ; Nasua, coati-
mondi.

Order 6. CETACEA.

Balcena, whale ; Phocana, porpoise.

Order 7- PACHYDERMATA.

Equus, horse ; Elephas, elephant ; Ha-
licore, dugong ; Sus, hog ; Hippopota-
mus; Cheiropotamus.

Order 8. RUMINANTIA.

Bos, ox; Camelus, camel; Cervus,
deer ; Capra, goat ; Ovis, sheep.

Order 9. EDENTATA.

Dasypus, armadillo; Brady pus, sloth.

Order 10. RODENTIA.

Cavia, guinea-pig ; Lepus, hare ; Sorex,
shrew ; Mus, mouse and rat ; Sciurus,
squirrel ; Castor, beaver and musk-
quash; Chinchilla.

Order 11. MARSUPIALIA.

Macropus, kangaroo ; Didelphys, opos-
sum.

Order 12. MONOTREMATA.

Ornithorhynchus, duck-billed platypus.

Class II. AVES, birds.

Order 1. ACCIPITRES.

Aquila, eagle ; Strix, owl.
Order 2. PASSERINA.

Fringilla, finch ; Hirundo, swallow ;

Turdus, thrush, blackbird.
Order 3. SCANSORES.

Cuculus, cuckoo ; Psittacus, parrot.
Order 4. GALLINA.

Gallus, fowl ; Columba, pigeon.
Order 5. GRALL^E.

Struthio, ostrich ; Grus, crane.
Order 6. PALMIPEDES.

Larus, gull; Anas, duck; Anser, goose.

Class III. REPTILIA.

Order 1. PERENNIBRANCHIATA.
Siren.

Order 2. CHELONIA.
Testudo, tortoise.

Order 3. SAURIA.

Crocodilus, crocodile ; Lacerta, lizard.

Order 4. OPHIDIA.
Boa ; Coluber, snake.

Order 5. BATRACHIA.

Rana, frog ; Bufo, toad ; Triton, water-
salamander; Menopoma.

Class 4. PISCES.

Order 1. GANOIDEA.

Lepidosteus, bony pike ; Sturio, stur-

Order 2. PLACOIDEA.

Squalus, shark ; Raia, ray.
Order 3. CTENOIDEA.

Perca, perch.
Order 4. CYCLOIDEA.

Salmo, salmon ; Clupea, herring ; Cy-

prinus, carp.

Subkingdom. INVERTEBRATA.

Class I. MOLLUSCA.

Order 1*. TUNICATA.

Ascidia, Salpa.
Order 2*. BRACHIOPODA.

Terebratula.
Order 3*. LAMELLIBRANCHIATA.

Ostrea, oyster; Mytilus, mussel.
Order 4f. PTEROPODA.

Clio.
Order 5f. GASTEROPODA.

Helix, snail ; Limasc, slug.
Order 6. CEPHALOPODA.

Sepia, cuttle-fish.

*** These three orders form the Acephala
of some authors.

ft These orders form the Cephalophora.
Class II. CRUSTACEA.

Order 1. PCECILOPODA.

liimulus, king-crab.

Order 2. SIPHONOSTOMA (Ichthyo-
phthira).

Lerncea, Argulus.
Order 3f. OSTRACODA.

Cypris.
Order 4f. COPEPODA.

Cyclops.
Order 5. CIRRIPEDIA (Cirrhopoda).

Balanus, acorn-shell ; Anatifer.

ANIMAL KINGDOM.

ANISONEMA.

Order 6f. CLADOCERA.

Daphnia.
Order 7t- PHYLLOPODA.

Branchipus, Artemia.
Order 8. ISOPODA.

Oniscus, wood-louse.
Order 9. AMPHIPODA.

Gammarus.
Order 10. STOMAPODA.

Squilla.
Order 11. DECAPODA.

Cancer, crab ; Astacus, lobster and

cray-fish.

tttt These four orders form the Entomo-
straca of some authors.

Class III. ARACHNIDA.

Order 1. PYCNOGONIDA (Polygonopoda}.

Pycnogonum.

Order 2. TARDiGRADA(CoZq/)0£?a) (water-
bears).

Milnesium, Macrobiotus.
Order 3. ACARINA.

Icarus, mites.
Order 4. PHALANGITA.

Phalangium, harvest-spider.
Order 5. PSEUDOSCORPIONES.

Chelifer.
Order 6. SOLIFUGA.

Galeodes.
Order 7. PEDIPALPI.

Scorpio, scorpion.
Order 8. ARANEIDA.

Aranea, house-spider.

Class IV. INSECTA.

Order 1. MYRIAPODA.

lulus.
Order 2. THYSANOURA.

Lepisma, Podura.
Order 3. ANOPLURA (Parasitica).

Pediculus, louse.
Order 4. APHANIPTERA (Siphonaptera

or Suctorid).

Pulex, flea.
Order 5. STREPSIPTERA.

Stylops.
Order 6. DIPTERA.

(Estrus ; Musca, fly.
Order 7. HYMENOPTERA.

Apis, bee ; Vespa, wasp ; Formica, ant.
Order 8. LEPIDOPTERA.

Butterflies and moths.
Order 9. NEUROPTERA.

Ephemera; Libellula, dragon-fly.
Order 10. HEMIPTERA.

Cimex, bug.

Order 11. ORTHOPTERA.

Blatta, cockroach ; Acheta, cricket.
Order 12. COLEOPTERA.

Beetles.

Class V. ANNUL ATA (Annelida or Anellidd).
Order 1. TURBELLARIA.

Planaria.
Order 2. SUCTORIA.

Hirudo, leech.
Order 3. SETIGERA.

Lumbricus, earthworm; Nais.

Class VI. ROTATORIA (Rotifera).
Order 1. ROTATORIA.

Class VII. ENTOZOA.

Order 1. STERELMINTHA. 1 Intestinal
Order 2. CCELELMINTHA. / worms.

ClaSS VIII. ECHINODERMATA.

Order 1 . PEDICELLATA.

Asteria, star-fish; Echinus, sea-hedge-
hog.

Order 2. APODA.
Sipunculus.

Class IX. ACALEPKLE.
Order 1. SIPHONOPHORA.

Physalia, Portuguese man-of-war.
Order 2. CTENOPHORA.

Beroe.
Order 3. DISCOPHORA.

Rhizostoma, Cyancea.

Class X. POLYPI (Zoophytes}.
Order 1. ANTHOZOA.

Hydra, Gorgonia, Actinia.
Order 2. BRYOZOA (Polyzoa}.

Flustra, Cellularia.

Class XI. PROTOZOA.

Order 1. FORAMINIFERA.

Order 2. POLYCYSTINA.

Order 3. SPONGI^E.

Order 4. LAGEN^B.

Order 5. INFUSORIA.

BIBL. Rymer Jones, Animal Kingdom ;
the various zoological articles in Todd's
Cycl. of Anat. and Phys. ; Siebold and
Stannius, Lehrbuch d. Vergleich. Anat. ;
V. d. Hoeven, Handbuch der Zoologie;
Owen, Hunterian Lectures ; Carpenter,
Comparative Physiology; Cuvier's Animal
Kingdom, by Blyth, Mudie, Johnstone,
Carpenter and Westwood; also the new
French edition of the Regne Animal.

ANISONEMA, Duj.— A genus of Infu-
soria, belonging to the family Thecamonadina.

ANKISTRODESMUS. [

Char. Body colourless, oblong, more or
less depressed, covered with a resisting tegu-
ment, from an aperture in which two filaments
emanate ; one flagelliform and directed for-
wards ; the other thicker, trailing and retract-
ing the body of the animal; movement slow.
2 species : —

1. A. acinus. Movement directly forwards,
colourless, aquatic; length 1-1280 to 1-810".

2. A. sulcata (PI. 23. f. 12). Movement
vacillating in a circle ; colourless, aquatic ;
length 1-1100".

Dujardin suggests that the Bodo grandis
of Ehrenberg is referable to one of these
species, ac also to the genus Heteromita,
Duj.

BIBL. Dujardin, Infusoires, p. 345.

ANKISTRODESMUS, Corda.— A genus
of Desmidiacea?.

Char. Cells elongated, attenuated, entire,
aggregated into faggot-like bundles.

The cells only differ from those of Closte-
rium in their aggregation. Species : —

1. A.falcatus, Corda (Rhaphidium fasci-
culatum, Kiitz.). Cells numerous, crescent-
shaped; aquatic; length 1-549"; breadth
1-7353"; common (PI. 10. fig. 47).

2. A.fusiformis, Corda. "I Carlsbad: nei-

3. A. convolutus, Corda. / ther of these
species are admitted into Kiitzing's Spec.
Alg.

BIBL. Ralfs, Brit.Desmidiece,^. 179 and
222; Corda, Almanach de Carlsbad, 1835,
p. 121 ; 1838, p. 199.

ANNUAL RINGS.— The concentric lines
seen in transverse sections of Dicotyledonous
stems (fig. 21).

Fig. 21.

]

ANNULATA.

Cross section of a Dicotyledonous stem with annual
rings.

These markings depend on the difference
of the character or condition of the tissues
produced at different seasons. Ordinarily
there are a number of ducts grouped near

the inner part of each concentric layer of
wood, as in the Oak. In the Sumach a layer
of cellular tissue occurs at the boundary of
each ring. In the Conifers the markings
result from the greater thickness of the
secondary deposits on the walls of the cells
in the outer part of each layer, no ducts

Fig. 22.

Magnified cross-section of stem of Pinus exhibiting parts
of three annual rings, 1, 2, 3.

existing in their wood (fig. 22). Many
modifications occur in tropical trees.

It seems that these rings cannot be taken
strictly as annual rings in all trees, especially
in those of equable climate, since they seem
to depend upon external influences affecting
the activity of vegetation ; and thus, even in
temperate climates, a great loss of foliage in
the summer, followed by recovery, may
produce two rings in one year ; in moist
tropical climates, where the leaves reappear
almost continuously, therings probably answer
to periods of great renewal of foliage.

ANNULATA, Anellida or Annelida.—
The class of red-blooded worms.

Char. Elongated animals, living in water
or moist earth, not parasitically within other
animals ; body usually jointed ; feet not
jointed, and frequently replaced by bristles
or retractile setigerous tubercles. Respira-
tion effected either by external branchiae or
by internal vesicles, or by the skin itself.
Distinct organs of circulation present, con-
tractile vessels replacing a heart. Nervous
system consisting of a single or double
ventral cord, furnished with ganglia at inter-
vals, and encircling the resophagus above.

The skin consists of a very delicate struc-
tureless and transparent epidermis, beneath
which (in Hcemocharis (Piscicola), Clepsine
and Nephelis), there is a layer of cells, which, in
the adult animals, presents the appearance of
a fenestrated membrane (PI. 40. fig. 16).
The cells (PL 40. fig. 16 b) leave spaces
between them which appear like holes ;
but the addition of acetic acid brings to light

ANNULATA. [ •

in each space a distinct nucleus (PI. 40.
fig. 16 c), and in very young animals the
clear spaces are distinct cells, distinguishable
from the surrounding cells by their size and
containing numerous clear vesicles as well as
a nucleus. The smaller cells contain a
nucleus and numerous nuclear granules.
Beneath this cellular layer are numerous
large fat-cells, pigment cells and connective
tissue, the latter consisting of a transparent,
homogeneous, semisolid mass. A layer of
fine but firm fibres, crossing each obliquely,
is said to be sometimes met with beneath the
epidermis and forming a corium or true
skin.

In the Turbellaria, the outermost cuta-
neous layer consists of ciliated epithelium.
The opalescent and often beautifully coloured
skin of many of the Annulata does not gene-
rally owe its tints to distinct pigment, but to
iridescence produced by the fibres.

The rings of the body are usually furnished
with bristles or hairs, sometimes arranged in
tufts, at others covering the greater part of
the surface of the body. Sometimes foli-
aceous appendages cover the body like scales.
Most of the Annulata are covered with a
kind of mucus, secreted by the cutaneous
glands ; some live in leathery tubes or
sheaths, in others a case is made by the con-
solidation of the secretion from some part of
the skin with fragments of shells, grains of
sand, &c. ; in others, again, the calcareous
tubes appear to be wholly secreted by a
portion of the cutaneous surface.

The muscular system is usually well deve-
loped. The muscular fibres are in some
arranged in three layers, an outer consisting
of annular, an inner of longitudinal, and an
intermediate of oblique fibres; in others
there is an outer layer of oblique fibres, an
inner of longitudinal, with annular fibres at
the two ends of the body. The muscular
fibres consist of cylinders, the transverse
section of which is rounded (PI. 40. fig. 17«),
flattened or incurvated (PL 40. fig. 17 b].
They are covered externally by a delicate
sheath or sarcolemma (PL 40. fig. 18 b}. The
cylinders themselves consist of a clear, ho-
mogeneous, cortical substance (P1.40. fig. 18a),
and an internal cavity (c), the latter being
filled with a finely granular substance, in
which scattered nuclei are imbedded (PL 40.
fig. 17 c}. At the two ends of the body, the
muscular fibres branch dichotomously (PL 40.
fig. 19 c). The fibres are usually smooth,
but sometimes longitudinally or transversely
striated ; this appearance arising either from

\ ] ANNULATA.

folds in the sarcolemma or proper sheath, or
from the granules being arranged in linear
series.

In the Turbellaria, the muscular system is
but slightly developed, the tissue beneath the
skin consisting of globular masses resembling
the general parenchyma of the body ; and in
this, peculiar cellular bodies are often im-
bedded, resembling the urticating organs of
the polypes. These enclose six, eight, or
more rod-shaped bodies, which are sometimes
parallel with each other, sometimes somewhat
spirally curved. The cell-membrane of these
bodies subsequently disappears, and they
frequently project beyond the skin. Ley dig
figures similar rod-shaped bodies as occurring
in the nuclei of the fat-cells situated beneath
the skin.

In many of the Annulata, the muscular
fibres are grouped into distinct bundles,
serving to move the bristles, parts of the
mouth, &c.

Beneath the skin at the ends of, or all
over the body, a number of peculiar glands
exist ; these consist at the closed end of a
nucleated cell (PL 40. fig. 19 b, d), and a
long, somewhat coiled duct opening at the
surface of the body.

The nervous system consists of a longitu-
dinal, single or double series of ventral
ganglia, connected by longitudinal cords ;
the uppermost ganglion lies above the osso-
phagus, and the two cords which connect
it with the second ganglion encircle this
organ. In some, the ventral ganglia are
absent.

The uppermost ganglion is enveloped in a
neurilemma consisting of longitudinal and
transverse fibres, and not unfrequently pecu-
liar pigment cells. The cords and filaments
are composed of extremely delicate primitive
fibres, between which, in the ganglia, gan-
glion-globules are situated. The filaments
distributed to the body arise principally from
the ganglia.

Many of the Annulata are furnished with
eyes; these are usually denoted by the brown,
black or red spots seen upon various parts of
the body. If, is a disputed point whether
all these represent true eyes or not; but
M. Quatrefages has described a lens, trans-
parent cornea and vitreous humour in some
of them, and he has no doubt that the red
points found at the sides of each ring in
several species of Nais are true eyes.

In some Annulata, no distinct head is
present ; in others this is distinguishable by
its form, and is furnished with eyes and one

ANNULATA.

ANOPLURA.

or more filaments, which are regarded as
antennae. In those in which the head is not
distinct, the mouth is situated at the anterior
end of the body ; in the others the mouth is
on the ventral surface, and is furnished with
a muscular proboscis. The mouth is usually
surrounded by turgid lips, and sometimes
possesses a distinct dental armature (see
HIRUDO). The oral aperture is frequently
surrounded by a number of erectile tentacles
or cirrhi.

The intestinal canal is usually straight,
and furnished with lateral appendages, or
constricted at intervals; sometimes a distinct
oesophagus, stomach and intestine are distin-
guishable.' The inner, and sometimes the
outer surface of the alimentary tube is
covered with ciliated epithelium. A yellow
or brown glandular layer surrounding the
alimentary canal represents the liver.

The general arrangement of the circulatory
system is, that two main vascular trunks, one
dorsal, the other ventral, traverse the body
longitudinally; and it appears that the blood
moves hi the dorsal vessel from behind
forwards, whilst in the abdominal vessel it
moves from before backwards ; these trunks
are connected by transverse vessels or meshes
of them. The anterior portion of the dorsal
vessel is usually broader, and appears to
form the rudiments of a heart.

The respiration of the Annulata is effected
either by the skin ; by external gills in the
form of filaments or tufts, sometimes ciliated;
by internal ciliated canals or water-vessels ;
by ciliated depressions, or by vesicles at the
sides of the body. In many instances, a
transparent colourless liquid occupies the
interstices between the skin and the organs
of the body ; this contains colourless (rarely
coloured) corpuscles much resembling the
colourless corpuscles of the Vertebrata ; and
in this lie coils of vessels containing the
coloured blood. The colourless liquid is the
" chylaqueous fluid " of Dr. Williams.

The Annulata are propagated by transverse
division, and by means of sexual organs.

See the articles APHRODITA, H^EMO-
CHARIS, H^MOPIS, HIRUDO, NAIS, NE-
PHELIS and PLANARIA.

BIBL. V. d. Hoeven, Handbuch der Zoo-
logie, vol. i.; Siebold, Lehrb. d. Vergl. Anat.
pt. 1; Todd's Cycl. of Anat. fy Phys., vol.i.
(Milne-Edwards) ; Quatrefages, Ann. d. Sc.
Nat. 3rd ser. vols. viii., ix., x. and xii. ;
Leydig (on Heemocharis (Piscicola}}, Siebold
and Kolliker's Zeitschr.f. Wissens. Zoolog.
vol. i. ; Johnston's Index to British An-

nelida, Ann. Nat. Hist., 1845, xvi.
p. 433.

ANOMALOCERA, Temp.— A genus of
Entomostraca, of the order ^Copepoda and
family Diaptomidae.

Char. Head distinguishable from the
body, with a bifid beak and a hooked spine
at the base on each side; thorax with six,
abdomen with four segments ; foot-jaws
three pairs ; last pair of legs differing from
the others ; eyes single, pedunculated in the
male ; right superior antenna with a swollen
hinge-joint (in the male) ; inferior antennae
not branched, three-jointed, basal joint with
a slender twig. 1 species : —

A. Patersonii (PI. 14. fig. 6, the male).
Marine.

BIBL. Baird, Brit. Entomostr. p. 229;
Templeton, Trans. Entom.Soc.vol.ii. 1837.

ANOMODON, Hook, and Taylor. — A
genus of Mosses. See NECK ERA and
HYPNUM.

ANOPLURA. — An order of Insects ;
sometimes termed Parasitica or Epizoa.

Char. Feet six ; wings none ; parasitic,
and not undergoing metamorphosis; eyes
two, simple, or none.

These insects are parasitic upon mammals
and birds, and are commonly known as lice.
The order is thus subdivided : —

Suborder I. HAUSTELLATA or
RHYNCHOTA.

Mouth with a tubular, very short haustellum.
Fam. 1. Pediculidce.

a. Legs of two kinds, anterior

ambulatory, posterior scan-

sorial Phthirius.

b. Legs all scansorial Pediculus.

Hcematnpinus.

Suborder II. MALLOPHAGA or
MANDIBULATA.

Mouth with two horny mandibles.

Fam. 2. Philopterid^e. Antennas filiform,
maxillary palpi wanting.

a. Antennae five-jointed, tarsi

two-jointed (i. e. two claws) . Philopterus.

b. Antennse three-jointed, tarsi

one-jointed Trichodectes,

Fam. 3. Liotheidce. Antennae clavate,
maxillary palpi conspicuous.

a. Tarsi two-jointed Liotheum.

b. Tarsi one-jointed Gyropus.

It appears that although the Anoplura do
not undergo metamorphosis as in the more
perfect insects, consisting of larva, pupa and

ANOURELLA.

[ 46 J

ANTENNARIA.

imago, widely differing from each other in
general appearance, habits and functions,
yet a series of semitransformations takes
place in the shedding of the skin a definite
number of times, by which the individual
acquires a greater symmetry of form, and
most probably a greater perfection of parts
or organs.

BIBL. Nitzsch, Germar and Zincken's
Magazin der Entomol. iii. ; Burmeister,
Gen. Insect. ; Leach, Zoological Miscellany,
iii.; Gurlt, Mag.f. die Gesammte Thierheil-
kunde, viii. ; Denny, Monograph. Anoplur.
Britann. ; Walckenaer, Hist. d. Insect, xiii.

ANOURELLA, Bory and DUJ. = ANU-
R.EA, Ehr.

ANTENNA, of Insects.— The two move-
able-jointed organs situated on the head,
near the eyes (PL 26, figs. I a, 3 a, 24 a, and
figs. 7 to 21 inclusive).

The form, number of joints, &c. of the
antennae are used as characters for distin-
guishing the genera and species of Insects.

Three parts are generally distinguishable
in the antennae : I, the scapus or basal joint
(figs. 10, 18 and 19 a}, is often very long,
and is connected with the torulus, or part
upon which it moves, by a ball and socket
articulation ; 2, the pedicella or second joint
(the same figs, b], which is mostly minute
and nearly spherical, allowing of the freest
motion, and supporting the remaining portion
of the antenna, which forms, 3, the clavola
(figs. 10 and 18 c). The principal terms
applied to the antennae according to the
form and arrangement of the joints of the
clavola are these : —

Theyare called setaceous when the success-
ive joints gradually diminish in size from
the base to the apex, as in the families
Achetidae, Blattidse and Gryllidae (fig. 7);
ensiform when the successively diminishing
joints are angular at the sides, forming a
sword-like organ, as in some of the Locust-
idae (fig. 8) ; filiform when all the joints of
the clavola are of uniform thickness, as in
the Carabidae (fig. 9) ; moniliform when the
joints are spherical or rounded, as in the
Tenebrionidse and Blapsidae (fig. 10) ; ser-
rated when the joints appear like inverted
triangles, with the inner margin more pro-
duced than the outer, as in some of the
Elateridae (fig. 11); imbricated when the
acute base of each joint is inserted into the
middle of the broad apex of the joint behind
it, as in the Prionidse (fig. 12) ; pectinated
when each joint is developed on one side
into a process or spine, as in the Lampyridae

(fig. 13) ; bipectinated when a process or
spine exists on each side of the joints, as in
the Bombycidae (fig. 14) ; flabellate when
each of the processes is flattened, and nearly
as long as the whole of the succeeding joints
taken together, as in some of the Elateridae
(fig. 15) ; clavate when the clavola ends in a
gradually formed knob (fig. 16), or capitate
when the knob is suddenly formed (fig. 17),
as in the Pentamerous Coleoptera ; plumose
when one or more minutely pectinated
branches arises from the joints, as in some
of the Muscidse (fig. 20), or when tufts of
capillary filaments arise from the joints, as
in the Culicidae (fig. 21) ; lamellate, as in the
lamellicorn Coleoptera, when the knob is
composed of a number of lamellae or plates
(fig. ISd), and perfoliate when the joints of
the knob are separated slightly from each
other by a minute foot-stalk. There are
many curious variations in the structure of
the antennas ; thus, in some of the Muscidse,
the filamentous portion represents the true
clavola, while the larger lobe is simply an
appendage (fig. 20) ; in Globaria Leachii
the pedicella is not a small rounded joint,
but is elongated like the scapus (fig. 19 b],
whilst the clavola (c) ends in a large capitu-
lum, attached laterally to the base of the
fifth joint, and directed backwards.

The use of the antennae is not agreed upon
by entomologists : Mr. Newport believed that
the primary function is that of hearing or
feeling the vibrations of the atmosphere,
an additional function in many insects being
that of common feeling or touch.

BIBL. Kirby and Spence, Introduction to
Entomology; Burmeister's Manual, fyc.,
translated by Shuckard; Newport, Art.
Insects, Todd's Cycl. Anat. and Phys. ii. ;
Westwood's Introduction fyc.

ANTENNARIA, Link.— A genus of An-
tennariei (Physomycetous Fungi). They are
byssoid products growing upon dead or living
structures, or sometimes in cellars. The my-
celium consists of a densely interwoven mass
of filaments, generally of dark colour, some-
times of very great extent. Species : —

1. Antennaria cellaris, Fries. Mycelium
very thick and abundant, lax, composed of
septate filaments, olive-black; perithecia glo-
bose, seated on the mycelium, and supported
by simple filaments. On casks, bottles, &c.,
often hanging down a foot or more from the
roof, in almost all close cellars.

Racodium cellare, Pers. ; Greville, Sc.
Crypt. Flora, t. 259. — Fibrillaria vinaria,
Sowerb., t. 432, 387, fig. 3.

ANTENNARIEI.

ANTHER.

2. A. semiovata, Berk and Br. Barren
filaments creeping, often united into an ir-
regular membrane. Fertile filaments erect,
generally slightly branched, sometimes sub-
dichotomous; pycnidia semiovate, sporanges
curved, acuminated. Clothing leaves of
Lastr&a Filix-mas with dense matted felt.
Ann. Nat. Hist. 2 ser. vol. xiii. p. 468. See
CAPNODIUM.

Antennaria leevigata, of which we give

Fig. 23.

Antennaria laevigata (highly magnified).

Corda's figure (fig. 23), is found upon the
bark of the birch in Germany. Diameter of
its spores about 5-2000".

ANTENNARIEI.— A tribe of Physomy-
cetous Fungi, consisting of diffuse plants,
forming flocculent or byssoid patches upon
leaves or bark, or upon walls in cellars. The
many-spored large sporange sessile on the
sides of erect, or in the midst of radiating
filaments, at once distinguishes these plants
from the Mucorini, where the microscopic
sporanges are supported at the tips of simple
or branched filaments.

Synopsis of British Genera.

I. Antennaria. Sporange membranous,
at first closed, then open, borne on a persist-
ent radiating mycelium composed of septate
filaments.

II. Pleuropyxis. Sporanges adnate to
the sides of simple, septate ascending fila-
ments, opening by a longitudinal slit.

III. Pisomyxa. Sporange membranous,
ostiolate, innate, on a persistent, radiating
mycelium, composed of septate filaments.

ANTHER.— The essential part of the
male or fertilizing organ of Flowering Plants,
supported on a longer or shorter stalk or
filament, and constituting with it the stamen.
The microscopic examination of anthers
turns in two distinct, both very interesting
directions, namely, study of the development
and characters of the pollen produced in the
anthers, and examination of the cellular
structure of the walls of the perfect anther.
For the former, see POLLEN.

The walls of the anthers of almost all plants
exhibit deposits of a more or less fibrous cha-
racter, varying much in the patterns accord-
ing to which the fibres are placed, and the
extent to which they are developed; and
these are elegant microscopic objects.

The anther is clothed with a very delicate
epidermis, sometimes provided with stomates;
this epidermis usually remains unaltered, but
in some cases (l/upinus) the walls acquire

Fig. 24.

fibrous thickening. Be-
neath this epidermis ordi-
narily lies one or more
layers of cells which form
the spiral-fibrous tissue C -
(fig. 24) . This may extend
all round the anther, or be Section of wall
wanting at certain points, c^dermal cells,
especially over the con- E. Fibrous tissue.
nective, before and behind; Magnified 250 diams.
sometimes all the cellular tissue of the con-
nective itself assumes the same character
(with the exception of its vascular bundle).

Purkinje has furnished a most extensive
notice of the conditions of these fibrous cells
in the different families of Flowering Plants.
The following plants are selected as affording
considerable diversity of forms : —

a. Spiral fibres. Narcissus poeticus, Po-
pulus alba, Lonicera tatarica, Hyoscyamus
orientalis, Datura Stramonium, Cheiranthus
Cheiri (PI. 32. fig. 1).

b. Annular fibres. Iris Jlorentina, Hya-
cinthus orientalis, Bunias orientalis, Chei-
ranthus Cheiri, Convallaria.

c. Reticulated fibres. Fritillaria imperi-
alis (on the internal face), Tulipa Gesneriana
(ditto), Viola odor at a (ditto), Saxifraga
umbrosa (PL 32. fig. 2).

d. Fibres arched (founed on three sides
of the walls, the fourth being free). Nuphar
lutea, Bryonia dioica, Cynoglossum, Pulmo-
naria, Primula sinensis, Passiflora ccerulea,
Ligustrum vulgare, Cucurbita, Pyrus, Lupi-
nus (PI. 32. fig. 3).

e. Fibres short and straight, pieces upon
the walls standing vertically to the epidermis.
Arum, Calla athiopica, Calceolaria, Del-
phinium, Anemone.

f. Like d, but converging towards the
centre of the upper wall of the cell, some-
times forming a star. Corydalis lutea, Im-
patiens, Fumaria, Cactus (PI. 32. fig. 4),
Polygonum, Tropaolum majus, Veronica
perfoliata, Polygala Chamabuxus, Rubia
tinctorum, Armeria.

g. Fibres vertical, very short, numerous
and close, like teeth on the walls. Grasses,

ANTHERIDIA.

48 ]

ANTHINA.

Casuarina, Myosotis, Phlomis fruticosa,
Robinia, Adonis vernalis, Glaucium luteum,
Chelidonium majus, Magnolia, Liriodendron,
Dahlia, Leontodon, Solidago, Bellis perennis
(PI. 32. fig. 5), Geranium, Pelargonium,
Pinus, Cupressus, Juniperus.

h. The walls simply thickened like wood-
cells. Zamia.

Other intermediate modifications exist, and
it is necessary to observe that the character
of the markings often differs in different
parts of the wall of the anther. The side of
the cell-wall next the cavity is that generally
most marked; the outer-wall lying next
under the epidermis is often smooth and
unmarked.

A similar structure is found on the walls
of the sporanges of many of the Hepaticae,
such as Marchantia (PI. 32. fig. 35), Junger-
mannia, &c. (see HEPATIC^B). Also on the
walls of the sporanges of Equisetum (see
EQUISETACE^E). For further particulars
respecting the relations of these cells to other
spiral-fibrous tissues, see SPIRAL STRUC-
TURES.

BIBL. Purkinje, De cellulis antherarum
fibrosis, Wratislaviae, 1830.

ANTHERIDIA.— The general name ap-
plied to all the various structures in which,
certainly or probably, the fertilizing function
of reproduction resides in Flowerless Plants,
and which consequently correspond physio-
logically to the anthers of the Flowering
Plants. They all agree in one point, namely,
in the character of the final products, which
are extremely minute bodies, endowed with
spontaneous motion when placed in water.

The antheridia of the higher Flowerless
Plants, those with leaf and stem, produce
active filaments, coiled more or less in a spi-
ral form, and the motion is here connected
with the presence of cilia upon the spiral fila-
ments. With regard to those of the Thallo-
phytes, the antheridia are not so well under-
stood. Their existence is clearly ascertained
in the Fucacege, and the active bodies are
ciliated : this is not yet fully ascertained of
those of the Florideae, and the observations
relating to them in the Confervoideae are as
yet in a doubtful state. In the Fungi and
Lichens the antheridia seem to be repre-
sented by a different kind of structure,
which produces free minute stick-shaped
bodies, apparently endowed with spontane-
ous motion.

The moving bodies from the antheridia are
called spermatozoids, anther ozoids, or sper-
matic filaments in the higher Cryptogamia.

Fig. 26.

The active bodies of the Fungi and Lichens
have been provisionally named spermatia.

The antheridia of the Rhizocarpese are re-
presented by the smaller form of spore pro-
duced in the sporanges (see RHIZO CAR-
PED). This is also the case in regard to the
Lycopodales so far as Selaginella and Isoetes
are concerned (see LYCOPODALES). In the
Ferns and Equisetaceae the antheridia are
produced along with the
archegonia on the prothal-
lium or cellular frond re-
sulting from the germina-
tion of the spore (see
FERNS and EQUISETA-
CE.E). In the Mosses and
leafy Liverworts, the an-
theridia are produced in
terminal or axillary buds,
associated with or separate
from the archegonia (fig.
25). In the frondose Liver-
worts, they are imbedded Bartramia fontana.
in the frond, or more Or less Male inflorescence with

raised from it on special S^^&ffS

receptacles (see MOSSES diameters.
and HEPATICAE).

The supposed antheridial organs of the
Lichens are called spermagonia, and will be
found described under LICHENS, and the
analogous structures found in certain Fungi
called by the same name, are described un-
der CONIOMYCETOUS FUNGI, also under the
heads of certain genera of that family. The
antheridia of the Algae are best known in the
Fucaceae, and are described under that head,
and more particularly under Fucus. For
those of the FLORIDE^E see that heading, and
for the statements in regard to the Confer-
voidese, see OSCILLATORIE^E, CONFERVA-
CE,E, also MICROGONIDIA and SPERMATO-
ZOIDS. See also CHARA.

BIBL. See under the special heads re-
ferred to.

ANTHEROZOIDS.— The term applied
by the French authors to the moving bodies
of antheridia. See SPERMATOZOIDS.

ANTHINA, Fries. — A genus of Isariacei
(Hyphomycetous Fungi), composed of mi-
nute fibrous plants, often of bright colours,
growing upon dead leaves, &c. in autumn.
One British species is recorded.

A.flammea, Fr. Attenuated downwards,
smooth, crimson- saffron, dilated upwards,
feathery, yellow. Clavaria miniata, Purton.
A beautifully coloured Fungus, varying as
to the degree of ramification, scarcely 1-2'"
thick at the base j thickened upwards, as also

ANTHOCEROS.

ANTHOPHORA.

are the branches; fibrous and feather}7 at the
summit; solitary; from 1-2" to l"high; turn-
ing blackish when dried. The spores sepa-
rate very readily when the specimens are
placed in water for examination.

BIBL. Purton, iii. t. 18; Nees and
Henry, System der Pilze, 1837, t. 6.

ANTHOCEROS, Mich.— A genus of An-
thoceroteae (Hepaticaceae). Fruits scattered.
Perichaete produced by the thrusting-up of
the substance of the frond, truncate or some-
what lobed round the mouth ; -pi*. 26
perigonenoiie; epigone conic-
al, bursting below, fugacious ;
sporange "pod-shaped, two-
valved, pedicellate, with a
central, persistent, filiform
column; elaters with spiral
fibre absent or rudimentary;
antherids surrounded by a
toothed, cup- shaped peri-
chaete.

The forms found in Britain
are regarded by Hooker as
varieties of one species. By
the continental botanists they
are divided into two : A.punc-
tatus, with the frond dotted
and divided at the margin;
and A. l&vis, with the frond
smooth (fig. 26).

These plants are found in very moist situ-
ations, at the sides of ditches, &c., fruiting
in spring. The ovate-oblong fronds are
from £ to f of an inch long, lying flat, and
often forming round patches, overlapping
one another, radiating from a centre, and
more or less divided at the margin. The
texture is between membranaceous and fleshy,
inclining to the latter; the colour deep green,
lighter at the margins. The antheridia and
archegonia are usually abundant on the same
individual. The antheridia are spherical,
with short stalks, of a yellowish-orange co-
lour, included in cup-shaped, deeply toothed
receptacles on the upper face of the fronds.
The young archegonia differ from those of
any other Hepaticaceae in their structure,
since, instead of free, flask-like cases, they
are tubular cavities running down from the
upper face of the frond, with an embryonal
cell at the bottom, which increases by de-
grees into a conical body, and finally emerges
on the surface, surrounded by a perichaete
continuous with the epidermis of the frond.
The conical body by degrees grows up into
the narrow pod-like sporange, which attains
a length of about 2 inches, and is supported

Anthoceros Isevis.
Nat. size.

on a short pedicle, 2 to 3 lines high, almost
concealed in the perichaete. The sporange
splits down the middle into two valves, which
become slightly twisted, and leave in the
centre a thread-like column, to which adhere
for a time many of the spores and elaters.
The spores, — the development of which has
been a subject of much study, and is very
instructive, — from the long sporange con-
taining specimens of successively older form-
ation from one extremity to the other,— are
of the ordinary character of these tribes,
having a reticulated outer coat, marked by
ridges indicating the mutual pressure of the
four spores formed in each parent-cell. The
elaters are much simpler than usual, consist-
ing merely of membranous tubes, not very
long, but sometimes irregularly curved or
branched, without any spiral fibre in their
interior. Gemmae also occur on the frond of
Anthoceros.

BIBL. Dev. of the Fruit generally: Hof-
meister, Vergleich. Unters. Hohern Krypto-
gamen, Leipsic, 1851 ; Schacht, Entw. die
Frucht und Spore von Anthoceros lavis, Bo-
tanische Zeitung, 1850. Spores : Mohl, Lin-
n<ea, 1839; Vermischte Schrift, Tubingen,
1846; Nageli, Memoir on Vegetable Cells,
translated in Ray Society's Reports and
Papers on Botany, 1846 (p. 229), from Schlei-
den and Nageli's Zeitschr.fur Wiss. BotaniJc.

ANTHOCEROTE^E.— A tribe of Liver-
worts or Hepaticaceae (which see), containing
the single genus ANTHOCEROS.

ANTHOPHORA, Latr.— A genus of In-
sects, of the order Hymenoptera, and family
Apidae.

Char. Wings with three complete sub-
marginal cells of equal size ; labial palpi with
the third joint affixed obliquely; maxillary
palpi 6-jointed; intermediate legs of male
with long brushes of hair.

There are two species, A. retusa and A.
Huworthana.

A. retusa is commonly seen flying about
sunny and sandy banks in March, April, May
and the beginning of June. Its head and
trophi are represented in PI. 26. fig. 24.

The antennce (a) are inserted in the centre
of the face, not approximating, short, geni-
culated, and 13-jointed in the male; basal
joint (scapus) very pubescent, second (pedi-
cella) globose, third as long as the first,
fourth shorter than any of the following,
which are oblong; they are similar in the
female, but a little longer, and 12-jointed.
Labrum (e) deflexed, convex, with two black
spots at the base, anterior margin a little

ANTHOPHYSA.

ANTLIA.

convex and ciliated. Mandibles (/) slightly
curved, clothed with long hairs, notched
near the apex ; larger in the females, and but
slightly notched below the apex. Maxilla
(g) with the basal portion short and broad,
hairy, the edge above pectinated, terminal
lobe long and lanceolate, with a small pencil
of hairs at the apex. Palpi (h) rather long
and setaceous, 6-jointed, basal joint short,
second long, the remainder decreasing in
length. Mentum rather short and linear.
Tongue (*) very long and slender, ringed and
tubular, the interior margins very pilose,
terminated by a lanceolate appendage. Para-
glossce (x) lanceolate. Palpi (&) extending
as far as the tongue (in our figure the tongue
is represented as longer than natural), slen-
der, tapering, 4-jointed, basal joint very long,
second not half the length, ciliated towards
the apex, third inserted below the apex, and
very small, as well as the fourth. Head sub-
trigonate ; eyes (c) long and narrow ; ocelli
(b) three. Thorax much broader than the
head in the female. Legs rather robust;
tibias, posterior dilated, and very pilose ex-
ternally, and the intermediate ones also in
the females ; tarsi, intermediate pair long in
the males, the basal joint of the 4 posterior
dilated in both sexes, and furnished with a
strong brush at the apex in the hinder pair
of the female. Claws bifid in the males,
with a tooth on the underside in the females.
Pulvilli distinct. Male thickly and minutely
punctured, and clothed with fulvous or yel-
lowish hairs, more or less black at the apex
of the abdomen ; female black, very pilose.
See INSECTS.

BIBL. Curtis, British Entomology, viii. p.
357; Westwood, Introduction, &c., ii. p. 86.

ANTHOPHYSA, Duj.— A genus of Infu-
soria, of the family Monadina (Duj.).

Char. Animals ovoid or pyriform, with a
single anterior flagelliform filament, and ag-
gregated at the ends of the branches of a
support or polypidom, which is secreted by
them. The groups, when free, resemble Uvel-
la, and revolve in the liquid containing them.

The branched support is of an irregular
arborescent form, at first soft and glutinous,
afterwards becoming brownish, horny, and
nodular in appearance.

A. Mullen (PI. 23. fig. 13). Body thicker
in front; aquatic; length of stalks 1-250 to
1-120", length of single animal 1-2600".
Fig. 13 b represents a detached animal with
its flagelliform filament. This is the Epistylis
vegetans of Ehrenberg.

BIBL. Dujardin, In/us.', Ehr. Infusionsth.

ANTHOSOM A, Leach.— A genus of Crus-
tacea, of the order Siphonostoma, and family
Ergasilina.

Found upon the gill-covers and gills of
sharks.

BIBL. Baird, Brit. Entom. ; Desmarest,
Cons, gener. sur I. Crustac.

ANTIGRAMMA, Presl. — A genus of
Scolopendrie8e(Polypodaeous Ferns). Exotic.

ANTIMONIATE of soda.— The produc-
tion of this salt by the addition of antimo-
niate of potash to a neutral or alkaline solu-
tion of a salt of soda, is used as a test of the
presence of soda. The crystals are represented
in PI. 6. fig. 2.

BIBL. See CHEMISTRY.

ANTIMONY. See ARSENIC.

ANTLIA. — The spiral tongue or proboscis
of the Lepidoptera.

This well-known beautiful organ (PI. 26.
fig. 28), when extended, forms a long sucto-
rial tube, and when coiled up represents a
flat spiral, like the main-spring of a watch.
It consists mainly of two modified maxillae
(see INSECTS). According to Mr. Newport,
each maxilla is composed of an immense
number of short transverse muscular rings ;
these are convex externally and concave
internally, and the two connected organs
form a tube. Within each there are one or
more large tracheae (fig. 28 c*!) connected
with the tracheae in the head. The inner or
concave surface which forms the tube
(fig. 28 c f) is lined with a very smooth
membrane, and extends along the anterior
margin throughout the whole length of the
organ. At its commencement at the apex
(fig. 28 / *), it occupies nearly the whole
breadth of the organ, and is smaller than at
its termination near the mouth, where the
concavity or groove does not occupy more
than about l-3rd of the breadth. In some
species, the extremity of each maxilla is
furnished along its anterior and lateral
margin with a great number of minute
papillae. These, in Vanessa Atalanta (the
red admirable butterfly) for instance, form
little barrel-shaped bodies (fig. 28 b, «, /),
furnished at the free end with three or more
marginal teeth, and a larger pointed body in
their centre. There are seventy-four of
these in each maxilla, or half the proboscis.
Mr. Newport regards them as probably
organs of taste. There are also some curious
appendages arranged along the inner anterior
margin of each maxilla, in the form of
minute hooks, which, when the proboscis is
extended, serve to unite the two halves

ANTROPHIUM.

[ 51 ]

APHANIZOMENON.

together, by the points of the hooks in one
half being inserted into little depressions
between the teeth of the opposite side ;
sometimes these are furnished with a tooth
below the apex (fig. 28 c).

This description of the structure of this
interesting organ does not appear to be
correct. We believe that the older view, re-
garding each half of the Antlia to contain a
distinct canal, to be true; and that the trans-
verse rings, in fact the entire frame-work of
the organ, consists of chitine. But the subject
requires further investigation. The only
muscular structure we have detected in the
organ, consists of bundles of muscular fibres
taking an oblique longitudinal direction.

BIBL. Newport, Todd's Cycl. of Anat.
and Phys. ii. p. 901. See also INSECTS.

ANTROPHIUM,
Kaulf. — A genus of
Gymnogrammeae (Po-
lypodaeous Ferns),
with the sori imbedded
in a kind of groove
along the backs of the
veins. Exotic.

The annexed magni-
fied figure (fig. 27) re-
presents part of a sorus
with some of the theca
or sporanges in situ,
having the perpendi-
cular annulus charac-
teristic of this family.

Fig. 27.

Antrophium Lessoni.

Part of a sorus.

Magnified.

ANUR^EA, Ehr.— A genus of Rotatoria,
of the family Brachionaea.

Char. A single (red) eye-spot at the back
of the head, no foot or pediform tail.

In seven species the back of the carapace
is furnished with facets, in four with longi-
tudinal striae, in three it is smooth; in
thirteen it is furnished with teeth or spines
in front, in seven also behind. One species,
A. biremis, has two moveable spines on each
side.

Dujardin gives the following characters.
Carapace in the form of a depressed utricle
or sac, toothed in front and with a wide
orifice to allow of the protrusion of the rota-
tory organs, which are usually well developed
in the form of two rounded lobes, accompa-
nied with setae or non-vibratile cilia in several
bundles ; no tail ; jaws digitate ; a red eye-
spot above the jaws ; ova voluminous, often
adherent to the parent.

The species are both aquatic and marine,
and many of them are common in pure fresh
water; length from 1-240 to 1-120".

1. A. quadridentata, E.

2. A. squamula, E.

3. A.falculata, E.

4. A. curvicornis, E. (PI. 34. fig. 5, viewed
from above ; fig. 6, side view).

5. A. biremis, E.

6. A. striata, E.
7- A. inermis, E.

8. A. acuminata, E.

9. A.foliacea, E.

10. A. stipitata, E.

11. A. testudo, E.

12. A. serrulata, E.

13. A. aculeata, E.

14. A. valga, E.

To these Mr. Gosse adds, A.jissa, A. tecta,
A. brevispina and A. cochlearis.

BIBL. Ehr. In/us.-, Duj. Infus.; Gosse,
Ann. Nat. Hist. 1851, viii. p. 202.

ANYSTIS, Heyd. (Erythraws, Duges;
Trombidium, Herm.). — A genus of Arachnida,
of the order Acarina, and family Trombidina.

Char. Palpi large, free, bi-unguiculate (?);
mandibles unguiculate ; body entire ; legs at
their insertion contiguous, cursorial, i. e.
unguiculate, long, the last joint slender and
very long ; posterior legs the longest.

1. A. parietinum. Colour vermilion ; palpi
with a single claw, mucronate below. Found
between stones and in moss ; and on book-
shelves. Tromb. parietinum, Herm. Mem.
Apterol.ip.37.pl. 1. f. 12.

2. A. ruricola. On stones and on dry
paths. (PI. 2. fig. 3.)

3. A.flava (Tr.flavum).

4. A. ignipes.

5. A. cursoria.

6. A. cornigera.

BIBL. Hermann, Mm. Apterol.\ Duges,
Ann. d. Sc. nat. 2 ser. i. and ii. ; Koch,
Deutsch. Crust. &c. ; Hey den, Isis, 160;
Gervais, Walckenaer's Hist. d. Insectes, iii.

APHANIZOMENON, Morren (Limno-
chlide, Kiitzing). — A genus of Nostochineae
(Confervoid Algae) forming a delicate bluish
mucous stratum on the surface of lakes or
standing water. The filaments are very
slender, flaccid and obscurely jointed. No
vesicular cells have been detected ; the sper-
matic cells are much elongated, either
scattered or, more frequently, solitary near
the centre of the filament. Ralfs states that
he is not disposed to place much dependence
on the character of coherence in flat lamellae,
since he could not detect it in A. cyaneum.
which does not appear to differ generically
in other respects. This genus seems to form
a connecting link between the Oscillatorieae

E2

APHANOCAPSA.

APHID^E.

and Nostochineae, as indicated by Hassall.
Its filaments agree with Oscillatoria, but are
distinguished by the conspicuous spermatic
cells, resembling those of Dolichospermum,
and it differs from all the rest of the Nosto-
chinese in the absence of vesicular cells and
the obscurity of the articulations of the
filaments. Ralfs enumerates three British
species, viz. —

1. A. Flos-aqua, Linn. — Filaments cohe-
ring laterally in flat lamellae which separate
at their extremities into fasciculi ; spermatic
cells cylindrical, with an inconspicuous
covering. — Ralfs, Ann. Nat. Hist. ser. ii.
v. pi. 9. fig. 6. Syn. Oscillatoria Flos-
aquce, Agardh, Syst. Alg.; Nostoc Flos-
aquce, Jiirgens; Limnanthe Linncei, Kiitzing,
Linneea, xvii. 86; Limnochlide Flos-aqua,
Kiitz., Phycologia Generalis, Phycologia
Germanica, and Tabulae Phycologica, cent. i.
pi. 91. fig. 2 a. (PI. 4. fig. 1).

2. A. cyaneum, Ralfs. Filaments free, ag-
gregated into a thin mucous stratum; sporan-
gia linear, 8 to 12 times longer than broad, with
a conspicuous hyaline covering. — Ralfs, I. c.
pi. 9. fig. 7- Limnochlide Flos-aqua var.
hercynica, Kiitz., Species Alg.-, Tabula Phy-
cologica, cent. i. pi. 91. fig. 11 ?

3. A. incurvum, Morren. " Filaments
articulated, cohering together in flat laminae,
laciniated at the apex ; articulations 2 to 8
times longer than broad." Mr. Ralfs states
that the -Irish specimens identified by Morren
do not agree with this character, being held
together by the mucous matrix rather than
cohering, as in Flos- aqua, and they are
neither fasciculated nor laciniated at the
ends.— Ralfs, /. c. pi. 9. fig. 8. Aph. incur-
vum, Thompson, Ann. Nat. Hist. v. 82 ;
Harvey, Manual of Brit. Alga (ed. 1), 145 ;
Hassall, Brit. Freshivater Alga, t. 76.
fig. 6. Limnochlide Flos-aqua var. Har-
veyana, Kiitz., Tabula Phycologicoe, cent. i.
pi. 91. fig. 2.

BIBL. For further details consult Mr.
Ralfs's paper on the Nostochinea, Annals of
Natural History, 2nd ser. v. 339, 1850, and
the other works cited above.

APHANOCAPSA, Nageli.— A supposed
genus of Unicellular Algae. See PAL-
MELLA.

APHANOCH^ETE, Braun.— A genus of
Chsetophoreae (Confervoid Algae) allied to
Coleochate ; the bristles arising from the
backs of the cells are not sheathed, but arti-
culated in the upper part. Not yet detected
in Britain.

BIBL. Alex. Braun, Verjungung, p. 196,

&c. &c.; Ray Soc. Translation, Rejuvenescence
in Nature, 1853, p. 184, &c.

APHANOTHECE, Nageli.— A supposed
genus of Unicellular Algae. See PALMELLA.

APHUXiE. — Afamily of Insects belonging
to the order Hemiptera (Homoptera, West-
wood). This family comprises the insects
forming the lice of plants.

Rostrum more or less perpendicular or
inflexed, varying in length, being in some
species nearly half as longasthebody, and con-
sisting of four joints. Labrum long and pointed
at the tip ; antennae of moderate or of great
length, setaceous or filiform and 7-jointed,
the last joint being sometimes obsolete
and the third longest. The ocelli, three in
number, form a large triangle ; the eyes are
entire, prominent, and semi-globose. The
thorax is oval, with the protothorax forming
a transverse collar; the abdomen is short
and convex, ovate or elongate-ovate, soft,
and generally furnished with a more or less
elongated tubercle on each side near the ex-
tremity. The wings are very much deflexed
at the sides of the body, being almost per-
pendicular in repose; the fore wings much
larger than the posterior, with strong nerves,
the subcostal nerve terminating in an elon-
gated stigma, close to which runs another
longitudinal nerve, obliquely emitting two or
three straight nerves, which run to the hind
margin of the wing, the last of which emits
one or two branches ; the posterior wings
have two similar oblique nerves. The legs
are long, or very long and slender, formed
only for crawling; the tarsi short and two-
jointed, the basal joint being shortest.

The pupa state is active, and resembles
the imago, except in possessing rudiments of
wings upon the back; but some never acquire
wings, in which case the pupacannot be distin-
guished from the mature larva or imago states.

The species are found upon almost all
kinds of plants, the juices of the young parts
of wrhich they suck by the assistance of their
proboscis, producing frequently disease in
the plant, either by greatly weakening it, or
by distorting young shoots and leaves ; some
species raising vesicles, or other gall-like ex-
crescences, in which whole generations of
aphides are residents.

The above-mentioned anal tubercles se-
crete a saccharine fluid, of which ants are
very fond ; and it is this fluid dropped upon
the adjacent leaves, or the extravasated sap
flowing from the wounds caused by the
punctures of the insects, which is known
under the name of honey-dew.

APHIS.

APHTHA.

The mode of generation of these insects is
curious and interesting. Each family in
spring and summer consists of wingless in-
dividuals and pupae ; all of these are, how-
ever, females. The males are not born until
the end of the summer or autumn. They
fecundate the last generation produced by
the previously-born specimens, consisting of
wingless females, which then deposit fecun-
dated eggs, which remain through the winter,
and produce young in the spring capable of
reproduction without fresh impregnation.
Eleven generations have been known to be
produced .thus, without fresh impregnation.
According to Dr. Burnett, the members of a
third generation can be seen within the bodies
of the parents.

Many of these insects are covered with a
mealy matter, or with cottony threads se-
creted by the body.

These insects are of great interest, on ac-
count of the destruction they cause in agri-
cultural crops : as instances, we may mention
the hop-fly (A. humuli], the bean-dolphin
(A.faba), the turnip-fly (A. brassica), &c.
The Aphis rosce is a very common one, and
may be found upon most rose-buds. Apple-
blight is also probably produced by a species
of Aphis.

BIBL,. Westwood, Introduction, &c. ;
Walckenaer, Hist. d. Insect es; Burnett, Sil-
liman's Journal, 1854, xvii. pp. 62, 261;
Walker, Ann. Nat. Hist. 2nd ser. i. ii. iii.
iv.&c. (1848-49, &c.)

APHIS, L.— A genus of Insects, of the
family Aphidae.

Char. Abdomen bicorniculate ; antennae
long, setaceous ; fore wings with three ob-
lique discoidal nerves, the first trifid; pro-
boscis short, collar long.

The species are very numerous. See
APHID^B.

APHRODITA, L.— A genus of Annulata.
One species of this genus (A. aculeata) is
well known as the sea-mouse, and is com-
monly found on the sea-coast, and always
admired on account of the splendid iridescent
colours reflected from its spines and bristly
hairs. Its body is from 3 to 5 inches long,
H broad, and oval; the back of an earthy
colour. The head is small, entirely concealed,
with two round clear spots, or eyes, on the
vertex. The hairs and bristles run down
each side of the body ; the back is roughish,
with a thick felt of hair and membrane form-
ing a kind of skin. When this coat is cut
through, fifteen nearly circular plates or scales
(elytra) are found on each side, which partly

cover each other, and the middle of which
are the largest. If two of the plates lying
next each other be separated, we then see
upon the intermediate ring small tubercles
divided by a pit, furnished behind with pec-
tinate appendages, the gills or branchiae.

Antennae minute, palpi large, subulate,
jointed at the base. Mouth with a large re-
tractile edentulous proboscis ; the orifice en-
circled with a short, even, thick-set fringe of
compound penicillate filaments divided into
two sets by a fissure on each side. Thirty-
nine pairs of feet; biramous; the upper
branch carries the long, flexible, brilliantly
coloured bristles forming the silky fringe on
each side of the body.

This animal is a very interesting object to
the microscopist, as its tissues are very trans-
parent and easily examined.

The brilliant colours of the bristles and
hairs arise from iridescence, produced by a
number of longitudinal striae or interspaces
between the component fibres of which the
bristles and hairs consist ; they also exhibit
transverse splits or cracks; they are not
materially changed by the action of boiling
solution of potash, except that the external
coat of the hairs becomes transversely wrin-
kled, giving these the appearance of being sur-
rounded by a number of fibres (PI. 40. fig.
20).

BIBL. Johnston, Ann. Nat. Hist. 1839,
430; Van d. Hoeven, ZooL, p. 232.

APHTHA.— A disease affecting the mu-
cous membrane of the mouth, tongue, &c.
It exhibits itself in the form of rounded
patches of larger or smaller size, of a whitish
or yellowish colour, One form of it, vulgarly
called the " thrush," and in French muguet,
which occurs very frequently in children, and
in adults towards the fatal termination of
chronic diseases, is of special interest to the
microscopist, inasmuch as the patches con-
sist of numerous epithelial scales mixed with
filaments and isolated cells of a fungus. A
portion examined under the microscope
exhibits, — 1, numerous oval cells (a), PL 30.
fig. 1, rarely containing an internal globule
or nucleus ; 2, long filaments (6) exhibiting
a further advanced stage of development ;
the filaments are but rarely jointed ; 3, epi-
thelial scales, sometimes perfect (d), but
usually wrinkled and otherwise altered in
form, and frequently more or less opake (e),
so as to be hardly recognizable except when
treated with potash; intermingled with these
bodies are sometimes vibriones or bacteria
(Bact. termo, /) and a molecular form of

APIOCYSTIS.

APOTHECIUM.

matter (g}> probably an early stage of Bact.
termo, for it is always found with and
prior to it in decomposing liquids, in addi-
tion to the molecular granules found in all
animal liquids.

This fungus appears to arise in the same
manner as other analogous fungi, as those in
kept organic liquids, in urine, &c.; the spores
are probably always floating in the air and
dropping from it upon all the exposed parts
of the body ; and wherever they find a pro-
per nidus, there they grow. In diseases
accompanying or preceding aphtha, the re-
generation of the oral epithelium is probably
to a great extent checked, the secretion of
the saliva also, which would wash away
these organisms ; why they occur so fre-
quently in infants, is probably owing to the
saccharine nature of the diet, which is espe-
cially favourable to their development. See
OIDIUM.

BIBL. C. Robin, Histoire Naturelle des
Vegetaux Parasites, 2nd ed., Paris, 1853,
p. 488, where many other works are men-
tioned.

APIOCYSTIS, Nageli.— A genus of Pal-
mellacese (Confer void Algae). Aquatic plants
parasitical upon Confervse, consisting of
pear-shaped or clavate vesicles, from 1-50"
to 1-20" high, and about half as thick, at-
tached by the narrow extremity, and con-
taining numerous green primordial cells
about 1-2500" to 1-3500" in diameter. Young
sacs contain regularly 2, 4, 8, 16, 32, &c.,
and in large ones the number amounts to
300 to 1600. At first they lie irregularly in
the cavity, afterwards they lie upon the wall
in one or more layers ; sometimes they are
attached to the wall in groups of eight. At
a certain stage, the primordial cells become
again free in the cavity, move actively, and
finally escape by the rupture of the sac,
swarm as biciliated zoospores for a time,
then settle down and germinate.

A. Brauniana and the doubtful species
A. linearis represent this genus; they have
not been recorded in this country, having
been discovered at Zurich by Nageli.

BIBL. Nageli, Einzelligen Algen, p. 67.
t. 2. A. figs. 1 and 2.

APIS, L. — A genus of Hymenopterous
insects.

A. mellifica, the honey-bee, presents some
interesting points of structure.

The proboscis (PI. 26. fig. 25) agrees
essentially with that of Anthophora. The
" tongue " (labium*) is a very beautiful and
favourite microscopic object; its minute

structure requires a higher power than that
used in making our sketch, to render distinct
the elegant transverse ridges or folds and
the terminal hairy lobe.

The legs are peculiarly formed for the
special purpose of collecting and carrying
the pollen of flowers. The tibiae of the
hind legs are dilated, smooth on the outside
in the neuter or working bees, and hollowed
into a shining plate (PL 27. fig. 4 b), whilst
the basal joint of the tarsi is hooked at its
outer superior angle and dilated into an
oblong or somewhat triangular plate (PL 27.
fig. 4 a), which is furnished with transverse
rows of hairs, forming pollen-brushes.

BIBL. Westwood, Introduction, &c.; Cur-
tis, Brit. Entom. 769.

APOTHECIUM.— The name applied to
the spore-fruits of the Lichens, sometimes
restricted to those of the open-fruited genera
(Gymnocarpi), the term perithecium being
applied to those of the closed-fruited (An-
giocarpi). Several special names have been

Fig. 28.

Dirina Ceratonise.

applied to the apothecia, namely, pelta,
scutella, patella, scyphus, orbiculus, lirella,
and verruca, indicating the forms occurring
in particular genera. They are shield-
shaped, flat, cup- shaped, globular, papilliform
bodies or linear ridges, upon the upper

APTOGONUM.

ARACHNIDA.

surface of the thallus, either immersed, super-
ficial or elevated on peduncles. They con-
tain the thecae or spore-cases. For the
structure, see LICHENS.

Fig. 28, Dirina Ceratonia, natural size.
Fig. 29, several apothecia magnified about
5 diameters. Fig. 30, part of a vertical
section through an apothecium, showing theca
with spores, together with barren thecae or
paraphyses, magnified 200 diameters.

APTOGONUM, Ralfs.— A genus of Des-
midiaceae.

Char. Filament elongated, triangular or
flattened ; joints bicrenate at the free mar-
gins ; an oval foramen between the joints.

Kiitzing and others place this organism in
the genus Desmidium, where it might very
well have remained.

1. A. Desmidium. Joints in front view
quadrangular, broader than long.

a. Filaments triangular, regularly twisted,
crenatures rounded; length of jointsl-1500",
breadth 1-1000" (PI. 10, fig. 55, front view;
fig. 52, side view).

/3. Filaments flattened; crenatures shal-
lower and slightly angular.

2. A. Bailey i. Filaments not crenate ;
joints about equal in length and breadth.
American.

The latter cannot be retained in this
genus, unless the characters be altered, on
account of the absence of the crenatures.

BIBL. Ralfs, Brit. Desmid. pp. 63, 208.

APUS, Scop. — A genus of Entomostraca,
of the order Phyllopoda, and family Aspide-
phara.

Char. Head, body and greater part of the
abdomen covered by a shield-like carapace,
which is deeply notched behind ; eyes two,
sessile and approximate ; a single pair of
minute, short, styliform and 2-jointed
antennas ; feet, sixty pairs, the first pair
furnished with three long, jointed branches,
extending beyond the carapace, the rest
branchial ; body composed of numerous
rings ; two long-jointed caudal appendages.

1. A. cancriformis. Aquatic; brownish-
yellow ; length 2^ inches.

2. A. productus. Not British; an elon-
gated oval lamina between the two caudal
appendages.

BIBL. Baird, Brit. Entom. p. 18.

AQUATIC,— This term is used through-
out this work to signify an inhabitant of
fresh water as opposed to marine, inhabiting
the sea.

ARACHNIDA.— A class of animals, con-
taining the spiders, scorpions, &c.

Char. Head united with the thorax,
forming a cephalothorax ; antennae none;
eyes simple (ocelli) ; legs eight, jointed.

The integument of the Arachnida is usually
soft and leathery, rarely horny or brittle, and
consists principally of chitine. Two layers
may usually be distinguished, an outermost
or cuticle, which is the firmest and strongest,
and not unfrequently exhibits a cellular
appearance in the extremities and the cepha-
lothorax. The cuticle of the abdomen of
the Araneae, Acarina, &c., presents very
beautiful wavy or undulating lines, some-
times surrounding the roots of the hairs, &c.
concentrically, and arising, in some cases at
least, from the existence of folds (PL 2. fig. 4

6 5). The cuticle of the Arachnida is fre-
quently covered with warty and bulbous
excrescences, bristles and simple or feathery
hairs, and sometimes with scales.

The innermost cutaneous layer consists of
a very delicate and almost colourless mem-
brane, of a finely granular or fibrous appear-
ance; closely beneath which is situated a
layer of pigment granules and cells, which
are visible through the general integument,
and to which the beautiful colours of many
of the Arachnida are owing.

The organs surrounding the mouth vary
in structure in the different families. In the
Spiders, two mandibles are situated at the
front of the head. These consist of two
joints, a basal very thick one (PL 2. fig. 6 a &

7 «), and a terminal curved and sharply
pointed one (fig. 6 b & 7 b). The latter is
traversed by a canal terminating at its apex,
through which the secretion of a poison-
gland passes into any body transfixed by the
claw. These mandibles are perhaps, strictly,
modified antennas. Next come two maxillary
palpi (fig. 7 c), which do not diifer in struc-
ture from the legs, except in their tarsi
being composed of a single joint, generally
terminated in the females by a small hook,
but in the males of more complicated struc-
ture: the basal joints of these palpi are
enlarged and project forward, forming the
maxillae (fig. 7 d) ; in the scorpions, the
mandibles and maxillary palpi terminate in
pincers or forceps ; lastly a labium, situated
between the maxillae (fig. 7 e), and consisting
of a single piece.

The mouth in the other famines is de-
cribed under the respective heads.

The eyes are simple (ocelli, stemmata),
but they are absent in the parasitic Acarina ;
they consist of a simple arched cornea; a
spherical lens and a concavo-convex vitreous

ARACHNIDA.

[ 56

ARACHNIDA.

body, with a cup-shaped retina, and a layer
of pigment corresponding to the choroid.

The cephalothorax is usually separated from
the abdomen by a well-marked constriction.

The legs of the Arachnida do not coincide
exactly with those of insects. They usually
consist of seven segments tapering towards
the end, so that the tarsi are less distinct
from the other parts than in insects. If we
suppose that the two last joints belong to the
tarsus, the tibia then consists of two joints,
of which, in some (the scorpion and Phrynus]
the first, in others the second is the longest.
The preceding long joint is the femur, to
which comes next an annular or inverted
conical joint, corresponding to the trochanter
of the six-footed insects. The first, broad,
usually inversely conical joint, which is
adherent to the cephalothorax, corresponds
to the coxa of insects. The last joint of the
tarsus usually supports three curved hooks
or claws (PI. 2. fig. 8), which are frequently
toothed on the concave margin, and in some,
a membranous vesicular or hairy cushion
(pulvillus) on its under side. The most cha-
racteristic feature of the Arachnida consists
in the division of the tibia into two unequal
pieces.

The alimentary canal is mostly short and
straight. In the Araneae the oesophagus
enlarges into a prismatic muscular expansion
just before its termination in the stomach;
the stomach splits just behind the above
apparatus into two branches which curve
forwards and form a ring, from which five
pairs of diverticula pass to the roots of the
legs and palpi.

Salivary glands are present, consisting in
the Araneae of a transparent glandular mass
situated in a cavity above the palate. Also a
hepatic apparatus, in the form of a compact
mass, consisting of a number of ramified and
closely-crowded caeca, containing the hepatic
cells and opening at about the middle of the
alimentary canal in four short ducts. This
hepatic apparatus was formerly mistaken
for the fat-body. In the Tardigrada, Acarina
and some others, the liver is represented by
the granule-cells, usually brownish-yellow, of
the walls of the diverticula of the stomach.

The poison-glands of the Aranese consist
of two long, sometimes slightly curved
blind sacs, the walls of which are surrounded
by a simple spiral layer of muscular fibres.

Circulatory System. — In the lower Arach-
nida, as the Tardigrada, Acarina, &c., there
is neither dorsal vessel nor blood-vessels.
Hence in these there is no regular circulation

of blood, but the nutritive fluid or the blood
is distributed free in the interstices of the
body, and is irregularly moved backwards
and forwards, propelled in the cavity of the
body, and into the extremities, by muscular
movements and the contractions of the in-
testinal canal.

In the Araneae there is a dorsal vessel,
consisting of a spindle-shaped tube lying
principally in the abdomen, constricted at
intervals and furnished with lateral apertures
and valves. This heart sends off lateral and
terminal arterial branches, which gradually
become lost. There are no veins, but the
further course of the blood takes the form of
lacunal currents, which re-enter the heart at
the valvular orifices.

In the scorpions, there are veins as well as
arteries.

Respiratory System. — In the Tardigrada
and some parasitic Arachnida, Demodex,
Sarcoptes, Acarus, &c., no tracheae or other
respiratory organs have yet been discovered ;
hence the respiration must be cutaneous. The
higher Arachnida breathe either by tracheae
(many Acarina), or lungs and tracheae together.

The tracheae of the Acarina are remarkably
delicate, so that the spiral fibre is with great
difficulty distinguishable. They arise usually
in an unramified bundle from two stigmata,
which are sometimes situated anteriorly be-
tween the front legs, as in the Hydrachnea,
and much concealed, at others, at the sides
of the body above the third pair of feet, as in
the Gamaseae, or behind the last pair, as in
the Ixodeae.

In the Hydrachnea, which live in the wa-
ter, and do not rise to the surface to respire,
the tracheae must possess the power of ab-
sorbing the air from the water. In the
Araneae, the lungs consist of rounded sacs
situated at the anterior part of the under
surface of the abdomen, and open externally
by a transverse slit. At the outer convex
surface of each lung-sac there are a number
of thin but firm triangular or rhomboidal
plates, like the leaves of a book, closed to-
gether (PI. 2. fig. 9). When examined by
reflected light, they reflect a silvery lustre ;
whilst by transmitted light they appear dark
violet, or almost black. Each of these plates
consists of a fold of the skin, between which
the air of the sac is widely distributed : they
contain no blood-vessels, hence probably the
blood brought by the arteries is poured out
around the lungs, and so bathes the lung-
plates. The position of the lung-sacs is in-
dicated externally by a triangular and horny

ARACHNIDA.

I 57 ]

ARACHNIDA.

cutaneous plate, at the posterior margin of
which the respiratory fissure exists. Behind
these fissures there are two other openings,
the orifices of a tracheary system which
does not differ materially from that of such
as have tracheae only.

Nervous System. — Varies indegree of com-
plexity. In its simplest form, it exists as a
single oesophageal ganglion, sending off ra-
diating branches; and in its most compound
forms, it presents a large cephalo-thoracic bi-
lobed ganglion, and one or two ventral gan-
glial chains or cords.

The primitive nervous fibres and ganglion-
cells are very small and delicate.

Spinning organs. — These organs, by means
of which the Araneidse form their webs, are
of great interest. The external organs con-
sist of three or rarely two pairs of cones or
conical papillae, or spinnerets, placed at the
end of the abdomen, below the anus : they
are somewhat flattened at the summit, and,
usually, the middle pair consists of two joints
and the anterior and posterior pairs of three
joints. The sides of the cones are covered
with hairs, and on the summits are a number
of delicate horny spinning tubes, at first sight
closely resembling hairs; these form con-
tinuations of the spinning vessels. Some-
times, however, the lower portions of the sides
of the cones are furnished with spinning-
tubes, the remainder being covered with
hairs. Each spinning-tube consists of two
parts: a thicker basal portion, and a thin
terminal portion, from the orifice of which
the substance of the fibre exudes (PL 2. fig.
10, 10 a, a separate tube). The number of
these spinning-tubes varies according to the
species, the sex, and the age of the spiders.
In some there are more than 1000, in others
400, 300, 100, &c., and in others still fewer.
The glands which secrete the tenacious tran-
sparent secretion are very variable in num-
ber, form, and arrangement, and occupy the
interstices of the other abdominal viscera,
consist of sacs and tubes, lined with nucleated
cells, and either simple or variously ramified,
terminating in ducts which open at the roots
of the spinning-tubes.

The filaments of which the webs of many
spiders are composed are not all alike. The
radiating filaments are but little elastic, and
are composed simply of one or more threads ;
whilst the more numerous filaments con-
necting these are covered at tolerably regular
intervals with minute spherical masses of
glutinous matter (PI 2. fig. 11), the filaments
themselves being highly elastic. These masses

give the fibres an elegant beaded appearance
under low powers of the microscope. The
viscid masses cause the more ready adhesion
of the filaments to insects which may acci-
dentally become entangled in them, and
render the spider more sure of holding his
prey.

Propagation. — The Arachnida generally
are propagated by sexes, but an exception is
formed by the Tardigrada, which are her-
maphrodite, and do not possess copulating
sexual organs. The sexual apparatus con-
sists of two ovarian or seminal sacs, some-
times fused together in the middle line ; they
are situated in the abdomen, and terminate
in two excretory ducts, which usually open
at a common orifice placed at the base of the
abdomen, or below the cephalothorax. A
penis is not generally present ; the seminal
fluid is applied to the vulva of the female by
the maxillary palpi of the male.

Spiders are oviparous, and the eggs are
enveloped in a cocoon.

The Arachnida may be thus subdivided :
SECTION I. Cephalothorax divided into

four segments ; neither stigmata nor distinct

respiratory organs present.

Order 1. PYCNOGONIDA (Polygonopoda).
Legs as long as or longer than the body ;
abdomen rudimentary (small and conical).
Genera. — Pycnogonum, Phoxichilus,
Phoxichilidium, Pallene, Parib&a, Nym-
phon, Endeis, Ammothea.

Sluggish marine animals, living on the
sea-shore under stones or upon marine
plants.

Order 2. TARDIGRADA (Colopoda). Legs
rudimentary, very short, conical, indi-
stinctly three- jointed, and with three orfour
claws; abdomen not distinct from the
thorax; (aquatic).

Gen. Emydium, Macrobiotus, Milne-
sium.
SECTION 2. Cephalothorax undivided;

respiratory organs usually distinct, internal

(but sometimes absent), with two or more

abdominal stigmata.

OrderS. ACARINA. Abdomen not jointed,
fused with the cephalothorax; palpi simple;
mouth in many forming a rostrum ; (respi-
ratory organs consisting of tracheae or
none) .

Fam.l. Acarea. Head terminated in front
by an emarginate labium, or single bifid
process ; palpi adnate or adherent to the
labium, difficultly distinguished; mandi-
bles chelate; no distinct ocelli; feet ge-

ARACHNIDA.

[ 58 ] ARACHNOID MEMBRANE.

nerally terminated by a vesicle or adhesive
acetabulum and claws.

Gen. Acarus (Tyroglyphus) , Trichodac-
tylus, Psoroptes, Sarcoptes, Demodex.

Fam. 2. Oribatea (Notaspidea). Body
covered by a hard horny envelope ; man-
dibles chelate; palpi fusiform, five-jointed;
feet furnished with claws, but no vesicle
nor acetabulum,

Gen. Oribata (Notaspis), Hopophora,
Damans, Zetes, Pelops.

Most of the species live in mosses at the
roots of trees ; in some the body is sur-
rounded by a projecting lamella on each
side.

Fam. 3. Ixodea.

Gen. Ixodes.

Fam. 4. Gamasea. Palpi free, filiform;
mandibles chelate ; feet with two claws
and a caruncle, or a lobed membranous
appendage ; ocelli none or indistinct.
(Generally parasitic.)

Gen. Dermanyssus, Uropoda, Caris,
Gamosus.

Fam. 5. Hydrachnea. Palpi with the
last joint unguiculate or spinous ; two or
four distinct ocelli ; coxae broad, legs ge-
nerally ciliated, natatory, the posterior
longest. (Aquatic.)

Gen. Limnochares, Eyldis, Hydrachna,
At ax, Arrenurus, Diplodontus.

Fam. 6. Bdellea. Palpi antenniform ;
mandibles terminating in claws or pincers;
rostrum resembling an elongated head;
body generally divided between the second
and third pairs of feet by a transverse fur-
row or stricture ; (abdomen many-jointed).

Gen. Bdella.

The species consist of minute animals,
more or less soft, variously coloured, and
living in damp places beneath moss, upon
sand of caves, &c.

Fam. 7. Trombidina. Palpi with the
last joint obtuse, the second joint very
large; the last but one (penultimate)
resembling an incurvated claw ; feet cur-
sorial, terminated by two claws.

Gen. Anystis, Cheyletus, Tetranychus,
Megamerus, Pachygnathus, Raphignathus,
Smaris, Erythrceus, Trombidium(Leptus).
Order 4. PHALANGiTA(Opilionina). Cepha-
lothorax conjoined with the abdomen ;
abdomen annulate or transversely plicate ;
palpi simple, filiform; mandibles didac-
tyle ; feet elongate, terminated by a single
claw.

Gen. Trogulus, Phalangium, Eusarcus,
Gonyleptes.

Order 5. PSEUDOSCORPIONES. Cephalo-
thorax conjoined with abdomen; abdomen
annulate ; palpi large, chelate.
Gen. Obisium, Chelifer.
Order 6. SOLIFUG^E. Cephalothorax distinct
from the abdomen ; abdomen annulate ;
palpi filiform, extended, equalling the feet
in length.
Gen. Galeodes.

Order 1. PEDIPALPI. Abdomen jointed, di-
stinct from cephalothorax; palpi large,
resembling feet, chelate at the apex ; pul-
monary sacs, but no tracheae; stigmata
four or eight.

Gen. Thelyphonus, Phrynus, Scorpio, An-
droctonus, Buthus.

Order 8. ARANEIDA. Abdomen not jointed,
nor cephalothorax separated by a constric-
tion ; respiratory organs consisting of tra-
cheae and pulmonary sacs.
Gen. Aranea ( Tegenaria), Epeira, &c.
BIBL. Treviranus, Ueber den inner. Ban
der Arachniden ; id. Vermisckte Schriften,
Sec. Bd. 1, 1816; Dufpur, Ann. d. Sc. phy-
siq. de Bruxelles, iv.-vi.; Walckenaer, Hist,
nat. d. Ins. Apt., i.-iii. ; Van der Hoeven,
Handb. der Zoologie, i.; Siebold & Stannius,
Lehrb. d. Vergleich. Anat. i.; Owen, Hunter.
Lectures, i.; Blackwall, Ann. N. Hist. xv. Apr.
1845, and Linn. Trans, xvi ; Blanchard, Ann.
N. H. 1850, vi. 67 ; and 1852, x. 150; New-
port, Phil. Trans. 1843; Koch, Deutschlands
Crustac. fyc.

ARACHNOID MEMBRANE (Tunica
arachnoidea) — Is a delicate transparent mem-
brane, lying between the cranial dura mater
and the brain, and extending between the
spinal cord and its dura mater so as to enve-
lope these nervous centres. It does not dip
between the convolutions of the brain, but
enters and lines its ventricles. Its outer sur-
face is covered by a delicate epithelial layer;
its inner surface is smooth, but not covered
with epithelium. It is reflected upon the
surface of the dura mater as an epithelial
layer only. It consists principally of reticu-
lated bundles of areolar (cellular) tissue, with
fibres of elastic tissue coiling around or pur-
suing a rectilinear course through them. In
some parts the fibrillae of the former run par-
allel without forming bundles, and contain,
as do the bundles, round, " elongated, or
spindle-shaped nuclei. In others, areolar
tissue of a rather homogeneous appearance
here and there forms a coat to the bundles,
or is situated between them.

Fig. 31 represents two bundles of the areo-
lar tissue of the human arachnoid, after the

ARACHNOIDISCUS.

[ 59 ]

ARCELLA.

addition of acetic acid, showing the fibres of
elastic tissue.

Fig. 31.

Areolar and elastic tissue of arachnoid, after treatment
with acetic acid. Magnified 350 diameters.

BIBL. Kolliker, Mikroskop. Anatomic, ii.;
Henle, Allgemeine Anat.

ARACHNOIDISCUS, Bailey.— A genus
of Diatomaceae.

Char. Frustules disk-shaped, single, ad-
herent ; valves circular, flat, or very slightly
convex, exhibiting (even under a low power)
concentric and radiating lines, with appa-
rently cellular markings occupying the inter-
spaces, and a central clear space (pseudo-
nodule).

The cellular appearance arises from the
existence of the ordinary depressions. Ehren-
berg mentions imperfect septa.

This genus corresponds to the Hemiptychus
of Ehrenberg, who observes that as the term
Hemiptycha has been previously applied to
a genus of Hemiptera, that of Arachnoidiscus
will be preferable.

A . Ehrenbergii, Bail. Pseudo-nodule sur-
rounded by an inner ring of linear radiating
and an outer ring of circular or angular
markings (depressions) ; marine ; breadth
1-200 to 1-60"; occurs also in guano (PI.
12. figs. 12 & 13, side view).

A. ornatus, Ehr. South America.

BIBL. Ehr. Eer. d. Eerl. Akad. 1848 &
1849; Smith, Brit. Diat.-, Shadbolt, Trans.
Micr. Soc. iii.

ARANEA, Latr. (Tegenaria, Walcken.)— A
genus of Arachnida, of the Order Araneidea.

A. civilis and domestica, house-spiders;
readily accessible for examining the struc-
tural peculiarities of spiders, the organs of
the mouth, maxillary palpi, spinnerets, legs,
&c. See PL 2.

BIBL. Walcken. Apteres, i. ; Koch, Die
Arachn. viii. ; Treviranus, Ueb. d. inn. Bau
d. Arachn.

ARAUCARIA, Jussieu.— A genus of Co-
niferae (Gymnospermous Flowering Plants),
remarkable for the character of the markings
on the walls of the cells of the wood, where
the disks or bordered pores appear in two or
more parallel rows (PL 39. fig. 5). Arau-
caria (Eutassa] excelsa is the Norfolk Island
Pine, which grows to an immense size, as do
also A. brasttiensis, A. imbricata, &c. The
reservoirs of turpentine seem to be in the
bark and not in the wood. See CONIFERS,
WOOD, and SECONDARY LAYERS.

ARAUCARITES, Goeppert (Dadoxylon,
Endlicher ; Pinites, Lindl. and Hutt.). — A
genus of Fossil Conifers (Gymnospermous
Flow. Plants), characterized by the many
rows of disks on the walls of the wood-cells.
Mostly occurring in the carboniferous forma-
tions. See CONIFERS.

BIBL. Witham, Internal Structure of Fos-
sil Vegetables, p. 72, pi. 4-11, Edinb. 1833;
Lindley and Hutton, Fossil Flora, 1. t. 2, 3.

ARCELLA, Ehr. — A genus of Infusoria,
of the family Arcellina.

Char. Animals contained in a carapace,
from an orifice in which one or more variable
flattened expansions are protruded ; carapace
discoid or hemispherical, with the orifice
upon the flat surface.

The Arcellae correspond to Amoebae contained
in a carapace. In some species, the carapace
is membranous and uniform ; in others, it is
siliceous and exhibits fine stria3, depressions,
or granules (?) spirally arranged. Not un-
frequently it contains particles of sand, mi-
nute Diatomaceae, &c., imbedded in its sub-
stance. The gastric cells and contractile
vesicle of the Infusoria have been observed.

Dujardin places this genus among the
RHIZOPODA. The species (?) are numerous ;
the most common are —

1. A. vulgaris (PL 23. fig. 14 a). Carapace
brownish-yellow, plano-convex, or hemi-
spherical, covered with depressions. These
markings or depressions are very beautiful

ARCELLINA.

[ 60

ARCYRIA.

arid interesting. They agree exactly with
those upon the valves of the Diatomaceae in
regard to the requirements for their display;
with unilateral oblique light, lines only are
visible. Their true structure resembles that in
PI. 11. fig. 48, or PI. 13. fig. 29, except that
the rows are somewhat wavy or even spiral.
Aquatic; breadth 1-500 to 1-200". In the
young state it is very transparent and pale,
and the markings are with difficulty distin-
guished. PI. 25. fig. 24. represents the ani-
mal with its processes protruding from the
carapace.

We have seen two of these animals con-
jugating and so firmly united by the soft in-
ternal substance, that they were not separable
by rolling them over between two plates of
glass.

2. A. aculeata (PI. 23. fig. 14 b). Carapace
brownish, discoidal, convex above, with one
or more irregular spinous prolongations at
the margin ; aquatic; breadth 1-200" without
the spines.

3. A. dentata (PI. 23. fig. 14 c). Hemi-
spherical, anguloso - polygonal ; carapace
membranous, homogeneous, yellowish or
greenish ; aquatic ; breadth 1-560 to 1-200".

4. A. aureola (Cyphidium aureolum, Ehr.).
(PI. 23. f. 38). Carapace yellow, angular,
with numerous tubercles, four of which are
larger and more projecting; a single expan-
sion of varied size ; breadth 1-560 to 1-420 "5
aquatic. Fig. 38 a represents the carapace
viewed from above, b the same supported
upon one angle, and the single expan-
sion.

BIBL. Ehrenberg, Infusionsth.-, Dujardin,
Infusoires.

ARCELLINA, Ehr.— A family of Infu-
soria.

Char. Animals contained in a univalve
carapace, of an urceolate or shield- like form,
with a single orifice from which one or more
irregular and variable expansions are pro-
truded, which form the organs of locomo-
tion.

The substance of the body resembles that
of an Amoeba.

Dujardin places this family among the
Rhizopoda.

Genera : Arcella (including Cyphidium,
Ehr.) and Difflugia (including Trinema,
Din.).

See SPIRILLINA.

ARCHEGOT^IUM. Also called pistilli-
dium. The rudimentary organ representing
the ovule in the higher Flowerless Plants,
such as Mosses, Ferns, &c. (excluding the

Thallophytes). These organs are more mi-
nutely described under the heads of the va-
rious Classes, in speaking of their reproduc-
tion.

In the Mosses and Liverworts they are
flask-like cellular bodies, found in terminal
or axillary buds on the leafy stems (figs. 32

Fig. 32. Fig. 33.

Archegonia of Mosses.
Magnified 50 diameters.

& 33). In the Ferns and Equiseta they are
produced on the prothallium, after the ger-
mination of the spores. In the Lycopodiaceae
and Marsileacere they are produced upon the
cellular plate, representing a prothallium, de-
veloped in the large spores when these be-
gin to germinate. The corpuscula of the
Coniferae are analogous bodies to the last.
See HEPATICACE^E, MUSCACE.E, FILICA-

CE^E, EftUISETACE^E, LYCOPODIACE^,

MARSILEACE^E, also CONIFERS and CHA-

RACE.E.

ARCHIDIUM, Brid.— A genus of Bru-
chiaceae (Acrocarpous Mosses), including
some of the Phasca of Linnaeus, &c.

A. phascoides, Brid.= Phascum alternifo-
lium, Hook, and Taylor.

ARCYRIA, Hill.— A genus of Myxogas-
tres (Gasteromycetous Fungi), growing on
rotten wood, with bright-coloured spores
and filaments. The elastic filaments of the
capillitium have no spiral fibres, but are a
little tuberculated. Species :

1. A. punicea, Pers. Common; spores
and capillitium purplish vermilion. Grev.,
Sc. Crypt. Flora, t. 130.

2. A. incarnata, Pers. Not uncommon ;
smaller, with a shorter stipe and with flesh-
coloured spores and capillitium.

3. A. cinerea, Bull. Spores and capil-
litium cinereous.

4. A. nutans, Bull. Spores and capil-
litium dirty-yellow ; capillitium nodding.
Trichia nutans, Sowerby, t. 260; Arcyria

flava, Grev., Sc. Crypt. Fl. t. 30.9.

5. A. umbrina, Schum. Spores and

ARECA.

ARROW-ROOT.

eapillitium ochraceous, capillitium erect ;
peridium ovate.

6. A. ochroleuca, Fr. Spores and capil-
litium pale-ochraceous, peridium globose,
evanescent ; smaller than the preceding ;
1-12" high.

ARECA, L. — A genus of flowering plants
(Fam. Palmaceae). The albumen of the seed
of the Areca catechu, the Areca nut as it is
called, affords a good instance of horny con-
sistence produced by secondary layers upon
the cell-walls (PI. 38. figs. 21 & 22). See
ALBUMEN (of seeds).

AREGMA, Fries. See PHRAGMIDIUM.

AREOLAR TISSUE of animals. See
CELLULAR TISSUE.

ARGAS, Walck.— A genus of Arachnida,
of the order Acarina and family Gamasea.

Char. Rostrum inferior, concealed, as
also the palpi, beneath a projection of the
anterior part of the body; under part of
body granular, not scaly, and consisting of a
single piece ; first joint of the palpi longest ;
legs approximate at their insertion, feet
terminated by two claws, but no vesicle.

These animals are frequently parasitic upon
pigeons, fowls, &c. ; some live in gardens.

A. reflexus (Rhynchoprion Columbce,
Herm.). Body marked with tortuous fur-
rows and depressions, yellowish or violet after
food. On pigeons, especially when young.

A. persicus. Blood-red colour, back co-
vered with scattered elevated white spots.
The venomous bug of Persia ; said to cause
death in the human subject.

There are other species.

BIBL. Walcken., Apteres, iii. (Gervais).

ARGULU S,Mull.-A genus of Crustacea, of
the order Siphonostoma and family Argulidse.

Char. Carapace membranous, covering
the cephalothorax like a shield; antennae
four, short, concealed beneath the carapace ;
anterior two-jointed, terminal joint hooked,
posterior four-jointed ; rostrum acuminate ;
five pairs of legs, the place of the first (6th)
pair being occupied by two suckers ; second
pair short, five-jointed, the two basal joints
spinous, the last joint with two small hooks ;
the last four pairs of legs two-cleft, and fur-
nished writh ciliated filiform processes.

A.foliaceus (PL 15. fig. 1). Parasitic on
the stickle-back (Gasterosteus) and other
fishes ; carapace greenish.

BIBL. V. d. Hoeven, Handb. d. Zool. ;
Baird, Brit. Entomostraca.

ARPACTICUS, Baird.— A genus of Ento-
mostraca, of the order Copepoda and family
Cyclopidae.

Char. Head undistinguishable from thorax;
foot-jaws two pairs, forming strong cheliform
hands; antennae in male furnished with a
swollen hinge-like joint; antennules (infe-
rior antennae) simple; legs five pairs, the
fifth pair rudimentary ; eye single ; ovary
single. 2 species : —

A. chelifer and A. nobilis. Marine, closely
resembling Cyclops.

BIBL. Baird, Brit. Entom.

ARRENURUS,Duges.— A geuusof Arach-
nida, of the order Acarina and family
Hydrachnea.

It contains those species in which the
posterior part of the body of the male is
narrowed and produced into a truncate or
cylindrical appendage. The body of the
female is truncated posteriorly. The prolon-
gation is terminated by two angles and a
sinuous intervening margin. At the middle
of the latter is situated the penis; above
which are two hooks. In both sexes the
back is hard, crustaceous, as if shagreened,
or spinous. In some species the thicker
layer of the skin is furnished with a number
of conical apertures (PI. 2. fig. 12). The
eyes are two, distant, blackish. The intes-
tinal caeca are distinguishable through the
skin. The mouth is round and surrounded
by a kind of hood (PL 2. fig. 13 e).

Arrenurus viridis, Duges' typical species
(PL 2. fig. 13), has the palpi short and clavate
(a) ; the fourth joint longest and largest, the
fifthfalcate and the mandiblesunguiculate (b).

The species are very numerous and of almost
all colours, red, green, yellow, grey, purple.

BIBL. Walcken. Apteres, iii. ; Duges,
Ann. d. Sc. nat., 2 ser. i. ; Koch, Ueber-
sicht des Arachnidensystems.

ARROW-ROOT.— A name given to va-
rious kinds of starch, derived from the plant
Mar ant a arundinacea, and other species.
True West India arrow root is from this
(PL 36. fig. 18) and M. Allonga and M.
nobilis (N. O. Marantaceae). East India
arrow-root is obtained from species of Cur-
cuma (N. O. Zingiberaceae) (PL 36. fig. 19),
but Maranta arundinacea is also grown
there, as its fecula is brought from Singa-
pore. Tahitan arrow-root (PL 36. fig. 22)
is obtained from the plant called Tacca pin-
natifida (N. O. Taccaceae), and the substance
called Portland arrow-root (PL 36. fig. 11),
is extracted from the Arum maculatum
(N. O. Araceae), a common hedge-weed in
this country. In all these cases the fecula
consists of starch- grains, which are produced
in great quantity before the season of rest, in

ARSENIC.

ARTERIES.

the succulent root-stocks or rhizomes of the
plants ; the arrow-root is extracted from the
grated root-stocks by washing, to separate
the cellular tissue and remove the often acrid
juices. See STARCH.

ARSENIC.— The common term for arse-
nious acid. Arsenious acid assumes two
crystalline forms and occurs also in an
amorphous state.

The most common form is the octohedral
or tetrahedral. The second (right rhombic)
is less common, and is only obtained by sub-
limation. Attention to the form of the
crystals is important, because it is used as a
means of identifying arsenic in cases of
poisoning. It must, however, be borne in
mind that protoxide of antimony (Sb O3)
yields crystals by sublimation of exactly the
same form as those of arsenious acid (PL 6.
fig. 3).

Solution of arsenious acid is sometimes
used as a preservative liquid for animal pre-
parations.

BIBL. See CHEMISTRY.

ARTEMIA, Leach.— A genus of Ento-
mostraca, of the order Phyllopoda and family
Branchiopoda.

Char. Abdomen prolonged in the form of
a tail, composed of nine segments or joints,
the end joint simply divided into two lobes ;
superior antennae slender and filiform in
both sexes; inferior antennae in the male
large, flat, curved downwards and two-
jointed, resembling horns ; in the female
short, pointed and slightly curved; basal
joint of male inferior, antennae provided with
a short conical process.

A. salina. The Lymington shrimp or
brine-worm. Found in the salt-pans at
Lymington. Length about 1-2".

Each segment of the thorax shortly bilobed
at the apex, and with a pair of branchial
feet ; each lobe of the end joint of abdomen
giving off several short setae. Agrees gene-
rally in structure with Branchipus.

BIBL. Baird, Brit. Entom. ; Rackett,
Trans. Linncean Soc. xi.

ARTERIES.— These are the tubes or
vessels which convey the blood from the
heart to the various parts of the body. The
structure of the arteries is very complicated
and difficult of investigation, and the coats
or tunics of which they consist are so inti-
mately connected as to be by no means
easily separable.

In the larger arteries, three coats are
usually distinguishable, an outer or adven-
titious coat, a middle and an inner coat.

Their composition and thickness varies in
arteries of different sizes.

The middle coat is usually thick and
strong, consisting of several layers, and its
elements run transversely. In the largest
arteries it is yellow, very elastic and of great
strength; as the vessels become smaller, it di-
minishes in thickness, becoming redder and
more contractile ; and near the capillaries it is
very thin, finally disappearing. The inner coat
is always thin, yet thickest in the large
vessels ; whilst the outer coat is absolutely
thinner in these than in those of a moderate
size, in which it equals or even exceeds the
middle coat.

In the smaller arteries the inner coat con-
sists of pale, flattened, fusiform cells with
longish, oval nuclei ; these possess no slight
resemblance, on the one hand, to the fusi-
form cells of pathologists (as also to the
formative cells of elastic and areolar tissue),
and on the other to contractile (smooth
muscular) fibre-cells; yet they differ from
the former in the less acumination of their
ends and their paleness, and from the latter,
in their rigidity, the form of their nuclei
and their chemical reactions.

An elastic layer is expanded beneath the
epithelial layer in the living vessels, whilst
in these, when empty, it exhibits numerous
transverse or longitudinal folds. It forms

Fig. 34.

Magnified 350 diameters.
Muscular fibre-cells from human arteries. 1, from the
popliteal : a, before, b, after the addition of acetic acid;
2, from a twig of the anterior tibial artery : a, nuclei.

what is called a fenestrated membrane, gene-
rally exhibiting more or less distinct reticu-
lated fibres and usually small elongated

ARTERIES. [

openings ; more rarely a very dense network
of principally longitudinal elastic fibres, with
narrow elongated fissures.

The middle coat of the smaller arteries is
purely muscular. The fibres or fibre-cells,
which are connected into layers, may be
isolated by dissection, or by maceration and
boiling in a mixture of nitric acid with four
parts of water.

The outer coat consists of areolar tissue
with elongated nuclei and fine elastic fibres,
and is nearly as thick as, or even thicker
than the middle coat.

Magnified 350 Diameters.

A small artery (a) and vein (6) (about 1-180" in diameter) from the me-
sentery of a child, after the addition of acetic acid : a, external coat, with
elongated nuclei ; /3, nuclei of the muscular fibres of the middle coat, partly
seen from the surface, partly the sectional view ; y, nuclei of the epithelial
cells ; $, fibrous layer of elastic tissue .

In the smallest arteries, the outer coat
gradually ceases to contain elastic tissue,
consisting merely of areolar tissue and the nu-
clei ; this gradually loses its fibrous character,
next becoming homogeneous, and finally, a
thin perfectly structureless membrane, and
disappearing. In the same manner the mid-
dle coat gradually loses its layers of muscular
fibres, until these and the fibres themselves
ultimately vanish. On tracing the smaller
arteries downwards, the inner coat is first
found to lose its elastic fibres, and at last the
epithelial cells cease to be isolable, all that
canbe distinguished consisting of their closely
aggregated nuclei.

] ARTERIES.

In moderate-sized arteries the middle coat
increases in thickness, but in addition to a
larger number of muscular layers, fine elastic
fibres in open networks are added, at first run-
ning somewhat irregularly through the muscu-
lar elements, and in the larger vessels of this
category mixed with areolar tissue, and here
and there forming layers alternating with
those of the muscular fibres. The inner coat
sometimes contains between its elastic layer
and the epithelium several other layers, form-
ing with fine networks of elastic tissue more
externally situated in homogeneous granu-
lar or fibrillar areolar tissue, a strong middle
layer, the elements of which
are longitudinal. The outer
coat in these vessels contains
more elastic tissue, in the
form of laminae.

In the largest arteries, the
epithelial cells of the inner
coat are not so elongated,
and the inner coat consists
principally of layers of a ho-
mogeneous, striated, or even
distinctly fibrillar substance,
agreeing with areolar tissue,
traversed by finer and coarser
longitudinal networks of elas-
tic tissue. Immediately be-
neath the epithelium the net-
works of elastic fibres are
either very fine, or are re-
placed by one or more striated
layers, which when nucleated,
often appear as if composed
of fused epithelial cells, and
when homogeneous, resemble
pale elastic membranes. The
middle coat contains, as a
new element, elastic mem-
branes or plates, as many as
50 or 60, which, except in
their transverse direction, resemble the elas-
tic inner coat, sometimes forming the densest
networks of elastic fibres, at others fenes-
trated membranes. These layers alternate
with those of the muscular fibres traversed
by areolar tissue and networks of elastic
tissue. The muscular layer of the middle
coat is less developed, its cells smaller and
less regularly and perfectly formed.

The outer coat is relatively and absolutely
thinner than that of the smaller; but the
structure is the same, except that its inner
elastic layer is much less developed.

In some of the larger arteries of man, as
the axillary and popliteal, and the mesenteric

ARTIIONIA.

ARTHROCLADIA.

arteries of other mammals, the internal coat
contains unstriped muscular fibres. This is

Fig. 36.

Magnified 30 diameters.

Transverse section of the human aorta below the superior mesenteric artery,
after acetic acid. 1. Inner coat: a, epithelium; b, striated layers; e, elastic
layers. 2. Middle coat : d, its elastic layers; e, the muscular and areolar tis-
sues ; 3, outer coat with its network of elastic tissue.

kind of velvety surface ; spores numerous,
angular, or like a double cone, attached in
whorls at the joints of the
filaments.

BIBL. Berkeley, Ann.
Nat. Hist. i. 436 ; Torula
Eriophori, Berk. English
Flora, v. p. 2. 35.9.

ARTHROBOTRYS, —
Corda. — A genus of Mu-
cedines (Hyphomycetous
Fungi) bearing elegant no-
dular groups of septate
spores. No species is yet
recorded in Britain. Corda
describes one species, A.
superba (fig. 37) ; in this
the spores are about 1 - 1 500"
long. Fresenius describes

the case also with the outer coat of the larger
arteries in animals, but not in man.

All except the smallest arteries are fur-
nished with nutrient blood-vessels, the vasa
vasorum-, these ramify principally in the
outer coat, in the larger ones extending into
the middle coat. They also receive branches
of the sympathetic and spinal nerves.

The most important pathological changes
to which the arteries are subject, consist of
the deposition of fat in their substance —
fatty degeneration, — and of atheromatous
matter. These will be noticed under the
heads FATTY DEGENERATION and ATHE-
ROMA. See also VESSELS.

BIBL. Henle, Allgemeine Anatomie ; K61-
liker, Handbuch der Gewebelehre ; Wedl,
Grundzuge der pathol. Histol. ; Rokitansky,
Ueber einige d. wichtig. Krankh. d. Arterien.

ARTHONIA, Acharius.— A genus of Gra-
phideae (Gymnocarpous Lichens), distin-
guished by the small roundish or irregular
apothecia, scattered over the thallus, devoid
of an excipulum. Mr. Leigh ton describes
eight British species, growing on the bark of
trees, some of which have been described by
others as species of Opegrapha, &c.

BIBL. Leighton, Ann. of Nat. Hist. Ser. 2,
vol. xiii. p. 436. pi. 7. 8. 1854.

ARTHRINEUM, Kze.— A genus of De-
matiei( Hyphomycetous Fungi), of which one
species has been found in Britain, growing
upon dead leaves of Eriophorum angustifo-
lium.

A.Puccinoides, Kze. Filaments elongated,
tufted, often not more than 1-50" long, but
frequently confluent in a linear form, with a

Fig. 37.

Fig. 38.

Arthrobotrys superba.

37. A fertile filament with many groups of spores.

Magnified 200 diameters.

38. A fertile articulation of ditto, with most of the

spores detached from the spine-like pro-
cesses on which they are borne.
Magnified 600 diameters.

another, A. oligospora, perhaps not distinct,
which has the erect filaments about 1-50"
high, solitary, not in tufts, and mostly with
only one group of spores ; these are pear-
shaped, 1-700' long, and have the septum
below the middle : it was found on damp
wood, fruit and earth, in a fungus-bed. See
FUNGUS-BED.

BIBL. Corda, Prachfl. eur. Schimmelb. p.
43. t. 21 ; Fresenius, Beitr. zur Mycologie,
Hefti.p.18. pi. 3. figs. 1-8.

ARTHROCLADIA, Duby.— A genus of
Sporochnaceae (Fucoid Algae). A. villosa,
Huds., is a rather rare British annual sub-
marine species, growing in 4 to 5 fathoms

ARTHRODESMUS.

ASCOMYCETES.

water ; bearing a curious pod-like nucleated
fruit.

BIBL. Harvey, Brit. Marine Alga, 2d ed.
p. 24. pi. 5 C.; Phyc. Brit. t. Ixiv.; Eng.
Bot. t. 546 ; Derbes and Solier, Ann. des Sc.
nat. 3 ser. xiv. p. 33. figs. 18-20.

ARTHRODESMUS, Ehr.— A genus of
Desmidiaceae.

Char. Cells single, compressed, constricted
in the middle ; segments entire, with a single
spine on each side. Species :

1. A.convergens. Segments elliptic (PI. 10.
fig. 27); length 1-598 to 1-539".

2. A. inous, Kiitz. Segments with trun-
cated ends; length 1-1103".

3. A. minutus, Kiitz.

4. A. truncatus, Ehr.

5. A. subulatus.

BIBL. Ralfs, Brit. Desmid. pp. 117, 200;
Kiitzing, Sp. Alg. p. 1/6; Ehrenberg, Infu-
sionsth. p. 158.

ARTHROMITUS, Leidy.— Described as
a genus of the Leptothriceae of Kiitzing
(Algae Confervoideae). Two species, A. cris-
tatus and A. nitidus, were found in the in-
testinal canal of lulus marginatus, a kind of
millipede. These objects appear to have been
imperfect forms of some filamentous Fun-
gus. See PARASITIC FUNGI.

BIBL. Leidy, On thepresence ofEntophyta
in healthy Living Animals, Proc. Acad. of
Philadelphia, iv. p. 225. 1849, extracted
in Ann. Nat. Hist. 2nd ser. v. p. 71«

ARTHRONEMA, Hassall.— A genus of
Oscillatorieae (Confervoid Algae) growing in
fresh water, consisting of widely spreading
olive-coloured or brown tufts of floating fila-
ments, with close and conspicuous cross stria?;
the coloured tubes lie singly, in lengths of
1-2 to 1", in a gelatinous sheath, the ends of
contiguous lengths overlapping obliquely.

A. cirrhosum, Hass. Brit. Freshw. Algce, p.
238. pi. 78. fig. 7; Scytonema cirrhosum,
Carmich, Hook, Br. Fl. (PI. 4. fig. 20).

ARTHROSTPHON, Kiitzing. See PE-

TALONEMA.

ARTOTROGUS, Mont.— A genus of Se-
pedoniei (Hyphomycetous Fungi) containing
one species growing and fructifying in the
intercellular passages of germinating pota-
toes.

A. hydnosporus, Mont. Berkeley, Journal
of the Horticultural Society, vol. i. p. 3. pi. 4.
figs. 27-29.

ARUM, L. — A genus of Araceae (Flow.
P. ants). Arum maculatum, the common
Cuckoo-pint, has a tuberous rhizome in
which is produced much starch. This starch

is extracted in the same way as Arrowroot
starch is from the rhizomes of Marantaceas,
&c., and is called Portland Arrowroot.
(PI. 36. fig. 11.) See STARCH.

ASCARIS.— A genus of Entozoa, of the
order Ccelelmintha and family Nematoidea.

Char. Body cylindrical, narrowed at each
end ; head furnished with three tubercles or
valves; mouth terminal, situated between
the three tubercles; male with one or two
spicula.

The species are very numerous, occurring
in all the classes of the Vertebrata and doubt-
fully in Insects. They are most commonly
found in the alimentary canal. We shall only
notice the two species met with in man.

1. A. lumbricoides. The common round
worm. Inhabits the human small intestine ;
sometimes found also in that of the ass,
wild-boar, pig and ox. Varies in length
from 3 to 15"; is of a whitish colour; the head
distinct, with the three valves (PI. 16. fig. 9)
finely denticulated on their inner border, and
each furnished near the summit with a
slightly projecting papilla. Female larger
and more common than the male. Spicula
two.

2. A. vermicularis (Oxyuris verm.). The
human thread-worm. Found usually in the
rectum. White ; head frequently appearing
winged, or exhibiting two lateral vesicular
expansions (PL 16. fig. 8 a), produced by en-
dosmosis. Mouth round when contracted,
exhibiting the three lobes when expanded.
CEsophagus (e) containing a triquetrous
canal, and separated by a constriction from
the spherical stomach (d). Length, female
3 to 4-10ths of an inch ; male shorter, with
the tail spirally coiled, much more rarely
met with. Anus (g) about 1 -8th from the end
of the body; spiculum single, with an appen-
dage. Uterus consisting of two lobes (h)
(ovaries), oviduct (k) opening externally
near the middle of the body.

BIBL. Dujardin, Hist. d. Helminthes ;
Blanchard, Ann. d. Sc. nat., Zool., 3 ser. x. ;
Cloquet, Anat. d. Vers. Int.

ASCLEPIADACE^E.— A family of Dico-
tyledonous flowering-plants, presenting some
remarkable characters in the pollen (see
POLLEN). The stems of some of these
plants contain very tenacious fibres, which
have been used for ceconomical purposes (see
FIBRES, vegetable).

ASCOMYCETES.-A.il order of Fungi
characterized by producing the spores in
tubular sacs (asci or thecce), frequently inter-
mixed with empty filiform sacs (paraphyses)

ASCOMYCETES. [

(fig. 40), and hence bearing a near relation
to the Lichens, which, indeed, are included

Fig. 39.

Fig. 40,

Spathulea flavida.

Fig. 39. Entire plant (reduced).

Fig. 40. Highly magnified section of fructification,
showing asci and paraphyses arising from the hymenium.

under this order by some botanists; but the
existence of green colouring matter in the
cells, and of gonidia or brood-cells, in the
Lichens, forbid such an association. The
Ascomycetes differ much in external form, and
approach in this particular several tribes
belonging to the other orders; thus the
Tuberacei are very much like many of the
Gasteromycetes, the Helvellacei, like some
Hymenomycetes, &c., differing chiefly in the
mode of the production of the spores (figs.
39-42).

Fig. 41.

Fig. 42.

Leotia geoglossoides.

Fig. 41. Group of plants (reduced).

Fig. 42. Highly magnified asci with spores.

The Onygenei are little Fungi growing on
dead animal substances, feathers, horn, &c.,
and have a flocculent mycelium, bearing little

| ASCOMYCETES.

columnar bodies terminating in a thickened
head, the sporange, which is a kind of hood
falling off at maturity. The sporiferous struc-
ture, loosely filling up the hood, is composed
of interlacing branched filaments, bearing at
their free ends globular cells (asci or thecce]
filled with spores. The Perisporacei are like-
wise very simple,consisting of parasitical Fungi
growing upon the leaves of trees or herbaceous
plants. They have a flocculent mycelium,
often radiating from a centre, where is found
a membranous, sac-like, globular sporange,
containing sometimes a definite, sometimes
an indefinite number of clavate sacs or asci,
alone or mingled with paraphyses, and con-
taining ovate spores. The sporange bursts
either regularly or irregularly at the summit.
The Sphaeriacei have the conceptacles more
developed, either single, or associated on a
common receptacle, and consisting of a firm
capsular structure, lined with asci, and open-
ing at the apex by a regular pore in the form
of a papilla or beak when mature. The
Phacidiacei differ chiefly in the dehiscence
by slits, either single and longitudinal, or
several and parallel or stellate, or circular so
as to detach a lid; most of these have the
sporanges collected on a common receptacle,
either of horny or fleshy consistence. These
two tribes are but imperfectly understood,
since it is in this portion of the Ascomycetes
that Coniomycetous forms of spore are found
upon the same receptacle, either contempo-
raneously or at different stages of develop-
ment. Attention is directed to this subject
under the head of that order, and more will
be found under SPH^ERIA, TYMPANIS,
RHYTISMA, DOTHIDEA, CORDICEPS, &c.

The Tuberacei are Ascomycetous repre-
sentatives of the Hypogseous Gasteromycetes,
being subterraneous, solid, globular or lobed
bodies, of fleshy consistence, the Truffle
being a well-known example. The organ-
ization of the Tuberacei is analogous in all
cases, but the structures differently arranged.
They all have an inconspicuous flocculent
mycelium, from which arises the solid spo-
range. The sporange exhibits, when cut
across, an outer tough coat (peridium}, enclo-
sing a fleshy structure, excavated with sinuous
cavities giving it a marbled appearance.
These sinuous cavities are produced by the
convolutions of the spore-bearing layer, which
is folded and reflected backwards and
forwards, leaving interstices which are lined
with the asci or spore-sacs containing four or
eight spores. The degree of complexity of
the lacunose mass differs in different genera,

ASCOMYCETES.

ASELLUS.

being sometimes simple, in others very com-
plicated.

The sporanges of the Helvellacei vary much
in form, the simpler resembling closely
some of the Phacidiacei; some kinds are
minute fleshy cups lined with asci forming a
superficial layer, as in Propolis, or they are
large fleshy cups raised often on a stalk
(Peziza), these cups being closed at first, but
opening widely afterwards. In the Helvellce,
the cup is converted into a stalked mitre-
shaped body clothed above with asci. Others
are of columnar form, thickened at the sum-
mit, which is clothed with the asci, as if a
cup-shaped receptacle had been turned down
over it (Spathulea, fig. 39), this thickened
head becoming more considerable and exca-
vated into little pits in Morchella. These
plants are mostly found on the ground or
decaying vegetable substances, in damp
places, and are frequently of gelatinous con-
sistence.

If a Peziza, Morchella, a Rhytisma aceri-
num, or similar Fungus, in its last stage of
development, is kept shut up in a bottle for
several hours, and then gently taken out,
the contact of the external air causes an
immediate and abundant explosion of spores,
which may be collected on slips of glass for
microscopic examination. If care is taken
in the experiment, it will be found that a
considerable quantity of a colourless liquid is
expelled with the spores, which liquid con-
tains minute molecules, and evaporates very
rapidly, leaving more or less apparent spots
on the glass.

Synopsis of the tribes :

1. HELVELLACEI. Sporange fleshy, of va-
rious forms, ultimately expanded, clavate, ca-
pitate, stalked, mitre-shaped, cup-shaped or
bell-shaped, the upper surface clothed by elon-
gated sacs (asci), each containing eight
simple or septate spores.

2. TUBERACEI. Sporange (subterraneous)
globular, with an adherent peridium; solid
and fleshy within, and excavated sinuously
into numerous cavities clothed by asci
containing four or eight spores ; the internal
mass drying up or becoming pulverulent or
floccose when mature.

3. PHACIDIACEI. Sporange fleshy, sim-
ple or branched, more or less cup-shaped in
the sporiferous region, which opens widely or
by a slit when mature, and exposes a cavity
lined with elongated asci mixed with para-
physes.

4. SPH^ERIACEI. Sporanges usually col-
lected on a common, usually horny, receptacle,

opening by a terminal pore into a cavity lined
with asci.

5. PERISPORACEI. Common receptacle
floccose, radiating from a centre, bearing a
globular sessile conceptacle, opening by a
terminal pore, and irregularly lined with asci
filled with simple ovate spores.

6. ONYGENEI. Mycelium floccose, bearing
capitate, stalked sporanges, which open by a
circular slit at the base, causing the upper
part to fall off like a cap ; exposing a spori-
ferous structure composed of interlacing
branched filaments, bearing globular asci
at the free extremities of the branches.

BIBL. See under the heads of the Tribes.

ASCOPHORA, Tode. See MUCOR.

ASCOTRICHA, Berk.— A genus of Peri-
sporacei (Ascomycetous Fungi), containing
one species.

A. chart arum, a kind of mildew growing
on paper, forming a brownish, angularly
and dichotomously branched mycelium, from
which arise globose, black hairy peridia con-
taining linear asci, each containing a single
row of chocolate-coloured spores. Peridia
from 1-20" to 1-30" in diameter.

BIBL. Berkeley, Ann. Nat. Hist. i. 257.
pi. 7. fig. 8.

ASCUS.— The term applied to the cylin-
drical or clavate tubular sac forming the pa-
rent cell of the spores in the Ascomycetous
or Thecasporous Fungi. It is frequently
called a theca also (figs. 40 and 42). See
ASCOMYCETES.

ASELLUS, Geoftroy (the aquatic wood-
louse). — A genus of Crustacea, of the family
Isopoda.

Char. Antennae four, outer much longer
than the inner ones ; legs shorter than the
body, the first pair terminated by a minute
subcheliform hand, the others by a simple
hook or claw; two abdominal jointed append-
ages, each terminated by two elongate and
jointed filaments.

A. vulgaris. Length 1-4 to 1-2" or more.
This animal is particularly interesting to the
microscopist, on account of its forming the
most readily procurable object for examining
the dorsal vessel and circulating liquid in
motion. It is found in almost all stagnant
waters. The two currents of the circulating
liquid, with the colourless corpuscles, are
readily seen streaming through every part of
the body. Beneath the large scutiform
joint of the body (the abdomen), are three
flattened branchial false legs or gills on each
side, each protected by a gill-cover; these
are in constant motion during life.

F2

ASPERGILLUS.

ASPEROCOCCUS.

Fig. 43.

BIBL. Desmarest, Consid. General, s. I.
Crustaces ; Treviranus, Vermischte Sckrif-
ten, i. ; M.-Edwards, Crustaces, iii. (Suites
a Buff on).

ASPERGILLUS, Micheli.— A genus of
Mucedines (Hyphomycetous Fungi) forming
common moulds, such as the blue mould of
cheese, A. glaucus. The chains of spores
arise from a more or less globular head at
the apex of the fertile fila-
ments (fig. 43). It is gene-
rally stated that the heads
of spores are originally en-
closed in a peridium ;
according to our observa-
tions this is not the case ;
the spores bud out from
the capitular cell, which
enlarges very much during
the formation of the head
of spores, and when these
have been detached, the
head is left bare, but
covered with short spiny
processes (the points of
attachment of the chains Aspergiiius glaucus.

Of spores), and then looks A fertile filament
r,i . ' V1 with chains of spores

something like a young on a giobuiar head.

peridium of MuCOr. Brit. Magnified 50 diame-

species : ters<

* Fertile filaments simple.

1. A. glaucus, Link. Sporidia globose,
variable, white to glaucous, close (A. can-
didus, Link) or lax. Heads about 1-100"
in diameter when mature. On cheese, lard,
bread, &c., very common. It has been found
also in the lungs and air cavities of birds
(fig. 43). Mucor glaucus, L.

2. A. roseus, Lk. Sporidia globose, very
small, rose-red ; fertile filaments not septate.
On damp paper, lint, carpet, &c.

3. A. aureus, Berk. Sporidia large, ellip-
tical, thinly scattered, golden-yellow ; fertile
filaments without septa. On bark.

4. A. aurantiacus, Berk. Sporidia oval,
the lowest of the chain much larger, myce-
lium rusty-orange, the heads often prolife-
rous, so as to produce a complicated mass.
On bark. Ann. Nat. Hist. vi. p. 436. pi. xiii.
22. Nematogonium aurantiacum, Desmaz.
Ann. des Sc. Nat. 2 ser. ii. p. 69. pi. 2. fig. 1.

** Fertile filaments branched.

5. A. maximus, Lk. Sporidia very large,
at length yellow brown, mycelium a fleecy
mass of the same colour; fertile filaments
dichotomous, clavate above. On decaying
Fungi.

6. A. mollis, Berk. Sporidia large, sub-
globose, white, mycelium white ; fertile fila-
ments dichotomous, standing in minute,
scattered white bundles.

7. A. virens, Lk. Sporidia, like the fila-
ments, greenish ; tufts of fertile filaments
rather dense, entangled, suberect. On de-
caying fungi and other bodies.

8. A. alternatus, Berk. Sporidia grey-
black, subtruncate ; fertile plants branched
alternately in a zigzag manner, erect or
decumbent, forming extremely minute orbi-
cular patches on damp paper. Ann. Nat.
Hist. i. p. 262. pi. 8. f. 11.

9. A. dubius, Corda, would appear to
differ generically from the above. Mr. Ber-
keley states that its capitular cells bear
linear processes, each surmounted by four
steriginata, on which are attached the chains
of spores. On dung. Corda, Icones, ii.

1. 11. fig. 77.

BIBL. Berkeley, in Hooker's Br. Flora,
vol. ii. part 2. p. 339; Ann. Nat. Hist. i.
262. vi. 436. 2nd ser. vii. 100; Fries, Sy-
stema Mycologicum, iii. 383 ; Corda, Icones
Fungorum; Robin, Veg. Parasites, p. 515.

ASPEROCOCCUS, Lamour. — A genus

Fig. 44.

Fig. 45.

Fig. 46.

Asperococcus Turneri, Dillw.

Fig. 44. Fronds reduced to l-3rd.
Fig. 45. Fragment of ditto, magnified 50 diameters.
Fig. 46. A section at right angles to fig. 45, showing the
sporanges and paraphyses, magnified 50 diameters.

of Dictyotacese (Fucoid Algse), of which
three species are found on the British coast.
The fructification consists of groups of spo-
ranges (commonly called spores), intermixed
with paraphyses, scattered over the whole
surface of the frond. When mature these
sporanges discharge zoospores.

BIBL. Harvey, Br. Marine Algce, 2nd ed.
p. 42. pi. 8 C. ; Phyc. Brit. t. xi., Ixxii. and
cxciv. ; Thuret, Ann. des Sc. Nat. 3 ser.

ASPIDULE.

ASPLENIEJS.

xiv. p. 238; Derbes and Solier, ibid, p. 268.
pi. 33. fig. 11.

ASPIDIE^E.— A subtribe of Polypods-eous
Ferns, with indusiate sori.

I. Cyclodium. Sori globose. Indusium
orbiculate, peltate. Veins anastomosing into
six-sided spots.

II. Sagenia. Sori globose. Indusium
orbiculate, peltate. Veins anastomosing,,
with free venules.

III. Aspidium. Sori globose. Indusium
orbiculate, peltate. Veins pinnate.

BIBL. See FILICACE^E.

ASPIDISCA, Ehr.— A genus of Infusoria,
of the family Aspidiscina.
Char. Those of the family.

^ 1. A. lynceus (P1.23. fig. 15 a, under view).
Carapace suborbicular, truncated posteriorly,
uncinate anteriorly; aquatic, among Con-
ferva, &c. ; length 1-1 100 to 1-560".

2. A.denticulata (P1.23.fig. 15£, side view).
Carapace suborbicular, rounded at the ends,
truncate and denticulate on the left side ;
aquatic ; length 1-560".

BIBL. Ehrenb.j , In/us. ; Duj., Infusoires-,
Stein, Infusionsthiere &c.

ASPIDISCINA, Ehr.— A family of Infu-
soria.

Char. A carapace present in the form of a
transparent flattened shield, projecting
beyond the mouth in front ; flexible bristles
on the ventral surface of the body, with
delicate oral cilia.

Ehrenberg describes an alimentary canal,
the inferior orifice of which is alone terminal.
Hence they correspond to Euplotes with
the excrementitial orifice terminal.

Dujardin places them among his Coccudinee.

The setae, styles or cirrhi serve for climb-
ing, whilst by the cilia the animals are
enabled to swim.

This family should not be retained, but
the single genus of which it is constituted,
Aspidisca, referred to the Euplota.

ASPIDIUM, Schott.— A genus of Aspi-

Fig. 47.

Aspidium trifoliatum.

dieac (Polypodaeoui Ferns), in its old sense

including many of our native species,
broken up into subdivisions, now raised to

Fig. 48.

Aspidium trifoliatum.
Fig. 47. An indusium covering a sorus.
Fig. 48. Side view of the same, cut through perpendi-
cularly.

Magnified 25 diameters.

the rank of genera ; as restricted here it is
synonymous with Polystichum.

ASPLANCHNA, Gosse.— A genus of Ro-
tatoria, of the family Hydatinsea.

Char. Foot, intestine and anus absent;
eye-spots (1 to 3) and mandibles present ;
sexes separate.

1. A. Brightwellii (Notommata Syrinx,
Ehr. ?). Female : jaws with a single tooth ;
eye-spot single ; tremulous bodies attached
to an extended filament; aquatic; length
1-24". Male : jaws, pharynx and stomach
absent; body truncate ; length 1-40".

2. A. priodonta (PL 34. fig. 7, female).
3 eye-spots ; tremulous bodies attached to a
tortuous filament ; aquatic ; length — female
1-48", male 1-110"; jaws of female serrated
(7 b).

BIBL. Brightwell, Ann. Nat. Hist. ser. 2.
ii. p. 153. pi. 6; Dalrymple, Trans. Royal
Soc. 1849, and Ann. Nat. Hist. ser. 2. iii.
p. 518; Gosse, Ann. N. H. ser. 2. vi. p. 18,
viii. p. 197.

ASPLENIEJE.— A subtribe of Polypo-
daeous Ferns with indusiate sori. The fol-
lowing genera are indigenous or readily met
with cultivated.

A. Veins pinnate.

I. Asplenium. Sori not marginal, elon-
gated ; indusium elongated, arising from the
nerve, free within.

II. Adiantum. Sori marginal, linear; in-
dusium marginal, linear or semilunar, free
within.

III. Cassebeera. Sori marginal, two
under each emarginate tooth of the leaf; in-
dusium roundish, marginal, covering the pair
of sori.

B. Veins anastomosing.

IV. Lonchitis. Sori in the incisions of
the lobes of the leaf, linear, semilunate ; in-
dusium marginal, semilunar, free within.

V. Doodia. Sori in one or two rows,
lunulate or linear, parallel with the rib ; in-

ASPLENIUM.

[ 70 ]

ASTASI^A.

dusium arising from the anastomosing branch
of the vein. Veins parallel, anastomosing
here and there.

VI. Woodwardia. Sori in a single row,
lunular or linear, parallel with the rib, im-
mersed ; indusium arising from the anasto-
mosing branch of the vein, flat, free within.
Anastomoses of the veins forming hexagonal

BIBL. See FILICACE^E.

ASPLENIUM, Presl., Spleen-wort.— A
well-known genus of Aspleniese (Polypodae-
ous Ferns), containing a number of indi-
genous species.

ASTASIA, Ehr. — A genus of Infusoria, of
the family Astasieea.

Char. Unattached, no eye-spot. Ehren-
berg adds, a longer or shorter tail. Du-
jardin says, with a flagelliform filament,
which is not expanded at the base, but arises
suddenly from the anterior part of the body,
or from a more or less deep notch in it.

Dujardin forms an unnecessary genus,
Peranema, to contain those species in which
the filament arises from the gradually nar-
rowed anterior extremity of the body.

1. A.Jiamatodes, E. (PI. 23. fig. 16). Fusi-
form, tail very short ; at first green, then red;
length 1-380".

The flagelliform filament was absent in the
specimens represented in the figure. The
substance of the body was insoluble in cau-
stic potash, even when heated to boiling,
merely becoming swollen. It exhibited nu-
merous vacuoles, which in some of the or-
ganisms were filled with green grains of
chlorophylle. The colour arose from di-
stinct granules of pigment, scattered through
the colourless substance ; when treated with
solution of iodine and then sulphuric acid,
the AstasifB became spherical, and were co-
loured blue, bluish-green and purplish-blue,
the purple tint apparently indicating the pre-
sence of cellulose. It was, however, after-
wards found that these colours were produced
by the acid alone (see PI. 25. fig. 25).

This curious organism colours the water of
ponds, &c. blood-red.

2. A. limpida, D. (PL 23. fig; 17). Fusi-
form, colourless; length 1-550".

There are other species, but they are ill-
defined. A. nivalis, Shuttleworth, found in
red snow, would appear to be an active form
of Protococcus nivalis.

BIBL. See ASTASI^BA ; also Shuttleworth,
Biblioth. de Geneve, Feb. 1840.

ASTASLEA, Ehr.— A family of Infusoria.

Char. Body of spontaneously variable

form, mostly with one or more flagelliform fila-
ments. (Insoluble in solution of caustic potash.)

This family corresponds nearly to the Eu-
glenia of Dujardin, who asserts the existence
of a contractile integument. The form of
the body is variable, sometimes becoming
spherical, at others cylindrical, fusiform, &c.,
and exhibiting a head- or tail-like process,
or both. In two genera, Colacium and Di-
stigma, the presence of the filament is doubt-
ful. The Astasiaea are distinguished from
the Amceba3a by the absence of the irregular
foot-like process sent out by the latter from
all parts of the body.

The forms included under the family thus
characterized are still very imperfectly un-
derstood, and it is probable that some of
them, separated genetically by Ehrenberg,are
only transitional conditions of others. Infu-
soria exactly resembling Astasia hcematodes
and Euglena viridis occur without the flagel-
liform filaments; Euglena also occurs in a
resting form, surrounded by a gelatinous en-
velope, like Chlamidomonas, and undergoes
division into 4, 8, 16 or more new indivi-
duals in this state, so as to form irregular,
floating Algoid patches; the green bodies
make their escape from the gelatinous enve-
lopes under certain circumstances, just in the
same way as the zoospores escape from the
cells of the Confervoid Algae. This resting
form also exhibits another character, espe-
cially in winter ; the gelatinous envelope ac-
quires a firm dense membranous coat over
its periphery, like the resting spores of the
Confervoids, and in some cases this coat is
polygonal and marked with ridges, &c. It
is probable that the colour of the species is
not constant, since it seems to depend upon
similar substances to that of the Palmellaceae,
which are known positively to change from
green to red, and vice versa, and even to fade
into an almost colourless state when kept in
the dark. These organisms still require much
careful examination, not of isolated speci-
mens, but by watching their developmental
history constantly for extended periods and
through different seasons. More is said on
this subject under PROTOCOCCUS.

The following table gives the genera of
Ehrenberg and Dujardin : —

Attached Colacium, Ehr.

Unattached.

No flagelliform filaments, 2 eye-spots Distigma, Ehr.
One flagelliform filament.
One eye-spot.

With a tail-like process Euglena, Ehr.

Without „ Amblyophis, Ehr.

No PVP <mnt / Astasia, Ehr. (&

No eye-spot ( Peranema, Duj.)

ASTATHE.

ASTEROPHORA.

Two flagelliform filaments.
Both alike.

Animals green, with a red eye-
spot ........................ Chlorogonium,'E,

Colourless, no eye-spot ...... Zygoselmis, Duj.

Several filaments ................ Polyselmis, Duj .

BIBL. Ehrenberg, In/us.; Dujardin, In-
fus.; Morren, Sur la Rubefaction des Eaux,
Brax. 1841 ; Cohn, Protococcus pluvialis,
Nova Acta Ac. L. C. N. C. xxii. p. 397-
(Abstract in Ray Society's Volume of Bota-
nical, 8fc. Papers for 1853, p. 362 et seq.}

ASTATHE. See PRIMORDIAL UTRICLE.

ASTERODICTYON, Ehr. (Ber. d. Berl
Akad. 1845). See MONACLINUS.

ASTERODISCUS, Ehr.— A genus of ex-
isting radiate Polythalamia or Foraminifera.

Char. Polysomatous ; animalcules acer-
vate, never articulate; gemmae protruding in
one plane, forming flat, discoidal polyparies,
with distinct oscula which are open after
death; marginal cells of the disk radiate,
unequal.

A. Forskalii. Discoidal; disk thin, margin
dentato-lacerate, surface foveolate, apertures
small. Suez and St. Domingo.

Mr. Johnson has given the same name to
a genus of Diatomacese, not differing, as far
as we can determine, from Asteromphalus,
Ehr.

BIBL. Ehrenberg, Abh. der Berl. Akad.
1848, pp. 121, 130 ; A. S. Johnson, Silliman's
Journ. 1852, xiii. p. 33; Pritchard, Inf. Ani-
mal. p. 319.

ASTEROLAMPRA, Ehr.— A genus of
Diatomaceae.

Char. Free; frustules single, equally
bivalve, circular; central portion imper-
fectly divided by thin septa, which do not
reach the margin, but alternate with rays
extending to the margin, unsupported by
septa ; fossil. Intermediate between Actino-
cyclus and Actinoptychus.

A. Marylandica (PL 19. fig. 5) . Marginal
rays eight, septa eight ; interstices between
the rays exhibiting elegant curved series of
dots; diam. 1-180". Found fossil in Mary-
land.

BIBL. Ehr., Ber. d. Berl. Akad. 1844.

ASTEROMA, D.C.— A genus of Sphae-
ronemei (Coniomycetous Fungi) growing
upon leaves and stalks, forming very minute,
slightly prominent spots, more or less con-
fluent, seated on more or less distinct
radiating filaments. Species :

1. A. reticulatum, D.C. Dothidea reti-
culata, Fr., Corda. On decaying leaves of

Convallaria. Hooker, Brit. Flora, ii. part 2.
p. 288.

2. A, Ulmi, Klotsch. On elm-leaves.
Hooker, Brit. Flora, ii. part 2. p. 289.

3. A. Prunella, Purt. On green leaves
of Prunella vulgaris. Hooker, Brit. Fl. ii.
part 2. p. 289.

4. A. Padi, Grev. On Prunus Padus.
Hooker, Brit. Fl. ii. pt. 2. p. 289 ; Berkeley,
Ann. Nat. Hist. vi. 364. pi. 11. fig. 4.

5. A. ROSCB, Lib. On rose-leaves. Libert,
Trans. Linn. Soc. of Paris, 1826; Berkeley,
Ann. Nat. Hist. vi. p. 364. pi. 11. fig. 5. *

6. A. lobes, Berk. On poplar leaves.
Berkeley, Ann. Nat. Hist. vi. 364. pi. 11.
fig. 6.

BIBL. As above.

ASTEROMPHALOS, Ehr.— A genus of
Diatomaceae.

Char. Frustules single, equally bivalve,
circular; valves marked with alternate rays
forming a double star ; central rays (imper-
fect septa) not reaching the margin, two of
them parallel, the others diverging; marginal
rays broader, smooth, flat, one being absent
or so far obsolete that the two central rays
enclosing it become parallel.

The species occur in the Antarctic ocean ;
the diameter of the valves lies between 1-900
and 1-47". They are distinguished by the
number and direction of the central rays.

A. Darwinii. Central rays five, flexuous.

A. Hookerii (PI. 19. fig. 2). Central rays
six, marginal five, straight.

A. Rossii. Rays six, inflexed.

A. Buchii. Rays six, straight.

A. Beaumontii. Rays seven, inflexed.

A. Humboldtii. Rays eight, straight.

A. Cuvierii. Rays nine, straight.

BIBL. Ehr., Ber. d. Berl. Akad. 1844.

ASTEROPHORA, Dittm.— A genus of
Sepedoniei (Hyphomycetous Fungi), com-
posed of minute fibrous plants, growing
parasitically upon dry blackened Agarics,
deriving their name from the angular, some-
what stellate spores. Two British species
are described :

1. A. agaricoides, Fr. Stipe solid, 1"
high, 1'" or more thick, villous, bearing a
head, at first hemispherical, then plane, about
1-2" wide, at first covered by a white fuga-
cious tomentum, with lamellae underneath ;
spores 6-angled. On decaying Agarics (A.
adustus, piperatus), in autumn, gregarious.
A. Ly coper dioides, Dittm. SturmDeutsch. Fl.

2. A. Ly coper dioides. Stipe 1" high or
obsolete; head hemispherical or globose,
without lamellae beneath; spores 5-6-angled.

ASTOMUM

AVANTURINE.

In similar situations, rather more common.
Ayaricus Ly coper dioides, Sow.

BIBL. Hook., Br. VI. ii. part 2. 322;
Sowerby, Funyi, t, 279 ; Sturm, Deutschl.
FL iii. t. 26; Bulliard, Herb. t. 166, 516,
fig. 1.

ASTOMUM, Hampe.— A genus of Bra-

Fig. 49.

Fig. 50.

Astomum subulatum. Astomum alternifolium.

A leaf showing the cellular Section of sporange.

structure.
Magnified 40 diameters.

Magnified 40 diameters.

chiaceae (Acrocarpous Mosses), including
some of the Phasca of Linnaeus, &c.

1. A. subulatum, Hmy. = Phascum subu-
latum, L. (fig. 49).

2. A. alternifolium, Hmp. = PA. alterni-
folium, Dicks, Crypt, (fig. 50).

3. A. nitidum, ~Kmp.=Ph. axillare, Dicks.
BIBL. See MUSCACE^E.

ATAX, Duges. — A genus of Arachnida, of
the order Acarina, and family Hydrachnea.

Char. Body ovoid ; a genital fissure bor-
dered by two plates, upon each of which
are three transparent, rounded tubercles ;
anterior coxae posteriorly in contact in the
median line, wedging the labium between
them anteriorly; the two groups of posterior
coxae distant; fourth coxa very broad, in
contact with the third throughout its whole
length; palpi with the fourth joint very
long, attenuate, slightly excavated towards
the end to receive the fifth joint in a state of
extreme flexion; fifth joint forming a pointed
claw ; mandibles consisting of a thick body,
cut off obliquely like the point of a pen pos-
teriorly, truncate anteriorly, and terminated
by a large, strong and slightly curved claw ;
labium oval, concave and bifid.

Several species, of various brilliant colours.

A. histrionica (Hydrachna histrionica,
Herm.) (PL 2. fig. 14). Body dark red, paler
in front of the eyes, a square black spot in
front of them ; dorsally marked with longi-
tudinal converging striae ; five black spots
on the anterior portion of the ventral surface ;
palpi and legs blackish green.

The black spots are produced by the
viscera indistinctly visible through the skin.

BIBL. Walckenaer, Apteres,\\\. (Gervais);
Hermann, Mem. Apterol. ; Duges, Ann. d.
Sc. nat, 2 ser. i. ; Koch, Deutschl. Crust.,
&c.

ATHEROMA. — Atheromatous deposits
consist of globules of oil of the most varied
sizes, frequently exceedingly minute, mixed
with albuminous matter in the form of amor-
phous masses or flakes and molecules, plates
of cholesterine and granules of carbonate of
lime.

BIBL. Works on Medicine and Surgery ;
Lebert, Phys. PathoL; Bennett, Edinb.
Monthly Journ. vii. ; Wedl, Grundz. d.
path. Hist.; Rokitansky, Ueber einig. d.
wichtig. Krankh. d. Arterien.

ATRACTOBOLUS, Tode.— Described as
a genus of Nidulariacei (Gasteromycetous
Fungi), but now stated to be the egg of a
Raphignathus.

ATROPIA (Atropine). See ALKALOIDS,
p. 25.

AULACODISCUS. See EUPODISCUS.

AULACOGRAPHA, Leighton.— A genus
of Graphideae (Gymnocarpous Lichens),
founded on the species Aulacographa (Ope-
grapha) elegans, Sm., distinguished by the
peculiar furrows of the proper margins sur-
rounding the disks of the lirellae. Grows on
the bark of trees.

BIBL. Leighton, Ann. of Nat. Hist. 2nd
ser. xiii. p. 389. pi. 7- 1854.

AULACOSIRA. See MELOSIRA.

AULOCOMNIUM, Schwsegr. See
MNIUM.

AURICULARINL— A tribe of Hymeno-
mycetous Fungi characterized by bearing
their basidiospores on the surface of papillae
situated on the under or outer side of a
tubular, cup-shaped or funnel-shaped spo-
range. See HYMENOMYCETES and BASI-
DIOSPORES.

AVANTURINE.— A mineral composed
of silex, with numerous minute scales of
mica interspersed through its substance, or
traversed in all directions by minute fissures
or cracks ; giving it an elegant sparkling or
iridescent appearance.

Artificial Avanturine consists of glass,

AZOLLA.

[ 73 ]

BALSAM.

with numerous minute crystals of metallic
copper distributed through it. These crystals
are mostly in the form of triangular or hex-
agonal plates, the angles sometimes curiously
prolonged or beaked.

It forms a beautiful microscopic object.

It was originally manufactured at Venice,
and the process kept secret. But MM. Fremy
and Clemandot have shown that it may be
prepared by heating glass with protoxide of
copper and iron-scale (protoxide of iron) ;
the latter reduces the protoxide of copper by
combining with the oxygen so as to form the
peroxide. -

BIBL. Wohler, Chem. Gaz. i.; Fremy and
Clemandot, I. c. iv.

AZOLLA, Kaulf. — A genus of Marsile-
aceae or Rhizocarpeae, consisting of a few
species of small floating plants, occurring in
Australia and throughout America. Their
mode of reproduction is evidently analogous
to that of Salvinia, but its development has
not yet been fully examined.

BIBL. R. Brown, Flinders's Voyage, ii.,
App. p. 611; Meyeu, Nova Acta Ac.
C. L. N. C. xviii. p. 507; Griffith, Calcutta
Journal of N. Hist. v. p. 227 ; Mettenius,
Linncea, xx. p. 259, 1847, transl. in Ann.
des Sc. nat. 3 ser. xi. p. 111.

B.

BACILLARIA, Gmelin.— A genus of
Diatomaceae.

Char. Frustules bacilliform, prismatico-
rectangular, linear, at first united transversely
into a straight tabular series, subsequently
forming oblique series ; marine.

B. paradoxa (PI. 12. fig. 14). Front view
of frustules linear, rectangular, valves linear-
lanceolate, transversely striated ; length
1-220". (a, front view of oblique series of
frustules ; b, valve.)

BIBL. Kutz. Sp. Alg. andBacill.-, Ehrenb.
In/us.

BACTERIUM.— A genus of Oscillatorieee
(Confervoid Algae), consisting of extremely
minute inflexible filaments, more or less di-
stinctly jointed, from imperfect transverse
division, exhibiting a vacillating (not undu-
latory) movement. Ehrenberg and Dujardin
place them among the infusorial animalcules
(Vibrionia, Ehr. and Duj.).

1. B. termo, Duj., Vibrio lineola, Ehr. in
part. Colourless, twice to five times as long
as broad, slightly swollen in the middle, com-
posed of one or two joints ; length 1-9000"

Fig. 51.

to 1-12,000"; breadth 1-12,000" to 1-50,000".
Placed by Ehrenberg with his Vibrio lineola,
Ehr. (PI. 3. fig. 17 a).

One of the earliest organisms appearing in
decaying and putrifying animal and vegetable
matters.

2. B. catenula, Duj. Filiform, colourless,
frequently three to five joints ; total length,
1-1250"; joints, 1-7000" to 1-6000" long,
1-60,800" broad (PI. 3. fig. 17 b}.

Probably only a degree of development of
Vibrio bacillus.

3. B. punctum, Ehr. Ovoid-elongate,
colourless, movement slow, vacillating, often
in twos; length 1-5000"; breadth 1-18,000"
(PI. 3. fig. 17 c).

4. B. triloculare, Ehr. Oval, two to five
times longer than broad, with from three to
six joints ; length 1-2000'' to 1-5000'' •
breadth 1-12,000" to 1-10,000".

BIBL. Ehrenberg, In/us.; Dujardin, Infus.

BACTRIDIUM, Kunze.-A genus of
Melanconiei (Coniomycetous Fungi); micro-
scopic plants of tufted habit, growing upon
decaying wood, old bark, &c.;
white at first but coloured
subsequently by the effusion
of the grumous contents of
the spores. One species
recorded as British :

B. atrovirens, Berk. Spo-
ridia 1- to 2-septate, dark
green. Winter.

B.candidum, Kunz. (fig. 51 ),
is a German species.

BIBL. Berkeley, Brit. Flora, ii. pt. 2.
p. 350; Kunze, My col. Heft i. pi. 1. fio-. 2
pi. 2. figs. 20 and 21 ; Nees, Nova Acta, ix.
pi. 1. fig. 3. pi. 2. fig. 21.

BADHAMIA, Berk.— A genus of Myxo-
gastres (Gasteromycetous Fungi), consisting
of little yellow sacs growing in patches on
decayed oak-branches, &c. ; allied to Physa-
rum, but remarkable for the spores, at first
enclosed in a common sac, adhering clusters.
Filaments of the capillitium broad.

BIBL. Berk. Linn. Trans, xxi. 152. pi. 19

B^OMYCES, Pers.— A genus of Leci-
dineae (Gymnocarpous Lichens), growing on
the ground or old walls, &c.

B. roseus, Pers. Engl. Botany, t. 374 ;
Schaerer, Enum. Critic, pi. 6. fig. 6.

BIBL. Hooker, Brit. Flora, ii. pt. 1. p. 141 ;
Schaerer, Enum. Crit. Lick. Eur. p. 182.

BALSAM (Canada). The liquid resin of
the Pinus Balsamea. Tins is the ordinarily
used and best medium for the preservation
of dry transparent objects. The more colour-

Bactridium can-

didum.

Magnified 200

diameters.

BANANA.

BARK.

rese
veae

less it is, the better. It should be kept in a
wide-mouthed bottle, covered by a large
cap, fitted by grinding. A piece of iron-
wire should be kept in the bottle, so that
the desired quantity can be at once removed.
It becomes thicker by keeping, but may be
rendered thinner by mixture with oil of tur-
pentine and digestion at a gentle heat. If
too thin, it should be exposed to a gentle
heat in a bottle covered with paper to
exclude dust.

See PRESERVATION.

BANANA. See MUSA.

BANGIA,Lyngb. — A genus of Porphy
(Florideous Algae), placed among the Ul
by most authors, but stated by M. Thuret to
be Florideous. They are marine, and form
purplish, brownish-green or red tufts of fila-
ments, upon rocks and stones or on the
fronds of other Algae, from 1 to 4 inches
long, or in B. ciliaris, only "half a line
long." Mr. Harvey admits five species,
three of them, however, as doubtful :

1. B. fusco-purpurea, Dillw. Brownish-
green or purple glossy, several inches long ;
near highwater mark. Phycol. Brit. t. 96 ;
Brit. Alga, t. 25 C ; English Botany, t. 2055
and 2085.

2. B. ciliaris , Carm. Forming a minute
pink fringe on Zostera marina.

3. Bl. ceramicola, Lyngbye. Purplish-
rose. On small Algae ; about 1" long.

4. B?. carnea, Dillw. Pale red tufts on
Confervae.

5. B?. elegans, Chauv. Minute tufts 1"'
or 2'" long, rose-red, parasitical on small
Algae, rare. Harv. Phyc. Brit. t. 246.

See SCHIZOGONIUM.

BIBL. Harvey, British Marine Alga, 2nd
ed. 1849.

BARBULA, Hedw.— A genus of Pottia-
ceous Mosses synonymous with Tortula,
which is indeed the prior name, but was
altered on account of its synonymy with a
genus of flowering plants (since abolished) .

1. Barbula rigida, Schultz = Tortula
enervis, Hook, and Grev.

2. B. ambigua, Br. and Sch. = T. rigida,
Hedw.

3. B. aloides, Br. and Sch. = T. rigida,
Hook, and Tayl.

4. B. brevirostris, Hook, and Tayl. = T.
brevirostris, Hook, and Tayl. (ed. 2).

5. B.papillosa, Wilson (Tortula}.

6. B. tortuosa, Web. and Mohr (Tortula).
7- B. squamosa, Brid. (Tortula}.

8. B. Hornschurchiana, Schultz=T. revo-
luta, Brid. var.

9. B. unguiculata, Hedw. (Tortula}.

10. B. convoluta, Hedw. (Tortula).

11. B.fallax, Hedw. (Tortula).

12. B. revoluta, Schw.=Tortula revoluta,
Hook, and Tayl.

13. B. subulata, Hedw. (Tortula).

14. B. muralis, Hedw. (Tortula).

15. B. cuneifolia, Hook, and Tayl. (Tor-
tula}.

16. B. Icevipila, Schw.=T. ruralis, var.
l&vipila, Hook.

17. B. ruralis, Hedw. (Tortula).
BARK. — The outer coat of the trunks

and branches of Dicotyledonous shrubs and
trees, succeeding to the epidermis as the
young shoots become solid and woody. Bark
is a complicated structure, composed of ele-
mentary tissues of various characters, and
the great differences of appearance which it
presents upon trees which have attained a
certain age, result from the growth and mul-
tiplication of the elementary organs being
subject to very different laws in different
plants. Bark is the collective term applied
to the entire cortical mass outside the
cambium region of the stem (see CAMBIUM).
It contains three distinct regions or forms of
structure, and in young branches, the epi-
dermis still remaining on the outside consti-
tutes a fourth.

If we examine a young shoot of the Maple
(Acer campestre} while still green, by making
transverse and perpendicular radial sections,
we find the surface to be covered by an epi-
dermis composed of small cells, closely con-
joined at their sides. Under this occur six
or eight strata of thin-walled, colourless
cells, which stand vertically over one another,
and when mature are elongated in the radial
direction of the branch. These form the
cork-substance, suberous layer, or phlaum.
Beneath or within these, we find a layer
composed of parenchymatous cells, filled with
chlorophyll granules, forming the cellular
envelope or parenchymatous layer; this is
continuous within with the external part of
the medullary rays. Interposed between
the cellular envelope and the Cambium region
occur the liber-bundles (see LIBER), forming
the fibrous layer of the bark. In the bark
of the Maple the corky substance grows very
fast at first, and soon splits the epidermis
above it, but after a certain number of years
its growth slackens, so that it seldom acquires
very great thickness, especially as it is very
soft and readily rubbed off; the cellular
layer does not grow fast, merely keeping
pace with the enlargement of the stem

BARK.

BARLEY.

which it surrounds. The layers of liber
increase year by year so as to form a very
distinct fibrous layer.

In the Cork Oak (Quercus Suber), the
bark of which, when young, does not differ
much from that of the Maple, the cellular
layer grows most in the earlier years, and
the epidermis is not destroyed until the
third, fourth or fifth; then the cork-substance
begins to increase in an important degree,
by the multiplication of its cells at the inner
side, bordering on the cellular envelope. New
layers of cork-cells are produced successively,
expanding • much in the radial direction.
They are thin-walled and destitute of con-
tents, of squarish form (pi. 38. figs. 16 & 17)
and soon become dry. The outer layers
being unable to expand sufficiently to allow
the enlargement of the stem, tear irregularly
and give the surface of the stem a rough and
cracked aspect. On old stems we observe
that the formation of these layers has not
been continuous, but in successive groups or
sets, which causes the appearance of a darker
and more solid structure, composed of tabular
cells, at the points where successive sets of
layers adjoin, just as is the case at the lines
of union of the annual rings of wood in
Dicotyledonous stems. But these lines are
here very irregular. The cellular envelope
takes no share in the formation of the cork
of this tree.

In the Birch (Betula alba), there is a very
decided distinction between the layers of the
cork-substance, namely, between the large
thin-walled colourless cells, and the denser
tabular cells forming the dark streaks in the
cork. The epidermis is succeeded here by a
periderm composed of tabular cells with
brown contents, corresponding to the darker
parts of common cork; in stems of 20 years'
growth, the bark presents as many as fifty
lamellae of this substance, which lamellae are
separated from each other by layers of the
lax, white cork-cells. The readiness with
which the latter structure gives way causes
the lamellae to peel off in thin scales, and
these bring away a portion of the white inter-
mediate structure on both faces, and thus
acquire their peculiar silvery aspect.

In the Beech (Fagus sylvaticd}, where the
bark is smooth, even on old trees, the growth
takes place chiefly in the liber-layers, and
the cellular envelope and cork-substance
merely expand to make room for the enlarge-
ment of the stem ; the cork-substance is here
a periderm, i. e. composed of the flat, tabular
cells, not loose cork tissue. The Holly, Ivy

and other smooth-barked trees are analogous
to this.

The scaling off of the bark of the Plane
(Platanus Occident alis) arises from the for-
mation of layers of tabular peridermal cells
between the layers of liber ; the bark outside
the layers dries and falls away by the tearing
of this peridermal layer. Here, therefore,
the periderm is produced from the cellular
envelope.

In the Lime (Tilia), the Oak (Q. Robur)
and other trees, a similar production of peri-
dermal layers within the liber takes place,
but the layers remain in situ for a long time,
and fall away irregularly, often persisting for
a considerable number of years as rugged,
many-layered scales.

In many of the Coniferae (such as the
Scotch Fir and Larch), the peridermal struc-
ture is in like manner developed from the
cellular envelope; here, however, the cells
are not tabular, but parenchymatous, and
multiply and enlarge so as to form a thick
layer of cork-like tissue, which loses all
relation with the medullary rays. The tur-
pentine canals and liber-fibres engaged in
this corky periderm, become disturbed and
displaced by its irregular growth.

In some plants, such as the Vine, the
Honeysuckle, &c., the bark is always stringy,
which arises from the formation of each annual
layer of liber being followed immediately by
the drying-up, and soon by the destruction, of
the layers of the preceding year, so that no
proper periderm, or suberous or cellular
layers exist here after the first year. The
same takes place in the third or fourth year
in the Clematis.

The inner layers of the bark are especially
distinguished by the presence of laticiferous
canals in those plants in which that tissue
exists ; in fact this appears to be in many
cases a modification of the liber tissue.
Further particulars are given on this head
under LIBER, where also the intimate struc-
ture of the liber will be explained. See also
LENTICELS and CORK.

BIBL. Text-books on Structural Botany ;
Mohl, Entwick. des Korkes, &c., Vermischt.
Schrift. 1845, p. 212; Hanstein, Ueber den
Bau, fyc., der Baumrinde, Berlin, 1853 ;
Schacht, die Pflanzenzelle, p. 237 et sea.
1852.

BARLEY.— One of the important cereal
grains, furnished by the Hordeum sativum and
its varieties (Monocot. Plants, N. O. Grami-
naceae). The starch of the albumen of the
seeds has a peculiar form, by which it may be

BARTRAMIA.

BASEMENT MEMBRAME.

distinguished under the microscope (PL 36.
fig. 9). (See STARCH.) Peaii-haiiey is
obtained by a peculiar mode of grinding, by
which the outer coat or shell of the grain is
removed.

BARTRAMIA, Hedw.— A genus of Bar-
tramioideous Mosses, containing several
common species.

B. Wilspni, C. Mull. = GlypJiocarpa ?
cernua, Wils.

BARTRAMIACE.E.— A tribe of Bartra-
mioidese (operculate Apocarpous Mosses)
containing several genera. British genera :

I. Conostomum. Calyptra dimidiate. Peri-
stome simple ; teeth sixteen, lanceolate,
erect when wet or dry, densely and nodosely
tuberculated, with a median line, connate in
pairs .at their apices, and coherent into an
oblique closed cone, arising at an equal
space below the orifice, at the base.

II. Bartramia. Calyptra dimidiate. Pe-
ristome either absent, simple or double.
External, of sixteen lanceolate, smooth, tuber-
culate teeth, with a median line or sometimes
separating in the Fig. 52,
middle, erect when

wetted, incurved
when dry, red. In-
ternal : a membrane
with sixteen folds,
produced into six-
teen lanceolate,
keeled,broad teeth,
ultimately split in-
to two divergent
articulated lobes,
with one to three

cilia interposed or Bartramia marchica.

none (fig. 52). Magnified fragment of peristome.

III. Catascopium. Calyptra hood-shaped,
smallish. Peristome simple ; teeth sixteen,
lanceolate, very short, truncate-lanceolate,
differing in form, unequal, transversely arti-
culated, with a median line, whitish, rugulose,
rigid and suberect. Capsule inclined on the
collum, globose, small, discelioid, shining-
brown and ultimately growing black, thick-
skinned, almost horny, without an annulus,
smooth.

BARTRAMIOIDE^E. — A family of oper-
culated Acrocarpous Mosses, of csespitose
habit and varying size. Leaves very va-
ried in form, erect or reflexed, with terete
nerves; cells parenchymatous, and, except
in certain species, furnished with solitary
papillae on the transverse walls on both
faces, mostly square or more or less hexa-
gonal ; lax or looseish, and densely filled with

chlorophyll, or with a persistent primordial
utricle, rarely thickened. Capsule with a
long neck, funarioid, pear-shaped or spheri-
cal, regular or asymmetrical, straight or va-
riously inclined, smooth or grooved, with an
operculum mostly hemispherical or conical,
rarely beaked. This family is divided into
two tribes :

1. MEESIACE^E. Areolation of the leaf
lax, smooth, often destitute of primordial
utricle (Meesia), or lax and densely papil-
lose (Paludella). Capsule erect, elongated,
with a more or less elongated neck, hence
more or less pear-shaped, smooth, the neck
bearing stomata.

2. BARTRAMIACE.E. Areolation either
lax and smooth, lax and papillose, dense and
smooth, or dense and papillose. Capsule
erect or inclined, horizontal or pendulous,
regular or asymmetrical, smooth or grooved,
but more or less spherical, devoid of stomata.

BARYTA.— A knowledge of the crystal-
line forms of the salts of baryta is sometimes
useful in determining the presence of this
substance.

Butyrate of baryta (PI. 6. fig. 4). When
rapidly separating from an aqueous solution,
it forms a pearly film upon the surface ; this
consists of dense aggregations of very trans-
parent crystalline laminse, not perfectly se-
parable from each other. When more slowly
formed, stellate groups of crystals are pro-
duced (PI. 6. fig. 4 a). The individual cry-
stals are rarely perfect, and some are so thin
and transparent thattheir outlines are scarcely
distinguishable.

Hydrojluosilicate of baryta (PI. 6. fig. 5).
Its production is a test for the presence of
baryta. The crystals are scarcely affected by
either nitric or muriatic acid.

Sulphate of baryta (PI. 6. fig. 6). When
rapidly formed, consists of crystalline gra-
nules (a). When more slowly precipitated
from dilute solutions, it consists of very
minute stellate foliaceous crystals, somewhat
resembling those of the ammonio-phosphate
of magnesia (&). See STRONTIA and LIME.

BIBL. See CHEMISTRY.

BASEMENT MEMBRANE, of Animals.
— Is a very thin, transparent, elastic and struc-
tureless membrane, lying between the cutis
and epidermis of the skin, and between the
epithelium and submucous tissue of the mu-
cous membranes and their prolongations.
It is of considerable firmness, and serves to
support the layer or layers of epidermal or
epithelial cells. It is not always easily sepa-
rable and demonstrable, but is perhaps most

BASIDIA.

BATRACHOSPERMUM.

readily so in the urinary tubules of the kid-
neys.

In chemical composition, this membrane
mostly resembles elastic and not areolar
tissue.

BASIDIA. See BASIDIOSPORES.

BASIDIOSPORES.— The name applied
to the acrogenous spores produced in groups
of fours on the hymenium of many Fungi,
the term basidium being applied to the four-
branched cell upon which they are attached.
Basidiospores are produced both by the Hy-
menomycetous and Gasteromycetous Fungi.
In the 'former they are found upon the ex-
ternal fruit-bearing surfaces, such as the gills

Fig. 53.

Development of the basidiospores of
Hymenangium griseum.

or vertical plates of Agarics, on the walls of
the tubes of Poh/porus, &c. In the Gastero-
mycetes they are produced upon the convo-

Fig. 54.

Fig. 55.

Basidia and basidiospores Basidia and basidiospores

of Melanogaster variegatus. of Octaviana asterosperma.

Magnified 400 diameters.

luted hymenium which occupies the interior
of the Fungus in the earlier stages of growth,
and when the spores are mature, the hyme-
nium and the basidia becoming dissolved, the
spores fall loose in the cavity. The basidio-
spores sprout out gradually from the basidia,
becoming soon shut off by a cross septum,
and in some cases they finally acquire a dense
and dark-coloured outer coat.

BIBL. Berkeley, Ann. Nat. Hist. i. 81.
pi. 4 and 5. iv. 155. pi. 5; Leveille, Ann.
des Sc. nat. 2 ser. viii. 321. pi. 8-11.

BAST or BASS. See LIBER.

BATRACHOSPERME^.— A family of
Confervoid Algae. Brownish-green or pur-
plish freshwater plants; filamentous, coated
with gelatine. The fronds composed of ag-
gregated longitudinal filaments, bearing at
intervals whorls of short, horizontal, cylin-
drical or beaded, jointed ramuli. Fructifica-
tion : ovate spores attached to the lateral
ramuli, which consist of minute dichotomous
filaments. British genera :

1. Batrachospermum. Lateral whorled
filaments beaded, spores collected in globular
knobs in the whorls.

2. Thorea. Stems continuous, whorled,
articulated, sometimes branched, ramuli cy-
lindrical, the spores at their bases.

BIBL. See these genera.

BATRACHOSPERMUM, Roth.— A ge-
nus of Batrachospermeae (Confervoid Algae),
consisting of delicate, branched, filamentous
plants of green, yellow, red, or purple colour,
growing in clear slowly-running fresh water.
The branched axes of the plants of Batracho-
spermum (fig. 56) consist of rows of large
cylindrical cells applied end to end, and in-
crease in length b\ the successive transverse

Fig. 56.

Fig. 57.

Fig. 59.

Fig. 58.

Fig. 56. Batrachospermum moniliforme. Natural size.
Fig. 57- A portion of an axis with whorls of branches.

Magnified.
Fig. 58. A tuft of branches with spores in the midst.

More magnified.
Fig. 59. Highly magnified view of a few cells of an axis

with nascent radiating ramules and their descending

cortical cells.

BEAN-FLOUR.

C 78 ]

BERKLEYIA,

cell-division of the terminal dome-shaped
cell. While the cells or joints of the axes
are still young, they send off a number of
radiating processes, which soon become cut
off by septa, so as to constitute distinct cells,
and then elongate and ramify so as to form
the whorls of articulated ramules (fig. 5.9),
which at length become very dense (fig. 57).
From the basal cells of these branches second-
ary branches grow down perpendicularly over
the cell of the main axis immediately below
(fig. 59), forming at length a kind of rind over
it. This differs from the analogous structure
in Cham, in the fact that there, branches grow
up as well as down from each articulation of
the axis, and meet half-way. Some of the
ramules which grow out free become fertile,
and produce spores at their extremities,
while others grow out into transparent capil-
lary points. The spores are produced in large
numbers on each tuft, forming an agglome-
rated heap (fig. 58) at each articulation.
The branches of the main axis are produced
by lateral budding of its cells, just above and
as it were in the axils of the smaller whorled
branches. It is supposed, but not ascertained,
that these plants produce zoospores.

The specimens frequently change colour
when dried upon paper, becoming usually
much darker. Bory St. Vincent carefully
examined the distinctive characters of this
genus, and he is followed by Hassall, who,
however, erects several of his varieties into
species. He gives the following : —

1. B. bombusinum, Bory. Frond green,
turning black on paper.

2. B. helmintosum, Bory. Bluish-green.

3. B. confusum, Hassall. Gray, violet
when decayed, very large.

4. B. stagnate, Hass. Yellowish-green.

5. JB. moniliforme, Hass. Deep brown-
gray.

6. B. pulcherrimum, Hass. Violet-gray.

7. B. vagum, Ag. Bluish-green, yellow
when old.

8. B. alpestre, Shuttlew. Blackish.

9. B. proliferum, Hass. Gray.

10. B. rubrum, Hass. Bright red.

1 1 . B. atrum, Harv., var. a setaceum,
bluish, ft capittinum, blackish.

BIBL. Bory St. Vincent, Ann. du Museum,
xii. ,188, 316 et seq. pi. 22, 29; Hassall,
Brit. Freshw. Alga, p. 101 et seq. pi. 13-16.
63 ; Decaisne, Ann. des Sc. nat. 2 ser. xvii.
p. 340. pi. 15, i.; Braun, Verjungung, p. 160;
Ray Society's Translation, 1853, p. 150.

BEAN-FLOUR. See FLOUR.

BEE. See APIS.

BEER.— The fermentation by which this
liquid is produced results from the growth of
the yeast-plant, a microscopic Fungus. See
YEAST and FERMENTATION.

When ammonia is added to beer, a precipi-
tate of the ammonio-phosphate of magnesia
falls, resembling that subsiding from urine
under the same circumstances (PL 9. fig. 3).

BELBA, Hey den (Damans, Koch).— A
genus of Arachnida, of the order Acarina and
family Oribata.

Char. Abdomen separate from the tho-
rax, rounded, as if bulbous ; legs long, geni-
culate.

BIBL. Walcken. Apteres, iii. (Gervais) ;
Koch, Uebersicht d. Arachniden Systems.

BENZOIC ACID.— This acid is well-
known as occurring naturally in benzoin resin
and some other resins. It is found in animal
secretions (urine) only as a product of the
decomposition of hippuric acid. It is also a
product of the oxidation of proteine com-
pounds. It is but slightly soluble in cold,
more readily in hot water and in alcohol,
also in aether.

Its crystals belong to the right rhombic
prismatic system. It is readily sublimed,
and the crystals thus produced form shining
delicate needles. When crystallized from a
solution, it usually forms dendritically ar-
ranged, superimposed plates, with angles of
90°, sometimes narrow six-sided needles or
prisms; occasionally the angles are trun-
cated, so that the inclination of the edges
amounts to an angle of 135°.

It is not unfrequently obtained from urine
when not fresh, in attempts to procure hip-
puric acid. It may be distinguished from
hippuric acid by its much greater solubility
in aether, by its crystallization in the plates,
and their form (PI. 7. fig. 13).

BERGMEHL.— The German expression
for mountain-flour. A powdery or more or
less coherent mineral, consisting principally
of the siliceous valves of the Diatomacese.
In some countries it is mixed with articles of
food in times of scarcity. See DIATOMACE^E.

BERKLEYIA, Greville.— A genus of Dia-
tomaceae.

Char. Phycoma spherical at the base,
giving off filiform branches, in which are
contained the densely aggregated frustules ;
frustules linear in the front view; valves
linear-lanceolate or lanceolate ; marine.

The valves are exceedingly thin, brittle
and transparent. No markings have been
detected upon them, but there can scarcely
be a question that they exist.

BETULA.

[ 79 ]

BILE.

B.fraaiUs(PL 14. fig. 8). Filiform branches
mostly simple, crowded; valves lanceolate,
obtuse; length 1-330". British.

Branches about 1 -4 " in length . Found upon
marine plants and rocks.

B, adriatica. Branches lax, subdivided,
attenuate and flagelliform ; valves narrowly
lanceolate, almost linear, somewhat obtuse ;
length 1-200".

In the Adriatic Ocean.

BIBL. Grev. Scot. Crypt. Flora, tab. 294;
Ralfs, Ann. Nat. Hist. 1845, xvi. p. 110;
Kiitzing, Bacill., and Sp. Alg.

BETULA, L.— The Birch-tree (Dicotyle-
donous Plants, N. O. Betulaceae), remarkable
for its peculiar silvery peri derm. See BARK.
The bark of B. nigra contains reservoirs filled
with an aromatic oil and also a peculiar re-
sin, called Birch Camphor, which is used in
the manufacture of Russia leather.

BIBLARIUM, Ehr.— A genus of Diato-
maceae.

Char. Frustules single, multivalve, com-
pressed and angular ; valves lamelliform, the
inner ones having a large median umbilicus
or aperture (?). Front view of valves trans-
versely vittate. Fossil.

This genus is allied to Striatella., Tabellaria
and Tessella.

Twelve species. Found fossil in Siberia
and Oregon.

BIBL. Ehrenberg, Ber. d. Berl. Akad.
1844-45 ; Kiitzing, Sp. Alg.

BICHROMATE OF POTASH. See
POTASH.

BIDDULPHIA, Gray.— A genus of Dia-
tomaceae.

Char. Frustules compressed, quadrilateral,
connected with each other by one of the
angles, thus forming a chain or filament ;
filament attached by a stipes ; angles of the
frustules equal and produced ; valves covered
with depressions (visible by direct light),
giving them a cellular appearance; ma-
rine.

This genus resembles Isthmia and Amphi-
tetras in the general appearance of the frus-
tules and valves. But it differs from the
former in the angles being alike, and from
the latter in the compressed side view of
the frustules. The frustules are said to be
subdivided by internal septa, which run par-
allel with their long axis ; these correspond
to the striae seen in the front view.

The species are not well determined;
those in which the angles are more prolonged
and acute, and the markings more delicate
and indistinct, are retained by Kiitzing in

the genus Odontella, Ag.(Denticella, in part,
Ehr.). See DIATOMACE.E.

B. pulchella, Ehr., (B. trilocularis, K.)
(PI. 12. fig. 15). Cellular appearance (pro-
duced by the depressions) distinct ; produced
angles blunt, rounded; length 1-400" to
1-200".

B. aurita (Odont. aurita, K.). Cellular
appearance indistinct, longitudinal striae (in-
ternal septa) none ; length 1-800".

Several other species, but not British (?).

BIBL. Kiitzing, Bacill. and Sp. Alg.;
Ehrenb. Ber. d. Berl. Akad. 1843 & 1844;
Ralfs, Ann. Nat. Hist. 1843, xii. p. 273.

BIFORINES.— Under this name Turpin
described certain cells occurring in the septa
of the air-chambers of the leaves of the Aj*a-
ceae, characterized especially by the presence
of a large bundle of r aphides. They contain
a thick fluid, and when they are placed in
water, endosmose causes them to burst and
discharge the crystals. Turpin's long ac-
count of them contains much useless disqui-
sition and various errors. See RAPHIDES.

BIBL. Turpin, Ann. des Sc. not. 2 ser. vi.
p. 5. pi. 1-5.

BILE. — Three colouring matters have
been obtained from the bile, viz. cholepyr-
rhine, biliverdine and bilifulvine. These
were formerly regarded as distinct ; but later
researches have tended to show that they
are modifications of the same pigment, pro-
bably in different states of oxidation.

Cholepyrrhine, the colouring matter in its
ordinary state, is characterized by the series
of tints through which it passes when treated
with nitric acid, especially if this contain
nitrous acid ; becoming first brownish, then
green, bluish, violet, red, and finally yellow.
It is sometimes found in bile in the form of
yellow semicrystalline grains; at others, it
enters into the composition of biliary calculi.

Bilifulvine is also sometimes found in bile
which has been retained in the gall-bladder.
The bile then appears thick and dark brown,
and exhibits small, dark, minute grains.
Under the microscope, the crystals of biliful-
vine are found in these grains. They form
longish, very fine needles, of a reddish-yel-
low colour, either single or several combined.
When the needles are aggregated, they some-
times resemble the crystals of urate of soda,
having a thick globular extremity and a fine
point, and they are often variously curved
and twisted. Caustic potash dissolves them
tolerably readily. When the solution is neu-
tralized and acidified, no precipitate nor se-
paration of crystals occurs. Acetic acid pro-

BILIFULVINE.

BLATTA.

duces no change upon them. Nitric acid has
but little effect upon them, except when the
action is very intense, when they are decom-
posed. Virchow suggests that bilifulvine
holds an intermediate place between hsema-
toidine and melanine. Virchow notices the
occurrence of these crystals upon the walls
of the cysts of Echinococci in the liver. We
have also found them there, and in the liquid
contents of the cysts. In this instance, two
kinds of crystals were met with (PL 9. fig. 15);
some of these were rhombs (a), others were
twisted and elegantly curved bundles of nee-
dles (6). When first examined, they were
yellowish-red, but after remaining a day or
two in the liquid of the cysts, they became
almost perfectly yellow. When mounted in
balsam, the rhombs remained unaltered,
whilst the Jong filamentous groups of needles
lost all colour, leaving a barely distinguish-
able transparent skeleton. Both kinds were
insoluble in acetic acid, but soluble in potash
with a yellow colour.

In morbid bile, crystals of cholesterine,
globules of fat, and small bundles of needles
of margarine are also occasionally found.

See H^MATOIDINE.

BIBL. Berzelius, Lehrb. der Chemie, ix.
p. 285; Simon, Handbuch d. Angewandt.
medizin. Chemie; Lehmann, Phys. Chem.
Syden. Soc.) ; Virchow, Ann. d. Pharm. und
Chem. 1851 (Chem. Gaz. x.); Griffith, Pract.
Man. on the Blood, &c.

BILIFULVINE. See BILE. Fig. 60.

BISPORA, Corda.— A genus of
Torulacei (Coniomycetous Fungi),
characterized by its uniseptate spores
forming simple and solitary bead-
like chains at the apices of short,
slender, erect filaments, destitute of
septa, arising from a creeping my-
celium. It was separated from To-
rula by Corda on account of the
double character of the spores. Ac-
cording to Fresenius, the chains of
spores are pedicellate as above de-
scribed, and the growth of the chains
appears to take place by division of
the terminal cell or spore.

B. monilioides, Corda, of which
fig. 60 represents the chains of spores
without the pedicels, is British (To- Magnified
rula, Auct.). On sticks. 200 diam.

BIBL. Corda, Icones Fungorum, vol. i.
pi. 2. fig. 143 ; Fresenius, Beitr. zur Myco-
logie, Heft 2. p. 57. pi. 6. figs. 46-54.

BITARTRATE OF POTASH. See
POTASH.

Hoides.

BLASIA, Micheli.— A genus of Pelliece
(Hepaticacese). The British species, B.pu-
silla, L., occurs on moist heaths, not uncom-
monly in the mountainous parts of England,
Scotland and Ireland. In addition to the
antheridia and pistillidia, and the sporanges
developed from the latter, this plant produces
gemmce of two kinds. One kind is formed
in receptacles hollowed out of the nerve,
furnished with a long tubular beak, whence
the gemmaj escape when mature. The se-
cond kind are described as black spherical
masses of granular or pulpy substance, and
occur within the epidermis on the under side
of the frond, often covered by the scales.

BIBL. Hooker, Brit. Jungermannice, t. 82
-84 ; Eng. Botafty, t. 1328 ; Brit. Flora, ii.
part 1. 130.

BLASTOTRICHUM, Corda.— A genus
of Dematiei -(Hy'phomycetous Fungi), of
curious habit, growing in and out of water
upon aquatic plants. B. confervoides, Corda
(fig. 61), forms felted tufts of an agreeable

Fig. 61.

rose - colour upon
living and dead
parts of aquatic
Euphorbia, in au-
tumn. The fila-
ments are very
much branched, the
branchlets dichoto-
mous and subulate;
the spores rose-co-
lour, containing a
gelatinous nucleus
within. The spores

are irregularly di- Blastotrichum confervoides.
vided and some re- Fragment of fertile filament.

main imperfect, but Masnified 20° diameters.
both these and the perfectly septate repro-
duce the plant when sown. The form oc-
curring above the surface of the water is
of closer habit than the submerged, in
which the filaments are longer and more lax.

BIBL. Corda, Icones Fung. ii. p. 10. pi. 9.
fig. 50.

BLATTA. — A genus of Orthopterous
Insects, of the family Blattidae.

Blatta orientalis is the common house
black-beetle or cockroach. The head and
the various organs of the mouth are figured
in PL 26. fig. 1, the upper and front view ;
fig. 2 the under view; fig. 22 the parts of the
mouth separate.

Head oval, and concealed beneath the
large plate of the protothorax. Antenna
(fig. 1 a, broken off) very long, setaceous,
pubescent and with very numerous joints;

BLECHNUM.

[ 81

they are inserted close to the inner margins
of the eyes ; basal joint stout and subovate,
second and third squarish, larger than any
of the following, which are ring-shaped
towards the base of the antennae, become
square (in the side view) at the middle, and
oblong at the apex. Labrum (fig. 1 e, fig. 22,
lower part of a) exserted, entire, roundish,
truncated at the base. Mandibles (fig. 22 b)
short, stout, toothed at the tip and on the
inner margin; basal portion of the inner
margin membranous, forming a little lobe.
Maxilla (figs. 1 & 2 g, 22 c) bilobed; inner
lobe (lacinia, fig. 22 c f) dilated and ciliated
on the inner margin, acute, curved inwards
at the apex so as to form a tooth ; outer
lobe (galea, fig. 22 c *) longer, thick, rounded
and naked ; maxillary palpi (figs. 1 & 2 A)
elongated, rough with short hairs, 4 -jointed,
the last joint somewhat hatchet-shaped.
Labium (fig. 22 e) elongated, bifid, with two
more slender inner lobes; labial palpi
(fig. 2 k) pubescent, 3-jointed, last joint
truncated obliquely. Mentum (fig. 2 /) short,
convex at the base. Eyes (fig. 1 c) kidney-
shaped.

Thorax semicircular, the base convex ;
elytra coriaceous, one overlapping the other
and with numerous nerves. Wings large,
folded longitudinally, with numerous nerves.
Females apterous. Abdomen flat, oval, and
terminated by two short, conical, compressed,
jointed appendages in both sexes; besides
which, in the male, there are two slender,
external, not-jointed appendages or styles,
also an elongated intermediate one. Legs
long and compressed; coxae elongated and
stout ; femora stout with a series of spines
beneath ; tibiae clothed with very strong
moveable spines; tarsi 5-jointed, three basal
joints gradually diminishing in length; claws
curved and acute.

See INSECTS.

BIBL. Westwood, Introduction Sec. ;
Kirby, Brit. En torn. i. 12.

BLECHNUM, Linn. -A genus of Pteri-

Fig. 62.

Blechnum. — Pinna with sorus. Magnified 5 diameter

BLIGHT.

deae (Polypoda3ous Ferns) (fig. 62). Bl.
Spicant, With., is the Hard Fern, called
sometimes BL boreale, and sometimes Lo-
maria Spicant.

BLIGHT. — This word is used in common
language in an exceedingly loose and unde-
fined way, being applied to almost every
cause of disease in plants, as well as to the
diseases themselves, which are variously ex-
plained by agencies of meteorological condi-
tions, parasitic plants and insects, operating
singly or in combination. Blight is, indeed,
' in the air ' in many cases, since a frequent
source of disease in vegetation is sudden change
of temperature or hygroscopic condition of the
atmosphere, deranging the processes of eva-
poration and respiration in the tender,
actively developing portions of the foliage or
inflorescence of plants. It is also often ' in
the air' in another sense, but much less
specially than is commonly supposed : the
plagues of parasitic fungi and insects which
sometimes cause such devastation, seem un-
doubtedly to arise immediately from the
transport of the microscopic reproductive
bodies, spores and the like, through the air ;
but the peculiar atmospheric conditions often
observed as accompanying the sudden irrup-
tion of large masses of such 'blights,' are
only collaterally connected with the develop-
ment of these bodies; the warm overcast
weather, almost proverbially designated as
the cause or the herald of blights, is merely
an index of a condition of the atmosphere
especially favourable to the rapid multiplica-
tion of the Fungi and Insecta which are seen
to increase so rapidly at such times, and the
germs of these must be already present,
through other causes, for the production of
the phenomena under such circumstances.

Only a few of the animal blights need be
referred to here, such as the plant-lice, the
most familiar form of ' blight ' in cultivated
plants (see APHIDES), the 'pepper-corn'
or 'ear-cockle' of wheat (see EAR-COCKLE
and ANGUILLULA), the wheat-midge (see
CECIDOMYA), the tur-
nip fly (see HALTICA),
and the species of Cy-
nips and allied genera
which produce galls and
similar excrescences by
the irritation of the ve-
getable tissue, resulting
from their presence.

Many caterpillars of
moths and butterflies
are exceedingly destruc-

BLIGHT. 82 ]

tive, and form a kind of blight, but these
scarcely come within onr province.

The vegetable blights, the parasitic Fungi
growing upon living specimens of the higher
plants, and displaying themselves either as
the cause or the accompaniment of some
disease and disorganization, have of late
years become objects of most earnest atten-
tion, on account both of the enormous
damage which the diseases have caused to
crops of plants of high importance to man,
and also of the many curious facts in their
history which have been brought to light.
The Potato blight and the Vine disease of
recent years have incited renewed efforts to
elucidate the history of these productions, as
yet, however, imperfectly made out. The
old notion, that these products were the
result of skin-diseases or exanthemata of
plants, is now pretty generally discarded,
especially as many of them have been grown
artificially from their spores.

The general history of the conditions of
their occurrence, and a summary of the in-
vestigations into their history, is given under
the head of PARASITIC FUNGI. The par-
ticular history of the more remarkable
genera will be found under the heads indi-
cated by the capitals in the following para-

BLOOD.

Corn-blights consist chiefly of mildew
(PUCCINIA), rust or red-robin (UREDO,
TRICHOBASIS), smut, bunt or brand (URK-
DO,USTILAGO, ~POL,YCYSTLS), pepper-brand
(TILLETIA), ergot (CLAVICEPS), &c. CYS-
TOPUS ( Uredo), attacks Cruciferous plants.
Mildews of pease, peaches, hops and many
other cultivated plants are produced by
species of ERYSIPHE. OIDIUM is a common
mildew, and is supposed in many cases to
be only an earlier condition of the Erysiphes.
BOTRYTTS is another common mildew.
vEciDiuM forms a kind of rust, as is the
case with the allied RCESTELIA infecting
pear-trees. See also UROMYCES, POLY-
CYSTIS, COL^EOSPORIUM, PROTOMYCES,
EPITEA, PHRAGMIDIUM, FUSISPORIUM,
TORULA, PERIDERMIUM, SCLEROTIUM,
SPILOCJSA, SPH^RIA.

BIBL. De Bary, Unters. ub. die Brandpilze,
Berlin, 1853, gives a copious list of the pre-
vious works relating to the smuts and brands,
in chap. 3. p. 102 ; -Berkeley, Trans. Hort.
Society, Gardener's Chronicle, passim ; A.
Braun, Krankheiten der Pflanzen, Berlin,
1854 (transl. Quarterly Journal of Microsc.
Science, July 1854) ; Sidney, Blights of the
Wheat, pub. by Rel. Tract 'Society ; article

Blight, in Brande's Dictionary, Penny
Cyclopeedia and Library of Entertaining
Knowledge.

BLINDIA, Br. and Sch.— A genus of
DicranaceousMosses,including some Weissice
and Gymnostoma of authors.

Blindia acuta, Br. and Sch. = Weissia
acuta, Hedw.

B. Stylostegium, C. Mu\\.=Gymnostomum
ceespititium, Web. and Mohr.

BLOOD. — This animal fluid, with the
general appearance of which in the higher
animals every one is so familiar, is no less
difficult in its microscopic study, than it is
complex in its chemical composition. In
man and mammalia, birds, reptiles and fishes,
it is a viscid liquid of a red colour. In those
of the lower classes in which it exists, it is
mostly colourless, sometimes, however, red,
bluish, purplish, greenish or milky.

When examined under the microscope the
blood is found to consist of a liquid portion,
containing in suspension a large number of
minute corpuscles, which are known com-
monly as the globules of the blood.

In the Mammalia, Birds, Reptiles and
Fishes generally, the liquid portion, or liquor
sanguinis as it is called, is nearly colourless,
or of a pale yellow tinge, and the corpuscles
are of two kinds, one of a red colour when
viewed in mass, but pale reddish yellow when
seen singly or separately, and to these the
red colour of the blood is owing ; the other
consists of perfectly colourless bodies.

The red corpuscles are far more numerous
than the colourless ones, and consist of delicate
membranous colourless cells enclosing a red
liquid. In the Mammalia they assume the
form of circular flattened discs or discoidal
cells, the sides of which are depressed or
hollowed out, so as to make them resemble
doubly concave lenses, with rounded mar-
gins (PI. 40. figs. 21, 22 & 23). In the Camel
tribe, however, they are elliptical and doubly
convex. In Birds (figs. 24 & 25), Fishes
(figs. 26 & 27) and Reptiles (figs. 28, 29 &
30), they are elliptical and flattened, the
form of the sides varying. Thus, in Birds and
Fishes they are convex, excepting the Cyclo-
stomes or lamprey family among the latter,
in which they are circular, flattened and
slightly concave, only differing from those
of man in being somewhat larger; and in one
genus of this family, Amphioxus lanceolatus
(the lancelet), there are no blood-corpuscles.
In the Reptiles, in which they are elliptical,
very large and comparatively thin, the
surfaces of the corpuscles are rather concave

BLOOD.

BLOOD.

than convex, the nucleus projecting some-
what laterally.

The red corpuscles of the Mammalia are
not furnished with a nucleus, whilst in Birds,
Fishes, and Reptiles a distinct nucleus exists ;
this is usually oval, but sometimes rounded
in the latter.

The colourless corpuscles of the Vertebrata
(figs. 21-30 b), or the lymph corpuscles as
they are sometimes called, are spherical, of
a granular appearance, highly refractive and
specifically lighter than the coloured corpus-
cles. They consist of a cell- wall containing
numerous larger or smaller granules and
molecules, with one or more nuclei. Acetic
acid dissolves the granules, and brings the
nuclei to view. The cell- wall is often undi-
stinguishable, unless water be added to the
corpuscles, which being imbibed, separates
it from the contents.

The blood of the Invertebrata has not
been so thoroughly examined. In many of
them there are two circulating liquids ; one
coloured, but containing no corpuscles, the
other colourless and containing rounded or
irregular granular colourless nucleated cor-
puscles (figs. 31-35), much resembling the
colourless corpuscles of the Vertebrata, but
remarkably prone to shoot out processes like
the Amoebae.

The sizes of the coloured corpuscles of
many vertebrate animals are given in the
subjoined list, nearly all the measurements
being those by Mr. Gulliver. It may be
remarked, that whilst the largest coloured
corpuscles occur in the Reptiles, the smallest
are found in the Mammalia; and that
the size of the corpuscles is in general
proportionate to the size of the animal,
in animals of the same order, but not in
those of different orders. Thus in the
larger Ruminants and Rodents, the corpus-
cles are larger than in the smaller ones;
whilst the smallest British mammal, the
Harvest-mouse, has corpuscles as large as
those of the Horse; and in the common
mouse they are larger than in the Horse or
Ox.

MAMMALIA.

Bimana.
Man..

1-3200 to 1-3500"

Quadrumana.

Chimpanzee( Simla Troglodytes) 1 -34 1 2

Monkey (Cercopithecus mono). 1-3468
Monkey, mean of eight other

species 1-3450

Lemur, mean of four species . . 1-4077"
Cheiroptera.

Bat (Vespertilio murinus) .... 1-4175
( Vespertilio pipistrellus) . 1 -4324

Insectivora.

Hedgehog(.Enwacetts europaus) 1-4085
Mole (Talpa europtea) 1-4747

Carnivora.

1-3940
1-3708
1-3542
1-4117
1-4322
1-3281

Badger (Meles vulaaris) . . .
Bear, mean of five species .
Dog ( Canis familiaris) . . .

Fox (Canis Vulpes)

Lion (Felis Leo]

Seal (Phoca vitulina)

Cetacea.

Dolphin (Delphinus Phoccend).
Whale (Balcena mysticetus] . .
(Balcena Boops]

Pachydermata.

Elephant (Elephas indicus) . .

Horse (Equus caballus)

Pig (Sus Scrofa)

Rhinoceros indicus . .

1-3829
1-4000
1-3099

1-2745
1-4706
1-4230
1-3765

Ruminantia.

Camel (Camelus bac-

trianus} Ig. 1-3123 br. 1-5876

Dromedary ( Camelus

dromedarius}. . Ig. 1-3254 br. 1-5921

Goat (Capra hircus) 1-6366

Musk (Moschus javanicus). . . . 1-12325

Stag (Cervus elaphus] 1-4324

Ox (Bos Taurus] 1-4267

Sheep (Ovis Aries) 1-5300

Edentata.

Armadillo (Dasypus sex-cinctus] 1 -3457
Sloth (Unau, Brady pus didac-

tylus) 1-2865

Rodentia.

Guinea-pig (Cavia cobaya). . , . 1-3538

Mouse (Mus musculus) 1-3814

Rabbit (Lepus cuniculus) 1-3607

Rat (Mus Rattus) 1-3754

Marsupialia.

Kangaroo (Macropus), mean of

three species 1-3460

Monotremata.

Platypus, duck-billed (Ornitho-

rhynchus paradoxus] 1-3000

G 2

BLOOD.

BLOOD.

Birds.

Chaffinch (Fringilla cce-

lebs)

Cuckoo (Cuculus cano-

rus)

Eagle (Aquild), mean of

four species

Fowl (Gallus domesti-

cus).

Gull (Mew-, Larus ca-

nus)

Humming-bird (Tro-

chilus ?)

Ostrich (Struthio ca-

melus)

Owl (Strix flammea) . .
Parrot( Psi^acws),mean

of twelve species . .
Pigeon( Columba) ,mean

of sixteen species . .
Sparrow (Fringilla do-

mestica)

length, breadth.

1-2253 1-4133"
1-2028 1-3600
1-1640 1-3651
1-2102 1-3466
1-1973 1-3839
1-2666 1-4000

1-1649 1-3000
1-1882 1-3740

1-2042 1-3724
1-2135 1-3679
1-2140 1-3500

Reptiles.

Crocodile (Crocodilus

acutus) 1-1231 1-2286

¥rog(Ranatemporaria) 1-1108 1-1821

Lizard (Lacerta vim-
para) 1-1660

Siren lacertina 1-435 1-800

Toad ( Bufo vulgaris) . . 1-1043 1-2000

Triton (Lissotriton
punctatus] 1-830

Fishes.

Carp (Cyprinus carpio) 1-2142 1-3429

Eel (Anguilla vulgaris} 1-1745 1-2842

Jack (Esox Indus] 1-2000 1 -3555

Miller's Thumb ( Coitus

gobio) 1-2000 1-2900

Perch(PercafluviatiUs) 1-2099 1-2824

Tench (Cyprinus Tinea) 1-2286 1-2722

The colourless corpuscles have not been
so extensively examined. They do not vary
so much in size in different animals as is the
case with the coloured corpuscles. Those
of the human blood are about 1-2500" in
diameter.

The red corpuscles of blood are easily
altered in form by most liquids; those of
less specific gravity than the liquor sanguinis
distend them, rendering them larger, paler
and more transparent, and effacing the len-
ticular appearance and the elliptical form
when present. If the liquid be added in
large proportion, the envelope or cell-mem-

brane becomes extremely thin and pale, until
at last it is no longer distinguishable ; some-
times it bursts. These phenomena are the
result of endosmosis. The red corpuscles
are not, however, all equally acted upon:
some are much more affected than others ;
some even appear almost entirely to resist
the action of endosmotic agents, and are
found but little altered, even when the blood
is mixed with a large proportion of water.
They then subside to the bottom of the
vessel. This has given rise to the erroneous
notion that water at first renders the red
corpuscles larger and then diminishes their
size ; but the real explanation is that above
given. Although water and other endosmotic
agents distend the coloured corpuscles, and
render their envelopes so extremely transpa-
rent that they can no longer be recognized,
yet many of them may be restored to view
by the addition of reagents wrhich either act
exosmotically, colour them, or render them
opake; as solution of iodine, of bichloride
of mercury, and various other salts. Many
of them, however, burst, and others disappear
entirely, apparently from being truly dis-
solved.

The smallest are generally those least af-
fected, and these are the oldest or the most
perfectly developed; for we shall see pre-
sently that during their earlier stages of de-
velopment, the coloured corpuscles are many
times larger than in their mature condition.
Dilute acids act nearly in the same manner as
water, but much more rapidly. Dilute solu-
tions of alkalies produce the same effect, but
soon dissolve them completely. Solutions
of neutral salts act exosmotically, rendering
them smaller, more flattened, and producing
wrinkles, folds, or a granular appearance in
the enveloping membrane. Frequently also
they appear covered with little points, giving
them an elegant stellate aspect. This stel-
late or crenate appearance is not unfrequently
seen immediately that fresh blood is exa-
mined under the microscope. Two principal
conditions are especially favourable to its
production, viz. a concentrated state of the
liquid, and an increase in the proportion of
alkaline chlorides.

The colourless corpuscles are much less
affected by reagents. Water distends them
slightly, rendering their granulations less
distinct. Acetic acid does the same to a
greater extent, bringing to light the nuclei.
Alkalies dissolve them. When blood is mixed
with a large quantity of water, the mixture
shaken and set aside, a pale buff precipitate

BLOOD.

BLOOD.

subsides ; this consists of some of the albu-
men thrown down from the serum, with
shreds and walls of ruptured coloured cor-
puscles, a few of the latter unaltered, and
some unaltered or but slightly changed co-
lourless corpuscles.

Almost immediately after the blood of the
Vertebrata has left the blood-vessels, it be-
gins to coagulate. This coagulation arises
from the gradual solidification of the fibrine,
which exists in a state of solution in the
living fluid. Within about three minutes,
the surface of the coagulating blood becomes
gelatinous; in about ten minutes it is gelati-
nous throughout, and after a further lapse
of time, the coagulation of the fibrine appa-
rently attains its maximum : this process is
not, however, really completed until from
twelve to thirty-six hours. We then find a
firm red clot immersed in a yellowish liquid.
The fibrine during its coagulation entangles
a large number of the corpuscles, which im-
part to it the red colour ; this is greatest to-
wards the lower part of the clot. The liquid
from which the clot has separated, the serum,
also contains some of the globules in sus-
pension ; most of those not entangled in the
clot, however, subside to the bottom of the
vessel. The sp.gr. of the serum is about 1030.
The appearances presented under the micro-
scope by a drop of coagulating blood are
very interesting. If examined immediately
after removal from the body, the cor-
puscles are seen to be diffused irregularly
over the field ; but after the lapse of about a
minute, the red corpuscles unite by their
broad surfaces, gradually arranging them-
selves into rows resembling strings of figs :
these interlace, forming an irregular red net-
work, within the meshes of which the colour-
less corpuscles are seen (PI. 40. fig. 37).
The latter remain isolated, having no ten-
dency to unite with the former. To observe
these phenomena, the thin glass covering
the drop of blood must not be pressed down,
otherwise the free motion of the corpuscles
will be impeded. After a time, the fibres
break up, and the corpuscles float separately
in the serum.

The coagulated fibrine is also seen distri-
buted over the field, partly in a granular
form, but mostly in that of a network of
very delicate fibres. Sometimes this running
together of the red corpuscles begins to take
place immediately the blood has left the
body, and the rows are seen to be formed
very much more rapidly than in the healthy
fluid ; and when this is the case, the upper

surface of the clot will be found to be
free from the red colour, and more or less
cupped or concave : this upper layer is called
the bufly coat, and is in general a sign of
inflammation. Considerable doubt still ex-
ists in regard to the nature of this buffy
coat. It is also met with in blood which has
been covered with a layer of oil before co-
agulation. But in the natural state it arises
from the subsidence of the corpuscles before
the commencement of the solidification of
the fibrine, whereby the particles of the lat-
ter are brought into closer contact, thus al-
lowing of its greater contraction. Certain
salts prevent the separation of the fibrine in
the form of fibres, and cause it to assume
the form of minute granules or glo-
bules.

In addition to the corpuscles above de-
scribed which are constantly found in the
blood, it sometimes contains globules of oil,
and, after meals especially, two distinct kinds
of a white, extremely fine molecular sub-
stance ; one consisting of fat, the molecular
base of the chyle, the other a very finely di-
vided albuminous substance. They render
the blood milky in appearance. The di-
stinction of the molecidar base of the chyle
from the molecular albuminous deposit must
be effected by a3ther, which dissolves the
latter but not the former; but great care
is requisite in judging of the action of
aether.

The colour of the blood of the Vertebrata
varies according to whether it is removed
from the arteries or the veins, in the former
case being of a much lighter and brighter red
than in the latter. It is beyond our province
to enter into the details of the causes of their
difference; suffice it to say, that it arises
principally from an alteration in the globules,
by which they are enabled to reflect light
more copiously.

In the Invertebrata the coagulation of the
blood is imperfect, and the clot much less
firm and copious than in the Vertebrata.

The uses of the blood scarcely require
mention. It is at the same time the nutri-
tive fluid from which all the tissues of the
body are formed and renovated, and that in
which the components of the secretions are
produced and from which they are separated.
The red particles are subservient to the pur-
poses of respiration ; they are most numerous
in those animals in which the respiratory
function is most active, and which consume
the largest proportion of oxygen, as birds
and mammalia.

BLOOD.

BLOOD.

Development of the Coloured Corpuscles. —
In the Vertebrata, two sets of coloured cor-
puscles are developed. The first, or embry-
onic blood-corpuscles, exist alone, until lymph
and chyle begin to be formed, when they are
gradually superseded by the second.

The first blood-corpuscles are formed
from colourless nucleated cells, with
granular contents, identical with the
formative cells of the embryo, by their
losing the granules and becoming filled
with hsematine. These coloured, nucleated,
primary blood -cells, which are spherical,
larger and more deeply coloured than the
coloured blood-corpuscles of the adult, form,
with the colourless formative cells, the only
elements of the blood. Soon, however, many
of them begin to increase by division (PL 40.
fig. 36), becoming elliptical and flattened,
and closely resembling the coloured corpus-
cles of Reptiles, producing two, rarely three
or four roundish nuclei, and then becoming
resolved into two, three or four new cells by
the formation of one or more annular con-
strictions. These corpuscles then gradually
lose their nuclei, become flattened and exca-
vated laterally, and form perfect coloured
corpuscles.

The formation of the second set, or those
produced after birth and in adults, is more
obscure. The most probable view appears
to be that they are produced from the smaller
chyle-corpuscles, by their losing their nuclei,
becoming flattened, and producing hsema-
tine. At all events, corpuscles apparently
identical with the so-called proper corpuscles
of the chyle, surrounded with a membrane
which is more or less distended with a red
liquid, are met with in the chyle, and occa-
sionally, but rarely, in the blood itself. Phy-
siologists are not agreed as to the above
views, but the preponderance of evidence
appears decidedly in their favour.

As unusual constituents of blood may be
mentioned, —

1. Cells, enclosing coloured blood-corpus-
cles; found in the blood of the spleen,liver, &c.

2. Granule-cells, either colourless or con-
taining granules of pigment.

3. Peculiar concentric bodies, three or
four times as large as the coloured corpuscles
of the blood, resembling those found in the
thymus gland.

4. An unusually large number of colour-
less corpuscles.

5. Pus-corpuscles.

6. Caudate cells, sometimes containing
pigment.

7. Crystals of hsematoidine, sometimes
within the coloured corpuscles, at others free.

8. The two molecular substances previ-
ously mentioned.

It sometimes becomes of importance to
be enabled to determine the presence of
blood, and to distinguish that of man from
that of animals. As regards the former
point, it is a matter of no great difficulty.
When blood has been dried at ordinary tem-
peratures, the dried serum and contents of
the corpuscles redissolve on digestion with
cold water ; and this is the condition under
which the blood is generally presented for
examination in such cases. We then have
the fibrine left undissolved, which may be
tested as to its chemical and microscopical
characters (FIBRINE). The liquid is de-
colorized by boiling, and the coagulum as-
sumes a brown colour (H^EMATINE). It
also contains iron, is unaltered in colour by
solution of potash, and contains a proteine
compound (PROTEINE). In heating very
minute quantities upon a glass slide, the
fluid must always be covered with a slip of
thin glass, to prevent its drying. The mere
presence of blood can thus be chemically
determined without much difficulty; for
these reactions may be observed under the
microscope in a very minute quantity. But
the distinction of small quantities of the
blood of man from that of animals by chemi-
cal means, is impossible. We have therefore
only the morphology of the elements to de-
cide from. The portions of blood presented
for examination will be almost invariably in
a dried state ; and the red corpuscles, when
dried in a very thin layer, retain so nearly
their natural size and outline, that any kinds
of blood which are distinguishable in the
fresh state, are certainly so when dried. But
it will seldom happen that the blood will be
dried upon a transparent substance, and in
thin layers, permitting of its examination by
transmitted light. We have then to separate
it from some fabric or structure, and restore
as nearly as possible its original appearance.
This can be done by digesting the blood in
a saturated solution of bichloride of mercury,
which has a remarkably slight action upon
the corpuscles, allowing both their natural
form and size to be judged of with great ac-
curacy; and by digesting the blood in a cold
solution of this salt, andplacingit under abell-
glass for some hours, the red corpuscles may
be detached with a camel's-hair pencil, and
examined. Of course, only those corpuscles
should be measured which evidently retain

BLOOD-VESSELS.

C

BCEHMERIA.

their natural form. The red corpuscles of
the mammalia are readily distinguishable
from those of the lower classes in the animal
kingdom by their circular discoidal form and
the absence of a nucleus ; but those of indi-
vidual species can only be recognized by a
difference in size.

We should recommend those who are
likely to undertake such investigations to
make their own table of sizes ; for it curi-
ously happens that in general the sizes of
the same objects given by different observers
varies considerably. This arises probably
from using loo low a power, want of practice,
and the use of a false standard. And we
should not advise any one to attempt to form
a judgment in a question of this kind except
he be thoroughly acquainted with the use of
the microscope and micrometric investiga-
tions, and has made numerous experiments
upon this special point.

The corpuscles of the blood are best stu-
died while existing in the serum of that li-
quid ; but the white of egg neutralized with
acetic acid exerts but little action upon them,
as is also the case with a solution of bichlo-
ride of mercury. The colourless corpuscles
are most easily recognized when the blood
has been mixed with water.

They are best preserved when dried in a
very thin layer upon a slide ; a drop of blood
being placed upon the slide, and the latter
placed in a perpendicular position, so that a
very thin layer will remain.

BIBL. Paget, Brit, and For. Med. Rev.
xiv. p. 260; Kolliker, Hand. d. Gewebel. p.
567; the Manuals on Physiology, by Miiller,
Valentine, Wagner, Carpenter, Kirkes and
Paget ; the Dictionaries of Todd and Bow-
man, and Wagner; Ha.sssi\\,Microscop.Anat.;
Wharton Jones, Trans. Royal Soc. Lond.
1846 ; Remak, Diagn. und Pathognet. Unter-
such. (Ed. Month. Journ.) 1845 ; Vogt. Ann.
d. Sc. nat. 3 ser. ii. ; Gulliver, Gerber's
Anat. ; Ann. Nat. Hist. xvii. ; Schmidt, die
Diagnostik verdacktigerFlecke, &c. 1848. See
also CHEMISTRY, H^EMATOIDINE, CHYL-
AQUEOUS LIQUID, and LITERATURE.

BLOOD-VESSELS. See VESSELS.

BLOXAMIA, Berk, and Br.— A genus of
Onygenei (?) (Ascomycetous Fungi), consist-
ing of minute, punctiform sacs, soon bursting
above, containing closely packed tubes pro-
ducing each a row of squarish spores. An
anomalous genus. B. truncata, has been
found on dead Wych elms.

BIBL. Berk, and Broome, Ann. N. Hist.
2 ser. xiii. 468. pi. 16. fig. 17-

Fig. 63.

Blytia Lyellii, nat. size.

BLYTIA,End-
lich. — A genus
of Pellie» (He-
paticacea3) foun-
ded on the Jun-
germannia Ly-
ellii of Hooker,
remarkable for
the double enve-
lope of the fruit,
the outer being
very short, den-
tate and lacini-
ated, while the
inner forms a
largish, some-
what plaited
cylinder. The
antheridia arising from the rib are covered
by incumbent scales, which are some-
times much laciniated and crowded together,
sometimes (J. hibernica, Hook. Brit. Jun-
germ.} scarcely toothed, lax and larger.

BIBL. Hooker, Brit. Jung. t. 77 & t. 78 ;
Nees, Lebermoose, iii. 313 ; Flora Danica, t.
2004.

BODO, Ehr. — A genus of Infusoria be-
longing to the family Monadina. (Monads
with a tail.)

Char. A tail ; no eye-spot present ; mouth
terminal ; animals sometimes united in the
form of a mulberry or a bunch of grapes.

Ehrenberg describes eight species.

Some of them inhabit the intestinal canal
of the frog. One is green, the rest are co-
lourless.

Dujardin regards one species (Bodo gran-
dis) as comprising both his Heteromita
ovata, and a species of Anisonema; the
others he considers as imperfectly examined
species belonging to his genera Cercomonas
and Amphimonas.

Bodo grandis, E. (Heteromita ovata, D.).
Aquatic; length J-940 to 1-720" (PI. 23.
fig. 18 a).

Bodo socialis, E. (PI. 23. fig. 18, b, c).
Aquatic; length 1-3000".

Pritchard describes a species found in the
liquid contained in an oyster-shell, under
the name of Bodo oystea.

BIBL. Ehrenberg, In/us.-, Dujardin, Infus.;
Pritchard, Infus. Animate.

BCEHMERIA, Jacq.— A genus of Urtica-
ceous plants closely allied to our common
Stinging Nettle, and characterized, like that
and other species of Urtica, by containing
tenacious liber-fibres. Two species are em-
ployed in the East Indies on this account.

BOLACOTRICHA.

[ 88 ]

BONE.

B. nivea, Gaudichaud, yielding the fibre from
which Chinese grass-cloth (PI. 21. fig. 25) is
manufactured, is a native of China, where it
is largely cultivated, also in Sumatra, where
it is called * Caboose,' and at Pulo Penang,
where it is called * Kami.' B.Puya, Wallich,
yields the 'Pooah' or 'Puya' fibre of Nepaul
and Sikkim (PI. 21. fig. 26), which has long
been extensively used in India, and is said to
equal the best European flax when properly
dressed ; being ordinarily roughly prepared,
it is dirty and bad-coloured, but makes excel-
lent sail-cloth and cordage.

BIBL. Hooker, Journal of Botany, vols.
i. & iii. 1849-51.

BOLACOTRICHA, Berk. & Broome.— A
genus of Dematiei (?) (Hyphomycetous Fun-
gi), containing one species, B. grisea, found
growing upon dead cabbage-stalks, old mats
made of Typha, &c., in tufts forming large,
effused gray patches. Messrs. Berkeley and
Broome express themselves doubtfully as to
its real affinities; in habit it approaches
Myxotrichum, but differs in its simple threads
and large spores, while the spores are not in
chains as in Sporodum, or minute and linear
as in Tricholechonium. The threads are pale
purple under the microscope, strongly curved
at the tips like tendrils,

BIBL. Berkeley and Broome, Ann. Nat.
Hist. Ser. 2. vii. p. 97. pi. 5. fig. 4.

BOLETUS, Dill.— A genus of Polyporei
(Hymenomycetous Fungi), consisting of pi-
leate Fungi, or ' toad-stools,' often of large
size, growing in woods. They have the ba-
sidia contained in tubes arranged perpendi-
cularly to the pileus and opening at its lower
surface ; the transverse sections of the tubu-
lar hymenium thus exhibit circular holes,
separate by double septa, each pore being
formed by a perfect tube; while in Pofyporus
the septa are single, from the tubes being in di-
stinguishably blended. See BASIDIOSPORES.

BOMBACE.E .— A subdivision of the fa-
mily of Dicotyledonous plants called Stercu-
liaceae, some genera of which are called Silk-
cotton trees, from the long hairs which enve-
lope their seeds, as in the true cotton plants.
These hairs (from Chorisia speciosa,Bombax,
sp. var., Eriodendron, sp. var.) cannot be
spun, but are used for stuffing cushions, &c.
The Adansonia, or Baobab-tree, produces a
pulpy fruit, which contains a considerable
proportion of starch. The wood of some
kinds, as of Bombax pentandra and Pachyra
( Carolined) minor, is remarkable for its light-
ness and almost corky texture, resulting
from being composed almost exclusively of

parenchymatous cellular tissue, with scattered
porous ducts and true wood-cells. See WOOD.

BONE.— It need scarcely be stated that
bone is the hard substance serving to give
firmness to the bodies of the Vertebrata, to
protect their delicate organs, and to form
points of attachment for muscles.

To the naked eye, bone appears to consist
of an apparently homogeneous basis, sur-
rounding certain cavities, areolae or cancelli;
these are most numerous and larger towards
the centre, where, in the Mammalia and Birds,
they form a larger cavity called the medullary
canal. This contains the marrow in the for-
mer class, but air in the latter. Hence we

Fig. 64.

Magnified 90 diameters.

Segment of the transverse section of a human meta-
carpal bone, a, outer surface of the bone, with the outer
laminae ; b, inner surface next the medullary canal, with
the inner laminae ^ c, orifices of the divided Haversian
canals, with their laminae ; d, interstitial laminae ; e, la-
cunae, with their canaliculi.

BONE.

[ 89 ]

BONE.

recognize in bone an outer
compact and an inner spongy
portion.

On examining a thin trans-
verse section of bone under
the microscope by transmitted
light and with a low power,
it is found to exhibit a num-
ber of round or oval apertures;
these are the orifices of the
divided vascular or Haversian
canals (fig. 64 c). These ca-
nals contain blood-vessels in
the natural state. They are
cylindrical, sometimes flat-
tened, communicate freely
with each other and the me-
dullary canal, and also open
upon the outer surface of the
bone. . They mostly run par-
allel with the axis in the long
bones ; whilst in the flat bones
they are parallel to the sur-
faces, frequently following a
radiating course. Thebranches
by which they communicate
with each other are either
transverse or oblique, and
pursue a radiating or tangen-
tial course.

Hence in a longitudinal or
superficial section of bone,
the canals are seen running
longitudinally, here and there
connected by anastomosing branches, and
forming elongated somewhat rectangular
meshes (fig. 66.).

In transverse sections of foetal and incom-
pletely developed bones, scarcely any of the

Fig. 65.

Magnified 60 diameters.

Haversian canals from the superficial layers of a human
femur, at eighteen years of aj-e, treated with muriatic acid.
ti, Haversian canals ; b, osseous substance with lacunae.

Magnified 25 diameters.

Segment of a transverse section of the shaft of the human femur, at eighteen
years of age. «, Haversian canals ; b, their internal orifices ; c, the external
orifices ; d, osseous substance, with lacunae. There are no transverse sections
of the Haversian canals, nor concentric laminae.

apertures are met with, but the canals are
seen pursuing a tangential or radial course
(fig. 65 a) ; so that the bones appear to con-
sist of short thick layers, each of which be-
longs to two canals, which separation is also
indicated by a faint median line in each
layer.

The Haversian canals vary considerably in
size, from about 1-1000 to 1-200".

The osseous substance or basis of bone
possesses a laminated structure. The lami-
nae are visible in sections of dried bone (fig.
64 a, &), but much more distinctly in bone
from which the inorganic matter has been
removed by digestion in dilute muriatic acid.
In this, the lamina? are easily separable.
They frequently exhibit a fibrous appear-
ance, and near the surfaces of the bones they
run parallel with these surfaces (fig. 64 6),
but in the other portions they mostly sur-
round the Haversian canals concentrically
(fig. 64 e).

When a section of bone is examined with
a somewhat high power, it exhibits nu-

r 90

BONE.

Magnified 350 diameters.

Portion of a transverse section of the shaft of the hu-
merus, treated with oil of turpentine. a, Haversian
canals ; b, their laminae, each lamina with a lighter and
darker portion and radiating striae in the latter ; c, darker
lines, probably indicating greater interruptions in the de-
position of the osseous substance; d, lacunae without
evident canaliculi.

merous dark spots, with fine lines branch-
ing from them on all sides ; the former are
the lacuna, bone-corpuscles, or bone-cells
(fig. 68 c, b), and the latter are the canali-
culi or calcigerous canals (fig. 69 b, c, d}.
They derive their dark appearance in dried
bone from containing air; if this be displaced
by immersion in oil of turpentine, they be-
come so transparent as to be scarcely di-
stinguishable (fig. 67) ; and when examined
by reflected light, they appear white. The
lacunae are generally longer than broad, and
flattened. They are about 1-1 100" in length,
1-2000 to 1-2800" in width, and 1-3800 to
1-6000" in thickness; but their dimensions
are subject to great variety. The canaliculi
vary in breadth from 1-20,000 to 1-60,000",
and at their narrowest part, which is furthest
from the lacunas, they anastomose with those
of the adjacent lacunas.

In a transverse section of bone, the lacunae

Magnified 100 diameters.

Section of the surface of the shaft of the femur, a, Ha-
versian canals ; b, side view of the lacunae in the
Haversian laniiuie ; c, surface view of lacunae.

of the laminae surrounding the Haversian
canals are seen to be placed tangentially to
the orifices of these canals, as in figs. 67 and
69; whilst those of the laminae near the
surfaces are parallel with these surfaces (fig.
64).

In a longitudinal section made through
the Haversian canals, they appear arranged
in numerous longitudinal rows running par-
allel with the Haversian canals (fig. 68).
The general arrangement is, that the long
axis of the lacunae is parallel with the laminae
in which they are contained, or between
which they are situated.

When the section coincides with the sur-
faces of a set of the lacunae, they present a
very elegant round or oval form (fig. 72),
irregularly surrounded by a perfect tuft of
canaliculi, which, being turned directly to-
wards the observer, appear more or less
shortened, and a small number of others,
which are diffused through the surface of the
lamellae. Here and there, in the thinnest

BONE.

Fig. 69.

[ 91 ]

Magnified 350 diameters.

Portion of the outer surface of a tibia of a calf. The
dots represent the orifices of the canaliculi, the larger
dark indistinct spots are their lacunae seen through the
osseous substance.

•^^p^lft;;llj

^^^'^'^:^imM

Fig. 71.

Magnified 300 diameters.

Part of a transverse section of the shaft of the humerus.
a, Haversian canals ; b, c, d, lacunae with their canaliculi.

Fig. 72.

Magnified 350 diameters.

Cartilage of bone, after boiling in water: a, lacunae
b nuclei •

a *

Magnified 450 diameters.

Lacunae (surface view) with the canaliculi, from the parietal bone. The dots seen
upon or between the lacunae represent divided canaliculi, or their orifices opening into
the lacunae ; a, a, a, groups of transversely divided canaliculi.

BONE.

BONE.

portion of the section, a group of trans-
versely divided canaliculi are seen (fig. 72
a, a], without the lacunae to which they
belong, giving the suhstance a sieve-like
appearance. At the outer and inner surfaces
of the bones, the canaliculi terminate by
open mouths (fig. 70) ; and those nearest
the Haversian canals open into them.

The contents of the lacunae are the same
as those of the cells of cartilage, viz. a trans-
parent, probably tenacious liquid, with a cell-
nucleus (fig. 71).

If the cartilage of bone be boiled for two
or three minutes in water or a solution of
caustic soda, the nuclei are often rendered
very distinct. After macerating bone in
dilute muriatic acid, the lacunae, with longer
or shorter processes, become isolated and
appear as independent formations, resembling
stellate cells; this phenomenon probably
arises from the circumstance that the portions
nearest the lacunae are more resisting than
the rest, and less acted upon by the acid.

In regard to the minute structure of bone,
independently of the lacunae and their cana-
liculi, a dry polished section exhibits a very
delicate dotted appearance, which makes the
bone appear granular, as if composed of
closely aggregated pale granules, about
1-50,000 to 1-60,000'' in size. This is best
seen in a transverse section.

When bone is calcined and the residue is
rubbed between two pieces of glass, or when
bone is digested in a Papin's digester, minute
inorganic granules are left ; these are oval
or oblong, frequently angular, and are about
1-10,000 to 1-20,000" in diameter.

Hence bone probably consists of an inti-
mate mixture of organic and inorganic
matter, in the form of minute, firmly- united
granules.

The above remarks apply to human bones;
and those of the other Mammalia agree
essentially in structure with the former.

In Birds, the Haversian canals are more nu-
merous and smaller than in the Mammalia,
and frequently run in a direction at right
angles to the shaft ; the lacunae are also more
numerous and smaller.

In Reptiles, the Haversian canals are few
and very large, larger than in either of the
other classes ; the lacunae and the canaliculi
are also very large and the latter very nume-
rous.

In Fishes, the structure is more irregular;
there are no concentric laminae; the Havers-
ian canals are sometimes absent, at others
very large and numerous; frequently the

lacunae are absent, whilst the canaliculi are
unusually long and elegantly wavy and
branched.

The structures representing the bones in
the Invertebrata are noticed under the respect-
ive classes.

The marrow or medullary tissue of bones
consists of ordinary fatty tissue, free fatty
matter, a particular liquid and cells, with
vessels and nerves, surrounded and traversed
by a small quantity of areolar tissue. Some
of the larger cells (?), found in foetal bones,
contain a large number of nuclei (fig. 73).

Fig. 73.

Magnified 350 diameters.

Peculiar granular cells, containing numerous nuclei,
from the very young marrow of the flat bones of the
human skull.

When animals, especially young ones, are
fed with madder, the bones speedily acquire
a beautiful red colour, principally around
the Haversian canals, because it is here that
the process of formation of new bone is most
active; and the earthy matter precipitated
from the blood carries down with it the
colouring matter of the madder.

The blood-vessels of bone which are dis-
tributed to the marrow (the nutrient vessels),
enter particular canals on their external sur-
face; whilst those connected with the Havers-
ian canals are derived from the periosteum
and those of the marrow. The two sets ana-
stomose freely.

Chemically, bone consists of gelatine, with
phosphate of lime, small quantities of carbo-
nate of lime, carbonate of magnesia, fluoride
of calcium, and sometimes a little oxide of
iron and magnesia.

By digesting bone with dilute muriatic or
other acids, the inorganic matter is removed,
and by treatment with solutions of alkalies

Magnified 20 diameters.
Perpendicular section of the ossifying margin
of the shaft of the femur of a child, two weeks
old. a, cartilage and its cells ; b, margin of
ossification ; the dark stripes represent the ossi-
fication of the intercellular substance, which
precedes that of the cartilage cells indicated by
the lighter portions ; c, compact osseous layer
near the ossifying margin ; d, spongy substance
with cancelli e, formed by the absorption of
the bony substance.

Magnified 300 diameters.

Section of the margin of ossification of the condyle of the femur o f
a child two years old, affected with rickets, a, cartilage-cells, single
and multiplying, in series ; b, c, more or less striated intercellular
substance ; d, cartilage-cells at the very commencement of their
conversion into bone-cells ; e, the same in a more advanced state,
with greatly thickened walls, indications of the canaliculi, and
commencing deposition of calcareous salts in the walls, hence their
darker colour, the nuclei still distinct ; /, still more developed and
ossified bone-cells imbedded in the intercellular substance g, which
is also becoming ossified.

or incineration, the organic substance or
cartilage may be separated.

In the development of bone, a temporary
cartilage closely resembling the permanent
cartilages in structure and chemical compo-
sition is usually first formed, and in this the
inorganic matter is subsequently deposited ;
in a few instances, however, a soft blastema,
consisting of areolar tissue, with nucleated
cells, is substituted for the cartilage. The
process of ossification commences at one or
more points in the internal portions of the
temporary cartilage ; these are called the
centres of ossification. Just before the

deposition of the earthy matter takes place,
the cells of the cartilage multiply by endo-
genous cell-growth. The earthy or inorganic
matter is then deposited in a finely granular
form, and first in the intercellular substance ;
so that in a section of ossifying cartilage, the
earthy matter is seen extending into the
intercellular substance beyond the adjacent
cartilage corpuscles (fig. 74).

The deposition next takes place in the
cells themselves, and in the same manner as
the secondary deposit in the cells of plants ;
the spaces left between the portions of sub-
stance forming the secondary deposit, corre-

BONNEMAISONIA.

BORACIC ACID.

spending to the canaliculi (fig. 75). This is
best seen in sections of rachitic bones.

The last and most curious part of the
process consists in portions of the bony

Fig. 76.

Magnified 300 diameters.

Bone-cells in progress of development, removed from
the same bone (fig. 75), still distinctly separate from the
intercellular substance, a, single bone-cells; b, com-
pound cells corresponding to one primary and two se-
condary cells; c, the same consisting of three cells.

substance becoming absorbed, rendering it
at first spongy, and then giving rise to the
formation of large cavities, the cancelli.

Abnormal or adventitious bone agrees in
general structure with the normal ; it is met
with in all stages of development.

To examine the structure of bone, thin
sections are requisite. The method of making
these is described under PREPARATION. By
macerating bone in muriatic acid, diluted
with from 10 to 20 parts of water, the inorganic
matter is removed, the cartilage being left.
Thin sections of this can then be readily made.

The canaliculi are not easily seen when
sections of bone are immersed in liquids, for
these fill them up. But it is a difficult
matter to measure the lacunae, unless the
section be moistened with turpentine or
other liquid.

Very thin sections may be preserved in
the dry state ; those which are thick may be
mounted in inspissated Canada balsam, which
does not easily enter the canaliculi, yet
greatly increases the general transparency of
the section.

BIBL. Kolliker, Mikrosk. Anat. ii.; Tomes,
Todd's Cycl. Anat. and Phys., art. Osseous
Tissue-, Quekett, Trans. Micros. Soc. 1846;
Paget, Report, fyc., Brit, and For. Med. Rev.
1842. See CHEMISTRY.

BONNEMAISONIA, Ag.— A genus of
Laurenciaceae (Florideous Algae), bearing
pear-shaped spores in stalked ceramidia.

B. asparaaoides is a sea-weed with a frond
4 to 1 2 inches long, growing near low- water
mark or deeper, of delicate feathery character
and deep crimson colour.

BIBL. Harvey, Pkyc. Brit. pi. 51; Brit.
Marine Alga, p. 97. pi. 12 D ; Greville, Algce
Brit. p. 106. pi. 13.

BORACIC ACID— Is the acid of the
well-known salt, borax, in which it exists
combined with soda, in the proportion of two
atoms of the acid to one of the base. Boracic
acid is prepared by mixing three parts of
borax dissolved in twelve parts of boiling
water with one part of sulphuric acid or
common oil of vitriol. As the mixture cools,
the boracic acid separates in the crystalline
form. It may be purified by re-solution in
hot water, and subsequent cooling; finally,
the crystals are pressed between blotting-
paper, and dried. Boracic acid belongs to
the doubly oblique prismatic system, and the
crystals possess two optic axes. Those de-
posited from the hot aqueous solution are
mostly six-sided plates : they exhibit the
phenomena of analytic crystals, but at their
lateral surfaces or edges only, and when their
entire surface appears dark or coloured with
the polarizer alone, the crystals are found to
be laminated. But when an alcoholic solu-
tion of boracic acid is evaporated on a slide,
or still better, when some phosphoric acid is
added to solution of borax, and the mixture
evaporated, minute disks or spherules of the
acid are formed ; these, when carefully ex-
amined, are seen to be composed of minute
needles radiating from a centre, exactly as in
the oxalurate of ammonia. In some of them
the needles are so closely in contact, that
they are undistinguishable, and the circum-
ference of the disk appears entire ; in others,
the free extremities of the needles are seen
projecting beyond the circumference. They
are perfectly colourless, and almost transpa-
rent when viewed by ordinary light, immersed
in balsam. But when examined with polar-
ized light, each disk exhibits the most beau-
tiful cross and coloured rings, just as in the
case of the oxalurate of ammonia, in which
we have described the phsenomenon more
fully.

In some of the specimens of boracic acid,
the crystals form elegant arborizations, which
also possess considerable analytic power.

The proportions of phosphoric acid and
borax requisite to produce the disks cannot
be laid down : they can only be prepared by
accident in a number of trials. Even the
same solution will sometimes yield them, at
others not. Drops of the solution should be
placed upon a number of slides, and these
laid upon a warm iron plate. The disks are
much more beautiful than those of oxalurate

BORRERA.

BOTRYDINA.

of ammonia, appearing more transparent and
the colours more brilliant, probably from
their being more highly refractive. They are
difficult also to preserve. Even when
mounted in Canada balsam, they deliquesce
after a time, and large crystals take their
place.

BIBL. Fox Talbot, Phil. Trans. 1837;
Brewster, Optics, 1853.

BORRERA, Ach. (Physcia, Schreber).—
A genus of Parmeliacese (Gymnocarpous Li-
chens), some species of which, such as B.
ciliaris, tenella and furfuracea, are common
on trunks of trees or old palings. B. ciliaris
is an especially favourable lichen for obser-
ving the organs called spermagonia (See Li-
CHENES). The specimens which possess
these display them under the form of pro-
jecting brown or black tubercles upon the
narrowest lobes of the thallus, mostly above.
The largest size which they attain is about
1-25" in diameter. Examined as opake ob-
jects under a low power, they display pores
or irregular fissures above. Fine sections
examined under high powers as transparent
objects, show that the fissures or pores lead
into sinuous cavities lined by delicate fila-
ments (sterigmata) bearing at their sides
minute cylindrical corpuscles about 1-6000"
long (spermatia), which readily become de-
tached, and exhibit a molecular motion in
water.

Hedwig first supposed these spermagonia
of Borrera ciliaris to be male organs, but the
idea was rejected until Itzigsohn pointed out
the existence of the spermatia and the mo-
lecular movement in the same species, which
he regarded as analogous to that of sperma-
tozoids. Tulasne has since elaborated the
whole question, and his statements will be
found under LICHENES.

BIBL. Systematic : Hook. Br. Fl. ii. part
1. 226; Schjerer, Enumeratio, &c. p. 10, 11.
pi. 2. fig. 1 (as Physcia). Physiological :
Hedwig, Theoria Generationis, p. 120. pi. 30,
31; Itzigsohn, Botanische Zeitung, viii. 393.
913. ix. 153 ; Tulasne, Memoire sur les Li-
chens, 1852. 136. pi. 2. figs. 16, 17. (Ext.
Ann. des Sc. nat. 3 ser. xvii. p. 160. pi. 2.
figs. 16, 17.)

BOSMINA, Baird.— A genus of Eritomo-
straca, of the order Cladocera and family
Daphniadae.

Char. Head terminated in front by a sharp
beak directed forwards, and from the end of
which project the long, many-jointed, curved
and cylindrical superior antennae ; inferior
antennas two-branched, one branch with

three, the other with four joints ; five pairs
of legs.

B. lonairostris (PI. 15. fig. 2). Superior
antennas with twenty joints.

Found in the New River and Hampstead
ponds. (Nat. size, fig. 2 *.)

BIBL. Baird, Brit. Entomostr.

BOSTRYCHIA, Fries. See CYTISPORA.
Bostrychia, Montagne, is a Florideous Alga
=Alsidium, Agardh.

BOTHRENCHYMA.— Pitted tissue of
Plants. See TISSUE, Vegetable, and refer-
ences under that head.

BOTHRIOCEPHALUS, Rudolphi.— A
genus of Entozoa, of the order Sterelmintha
and family Cestoidea.

Char. Body long, flat, soft and jointed ;
head slightly tumid, oval or somewhat qua-
drangular, with two opposite depressions, or
with four ear-like appendages, or with four
depressions furnished with hooks; genital
pores mesial.

The species are common in fish and birds,
more rare in mammalia, and very rare in
reptiles. They usually inhabit the alimentary
canal, sometimes the abdominal cavity.

Thirty-four species are enumerated by Ru-
dolphi, ten of which are doubtful. Dujardin
enumerates twenty-three species.

Bothriocephalus latus (Tania lata, the
broad tape-worm) is the only species which
inhabits the human intestines. In it the
head is somewhat ovoid, with two elongated
opposite depressions, but no hooks; the
neck generally not distinct. The joints of
the body are very broad in proportion to
their length. The orifices leading to the
ovaries are situated in the centre of the flat
surface of each joint, and around them the
oviducts are seen, having a radiated or stel-
late appearance. Sometimes a minute body
can be seen projecting from the genital pore
— the male organ. It exclusively inhabits
the small intestines. It is rare in England.
It is sometimes 20 feet in length.

See T^ENIA and ENTOZOA.

BIBL. Rudolphi, Entoz.Synops.; Bremser,
Ueber lebend. Wurmer, &c.; Dujardin, Hist.
Nat. d. Helminth. ; Eschricht, Anat. Phys.
Untersuch. ii. die Bothrio. ; Blanchard, Ann.
d. Sc. nat. 3 ser. xi.

BOTRYCHIUM, Swartz.— A genus of
Ophioglossaceous Ferns. Moon-wort (Bo-
trychium Lunaria) is an indigenous repre-
sentative.

BOTRYDINA, Breb.— A genus of Pal-
melleae (Confervoid Algae), consisting of one
species of green microscopic plants, B. vul-

BOTRYDIUM.

[ 96 J

BOTRYOSPORIUM.

garis, forming a somewhat gelatinous, black-
ish-green stratum on the ground, on trees,
or on mosses, in damp places.

The spores, ahout 1-10,000" in diameter,
increase by cell-division till they form sphe-
rical bodies composed of many cells, the pe-
ripheral layer of which is diaphanous, the
internal green from granular contents ; the
internal vesicles multiply, with constant in-
crease of size of the whole, until the little
fronds acquire the dimensions of a pin's head
(l-36"Kiitzing); the whole cellular struc-
ture is firmly coherent. These bodies require
further study of development.

BIBL. Brebisson, Nouv. Genr. d'Alg.
(1839) p. 3. fig. 3 ; Meneghini, Monog. Nos-
toch. p. 98. pi. 13. fig. 2 ; Hassall, Br. Freshw.
Alga, 320. pi. 81. fig. 2; Kiitzing, Tab.
Phycolog. pi. 10.

BOTRYDIUM, Wallr. (Hydrogastrum,
Desv.). — A genus of Siphoneae (Confervoid
Algae), of which one species is found in this
country, growing upon damp, clayey ground,
the dried-up bottoms of ponds, &c. A single
plant, as developed from a spore or gonidium,
exhibits a remarkable character, having a
lower branched filamentous portion, growing
in the ground, and an erect spherical or ob-
ovate portion, or head, about the size of a
mustard-seed, or a little larger, of a bright
green colour, the whole structure consisting
merely of a single cell,
with one continuous
cavity running through
the entire plant. The
figure (fig. 77) repre-
sents such a specimen,
with a second budding
from it by vegetative
increase ; and in this
way the plants come to
form tufts or groups,
like little bunches of
grapes; hence the name.
The cell - membrane
acquires considerable
thickness, and at the
period when it is soft-
ening, and about to
dissolve, to allow of the escape of the gonidia,
it is seen clearly to be composed of numerous
lamellae, like that of Hydrodictyon. The
globular head is lined, in the full-grown spe-
cimens, with a layer of protoplasm (primor-
dial utricle), containing abundance of chloro-
phyll globules ; and at a certain period, this
becomes broken up into numerous free glo-
bular portions, the gonidia. The gonidia do

Fig. 77.

Botrydium granulatum.
Magnified 10 diameters.

not appear to " swarm," but escape by the
gradual solution of the parent globular sac
in which they are all produced.

BIBL. Greville, Alga Brit. 196. pi. 19;
Hassall, Brit. Freshw. Alga, 305. pi. 77. fig.5;
Kiitzing, Nova Acta, xix. pt. ii. pi. 69. figs.
1-10; Braun, Verjungung in der Natur. pp.
136. 206. 236. 292; ibid. Ray Society's
Translation (1853), pp. 128, &c.

BOTRYOCOCCUS, Kiitzing.— Described
as a floating genus of Palmelleae( Confervoid
Algae), forming lobed and irregular bodies
about 1-24" in diameter, enclosed in a com-
mon, large, hyaline, membranous sac, and
containing a number of fixed granules,
1-7000 to 1-5000" in diameter, of a bright
or dark green or a red colour. Found in
lakes in Switzerland. It seems most likely
to have been a resting form of some Eu-
glena.

BIBL. Kiitzing, Species Algarum, p. 892.

BOTRYOCYSTIS, Kiitzing.— Described
as a genus of Palmelleae (Confervoid Algae),
found in stagnant fresh water, but apparently
forms related to Volvox. They are globular
hyaline vesicles containing green granular
cells. B. Morum is 1-1200 to 1-120" in dia-
meter, with sixteen internal cells ; B. Volvox
1-600 to 1-96" in diameter, with numerous
internal cells. Braun describes a form con-
taining eight internal cells, apparently refer-
rible to B. Morum, where each internal cell
bore two cilia, which projected externally.
We have met with a similar organism. See

VOLVOCINE^E.

BIBL. Kiitzing, Sp. Alg. p. 208; Tab.
Phyc. pi. 9 and 10 ; Braun, Verjungung, &c.
p. 170; ibid. Hay Translation, 1853, p. 159.

BOTRYOSPO1UUM, Corda (Stacliyli-
dium, Fries.). — A genus of
Mucedines (Hyphomyce-
tous Fungi) allied to Bo-
try 'tis, but distinguished by
the lateral position of the
sporiferous branches (fig.
78). British species :

B. diffusum, Corda (Sta-
chylidium diffusum,, Fr.,
Botrytis diffusa, Greville),
forms loose white tufts, a
quarter of an inch high, on
decaying herbaceous plants,
especially potatoes.

BIBL. Corda in Sturm

DeutScU. Fl. iii.; Prachtfi.

Enrop Schimm p. 39;

Greville, Sc. Crypt. if I. Magnified 200 diams

t. 126. fig. 2.

BOTRYTIS.

[ 97 J

BOTRYTIS.

BOTRYTIS, Mich.— A genus of Mucorini
(Hyphomycetous Fungi), among which are
found some of the commonest moulds of de-
caying vegetable substances, and some very
important parasitic fungi. Corda separated
the species with the filaments continuous in-
to a genus called Pcronospora (fig. 79), from

Fig. 79.

Fig. 80.

Botrytis (Peronospora).
Magnified 200 diameters.

Botrytis.
Magnified 200 diameters.

those with articulate filaments (fig. 80). The
Potato-fungus, and the Muscardine of silk-
worms, are species of Botrytis, as described
below ; their natural history is further treated
of under the head of PARASITIC FUNGI.
The following have been described as British
species, but some appear referable to other
genera : —

1 . B. ( Peronospora, Unger, Haplaria, Lk. )
grisea, Fr . Fertile filaments simpl e or forked,
gray, slender, rather rigid, septate, with little
heaps of globose gray spores at the apices
and sides. On decaying vegetables, usually
on Sparganium and allied plants. Corda,
Icon. Fung. i. pi. 4. fig. 246.

2. B. cinerea, Pers. Fertile filaments gre-
garious, almost simple, cinereous, soon stran-
gulated, with white spores attached here and
there. Not uncommon on stems of herba-
ceous plants.

3. B. cana, Schmidt. Fertile filaments cine-
reous or whitish, branched at the apex : spores
large, oval. On rotting stems and leaves.
Mucor racemosus, Bulliard, t. 504. fig. 7-

4. B. vulgaris, Fr. Fertile filaments gray,
divided at the apex into lobe-like branches,
on wrhich are collected the globose minute
spores. Common on rotting plants. B. aci-
norum, Pers. Fresenius, Beitr. z. Mycologie,
i. pi. 2. (?) Polyactis vulgaris, Nees, Syst.
fig. 57.

5. B. vera, Fr. Fertile filaments gray,
branched above, forming spikes about the

slender apices. On decaying substances,
fungi, &c. Mucor Botrytis, Bolton, pi. 132.
fig. 3.

6. B.crustosa,Fr. Fertile filaments white,
simple, trifid and verticillate ; spores globose,
terminal. On stems and leaves.

7. B.parasitica, Pers. Fertile filaments
white; branches ramulose; spores very large,
globose. On Cruciferae (turnips, cabbages,
&c.). Berkeley, Journ. Hort. Soc. i. pi. 4.
fig. 26; Corda, Icon. Fung. v. pi. 2. fig. 18.
Mucor Botrytis, Sowerby, pi. 359.

8. B. effusa, Greville. Fertile filaments
purplish-gray, branched above; branches
short, divaricate; spores large, oval. Fre-
quent on the lower face of leaves of spin-
ach.

9. B. citrina, Berk. Mycelium white;
fertile filaments erect, articulated, branched;
branches sub-cymose, and, like the obovate
spores, lemon-coloured. On dead branches
of cherry-trees. Berkeley, Ann. Nat. Hist.
i. p. 262. pi. 8. fig. 12.

10. B. curta, Berk. Fertile filaments sim-
ple, abbreviated, denticulate at the tips,
gray-brown; spores oval. On Anemone nem-
orosa, Berk. Ann. Nat. Hist. I. c. pi. 8. fig.
13.

1 1 . B. destructor. Fertile filaments gray,
erect, scarcely septate; branches alternate,
the last forked, hooked, and divaricated;
spores obovate, much attenuated at the base.
Very destructive on species of Allium (onions,
&c). Berk. Ann. Nat. Hist. vi. p. 436. pi.
13. fig. 23.

12. B. terrestris, Pers. Fertile filaments
white, quaternately divided at the tips, each
tip bearing a single globose spore. On rotten
sticks. Berk. /. c. pi. 14. fig. 24 ; Stachy-
lidium terrestre, Grev. Sc. Crypt. Flora, pi.
257.

13. B.Urtica, Libert, MSS. (Berk.). Fer-
tile filaments grayish lilac, loosely divided
above ; branches forming an acute angle ; ex-
treme branchlets simple or forked, sometimes
curved, rarely inflated ; spores large, ovate,
apex papilliform. On nettle leaves. Berk.
Ann. Nat. Hist. ser. 2. vii. p. 100.

14. B. Jonesii, Berk, and Br. Fertile fila-
ments erect, fawn-coloured, branched above;
branches and branchlets divergent, mostly
opposite, the last fasciculated, the centre al-
ways sterile and very acute ; spores roundish,
spiny. On dung. Ann. Nat. Hist. 2 ser.
xiii. pi. 15. fig. 12.

15. B. Arenarice, Berk. White; fertile
filaments dichotomous above, divaricate-
forked, not hooked at the tips; spore ovate.

H

BOTRYTIS.

[ 98 ]

BRACHIONUS.

On the leaves of Arenaria trinervis. Berk.
Journ. Hort. Soc. i. 31. pi. 4. fig. 22.

16. B. Vicice, Berk. White ; fertile fila-
ments sparingly branched, elongate; branch-
lets bifid, not hooked ; spores obovate, api-
culate. On common Vetches (a distinct
species, purple, is said to grow on peas).
Berk. /. c. pi. 4. fig. 23.

17. B. arborescens, Berk. White; fertile
filaments very much branched above, di-tri-
chotomous, somewhat forcipate at the apex;
spores smallish, sub-globose. On common
red poppy leaves. Berk. I. c. pi. 4. fig. 24.

18. B. ganglioniformis, Berk. White, in
patches; fertile filaments branched above;
branchlets curved, dilated in ganglioid thick-
enings below the tips ; spores small, sub-
globose. On garden lettuces. Berk. /. c.
pi. 4. fig. 25. B, geminata, Unger, Bot.
Zeitung. v. pi. 6. fig. 9. Bremia lactucce,
Regel, Bot. Zeit. i. p. 665. 1843. pi. 3 B.

19. B. (Peronospora} macrospora, Ung.
Fertile filaments erect, several from the same
point, white, branched above; spores very
large, elongate-pyriform. On leaves of pars-
nips and other TJmbelliferse. Unger, Exan-
theme, pi. 2. fig. 14 B.

20. B. Tilletei, Desm. Fertile filaments
branched, fulvous; branchlets very short,
whorled; spores sub-globose. On mosses
and various leaves. Desmaz. Crypt. Exs.
fasc. v. No. 226; Ann. des Sc. nat. 2 ser. x.
308.

21. B. infestans, Montague (PI. 20. figs. 5-
7). The Potato-fungus. This grows in tufts
on the lower surface of the leaves, and also on
the tubers of the potato, forming white mealy
spots. The mycelium ramifies in the inter-
cellular passages of the leaves, and sends out
the fertile filaments from the stomates, so
that these appear scattered among the hairs
of the epidermis; they are usually about
1-30" high upon the leaves, branched at the
apex, septate and white. The 2 to 6 branches
are erecto-patent, acute, virgate, nodose
from numerous elliptical thickenings. The
spores in large specimens are at first globular-
ovoid, then elliptical, and finally somewhat
of the shape of a gourd-seed, with a sub-
apiculate mamilla at one end, very shortly
pedicillate at the other, of the same colour
as the filaments, chiefly white, densely
filled with sporules enclosed in an endo-
spore, about 1-800" long, 1-1200" thick.
Berkeley, Journ. Hort. Soc. i. 30. pi. 2-4.
figs. 4-19. Botrytis Solanl, Auct. var.
B. fallax, Desmazieres. B. devastatrix, Li-
bert; Morren, Ann. de la Soc. de I'Ag. de

Gand. 1845. p. 287 ; Peronospora trifur-
cata, Unger, Botanische Zeit. v. 314. pi. 6.
figs. 1-6.

Botrytis Bassiana, Balsamo, is the fungus
growing on the bodies of silk-worms, causing
the disease called Muscardine, which some-
times produces most extensive destruction
in the districts where they are cultivated.
A figure of it is given by Mr. Berkeley in
the paper on the Potato-fungus referred to
above. Many papers on it exist in the
Comptes Tlendus, and the whole history, with
figures, will be found in Robin's Vegetaux
Parasites, 2nd ed. 1853. p. 560 et seq.

Botrytis lateritia, Fr., not uncommon in
the hollows of decaying potatoes, beet-root,
&c., appears to be Acrostalagmus parasitans,
Corda. See ACROSTALAGMUS.

BIBL. As given under the species.

BOX. — The wood of the box-tree, Emeus
sempervirens, L. (Nat. Fam. Euphorbiaceae,
Dicotyledon), is remarkable for its hardness,
offering a great contrast to that of Bombax
and the like. See WOOD.

BRACHION^EA. — A family of Rotatoria.

Char. A carapace (testula) present ; rota-
tory organs two, simple.

The rotatory organ sometimes appears to
consist of five parts, three median and two
lateral. The two larger lateral ones only are
rotatory organs, the cilia of the median ones
remaining extended without motion during
the action of others. The carapace resembles
that of a tortoise.

Genera :

Eye-spots absent ; foot forked Noteus.

Jr foot absent Anureea.

one \ foot forked .... Brachionus.

J3.jrc-.pwi. preacui^ r foot absent.... Pompholyx.

I X foot styliform. . Pterodina.

See HYDROCORA and DIPODINA.

BRACHIONUS, Hill.— A genus of Rota-
toria, of the family Brachionsea.

Char. A single eye-spot at the back of the
head ; foot forked.

The anterior margin of the carapace is
furnished with teeth, as in some species is
the posterior margin also.

B. amphiceros (PL 34. fig. 8). Carapace
smooth, furnished both at the anterior and
posterior margin with four teeth ; aquatic ;
length 1-70".

B. rubens. Carapace smooth, with six
acute teeth in front and rounded posteriorly;
body reddish; aquatic; length 1-50''. (Teeth,
PL 34. fig. 9).

Eleven other species have been described ;
some of them aquatic, others marine.

BRACHYCLADIUM.

BROMELIACEyE,

Fig. 81.

BIBL. Ehrenb. In/us.-, Dujardin, Inf.-,
Gosse, Ann. Nat. Hist. 1851, viii. p. 202.

BRACHYCLAD-
IUM, Corda. — A genus
of Mucedines (Hypho-
mycetous Fungi), form-
ing a delicate mould on
dry stems of herbaceous
plants. The filaments and
branches are formed of
squarish cells, swollen so
as to produce a monili-
form appearance, the
walls being thick and
coloured.

B.penicillatum,Corda,,
is said to extend over
stems, sometimes in Brachycladiimi penicil.
tracts a foot long ; the latum.

filaments and branches An erect filament with
are blackish the spores M
white (fig. 81).

BIBL. Corda, Icones Fung.

BRACHYODUS, Fiirnrohr.— A genus of
Leptotrichaceous Mosses, separated from
Gymnostomum or Weissia of some authors.

Br. trichodes, Yurnr.= Weissia trichodes,
Hook, and Tayl.

BRACHYSTELIUM, Reichb.— A genus
of Orthotrichaceous Mosses.

1. Brachystelium polyphyllum, Hsch.=
Trichost. polyphyllus, Schwaegr.

BRAIN. See NERVES.

BRAN. See CORN-GRAINS.

BRANCHIAE.— This term is synonymous
with gills. The latter term is, however,
usually applied to the aquatic respiratory
organs of fishes, whilst those of other animals
retain the name of branchiae. Their stiuc-
ture is described with that of the respective
classes in which they occur. See also EPHE-
MERA and LIBELLULID^E.

BRANCHIPUS, Schsffer (Chirocepha-
lus). — A genus of Entomostraca, of the order
Phyllopoda, and family Branchiopoda.

Char. Abdomen prolonged in the form of
a tail, composed of nine segments or joints,
the end joint with two well-developed plates
or lamellar appendages; superior antennae,
in both sexes, slender, filiform and many-
jointed ; inferior antennae in the male large,
curved downwards, two-jointed, furnished
at the base with fan- shaped and digitiform
appendages; in the female, stout, short,
somewhat acute, slightly curved, and not
furnished with appendages at the base.

B. stagnalis (PI. 15. fig. 3). An inch in
length ; tinged with red.

Fig. 82.

This beautiful animal is found in stagnant
water, as the ditches and deep cart-ruts on
the edges of woods and plantations.

BIBL. Baird, Brit. Entom.

BRAND.— A disease of Cereal Grasses
and other plants depending on Fungi. See
BLIGHT.

BREAD. — The interest of microscopic
examination of bread depends chiefly on the
impurities it may contain, or the peculiar
bodies developed in it during decay. The
former consist of spores of Uredines, &c.,
pollen-grains and other vegetable bodies, and
particles of chemical substances. Notices of
the others will be found under MUCOR,
PENICILLIUM, CRYPTOCOCCUS, TORULA.
The fermentation or "rising" of bread
depends on the yeast fungus.

BRIAREA, Corda.— A
genus of Mucedines (Hy-
phomycetous Fungi), near-
ly related to Penicillium,
Aspergillus and Moni-
lia, distinguished from the
first and last by the moni-
liform rows of spores
arising, directly, in a ter-
minal tuft, while the
erect fertile filament is
not expanded into a capi-
tulum to bear them as is
the case in Aspergillus.
Brit, species : —

Briarea penicillata (fig.
82), (Monilia, Fries, Asper-
gillus, Greville). The erect
filaments are simple and
geniculate, the spores hyaline, forming long
nodding moniliform rows. It is of dark
gray colour, and is found on damp grass,
mouldy hay, straw, &c.

BIBL. Corda, Icones Fung. v. 16, and in
Sturm, Deutschl. Flor. ii. pi. 6 ; Greville,
Sc. Crypt. Flora, t. 32; Berk, in Hook. Br.
Fl. 345.

BRINE-WORM. See ARTEMIA.

BRISTLE. See HAIRS.

BROMELIACE^E.— A family of Mono-
cotyledons (Flowering Plants), of which the
Pine Apple, Ananas or Ananassa, is the
most familiar example. This is interesting
microscopically from the scurfy character of
the epidermis of the leaves, dependent on
peculiar cellular scales. The cells of the
epidermis are of very elegant form (PL 38.
fig. 15), and the fibres of the leaf are manu-
factured into very fine muslin. See SCALES,
EPIDERMIS and FIBRES.

H2

Briarea penicillata.
Magnified 200 dia-
meters.

BRONCHI.

[ 100 ]

BRYACE.E.

BRONCHI. See LUNGS.

BRONCHOCERCA.— Monocerca with
the caudiform foot cleft at the end. Five
species have been described, but it appears
that they do not differ by well-marked
characters from the species of Monocer-
ca.

BIBL. Werneck, Ber. d. Berl. Akad.
1841.

BROOKE'S APPARATUS. INTRODUC-
TION, p. xix.

BRUCHIACEJL —A family of inopercu-
late Acrocarpous (terminal-fruited) Mosses,
gregarious or csespitose and terrestrial, in
which thefruit-stalkssometimesappear lateral,
through arising from innovations. The stems
are dwarf, and either simple or branched by
innovations ; the leaves lanceolate or awl-
shaped from a more or less oval base, com-
posed of parenchymatous cells, larger and
sometimes lax at the base of the leaf, smaller
and squarish toward the apex, and furnished
with a flattened broad nerve (fig. 49), and

Fig. 83.

Fig. 84.

Archidium.

Open capsules, devoid of columella and with large spores.
Magnified 40 diameters.

standing up like bristles, theperichsetial leaves
broader at the base and sheathing, all of firm
membranous character, shining and smooth.
Capsules oval or globose, mostly straight-
beaked (fig. 50). British genera : —

I. Archidium. Calyptra completely enclo-
sing the (globose) capsule, bursting above.
Inflorescence monoecious, bud-shaped.

II. Astomum. Calyptra dimidiate. Cap-
sule equal. Inflorescence either monoecious,
gemmiformand axillary, or with the antherids
and archegones together.

BRUCIA. See ALKALOIDS.

BRYACEJE.— A family of operculate
Mosses, acrocarpous, or by innovation pleu-
rocarpous, with lanceolate, oval, round or
spathulate leaves, composed of cells parallel-
ogrammic below, rhomboidal-parenchyma-
tous above, more or less dense, with much
chlorophyll or a persistent primordial utricle,
or at length empty, very smooth. Capsule
more or less pear-shaped, clavate, oval or

ylindrical , with a hemispherical or conical
operculum, erect, nodding or pendulous.
External peristome, when present, soft,
lamellose, internal membranous. British
genera : —

I. Mielichoferia. Calyptra conical-dimi-

Fig. 85.

diate, split at the side.
Peristome wanting or
simple, then of sixteen
equidistant, filiform,
flattish, articulated
pale teeth, sometimes
placed on a short
sulcate, reticulate,
basilar membrane
(fig. 85). Capsule
lateral, with a double
annulus.

II. Orthodontium.
Calyptra smallish,
hood-shaped, fugaci-
ous. Peristome arising below the orifice of
the capsule, double. External: of sixteen
lanceolate-subulate teeth, like those in
Bryum; when dry, deflexed below the orifice
of the capsule, when moistened, erect.
Internal : cilia alternating with the external
teeth, half as long or about equal, filiform
from a short, somewhat keeled membrane.
Capsule annulate or exannulate, with a
longish collum.

III. Bryum. Calyptra dimidiate, smallish,

Fig. 86.

Mielichoferia nitida.
Teeth from the peristome.
Magnified 150 diameters.

Bryum intermedium.

A portion of the peristome.
Magnified 150 diameters.

hood-shaped. Peristome double (fig. 86).
External: of sixteen lanceolate, soft, yellow-
ish equidistant teeth, flat on the back and
transversely trabeculated, with a flexuose

BRYOPSIS.

[ 101 ]

BRYUM.

longitudinal line in the middle, lamellate
within, hygroscopic. Internal : a large
delicate membrane with sixteen keels, pro-
duced into more or less perfect lanceolate
teeth, often with intermediate cilia, some-
times without. Capsules mostly annulate.

BIBL. See MUSCACE^J.

BRYOPSIS, Lamouroux. — A marine
genus of Siphoneae (Confervoid Algae), of
which the British species form beautiful
green, somewhat elastic, feathered silky tufts,
from l"to 4" high upon rocks or upon other
Algae, in tide-pools. The whole axis and

E roper branches of each plant consist of one
irge ramified cell, the cavity being continu-
ous throughout, the membranous wall rather
thick, somewhat gelatinous externally ; the
branches are naked below, but clothed above
by small ramuli, arranged like leaves, disti-
chously, spirally or irregularly. The main
axes and branches grow indefinitely by de-
velopment of the apices, the rarnuli are
limited in their development, and they are
ultimately shut off by septa, at last falling
off by the circular rupture of their wall, just
above their point of origin.

When examined early, the ramuli are
found to have their walls lined with largish
elliptical green grains, each of which has at
first a round light central body, colourable
blue by iodine when fully formed (starch-
corpuscle). The branches exhibit the phae-
nomenon of reproduction, in irregular order,
in the following way. The green bodies on
their walls multiply by subdivision, and
increase in size and number until they com-
pletely fill the tubular cavity of the ramule,
pressing upon one another so as to form a
compound dark green mass. A peculiar
swarming movement is next observed in the
green bodies, which increases more and more,
and the parent tube opening by a pore near
its apex, the green bodies escape, as elongated,
pear-shaped zoospores or active gonidia,
with cilia, according to Thuret two and four
in B. hypnoides, only two in B.plumosa. The
successive emission of the gonidia from the
various tubes of one plant occupies several
days.

After the gonidia have come to rest, they
acquire a spherical form and gradually
increase in size ; at the end of a month or
six weeks their diameter is twice or thrice
the original dimensions, and then they begin
to elongate into a tube similar to the parent.
Agardh found them elongate, either in one
direction or in two, at first, but one end soon
swelled into a thickened organ of attachment,

while the other began about the sixth week
to branch. British species : —

1. B. plumosa, Huds. Deep green, 1 to 4
inches high, more or less branched : the
branches pinnated with sub-opposite disti-
chous or rarelv irregular ramules. Harvey,
Br. Marine Algce, 2nd ed. pi. 24 B. ; Phycol.
Brit. pi. 3 ; Greville, Algce, pi. 19 ; Engl.
Botany ( Ulva plumosa), 2375.

2. B. hypnoides, Lamour. Yellow-green,
2" to 4" high, more slender and more
branched, branches repeatedly divided, ra-
mules irregularly scattered, somewhat pin-
nate, more or less dense. Harvey, Phyc.
Bn7.pl. 119.

BIBL. Systematic, as above, and Kiitzing,
Sp. Ala. p. 490; Physiology, &c., Agardh,
Ann. des Sc. nat. 2 ser. vi. 200. pi. 12; Na-
geli,Zeitschr.fur Wiss. Bot. 1844-6 (transl.
in Ray Society's Volume, 1845, p. 269. pi. vi.
figs. 11-12, 1849, p. 97. pi. 2. figs. 1-3);
Neuern Algen-Systeme, Zurich, 1847, p. 171 •
pi. 1. figs. 44-56; Thuret, Ann. des Sc. nat.
3 ser. xiv. 8. pi. 16. figs. 1-6 ; Alex. Braun,
Verjungung, 137, &c. (Rejuvenescence, &c.,
Ray Volume, 1853, p. 129, &c.).

BRYUM, Dill.— A genus of operculate
Mosses, usually acrocarpous, containing a
large number of British species, even in its
restricted condition.

1. Bryum roseum, Schreb.

2. Br. pallens, Sw. = B. turbinatum,
Hook. ex. part.

3. Br. pseudo-triquetrum, Hedw. = B.
ventricosum, Dicks.

4. Br. turbinatum, Hedw.=.B. nioricans,
Dicks.

5. Br. lacustre, Blandov.=.B. ccespititium.
var. Hook, and Tayl.

6. Br. inclinatum, Br. and Sch.=B. ven-
tricosum,v&r. Hook.

7. Br. uliginosum, Br. and Sch.

8. Br. torquescens, Br. and Sch.

9. Br. intermedium, Brid.=B. turbinatum,
var. Hook.

10. Br. capillare, Hedw.

11. Br. obconicum, Hsch.

12. Br. ccespititium, L.

13. Br. alpinum, L.

14. Br. cyclophyllum, Br. and Sch. = B.
obtusifolium, Turn. M. Hib.

15. Br. Zierii, Dicks.

16. Br. demissum, Hook.

17. Br. carneum, L.

18. Br. albicans, Wahlenb.

19. Br. Tozeri, Grev.

20. Br. argenteum, L.

21. Br. julaceum., Sin.

BUDS.

[ 102 ]

BURSARIA.

22. Br. pyriforme, Sw.

23. Br. Ludwigii, Spr.

24. Br. crudum, Schreb.

25. Br. nutans, Schreb.

26. Br. elongatum, Dicks.

BUDS. — The buds of plants form interest-
ing objects of microscopic investigation on
many accounts. First in tracing the deve-
lopment of the organs, and also of the tissues
of which these are formed; secondly, on
account of certain temporary structures which
they exhibit. The thick epidermis of the
scales of the winter-buds of ordinary trees,
as of the ash, &c., is a very favourable object
for sections to show the character of this
tissue when highly developed. The internal
soft scales and young leaves of very many of
these winter-buds, as well as other buds of
herbaceous plants, are clothed with glandular
hairs, which disappear when the buds have
expanded, and these often afford advantageous
material for studying cell-development.
These glandular hairs were mistaken by
Griesebach (Botanische Zeitung, ii. p. 661,
Sanderson, Ann. N. Hist. 2 ser. xvi. p. 141)
for bodies analogous to the antheridia of
Mosses. See GEMMAE.

BUG. See CIMEX.

BULBOCELETE, Ag.— A genus of Che-
tophorese (Confervoid Algae), forming dense
villous tufts 1-4" or 1-2" high, on freshwater
plants, &c., in lakes and pools, remarkable
for the structure surmounting its reproductive
cells, namely a slender elongated cell repre-
senting a bristle with a bulbous base. Hassall
supposed that a kind of conjugation took
place in this genus like that he assumed to
occur in (Edogonium (Vesiculifera], but this
does not appear to be correct. The fertile
cells are borne at the side of the upper end of
cells of the filaments; they are large, globular
or oval, and surmounted by the bristle-cell
(fig. 87), which often exists upon the

same point of the
stem-cell, without
any intermediate
sporiferous - cell.
The history of the
reproduction, as
given by Alex.
Braun,is as follows.
A branch is deve-
loped from the
upper end of a
stem-cell by a
pouch-like protru-
sion of the wall ;
when this has at-

Fig. 87.

Bulbochsete setigera.
Portion of a filament with a

sporiferous .cell.
Magnified 150 diameters.

tained a certain size, the green contents of the
parent-cell pass into it, leaving about half (the
lower) of the parent-cell empty of coloured con-
tents, and a septum then cuts the parent-cell
in the middle, so that two cells are formed, the
lower uncoloured, the upper green; the pro-
truding branch increases in size and expands
into a globular form, and then the rest of
the contents of the parent-cell (from the
upper half-cell) pass into it, and it also
becomes shut off by a septum. The bristle-
cell (with sometimes a small intermediate
cell) is formed after the sporiferous-cell has
been shut off by the septum from the stem-
cell.

The contents of the sporiferous-cell subse-
quently exhibit two kinds of development.
They either become isolated in their parent-
cell, acquire a thick proper membrane and
thus form resting -spores, which assume an
orange colour in autumn, or they accumulate
in like manner in the centre of the cell,
produce no membrane there, however, but a
crown of cilia. In either case they escape
from the parent-cell by the disarticulation of
the bristle-bearing cell, and the rupture of
the membrane of the sporiferous cell at that
point. Then the resting-spore falls out me-
chanically, while the ciliated body escapes by
active motion of its cilia as a zoospore or
active gonidium, which after a time comes to
rest, produces a membrane over its whole
surface and germinates as a spore.

B. setigera, Ag., is a common plant, and
is variable in the relative length and diameter
of its cells, on which ground Kiitzing has
separated a JB. minor, when the diameter is
equal or greater than the length. Hassall,
Fr. Conf. pi. 54. figs. 1-4; Dillwyn, Conferv.
pi. 59.

BIBL. Alex. Braun, Verjungung in der
Natur. (Rejuvenescence, fyc., Ray Volume,
1 853), passim ; Hassall, Ann. Nat. Hist. xi.
36; Br. Freshw, Conf. 209. pi. 54; Decaisne,
Ann. des Sc. nat. 2 ser. xvii. 335. pi. 14.
fig 5 ; Kiitzing, Species Alg. 422.

BUNT.— A disease of Cereal Grasses, Sec.,
depending on Fungi. See BLIGHT.

BURSARIA, Ehr.— A genus of Infusoria,
of the family Trachelina.

Char. Body ciliated all over ; anterior
portion projecting beyond the simple eden-
tulous mouth : no tremulous lamina.

Locomotion is effected by cilia usually
arranged in longitudinal rows, and somewhat
larger ones generally surround the mouth.

Ehrenberg describes fourteen species.
They are mostly found in stagnant fresh

BURSARINA.

[ 103 ]

BUXBAUMIACE.E.

water ; some in the intestines of the frog and
Nais.

B.vernalis(Panophrys,D.) (PI. 23.fig. 19).
Body ovate-oblong, turgid, green, rounded at
each end, somewhat narrowed posteriorly,
the mouth placed behind the anterior third
or fourth of the body; aquatic; length 1-130
to 1-110".

B. ranarum (Opalina ranarum) (PI. 24.
fig. 47). Body ovate, lenticular, compressed,
large, white, the dorsal and ventral surface
keeled, anterior part subacute, often truncate
posteriorly, mouth inferior, near the anterior
pointed end; length 1-210 to 1-70". In the
intestines of the frog.

The genus Bursaria of Dujardin, agrees
in part only with that of Ehrenberg. The
characters given are, —

Body ciliated, ovoid, usually broader and
rounded behind, with a large mouth, obliquely
situated at the end of a row of cilia arranged
spirally and arising from the front end.

It contains six species of Ehrenberg's
genus, as well as the Leucophrys patula and
sanguined, Spirostomum virens and Loxodes
Bursaria of Ehrenberg.

BIBL. Ehrenb. In/us.; Duj. Infus.; Stein,
Die Infus. auf ihr. Entwickel.

BURSARINA,Duj.— Afamilyoflufusoria.

Char. Body very contractile, of variable
form, usually oval, ovoid or oblong, ciliated
all over ; a large mouth surrounded by cilia
forming a fringe or arranged spirally.

Dujardin recognises five genera : Plaai-
otoma (Paramecium compressum, E.) ; Oph-
ryoglena, E. ; Bursaria (E. in part) ; Spiro-
stomum, D. ; and Kondylostoma, D.

BIBL. Duj. Infus.

BUTTERFLIES. See LEPIDOPTERA.

BUXBAUMIACE^.-A family of oper-

Fig. 88.

Fig. 89.

Fig. 90.

Buxbaumia aphylla.

Fig. 88. A. male antheridiferous plant, magnified 40
diameters.

Fig. 89. An autheridium burst and discharging sperma-
tozoids, magnified 100 diameters.

Figs. 90, 91 and 92. Archegoniferous plant, in different
stages, magnified 40 diameters .

Fig. 91.

Buxbaumia apbylla.

Fig. 92.

Fig. 93.

Fig. 93. A young fertile plant elevating its sporange,
covered by the calyptra, magnified 15 diameters.

Fig. 94.

Fig. 95.

Fig. 96.

Fig. 94. A ripe capsule, magnified 15 diameters.

Fig. 95. A plant in which the capsule has burst and lost
the spore-sac, &c., magnified 15 diameters.

Fig. 96. Spore-sac exposed by removal of the wall of
the capsule, showing the filaments by which the spore-sac
is suspended within the latter, magnified 40 diameters.

culated Acrocarpous Mosses, of very dwarf
stemless habit, arising from a minute tuft of
radical filaments (figs. 88, 90, &c.). The leaves
are small and flat, composed of few minutish,
hexagonal or polygonalparenchymatous cells,
empty, destitute of chlorophyll (fig. 90) . The
capsule (fig. 94), seated on an elongated,
thick, fleshy and very scabrous stalk, is more
oblique than in any other Mosses, very ven-
tricose on one side, obliquely erect on the
other, dorsal side, cup-shaped at the base,
articulated on its stalk, fungoid in general

BUXBAUMIA.

[ 104 ]

CLEOMACEI.

Fig. 97.

Fig. 98.

Buxbaumia aphylla.

Fig. 97. Mouth of capsule with double peristome and
recurved persistent annulus, magnified 150 diameters.

Fig. 98. Columella with adherent operculum, both
capsule-wall and spore-sac having been removed, magni-
fied 60 diameters.

habit, with an obtusely conical, straight
operculum, and a peristome (fig. 97). Inflo-
rescence monoecious. Brit, genus :

BUXBAUMIA, Hall.— A genus of Bux-
baumiacese (Acrocarpous Mosses), repre-
sented in Britain by B. aphylla, a plant of
remarkable character. The annulus which
persists after the operculum has fallen, re-
sembles a third, outer circle of peristomal
teeth (fig. 97) ; the real external peristome
is closely applied upon the inner, which form
a truncated cone, slightly twisted when dry.
When ripe, the wall of the oblique capsule
(fig. 95) gives way at one side, falls off and
exposes the spore-sac (fig. 96), which bursts
to discharge the spores. The columella
(fig. 98) is very large, and the operculum is
attached to its summit. The antheridia are
oval cellular bodies opening by the separation
of the cells like teeth above, to emit grumous
masses of spermatozoids (fig. 89).

BIBL. Bruch and Schimper, Bryol. Europ.
part 1.

C.

CABINET for holding microscopic objects.
See INTRODUCTION, p. xx.

CACTACE^E.— A singular family of Di-
cotyledonous plants, especially remarkable,
microscopically, for the peculiar structure of
their wood-cells. See SPIRAL FIBROUS
STRUCTURE, and WOOD.

BIBL. Schleiden, Beitr. z. Anat. der
Cacteen, St. Petersburgh, 184 ; Miquel,
Ann. des Sc. nat. 2 ser. xix. 165.

CADMIUM.— Solution of the oxide or

carbonate of this metal in sulphuric acid,
when evaporated on a slide, yields disks or
circular aggregations of minute radiating
needles (circular crystals) of the sulphate,
which exhibit essentially the same pheno-
mena under the action of polarized light, as
those of the oxalurate of ammonia. The
disks frequently exhibit irregular undulating
somewhat concentric dark bands, indicating
parts where no double refraction takes place.

PI. 31. fig. 10 gives but a very imperfect
idea of the appearances presented by these
crystals, when viewed by polarized light.

C^OMACEL— A family of Coniomyce-
tous Fungi (corresponding nearly to the
Hypodesmii, Fries), consisting of plants
forming a filamentous mass (mycelium) in
the substance of living plants, and finally
breaking out on the surface in patches,
margined or naked, containing simple or
compound spores, single or in beaded rows ;
sometimes preceded by other conceptacles
(spermagonia) bearing spermatia. These
plants, well known under the names of smuts,
brand, bunt, &c., are but imperfectly under-
stood at present, some appear to be dimor-
phous or even polymorphous, so that even
the genera are not well established. They
would appear also to be rather Ascomycetous
than really Coniomycetous plants.

Synopsis of British Genera.

1. Rastelia. Pseudo-peridium produced
into a cup fibril! ated at the margin, spores in
stalked beaded rows.

2. JEcidium. Pseudo-peridium emerging
as a regularly toothed, radiating cup; spores
in stalked beaded rows.

3. Epitea. Spores heaped up in definite
groups, on a stroma, without pseudo-peri-
dium, surrounded by paraphyses; spores
stalked, solitary.

4. Podocystis. Spores heaped on a distinct
stroma, paraphyses stalked, clavate ; spores
in chaplets borne on cylindrical pedicels.

5. Coleosporium. Pseudo-stroma flat,
without paraphyses ; spores in rows of three
or four, sessile.

6. Cystopus. Spores exserted, naked,
globose or square, in beaded chains, stalked
on a cylindrical vesicle, without paraphyses.

7. Triphragmium. Pseudo-stroma fleshy,
spores emergent, stalked, bilocular or trilo-
cular by the upper cell having a perpendi-
cular septum.

8. Phragmidium. Pseudo-stroma cellular,
bearing cylindrical rows of four cells, on
simple, elongated pedicels.

CALCIUM.

[ 105 ]

CALLIDINA.

9. Puccinia. Pseudo-stroma obsolete,
spores adherent, stalked, bilocular by a trans-
verse septum.

10. Uredo. Pseudo-stroma pulvinate,
spores globular, simple, stalked, without
paraphyses.

11. Podisoma. Stroma a clavate mass of
agglutinate filaments, bearing uniseptate
(sometimes 3- to 5-septate) spores.

12. Gymnosporangium. Stroma a soft, ge-
latinous, evanescent, expanded mass of fila-
ments bearing uniseptate stalked spores.

13. Polycystis. Spores on the substance
of the mature plant, globose, vesicular, single,
stalked on branched filaments.

14. Thecaphora. Spores of two forms,
variously shaped, conglomerated, scarcely
separating, in an evanescent ascus.

15. Tilletia. Spore globose, simple, on a
filiform pedicel.

16. Protomyces. Spores simple, without
a pedicel, scattered without order in the
intercellular passages of plants.

BIBL. Fries, Summa Veget. p. 509 ; Le-
veille, Ann. des Sc. nat. 3 ser. viii. 369 ;
Tulasne, ibid. vii. 12; Comptes Rendus, 1854;
Ann. Nat. Hist. 2 ser. 14. 76; De Bary,
Brandpilze, Berlin, 1853; Berkeley and
Broome, Ann. Nat. Hist. 2 ser. v. 460;
Unger, Exantheme.

CALCIUM, CHLORIDE OF. — This salt
may be prepared by adding excess of pre-
pared chalk to dilute muriatic acid, boiling
and filtering the solution, and then evapora-
ting it to dryness. The crystals belong to
the rhombohedric system, and are deliques-
cent.

An aqueous solution of chloride of calcium
is of great service in microscopic researches,
as objects which have been immersed in, or
moistened with it, do not become dry at
ordinary temperatures. Hence if a drop of
the solution be added to an object covered
with thin glass, and excluded from dust, it
may be preserved without the use of a
cement to enclose it in a cell (see PRESER-
VATION). Its use in determining the pre-
sence of cell-membranes has been already
alluded to (INTRODUCTION, p. xxxv. § 4).
When employed for this purpose, its action
must always be controlled by the action of
water, crushing, &c.

The strength of the solution may be about
one part of salt to two of water, or a saturated
solution may be used ; it should be kept in
one of the test-bottles (!NTROD. p. xxiii),
with a lump of camphor floating on its
surface.

It frequently happens that the solution in
which objects have been immersed (on a
slide), exhibits crystals. These usually
consist of either the chloride itself, the sul-
phate or the phosphate of lime, the two
latter formed from the alkaline salts derived
from the object.

CALCULI. See CONCRETIONS.

CALEPTERYX, Linn— A genus of Neu-
ropterous Insects, belonging to the family
LIBELLULID.E, which see.

CALIA, Werneck. — A genus of Polygas-
tric Infusoria, according to Ehrenberg's
system.

Char. Monads included in jelly (Pando-
rince) fixed to aquatic plants, not swimming
free. 2 species.

BIBL. Werneck, Ber. d. Berl Akad. 1841.
p. 377.

CALIGUS, Miiller.— A genus of Crusta-
cea, of the order Siphonostoma, and family
Caligina (Caligidce}.

Char. Head in the form of a large buckler,
having anteriorly large frontal plates, which
are furnished with a small suctorial disk or
lunule on the under surface of each lateral
portion; antenna small, flat and two-jointed ;
thorax with only two distinct articulations,
thoracic segments uncovered ; second pair of
foot-jaws two-jointed and not in the form of
a suctorial disk ; legs four pairs with long
plumose hairs, fourth pair slender, of only
one branch and serving for walking.

Four species. Found upon the brill, cod,
mackerel, plaice, trout, &c. ; length 1-5" to

BIBL. Baird, Brit. Entomos. pp. 256 and
269.

CALLIDINA, Ehr.— A. genus of Rota-
toria, of the family Philodinsea.

Char. Eye-spots absent ; a proboscis and
a foot with horn-like processes.

The rotatory organ is double, but not
furnished with a stalk; proboscis also cili-
ated; foot elongate, forked, and with four
accessory horn-like processes, hence with
six points altogether; teeth small and nume-
rous (two only in each jaw in one species,
Gosse). Aquatic.

1. C. elegans, Ehr. (PI. 34. fig. 10). Cry-
stalline; length 1-70". (PI. 34. fig. 1 1, teeth.)

2. C. rediviva, Ehr. Granular or fleshy,
ova red; length 1-70".

3. C. bidens, Gosse. Teeth two in each
jaw; length 1-45".

4. C. constricta, Duj. Rotatory organ
constricted; length 1-50".

BIBL. Ehrenb. Infus. p. 482; Dujardin,

CALLITHAMNION.

[ 106 ]

CALYPOGEIA.

Infus. p. 655; Pritchard, Infus. Animalc.
p. 664 ; Gosse, Ann. Nat. Hist. 1851. viii.
p. 202.

CALLITHAMNION, Lyngb.— A genus
of Ceramiaceae (Florideous Algae), containing
a large number of species, some common,
many rare. In the smaller species the
structure is very simple, the branched
feathery fronds being composed of single
rows of tubular cells ; in the larger species
the stem and larger branches are strength-
ened by external filaments, which grow over
the original axis, apparently originating at
the base of the upper branches and growing
down (somewhat as in Batrachospermum).
Antheridia have been observed in C. Borreri
and C. corymbosum, collected in tufts on the
ultimate branches. The favellce are naked,
and the tetraspores are tetrahedrally arranged.

BIBL. Harvey, Br. Mar. Alga, pi. 23 A. ;
Phyc. Brit. pi. 272. 230. 159, &c. ; Thuret,
Ann. des Sc. not. 3 ser. xvi. p. 16. pi. 4;
Nageli, Algen-systeme, 198. pi. 6.

CALOTHRIX, Ag.— A genus of Fig. 99.
Oscillatorieae (Confervoid Algae),
growing in tufts, the filaments
forming a branched frond by lying
in apposition and being concreted
by their sheaths here and there.
C. mirabilis, Ag. (PI. 4. fig. 22),
is. a rare freshwater species in
England, found on mosses in small
streams, aeruginous green, growing
blackish. Diameter of the filaments
about 1-1200" to 1-1800". Accord-
ing to Hassall, C. atroviridis, Harv.
is not distinct.

Fig. 99 illustrates the close an-
nulations on the filaments of this
genus; the nature of this annulated
structure will be treated more par- calothrix
ticularly under the head of OSCIL- Tomasi-

LATORIEJE.

BIBL. Hassall, Freshw. Conferva,
243. pi. 69. 1; Kiitzing, Tab. Phyc. filament.
cent. ii. pi. 29. ii. ; Dillwyn, Brit. ^JgjJJ^
Conferva (C. mirabilis), pi. 96.

CALYCIE^E.— AfamilyofGymnocarpous
Lichens characterized by their circular or
globular, more or less stalked apothecia,
furnished with special excipulum and filled
with a compact pulverulent mass. Br. genus
CALYCIUM.

CALYCIUM, Ach.— A genus of Calycieae
(Gymnocarpous Lichens), containing a large
number of species, growing upon bark, old
palings or epiphytically on other Lichens
(C. sessile). The spermatia produced in the

niana.
Fragment

spermagonia are stick-shaped and curved;
the spores are double and produced, six or
eight in each long tubular theca.

BIBL. Hook. Br. FL ii.pt. 1. 142; Engl.
Botany, pi. 810. 2520. 1832, &c. ; Tulasne,
Ann. des Sc. nat. 3 ser. xvii. 209. pi. 15.
figs. 15-20.

CALYMPERACE^.— A tribe of Pottioid
Mosses, containing one British genus :

1. Encalypta. Calyptra long, cylindrically
bell-shaped, narrow above on account of the
clavellate operculum, surpassing the capsule,
firm, entire, torn or ciliated below (fig. 101).

Fig. 100.

Fig. 102.

Fig. 101.

Fig. 100. Encalypta vulgaris . Peristome.

Fig. 101. E. ciliata. Calyptra.

Fig. 102. E. streptocarpa. Fragment of peristome.

Peristome absent, simple (fig. 100) or double
(fig. 102). External : sixteen lanceolate or
long-subulate, ciliiform teeth, mostly writh a
longitudinal line, reddish, rugulose. Internal :
a delicate membrane agglutinate to the teeth,
produced into cilia opposite or alternating
with the teeth.

CALYPOGEIA, Raddi.— A genus of Jun-
germannieae (Hepaticaceae), founded on Jun-
germannia Trichomanis, Dicks. The leaves
have a peculiar glaucous hue ; the sporange
is spirally twisted. Gemmae are produced at
the extremities of leafless prolongations of
the stem.

BIBL. Hooker, Brit. Jungermanniea, pi.
79; Eng. Botany, 1728.

CAMBIUM.

[ 107 ]

CAMPIUM.

CAMBIUM.— The name applied to the
young cellular layers from which the woody
structures of plants are developed. When
we make sections near the growing points
of any stems, as in terminal or axillary buds,
we find a quantity of extremely delicate, slen-
der, elongated cells, distinguished from the
generally rounded cells of the parenchyma,
and forming rudimentary cords in the situa-
tion of the future woody and vascular bun-
dles. In the Dicotyledons, they stand in a
circle, so as to separate the apex of the pith
from the young bark ; the ring may be seen
in cross sections a little below the growing
point. At the very apex of the stem all the
tissues merge into the delicate universal ge-
nerative tissue. In the apex of Monocotyle-
donous stems, and also those of Ferns and the
higher Flowerless plants, the cambium isfound
in delicate cords imbedded in the nascent
general parenchyma, indicating, even in this
early condition, the position and arrange-
ment of the isolated fibrous and vascular
bundles. Sections of the outer region of the
stem of Dicotyledons demonstrate the exist-
ence of a layer of cambium at the outer sur-
face of the youngest wood, which indeed
passes gradually into the cambium. This
cambium is the tissue from which the suc-
ceeding layers of wood are generated, and its
position on the outside of the fibro-vascular
bundles gives these their indefinite power of
development. The cambium of the Mono-
cotyledonous bundles becomes enclosed be-
tween the wood and vessels of individual
bundles so that their growth is limited. The
cambium of the outside of the wood of Di-
cotyledons forms new layers of liber, in most
cases, on the inside of the old ones, pari
passu with the development of the layers of
wood. Cambium, which is in great part only
an early and transitional form of cellular tis-
sue, afterwards to become developed into
wood, is composed of delicate cellulose
cells enclosing a primordial utricle, nucleus,
and abundance of nitrogenous protoplasm,
but usually without chlorophyll. The cells
multiply by transverse subdivision in the
elongation of the stem, and by perpendicular
division (tangental and radial) as the stem
expands in diameter. This process is effected
by the constriction of the primordial utricle
and gradual development of a septum, as in
ordinary vegetative cell-development. The
cambium of most Dicotyledons is gradually
matured into wood, from within outwards ;
but in the Monocotyledons and Flowerless
Cormophytes it often remains in great part

in a delicate and soft condition, forming
what are called by von Mohl the vasa pro-
pria, or proper vessels. Owing to the deli-
cacy of its structure, cambium was formerly
imagined to be a thick mucilaginous fluid
poured out in the growing regions of plants
(as between the wood and liber of Dicotyle-
donous stems in spring), which by degrees
became organized and converted into cellular
tissue, by the independent origin and subse-
quent coalescence of a number of cells gene-
rated in this fluid. This view, founded on
imperfect observation, was strongly supported
by Mirbel and others.

BIBL. Treviranus, Physiologic der Ge-
w'dchse, i. 159; Mirbel, Nouvelles notes sur
le Cambium, Ann. des Sc. nat. 2 ser. xi. 321;
Notes sur le Composition du Cambium, Ann.
des Sc. nat. 2 ser. xix. 197; Payen, Comptes
Rendus, 1839, 509; Schleiden, Grundzuge
der Botanik (Principles of Botany}; Henfrey,
Outlines of Structural Botany ; Nageli, Zeit-
schrift. fur Wiss. Botanik, iii. 64; Mohl, Die
Vegetabilische Zelle (The Vegetable Cell,
Transl. London, 1853); Schacht, Die Pflan-
zenzelle, Berlin, 1852.

CAMBRIC. — This name was formerly ap-
plied strictly to the finest kind of linen cloth.
It is used now in a loose sense in trade.
French cambric, however, ought to be linen.
Scotch and English cambrics are now com-
monly made of cotton, while Indian cambric
is made of the grass-cloth fibre. The fibres
may be distinguished under the microscope,
and the value of the fabric thus ascertained.
See FIBROUS SUBSTANCES and COTTON.

CAMERA LUCIDA. INTRODUCTION,
p. xix.

CAMPANULARIA, Lamarck.— A genus
of Polypi, of the order Anthozoa.

Char. Polypidom rooted, creeping, or
when compound, erect ; the main tube fili-
form, continuous, giving off its pedunculated
cells irregularly or in whorls; peduncles
ringed, usually long; cells campanulate;
vesicles scattered, sessile; polypes hydri-
form.

7 British species :

C. volubilis (PL 33. fig. 4). Stem a single
tube, creeping, filiform ; cells on long, slen-
der, ringed peduncles, campanulate, with a
serrated margin; vesicles ovate, wrinkled
concentrically.

Parasitic on sea-weeds, &c.; frequent. It
forms an elegant microscopic object.

BIBL. Johnston, Brit. Zoophytes, 1847.

CAMPIUM, Presl.— A genus of Acrosti-
cheae (Polypodaeous Ferns). Exotic.

CAMPTOCERCUS.

[ 108 ]

CAOUTCHOUC.

CAMPTOCERCUS, Baird(LynceM*,Mull.
in part). A genus of Entomostraca, of the
order Cladocera, and family Lynceidse.

Char. Carapace ovoid; beak blunt, di-
rected forwards or slightly downwards ; ab-
domen long, slender, tail-like, extremely
flexible and serrated. 1 species :

C. Macrourus (PL 15. fig. 4). Carapace
striated longitudinally, slightly sinuated and
ciliated on the anterior margin; beak rather
blunt ; aquatic.

BIBL. Baird, Brit. Entom., p. 128.

CAMPTOUM, Link.— A genus of De-
matiei (Hyphomycetous Fungi), allied to
Arthrinium. C. curvatum, Lk. (Arthrinium
curvatum, Kze.) grows in tufts of very slen-
der filaments, bearing very minute, curved
spores, upon Scirpus sylvaticus.

BIBL. Berk, and Br. Annals Nat. Hist.
2 ser. viii. 100; Fries, System. Myc. iii. 377;
Corda, Ic. Fung. iii. pi. 1. fig. 17.

CAMPTOSURUS, Presl.— A genus of
Scolopendrieae (Polypodeeous Ferns). Ex-
otic.

CAMPYLODISCUS, Ehr.— A genus of
Diatomaceae.

Char. Frustules single, free, disk-shaped;
disk curved or twisted (saddle-shaped) ; fur-
nished with mostly radiate markings, which
are frequently interrupted. Aquatic and
marine.

The Rev. Mr. Smith terms the markings
costse or canaliculi, and interprets them to be
minute canals forming means of communica-
tion between the internal cell-membrane and
the surrounding fluid.

Mr. Smith describes 7 species (British),
Kiitzing 12 others.

C. costatus. Smith (PI. 12. fig. 16). Valves
circular; radii (canaliculi) 30-40, extending
about half-way to the centre, which is mi-
nutely punctate; diameter 1-270"; aqua-
tic.

C. spiralis, Smith. Outline of front view
resembling a figure of 8; valves elliptical;
radii about 60, nearly parallel and transverse;
length 1-160"; aquatic.

C. Clypeus, Ehr. (PL 18. fig. 44). Valves
suborbicular, exhibiting a circular and a me-
dian transverse hyaline line; radii broad,
interrupted in the middle, which is punctate;
length 1-200" ; aquatic and fossil.

BIBL. Smith, Brit. Diat. i. ; Kiitzing,
Bacill. and Sp. Alg.

CAMPYLOSTELIUM, Br. and Sch.— A
genus of Leptotrichaceous Mosses, including
some Dicrana and Grimmice of other au-
thors.

Campylostelium saxicola, Br. and Sch. =
Grimmia saxicola, Hook.

CANADA BALSAM. See BALSAM.

CANALICULI. See BONE.

CANCER.— We have thought it best to
include the consideration of cancer in that of
tumours. See TUMOURS, CANCEROUS.

CANCROID. See TUMOURS, CANCROID.

CANDONA, Baird (Cfypm, in part MiilL).
A genus of Entomostraca, of the order Ostra-
coda, and family Cyprididae.

Char. Two pairs of antennae ; superior
long, with numerous joints and a pencil of
long filaments ; inferior stout and pediform,
without a tuft of long hairs or filaments (see
CYPRIS) ; eye single, motion creeping only.
Five British species ; aquatic.

C. reptans (PL 15. fig. 5). Shell ovate-
elliptical, slightly sinuate below ; valves
rather gibbous in the middle and glabrous,
the edges being fringed with rather long
hairs ; greenish-white, variegated with marks
on the anterior and posterior margins, of a
deeper colour at the sides; length about
1-10'' (fig. 5 a, inferior antenna).

BIBL. Baird, Brit. Entomostr.

CANNA. — A genus of Monocotyledonous
plants belonging to the same natural family
as the arrow-root (Marantacese), and valuable
from the same cause. Tous-les-mois is a
starch derived from the tubers of a Canna,
supposed to be C. edulis, Ker. The grains
of genuine Tous-les-mois have distinctive
microscopic characters, as shown in PL 36.
fig. 25, which is taken from a specimen in
the Kew Museum.

CANTHOCAMPTUS, Baird (Cyclops,
pt. Mull.). — A genus of Entomostraca, of
the order Copepoda, and family Cyclopidae.

Char. Foot -jaws small, simple; inferior
antennae simple ; ovary single.

Four species ; one aquatic, three marine.

C. minutus (PL 15. fig. 6). Thorax and
abdomen not distinctly separate, consisting of
ten segments, successively diminishing in size,
the last terminating in two short lobes, from
which issue two long filaments, slightly
serrate on their edges; antennas short, seven-
jointed in the male, nine in the female ;
inferior antennas simple, two-jointed, the first
joint with a small lateral joint, terminated by
four setae ; feet five pairs.

Common in ditches ; colour reddish ;
length about 1-15". (PL 15. fig. 6; a, in-
ferior antenna ; b, first pair of foot -jaws ;
c, second pair).

BIBL. Baird, Brit. Entom.

CAOUTCHOUC.— A gum-resinous sub-

CAPILLARIES.

[ 109 ]

CAPNODIUM.

staiice contained in the milky juices of many
plants, but most abundantly in those of the
families Euphorbiacese, Urticacese and Apo-
cynacese, whence the India-rubber of com-
merce is obtained. The caoutchouc appears
in the form of minute globules suspended in
a watery fluid containing a gummy substance,
so that the milky juices may be regarded as
a kind of emulsion. For further details, see
LATEX.

CAPILLARIES. — The minute vessels
which the blood traverses in passing from
the arteries to the veins.

The capillaries consist of a delicate, trans-
parent, tolerably resisting and elastic struc-
tureless membrane, and a number of oval or
rounded longitudinal nuclei. The diame-

Fig. 103.

Magnified 300 diameters.

One of the smallest vessels from the arterial side. 1,
smallest artery ; 2, transition vessel ; 3, large capillaries ;
4, small capillary, a, structureless membrane with few
nuclei, representing the adventitious coat; b, nuclei of
the muscular fibre-cells; c, nucleus inside the small
artery ; d, nuclei of the capillaries and intermediate
vessel. From the human brain.

ter of the human capillaries varies from
1-5000 to 1-1000", the most common being
perhaps 1-3000". The size of the capillaries
in the Vertebrata generally, bears a relation

to the size of the coloured corpuscles of the
blood. Thus, they are largest in Birds,
Fishes and Reptiles. The larger capillaries
have thicker walls and more numerous nuclei
than the smaller ones; and in the former,
the nuclei are situated in the substance of
the wall or membrane, whilst in the latter
they appear to be attached to its inner
surface.

The capillaries branch and anastomose
freely, giving rise to the beautiful networks,
so well known as favourite microscopic
objects when injected.

The most important pathological change
which the capillaries undergo is that of
FATTY DEGENERATION. The general
arrangement of the capillaries is best seen in
injected preparations (INJECTION). Their
structure may be examined in minute pieces
of well-washed brain, or of the retina; a
minute portion of washed lung, will answrer
the purpose well. These should be dissected
with the mounted needles. The relation of
the capillaries to the surrounding minute
structures may be shown in portions of tissue
which have been imperfectly injected, or
injected with a liquid containing a small
quantity only of colouring matter ; in these,
the capillaries may be recognized by their
containing the scattered granules of the
colouring matter. Acetic acid is frequently
of use in rendering the tissue transparent,
and bringing the nuclei to light.

See VESSELS and CIRCULATION.

BIBL. Paget, Report, fyc., Brit, and For.
Med. Rev. 1842, xiv.; Kolliker, Mikr. Anat.
bd. ii. ; Henle, Allgemein. Anat. ; Wedl,
Grundzuge d. path. Hist.

CAPNODIUM, Montagne.— A genus of
Antennariei (Physomycetous Fungi) growing
as a kind of mildew" on leaves and shoots,
forming a blackish flocculent coat composed
of short, branched, beaded or moniliform
filaments, densely interwoven. The peri-
thecia arise vertically from this, and are
either simple or branched, at first simple
sacs, but probably afterwards thickened by a
layer of cells; a number of threads ultimately
grow up from the mycelium, partially cover
the central sac, and, closely crowded, some
of their tips project beyond it, forming a
fringe; the cells of this fringe readily become
detached and appear to reproduce as conidia.
The central sac contains largish delicate asci,
probably often absorbed at an early period
so as to set the spores free in the cavity.

Most of the species are foreign, but C.
(Fumago) quercinum, Pers., grows on oak-

CARAPACE.

L

leaves, and P. Footii, Berk, and Desm., on
evergreens, the beech, and also on Mercurialis
perennis, but in this species the fruit has not
been observed.

BIBL. Berk, and Desm. Trans. Hort. Soc.
iv. 243 ; Montagne, Ann. Nat. Hist. 2 ser.
iii. 520.

CARAPACE, or LORICA. — A term some-
what indefinitely applied to the whole or a
part of the shell or outer coat of certain
animals ; as those belonging to the classes
Crustacea, Rotatoria, Infusoria, &c.

In regard to the Rotatoria and Infusoria,
it has been divided into the testa or testula,
an envelope resembling that of the tortoise,
within which the body of the animal is in-
closed, the head and the tail being free : as
in the genera Brachionus, Monura, Colurus,
&c. ; the scutellum, a round or oval envelope,
covering only the back of the animal, in the
manner of a buckler ; and the urceolus, a
membranous or firm envelope, sometimes
gelatinous, in the form of a bell or cylinder,
open at one end and closed at the other, and
within which the animal can completely
retract itself; as in DIFFLUGIA, &c.

Ehrenberg extended the use of this term
also to the external envelope of Volvox,
Gonium and the Diatomacese. As these
have been removed to the vegetable kingdom,
it is not now applied to them.

CARBONATE OF LIME. See LIME,
Carbonate of.

CARBONIC ACID.— The presence of
this gaseous acid is usually determined by
the addition of another acid, as acetic or
muriatic, to the object under the microscope;
and if colourless and inodorous bubbles
escape, it is concluded, and in most cases
correctly, that carbonic acid is present.

It must be borne in mind that if the object
be immersed in liquid, the gas may arise
either from this or the object ; for it is well
known that the escape of a gas from a liquid
charged with it, is greatly facilitated by the
presence of a solid and especially a pointed
body, and that the gas escapes from the
liquid at its surface or point ; thus the
false appearance is produced of the gas being
liberated from the body. Hence the import-
ance of washing the object before the addition
of the acid (INTRODUCTION, p. xxxvii).

When crystalline bodies of different forms
are present, these must be separated before
the addition of the acid, otherwise the bubbles
liberated from those of one kind, by escaping
at the surface of the others, may give rise to
the false conclusion, that they were derived
from the former.

Recollection of the fact that carbonic acid

o ] CARTILAGE.

is readily absorbed by solution of potash,
would allow of the distinction of bubbles of
this acid from those of air.

BIBL. See CHEMISTRY.

CARCHESIUM, Ehr.— A genus of Infu-
soria, belonging to the family Vorticellina.

Char. Pedicle branched, spirally flexible ;
bodies of the animals all alike (= branched
Vorticellce).

C. polypinum (PI. 23. figs. 20, 21). Body
conico-campanulate, colourless, broad and
truncate in front, margin prominent, pedicle
sub-umbellate ; aquatic ; length of body
1-580 to 1-430".

Ehrenberg describes two other species,
C. pygmceum and C. spectabile ; these are,
however, probably not distinct.

BIBL. Ehrenb. In/us, and Ber. d. Berl.
Akad. 1840, p. 199; Dujardin, Infus. p. 551;
Stein, Infusionsthiere, p. 48, &c.

CARIS, Latreille.— A doubtful genus of
Arachnida, of the order Acarina, and family
Gamasea.

The single species, C. vesper tilionis, is
found upon the bat (Vespertilio pipistrellce).
It is probably a young Dermanyssus.

BIBL. Latreille, Gen. Crustac. et Insect
i. p. 161 ; Audouin, Ann. d. Sc. not. Zool.
xxv. p. 412; Walckenaer, Apttres (Gervais),
p. 227.

CARMINE. — This beautiful pigment is
sometimes used to feed Infusoria and fill
their sacculi or gastric vesicles (INFUSORIA).

It has also been used as a colouring
matter for injections.

CARPAIS. See GAMASUS.

CARPOMITRA, Kiitz.— A genus of Spo-
rochnaceae (Fucoid Algae) containing one
rare British species, C. Cabrera, Clem., re-
markable for the peculiar mitre-shaped con-
ceptacle containing the spores.

BIBL. Harvey, Br. Marine Alg. pi. 5 B.,
Phyc. Brit. pi. 14.

CARTILAGE.— Cartilage consists of a
firm, but elastic, bluish, milky or yellowish
substance; which morphologically forms
either a simple parenchyma composed of
cells, or a structure consisting of cells
immersed in an intermediate basis.

The cells of cartilage are usually round,
oval, elongated or angular, frequently flat-
tened and sometimes spindle-shaped. In
some cartilage, they appear stellate,
as in that of the cuttle-fish, the sharks and
rays, and enchondromatous growths ; but it
has not been determined in these in-
stances whether they are really stellate, or
whether the stellate appearance arises from
the existence of secondary deposit within
cartilage-cells of the common forms (see

CARTILAGE.

CARTILAGE.

BONE, p. 93). The cell-walls are generally
thick, and frequently composed of several
layers. The contents consist of a clear liquid
and a nucleus; sometimes the cell and some-
times both the cell and the nucleus contain
one or more globules of oil. The cells also
frequently constitute parent-cells, i. e. cells
containing other or secondary cells within
them, these containing also nuclei or tertiary
cells.

Fig. 105.

Magnified 350 diameters.

Primary (parent-) cells with one and two nuclei, or two
and four secondary cells and intervening basis. From
the cranial cartilage of a full-grown tadpole.

The secondary and tertiary cells sometimes
exhibit well the internal layers.

Fig. 106.

Magnified 350 diameters.

Cells from the gelatinous nucleus of the intervertebral
ligaments. 1, large primary cell a, with a septum formed
by two secondary cells, and five tertiary cells or cells of the
second generation with concentric walls and shrunk nuclei
c in the small cell-cavities. 2, primary cell a, with two
secondary cells separated by a delicate septum b, with
thickened walls, a small cavity and a shrunk nucleus c.

The intervening basis, when present, is
either homogeneous, finely granular or
fibrous; sometimes the fibres are distinct
and can be isolated. The simplest form of
cartilage, viz. that composed of cells only, is
met with in the chorda dorsalis of embryos,

in the adult skeleton of many fishes, and in
the cartilage of the ear of many mammals.
It is beautifully seen in the chorda dorsalis
of a young tadpole or young Triton ; or in
the ear of the mouse (PI. 40. fig. 38). In the
latter instance, each cell is filled with a
globule of oil, which must be separated by
digestion in aether before the cell-structure
can be properly examined ; but boiling on a
slide in solution of potash, or the addition of
sulphuric acid will liberate the globules of
fat from parts of a section. This variety of
cartilage exactly resembles in appearance a
section of vegetable cellular tissue.

The second variety of cartilage, in which
the basis is homogeneous or finely granular,
or true cartilage as it is called (PI. 40. fig. 39),
is met with in the larger cartilages of the
respiratory organs, in the articular, costal,
ensiform and nasal cartilages. In this the
cell-walls are closely adherent to the inter-
cellular basis, so that they are rarely visible
without the use of reagents. The cells are
most numerous in the articular cartilages ;
and are mostly smaller the further they are
from the bone. Their long axes are placed
perpendicularly to the axis of the bone,
except in a thin layer next the surface of the
joints, in which they are parallel to the
surface.

The third variety of cartilage or fibro-car-
tilage (PI. 40. fig. 40) occurs in the human
epiglottis, the external ear, the Eustachian
tube, the intervertebral ligaments, &c. It con-
sists principally of fibres, single or in bundles,
sometimes running parallel, at others inter-
lacing, and between them lie the cartilage
corpuscles. Sometimes the basis of true
cartilage becomes fibrous, and true fibres may
be found in it. The chemical composition
of the components of cartilage has not been
satisfactorily determined. The homogeneous
basis usually consists of chondrine. The
cell-walls are composed of a substance allied
to elastic tissue ; they are not dissolved by
boiling in water and are acted upon with diffi-
culty by acids and alkalies. The liquid within
the cells is probably albuminous ; it is coagu-
lated by water and dilute organic acids, and is
readily soluble in alkalies. The fibrous
elements of the fibro-cartilages sometimes
agree in composition with white fibrous
tissue, at others with the yellow or elastic
tissue.

When sections of cartilage are subjected
to the action of Schultze's test, the cells are
coloured red, but not the basis.

The cartilage of bone is noticed under

CARYOPHYLL^US.

[ "3 J

CATHARINEA.

BONE (p. 92). The only instance of cartilage
occurring in the Invertebrata, is found in the
Cephalopoda (Sepia).

For an account of the minute anatomy of
cartilage in disease, we must refer to the
valuable papers of Dr. Redfern in the Edin-
burgh Monthly Journal for 1849, 1850, and
1851. See also ENCHONDROMA.

BIBL. Kolliker, Mikrosk. Anat. bd. i. ;
Paget, Brit, and For. Med. Rev. 1842. xiv. ;
Henle, Allgemeine Anat, ; Redfern, Ed.
Monthly Journal, 1854 ; Mulder (and Don-
ders), Versuch einer Allg. Physiol. Che-

CARYOPHYLL,EUS.— A genusof Ento-
zoa, of the order Sterelmintha, and family
Cestoidea.

Char. Body depressed, continuous (not
jointed), expanded at one end, which is lobed
or laciniate.

C. mutabilis. Yellowish white, expanded
end reddish. M. Blanchard regards the
expanded end as the head, whilst previous
authors consider this to be the tail. There
are no suckers, mouth nor intestine. The
vascular system is distinct, and can be in-
jected ; it consists of ten longitudinal,
slightly sinuous vessels. The ovaries form
longitudinal and transverse lines, extending
through almost the whole of the body. Its
size is said to vary from about the 1-6 to 2".
It is found in the intestines of the carp,
bream, &c.

BIBL. Dujardin, Hist. d. Helminthes ;
Blanchard, Ann. d. Sc. nat. 3 ser., Zool. x.

CASEINE is the proteine constituent of
milk. It possesses no microscopic charac-
ters.

Some years since a tumbler, containing
porter, at the bottom of which was a small
quantity of a whitish sediment, was brought
to us for examination; suspicion being enter-
tained that the white deposit consisted of
some poisonous substance which had been
added by a woman with a view of poisoning
her husband, the two not being on good
terms. The deposit examined microscopically
and micro-chemically was found to consist
of an amorphous substance, giving the che-
mical reactions of a proteine compound, with
entangled globules of oil. This rendered it
probable that it consisted of the caseine of
milk, with globules of butter. It was after-
wards recollected that milk had been put
into a tumbler kept in the place from which
this had been taken; and thus the matter
ended.

BIBL. See CHEMISTRY.

CASSAVA.— The coarser part of the
starch (tapioca being the finer) derived from
the tuberous root of the Jatropha Manihot,
L. (Janipha Manihot, Knth. ; Manihot uti-
lissima, Pohl.), a Brazilian plant of the family
Euphorbiaceae. The starch grains are repre-
sented in PL 36. fig. 14.

CASSEBEERA, Kaulf.— A genus of As-
plenieae (Polypodseous Ferns), nearly related
to Adiantum. Exotic.

CATASCOPIUM, Brid.— A genus of Bar-
tramioideae (Acrocarpous Mosses).

C. nigrita, T$ri&.= Weissia nigrita,JJ.edw.

CATENELLA, Grev.— A genus of Cryp-
tonerniaceae (Florideous Algse). represented
by one British species, C. Opuntia, which is
not uncommon on marine rocks near high-
water mark. It presents a mass of creeping
fibres, from whence arise densely matted
fronds 1-2" to 1'' high. Colour dull dark
purple. Thefavellidia are contained in the
lateral capsular bodies (fig. 107) ; the tetra-

Fig. 107.

Catenella Opuntia.

Fig. 107. Fragment of a frond, with lateral capsular
bodies containing the spores. Magnified 10 diameters.

Fig. 108. Transverse section of the axis, showing the
immersed tetraspores. Magnified 200 diameters.

spores are imbedded in the periphery of the
loosely cellular axis (fig. 108).

BIBL. Greville, Alg. Brit. pi. 17; Harvey,
Br. Mar. Alg. pi. 20 B. ; Phyc. Brit. pi. 88 ;
Engl. Botany (Rivularia Opuntia), pi. 1868.

CATHARINEA, Ehrh.— A genus of Poly-
trichaceous Mosses, containing some of the
Polytricha of some authors, having a naked
calyptra :

Catharinea Callibryon, Ehrh. = Polytri-
chum undulatum, Hedw.

C. hercynica, J£hih.=zPofytrichum hercy-
nicum, Hedw.

CECROPS.

CELL.

CECROPS, Leach.— A genus of Crustacea,
of the order Siphonostoma, and family Cali-
gina.

C.Latreillii. Found on the sun-fish (Ortha-
goriscus mola}. Female, length 1", male 1-3".

BIBL. Baird, Brit. Entomosi.; V. d.
Hoeven, Handb. d. Zoologie, i.

CEDAR.— The Cedar of Lebanon is the
Abies or Pinus Cedrus. The fragrant, so-
called ' Cedar,' of which pencils, &c. are
made, is the wood of Juniperus Virginiana.

See CONIFERJE, and WOOD.

CELL, ANIMAL. — The tissues and organs
of animals, like those of plants, are in great
part made up of cells, but the full-grown
structures of animals are strikingly distin-
guished from those of vegetables by the
departure from or disguisal of the primitive
cellular constitution.

Under the head of CELL, VEGETABLE,
the cell is denned as a vesicle or sac consist-
ing of a membrane composed of cellulose,
containing within it a nitrogenous structure,
the vital part, called the primordial utricle.
In animals this internal structure may exist
alone, without a membranous envelope form-
ing the true cell or closed sac, as in Amoeba,
and analogous organisms ; but ordinarily the
animal cell, like the vegetable, is a true shut
sac, enclosing liquid or gelatinous contents,
the membrane, however, being here almost
always composed of a nitrogenous compound,
and only in a few cases of cellulose or allied
substances such as prevail in the solid parts
of plants.

The membrane of animal cells is ordinarily
transparent and colourless, mostly smooth,
and so thin as to exhibit only a single
boundary line ; more rarely the membrane
is tolerably firm, presenting a measurable
thickness ; while it is sometimes very thick
and appears to consist of several layers.
Occasionally the membrane has a granular
appearance, arising from projections de-
pendent on granules lying on the inside.
No structure can be detected in the cell-
membrane itself.

The membranous cell generally contains a
liquid, the consistence of which varies; in
this float molecules, granules, globules or
other very minute cells. In addition to these,
we frequently find one or more of those
bodies which are termed nuclei, often
attached to some part of the cell-wall. The
nuclei again contain nucleoli. The cell-
contents likewise include, in particular
structures, products of secretion, — matters
separated by the cells from the circulating

fluid, as in the cells of the renal epithelium,
&c. ; also crystals.

The forms presented by animal cells are
not so varied, or generally so geometrical, as
those occurring in the cells of vegetables.

In regard to size, the largest are the yolk-
cells of ova, especially of Birds and Reptiles,
and of some animals consisting of a single
cell, as certain of those curious organisms,
the Gregarina.

The nuclei are usually spherical or lenti-
cular, transparent, and colourless or yellowish.
They are sometimes solid or homogeneous,
at others they are vesicles, with a very
delicate membrane. They sometimes contain,
exclusively of the nucleolus, a transparent,
colourless or yellowish liquid, in which water
and acetic acid produce a precipitate of
granules resembling those existing in the
cell-contents ; hence in the ordinary manner
of examining them, they seldom present
their natural transparency.

The nucleoli are rounded, well-defined,
very minute, sometimes immeasurable.

Chemically, the cell-membrane ordinarily
consists of aproteine-compound; it is mostly
dissolved, or rendered so transparent as to
become invisible, by acetic acid and solution
of potash. Cell- membranes composed of
cellulose occur in some animals, as in the
Tunicata, &c.; it is detected here, as in plants,
by the action of iodine and sulphuric acid.
The nucleoli consist also of a proteine-com-
pound ; they are soluble in potash, but not
in acetic acid. The action of potash distin-
guishes them from globules of fat. It must
be remarked that the appearances interpreted
to be nuclei and nucleoli, frequently are not
respectively identical in kind ; the nuclei are
sometimes homogeneous, at others true
cells; sometimes they relate to the formation
of the cell, at others they are young second-
ary cells, vacuoles, &c. ; the same applies to
the nucleoli. These important points have
not hitherto received sufficient attention.

Cells are endowed with peculiar vital
forces, by which they are capable of absorp-
tion and the elaboration of the absorbed
matter, of growth, reproduction, and of secre-
tion. The entire organism of the higher
and most of the lower animals, consists at a
certain period of life, of cells alone.

Formation of cells. — Cells are formed in
two ways ; either from a blastema or forma-
tive substance, existing without or contained
within other cells. The blastema or cyto-
blastema is a liquid or a semifluid substance,
consisting of proteine, fatty matter and salts.

i

CELL.

CELL.

The formation of cells in a free blastema
is not a general process ; the only instances
of its occurrence in man and the higher
animals, are in the formation of the chyle
and lymph corpuscles, the cells of certain
glandular secretions (seminal cells, ova), and
glandular organs (the closed follicles of the
intestine, the lymphatic glands, the splenic
corpuscles with the splenic pulp, and the
thymus) ; lastly, of the cellular elements in
the impregnated uterus, in the corpus
luteum, the marrow of foetal bones, and in
the soft ossifying blastemata. In the case of
the chyle and the spleen, at the commencement
of cell-formation, we find roundish, appa-
rently homogeneous bodies of 1-11000 to
1-5600" diameter, which, increasing in size,
some appear distinctly as vesicles (fig. 108),

Fig. 108.

Magnified 350 diameters.

Contents of a Malpighian body from the spleen of an
ox. a, small, b, larger cells ; c, free nuclei.

and on the addition of water, exhibit an
internal large body resembling a nucleolus,
as also several granules. The minute details
of this stage of the process of formation, are
not accurately known. As soon as the nuclei
are formed, cell-membranes are formed
around them, but not always in the same
manner. Sometimes the cell-wall is deposited
directly around the nucleus, so that it is but
little larger than the latter; at others the
nucleus becomes surrounded by a larger or
smaller quantity of blastema which becomes
more solid, and around which the cell-mem-
brane is subsequently deposited. The latter
occurrence has hitherto only been satisfac-
torily observed in the case of the ovum, in
which the germinal vesicle, i. e. the nucleus
of the ovum-cell, which is formed first,
becomes surrounded by a quantity of yolk,
before the vitelline membrane is formed.* On
the other hand, the formation of the cell-
wall directly around the nucleus, takes place
in all the other localities mentioned above,
and is especially shown by the occurrence of
free nuclei and larger cells, together with
very small cells closely surrounding the
nuclei, or separated from them by a slight
interval only. It is possible that in this
instance also, the cell-membrane, even at its

first formation, may be separated from the
nuclei by a quantity of blastema too minute
to be detected.

This free formation of cells is very general
in pathological productions, as in pus, exu-
dations, &c.; the cell-membrane being depo-
sited directly around the nucleus, the inter-
mediate layer of blastema rarely being
present.

This extra-cellular formation of cells is
unknown in plants.

The endogenous method, or the formation
of cells within others, is very common, and may
be readily observed in the tissues of embryos.
In the most ordinary form of this kind of cell-
formation an original or parent-cell produces
within it two secondary cells, which from
the first completely fill it. The first phseno-
menon observed in the parent-cell is the
increase of the nucleus, which acquires two
nucleoli, becomes elongated and resolved
into two nuclei. After this the nuclei
separate from each other, and a partition is
formed between the cells, dividing the parent-
cell into two perfectly distinct spaces, each
of which encloses a nucleus and half of the
contents (fig. 104). The exact manner in

Fig. 109.

Magnified 350 diameters.

An elongated nucleus, and one containing two secondary
nuclei, from the ovum of an Ascaris dentata.

which the increase of the nucleus occurs is
not certain, but it appears that the nucleoli
always become resolved into two by subdivi-
sion and then separate from each other. In
the nuclei, which at the same time become
elongated, the first trace of division is then
usually a median partition, which in favour-
able instances appears to arise from the
presence of two secondary cells in close
contact by plane surfaces and entirely filling
up the parent nucleus. Very frequently
nothing is seen but first an elongated nucleus
with a partition and two nucleoli, and then
two hemispherical nuclei in contact by their
plane surfaces (fig. 109), no endogenous
nucleus-formation being perceptible ; in this
case, division of the nucleus has taken place,
the parent-nucleus containing two nucleoli
becoming finally resolved into two by a
deeper and deeper constriction. This mode
of cell-formation is often continuously re-
peated, frequently so long as the growth of

CELL.

[ H5 J

CELL.

the organism continues. The parent-cells
then either continue their existence as such,
or they disappear sooner or later as histolo-
gically distinct formations, and become con-
solidated with the substance connecting the
cells.

The occurrence of this endogenous cell-
formation, which agrees essentially with the
formation of cells in a free blastema, is well
established in the case of the young cartilages
of all animals, and also probably occurs in
embryonic organs in general, in which, from
the period at which they consist of true
cells, the entire growth depends upon the
multiplication of the existing cells without
free cell-formation. It also occurs in patho-
logical products, as in cancer.

In addition to this, the most common kind
of endogenous cell-formation, there are
others, viz.

a. In the ova of most animals at the earliest
period of development, a peculiar process
occurs called the segmentation of the yolk,
which must be regarded as preliminary to
the formation of the first embryonic cells,
and which, as the ovum bears the import of
a simple cell, falls under the type of endo-
genous cell-formation. The segmentation
consists essentially of this : after the original
nucleus of the ovum-cell — the germinal
vesicle — has disappeared in consequence of
impregnation, the granules of the yolk are
no longer aggregated into a compact mass as

Fig. 110.

Fig. 111. Fig. 112.

Magnified 350 diameters.

Three ova of an Asraris nigrovmosa ; 1 , in the first,
2, in the second, and 3, in the third stage of segmen-
tation, with two, four and sixteen segmentation-globules.
a, outer coat of the ovum ; b, segmentation-globules. In
1 , the nucleus of the lowest globule, contains two nucleoli ;
in 2, the lowest globule, two nuclei.

before, but become distributed throughout
the entire cell. The first sign of commencing
development is then constituted by the for-
mation of a new nucleus, the first embryonic
nucleus, around a new nucleolus, which acts
as a centre of attraction to the yolk and
causes it to reunite into a globular mass — the
first globule of segmentation. In further
development two new nucleoli are formed

from the first nucleus by endogenous growth,
which, as soon as they are set free by the deve-
lopment of the parent nucleus, become sepa-
rate from each other, act as new centres to
the yolk-granules, and thus the first globule
of segmentation becomes resolved into two.
The increase of the nuclei and the globules of
segmentation continues in the same way,
the first always preceding, until a very large
number of small globules are present, which
entirely fill up the yolk-cell; sometimes,
but exceptionally, the globules are not re-
solved until the nuclei have become increased
to three or four, so that three or four
globules are formed from each, instead of
two. This process is termed total segmenta-
tion, because here the entire yolk is applied
to the newly-formed nuclei; partial seg-
mentation agrees with this in all essen-
tials, and only differs from it in the circum-
stance that in it, not the whole of the yolk,
but a larger or smaller part of it, according
to the different animals, envelopes the nuclei
in process of formation (figs. 110-112).

When the process of segmentation has
reached a certain stage, the segmentation-
globules become surrounded with membranes
and form true cells, whence it appears justi-
fiable to arrange this process with endogenous
cell-formation. In fact it is nothing more
than a preliminary to cell-formation in the
ovum-cell, and only differs from the ordinary
phsenomena of this kind in the circumstance
that, first, the nucleus of the parent-cell or
the germinal vesicle in most cases has
nothing to do with it; secondly, the pa-
rent-cell itself persists; and, thirdly, the
portions of the contents formed in it by the
successive increase of nuclei do not assume
the form of cells until subsequent genera-
tions. This view is moreover justified,
since the cells formed from the last seg-
mentation-globules continue for a long period
to multiply by endogenous production (or
division), and the entire segmentation pro-
cess may be regarded as a kind of endogenous
cell-formation, in which, on account of the
rapidity with which the nuclei increase, in
the first generation of globules it does not
come to the formation of membranes. (See
OVUM.)

b. In some respects allied to segmentation
are those forms of endogenous cell-forma-
tion, in which a greater or less number of
secondary cells are formed within persistent
parent-cells, as seen here and there in carti-
lage, the supra-renal capsules the pituitary
body, &c. In this case, either two second-

i2

CELL.

CELL.

Fig. 113.

Magnified 350 diameters.

Cartilage cells from a fibrous velvety articular cartilage
of the condyle of a human femur ; all lying in a fibrous
basis, and easily isolated, a, single cells, with or without
thickening of the cell-wall, and one or two nuclei ; b, se-
condary cells, or cells of the first generation with one or
two nuclei, — one, two, five and many cells in the parent-
cells b1 ; c, cells of the second generation, one to three in
those of the first, b, b ; d, free group of secondary cells.

ary cells are formed in the usual way in a
cell, almost or entirely filling it, and from
these other generations, either free, or all or
individual ones enclosed in parent-cells of
the second and suhsequent generations ; or
only one secondary cell is formed in a cell,
whence cell-formation then proceeds in either
manner (fig. 113) ; or the secondary cell is
formed in a bud-like protrusion of the parent-
cell (see ECHINOCOCCUS).

The formation of a larger number of
nuclei within cells may be well arranged
under endogenous cell-growth, which fre-
quently precedes cell-formation, but may
also exist alone. Even in ordinary endoge-
nous cell-formation (and also in segmenta-
tion) we not unfrequently find three and
four nuclei in one parent-cell, so that then,
instead of two, a larger number of secondary

cells are formed at once, as e. g. in
the liver-cells of embryos. In certain
animals (Cucullanus, Ascaris dentata,
Distoma and the Cestoidea), instead
of segmentation-globules in the first
stage of development, nuclei only are
formed in the ovum-cell, which do
not become surrounded by cell-mem-
branes until they have accumulated
in+o a large heap by successive endo-
genous growth. The same appears
to take place in the cells of the germ
of the Crustacea, in which from ten
to twenty nuclei frequently exist. The
numerous nuclei, however, in the
seminal cells of most animals appear
usually to have no connexion with
cell-formation, because the seminal
filaments are developed within them,
and the same applies to those cells of
the lower animals, the numerous
nuclei of which are converted into
urticating organs. Whether in these
cases the nuclei multiply by division
or endogenous growth is unknown.

Cell-formation by division has been
observed in the coloured blood-cor-
puscles of the embryos of Birds and
Mammalia, and the earliest colourless
blood-corpuscles of the larvae of frogs
(tadpoles) ; it also probably occurs in
the colourless blood-corpuscles of
embryos and the chyle-corpuscles of adult
Mammals. In all these cases, the cells first
become elongated, and the single nuclei

Fig. 114.

Magnified 350 diameters.
Ivory cells from the tooth of a dog.

CELL.

[ 117 ]

CELL.

appear to become divided into two; the cells
are then constricted in the middle and finally
resolved into two, each with a nucleus (PI.
40. fig. 43-6).

A peculiar kind of cell-growth, most nearly
allied to division, occurs in the cells of the
ivory of the teeth ; in which, while continu-
ally elongating, the nuclei enlarge from time
to time and become constricted, so that
whilst that portion next the ivory ossifies,
the remainder serves to a certain extent as a
reserve for the subsequent formation of
newly ossifying portions (fig. 114).

BIBL. The various treatises on Physiology,
Schwann, Ueber die Einstimmung, fyc. (Sy-
denham Society') ; ibid, Wagner's Physiology,
by Willis; Valentin, 1. c. ; Kolliker, Ge-
'webelehre d. Menschen (and the literature
therein) ; Siebold, Ueb. einzelllge Pflanzen,
und Thiere, Zeitschr.f. Wissench. Zoolog. i.
p. 2/0.

CELL, ANIMAL, artificial formation of. —
When oil is immersed in a liquid containing
albumen, it becomes surrounded by a layer
of coagulated albumen, forming a cell ; and
this cell will exhibit the phenomena of
endosmose and exosmose in the same manner
as any natural cell. The same phenomenon
has been observed with metallic mercury and
albumen, chloroform and albumen, chloro-
form and chondrine, &c. It has not yet
been satisfactorily explained. The natural
formation of cells has been supposed to be
produced by this method; but it appears
inapplicable to the purpose, as the nuclei or
masses of blastema, around which cells are
formed, do not consist of fat.

BIBL. (of the above). Ascherson, Mullens
Archiv, 1840, p. 44, &c.; Wittich,De hymeno-
gonia albuminis, Regimont, 1850 ; Halting,
Neder. Lane. Sept. 1851 ; Melsens, Bull, de
1'Acad. de Belg. 1850 ; Panum, Archiv f.
Path. Anat. iv. 2; Bennett, Ed. Month.
Journ. viii. p. 166 ; Kolliker, Gewebelehre
d. Mensch. p. 10; Schmidt, transl. in Taylor's
Scientific Memoirs, v. p. 10.

CELL, VEGETABLE. — The term cell has
long had a very definite and natural signifi-
cation in Vegetable Physiology, although the
same word has come to be used in a very
different sense among animal anatomists;
but recent investigations, together with the
conclusions which are properly derivable
from them, threaten to create some confusion
on this otherwise simple point. The fore-
going requires a little explanation which will
not be misplaced here. The definition of
the term cell in vegetable anatomy, ordina-

rily adopted, is, a closed sac composed of an
(originally] imperforate membrane formed of
the chemical substance called cellulose j this
membrane enclosing fluid contents so long as
the cell retains its vitality. All the solid
permanent structures of plants are formed of
cells answering to this character, the differ-
ences of the full-grown tissues depending
upon peculiar modifications and alterations
of the original cells. In regard to animal
structures, on the contrary, the term cell is
commonly used as indicating structures of a
totally different nature and origin, and indeed
in a manner which exhibits great want of
scientific precision; not only is it applied
to structures really analogous to the cells of
plants, but also to structures analogous to
the contents of the true cellulose cells, which,
however, are indeed in all cases the important
living parts of the structure. All young
vegetable cells contain a quantity of semi-
fluid nitrogenous formative substance called
protoplasm, which protoplasm may be chiefly
adherent as a thickish and more or less con-
tinuous layer to the inside of the cellulose
wall, forming a kind of lining to it, and
therefore enclosing all the rest of the con-
tents, in which case it is called the primordial
utricle (primordial-schlauch of Mohl), or this
dense protoplasm may fill up the whole
cavity of the cell as a gelatinous mass, — or,
finally, the gelatinous mass of protoplasm
may emerge from the cellulose sac, with a
definite form and organization, furnished
with cilia enabling it to move freely in water,
and here the primordial utricle presents
itself as independent, and indeed as the
primary element of all cellular tissue ; it is
found in this condition in the Confervoid
Alga3, in the zoospores. These free bodies,
devoid at first of a cellulose wall, are
evidently analogous to the cell constituting
certain animals, such as Amo2ba, while the
epithelium cells, &c. of animals are analo-
gous to the cellulose sacs of plants ; so that
the confusion which exists in the animal
tissues is likely to extend to vegetable
tissues if we adopt the name which has been
proposed by the Germans for these free
protoplasmic organisms, namely, that of pri-
mordial cells. Since the structure to which
the name cell is at present applied in vege-
table anatomy, is in pretty close accordance
with the common acceptation of that word
in ordinary language, indicating a hollow
case, it seems unadvisable to change the
received nomenclature, while it is evident
that the use of the prefix primordial to the

CELL.

CELL.

word cell is not distinctive enough, and will
beget confusion; hence it seems desirable to
apply a special name to the newly-detected
and definite form of organization, the free
protoplasmic globule. The term primordial
utricle seems to answer all requirements,
since the isolated body is chemically and
physiologically identical with the ordinary
primordial utricle lining a nascent cell, having
in like manner the function of forming a true
cell by secreting a layer of cellulose all over
its external surface and thus enclosing itself
in a sac.

In this work, then, the word cell, as applied
to vegetable structures, is always used in its
ordinary sense, and the character of the
"primordial-cell" of Cohn and other German
authors is given under the head of PRIMOR-
DIAL UTRICLE.

We have already defined a cell, above ; we
next proceed to describe the form and size.

Form. — Cells may present almost every
possible modification of form, and this
depends on two sets of conditions, the ori-
ginal development and shape, and the mode
of growth and expansion. It is frequently
stated that the primary form of all vegetable
cells is that of a sphere, or at all events that
this is the type from which all the others
must be considered deviations. This is true
only so far as it is intended to signify, that
all cells which originate free in the midst of
fluid, suffering no external compression,
have a globular form, and that in numerous
cases where cellular tissues are very lax and
free to expand in all directions, the compo-
nent cells acquire a globular form during
the enlargement to their full size. But in a
very large majority of cases the cells do not
originate in a free condition, they are pro-
duced by subdivision of older cells, and
consequently, when first developed, they have
the shape of the half, the quarter, or what-
ever segment it may be of the parent-cell ;
moreover, in a majority of these cases the
mode of expansion also depends upon a
special law of the particular tissue, or even
of such tissue in the particular group to
which the plant belongs, and not upon any
general law of globular expansion. This
law does prevail widely in some families, as
in the Fungi, and we very frequently see it
prevailing in pith up to a certain period, but it
will not hold as a general rule, for the lax
tissues of leaves, of succulent stems, &c., offer
most striking deviations, as do also the
cylindrical tubular forms so widely prevalent
in the lower Algae. It is further stated in

many books, that the effect of pressure on
cells having a tendency to become globular,
is the production of a dodecahedral form, but
this again is far too sweeping a generaliza-
tion, and the real fact is, that globular cells
of equal size expanding in a confined space,
often become twelve -sided by mutual pres-
sure, but far more often the cells of a tissue
are of diverse size, and hence a polyhedral
form is much more common (fig. 1 15). Cells

Fig. 115.

may be globular, as in the Yeast-plant, and
many lower Algse, in the lax tissue of young
pith of many Dicotyledons (PI. 38, fig. 14),
&c, ; oval, as is much more common in
parenchymatous tissues ; squarish, as in
cork (PI. 38. figs. 16, 17); or tabular, as
in the epidermis of numerous plants, under
which circumstances the side-walls may be
square, rhombic (Hyacinth-leaf), hexagonal or
irregular, as in many petals ; and the out-
lines may also be undulated or even beauti-
fully zig-zagged, as in the leaf of Helleborus
fcetidus, &c., the petals of many flowers, or
in the leaf of the Pine-apple (PI. 38. fig. 15),
&c. ; while the upper exposed face may be
flat or vaulted, as in most petals, or even
papilliform, as on the petals of the Sweet-
William, and of most flowers
with glistening surface. Cells
may also be cylindrical,andthen
either with flat ends (fig. 116),
as in the parenchyma of many
Monocotyledons and inthefila-
ments of Confervse, or round-
ed ends, or attenuated ends, as
in wood and liber tissue gene-
rally ; or they may be pris-
matic, and then square, or six-
sided, as in stems of most
herbaceous plants ; spindle-
shaped, as in a large number of woods, such
as that of Conifers, Box, &c., and, in fact,
of almost every conceivable form. In lax
tissues, the walls of the cells often grow very
unequally at different points, whence result
angular projections (by which the cells ordi-
narily cohere together) (fig. 117); or these

Fig. 116.

CELL.

J

CELL.

Fig. 117.

grow out into arms or rays,
producing stellate cells, as
in the pith of the Rush (PI.
38. fig. 18), and the paren-
chyma of many aquatic
plants, in the leaf-stalk of
the Banana, &c. Cells which
are free, as in the lower
Cellular plants, sometimes
grow out into long tubular
structures such as Vau-
cheria, with a continuous cavity, and
indeed sometimes ramify into a complication
of branches, as in Bryopsis and Codium,
while in Botrydium (fig. 77) the globular
cell sends down a number of root-like fila-
ments which are mere protrusions of its own
wall. The cells of Chara attain very large
size. In the Flowering plants we have an
example of extraordinary growth of a single
cell in the pollen-tubes, which, in some
cases, become as much as three inches long.

Size. — The dimensions of cells vary to
infinity, and, indeed, often extremely in one
and the same tissue, but not as a rule. And
the diameter of cells is very frequently
incomparably less than the length, as in all
filamentous and fibrous cells. Taking a very
general view, we may say that parenchyma
cells vary from 1-250" to 1-1000" in dia-
meter ; but the spores of many Fungi
measure no more than 1-6000" to 1-8000",
while the cells of the juicy parenchyma of
many fruits and piths attain as much as
1-100". In elongated cells, such as those of
liber and most woods, the diameter is ordi-
narily less than in parenchyma, while the
length is far greater; thus in wood the
length varies from about 1-40" to 1-12",
while the diameters are respectively 1-300"
and 1-100"; in liber the length may extend
to 1-8" or 1-4", with a diameter of 1-800",
and 1-400". (See FIBRES.) Hairs composed
of a single cell often attain a great
length, as in Cotton, where a single filamen-
touscell may measure 1" to 2". (See TISSUES,
Vegetable, and PRIMORDIAL UTRICLE.)

Cells may be examined either in situ, as
parts of tissues, or free, separated naturally
or artificially. For the first it is simply
requisite to make fine slices with a razor, in
various directions through the structure ; if
soft or thin it should be placed between the
two halves of a split vial-cork and sliced with
the cork, the cork being afterwards removed
from the object- holder with a needle. Slices
of many kinds of cellular tissue are made
more clear bv the addition of a little diluted

sulphuric acid, which, however, often swells
up some of the layers.

For examining isolated or nearly separate
cells, we may take the lower Algae or Fungi,
or germinating spores of the higher plants ;
or we may separate the cells of the tissues of
higher plants. The parenchymatous tissues
may usually be separated into their elemen-
tary cells by maceration in water; the decom-
posing ends of flowerstalks which have been
in water several days, will generally afford
tissue in such a state that it may be broken
up with a needle. Boiling will do with some
of the denser kinds, while for the woody
tissues it is requisite to leave fragments in a
mixture of a small crystal of chlorate of potass
and a drop of nitric acid, for 12 to 24
hours, and wash them well with water; liber-
cells, woody-cells., &c., may be isolated by
this means.

Formation of Cells. — This subject has
undergone a great amount of investigation
during the last few years, and the views
which have been propounded at various
times have conflicted strongly in many points.
It would be exceeding our limits, however,
to enter upon a critical examination of the
theories of cell-development, and we shall
therefore confine ourselves to a brief account
of those phenomena and laws of the repro-
duction of cells, upon which the diversity of
opinion only affects subordinate particulars.

All vegetable cells (using this term in the
sense of the cellulose sac with contents, as
defined above) in which the capacity for repro-
duction exists, contain an internal structure,
varying in its condition and appearance at
different epochs and in different plants or
parts of plants, called, in accordance with
MohFs proposal, the primordial utricle. This
structure consists of a collection of the proto-
plasm, a semifluid nitrogenous substance,
displaying itself either as a continuous layer
of variable thickness, lining the cellulose
wall of the cell, or as a mass filling the whole
cavity, either homogeneous or honey-combed
more or less by vesicular cavities filled with
watery cell-sap. All the other cell-contents
are enclosed or imbedded in this primordial
utricle, and with it they collectively consti-
tute what is called by some authors the
endochrome of the cell. The characters of
the PRIMORDIAL UTRICLE and of the
PROTOPLASM are given in the requisite
detail under their respective heads.

In a very large number of cases, we find
in the primordial utricle, at this time, a pecu-
liar body, called the nucleus, to which some

CELL.

[ 120 ]

CELL.

writers attribute great importance in the de-
velopment of cells. Its nature is not well
denned, but in the best observed cases it
consists of a small globular or lenticular
mass, apparently composed of protoplasm in
a condensed and granular (solid) condition.
It mostly exhibits one or more bright gra-
nules or points in its substance, which are
called nucleoli. It is well known that Schlei-
den considers this body as of the first import-
ance in cell-development ; but as we are by
no means satisfied as to the character of its
agency, its peculiarities and its relations to
the cell are spoken of separately under the
head of NUCLEUS (PI. 38. figs. 8,9w).

All development of new cells depends
upon the division of the primordial utricle
of existing cells into two or more portions,
which, becoming independent centres of life,
produce new cellulose membranes, and be-
come new cells. The phenomena in which
this law is manifested are far more varied
than would be imagined from this simple
statement. The numerous subordinate mo-
difications may, however, be arranged
under three principal heads : — 1. Cell-divi-
sion, sometimes called merismatic cell-
formation ; 2. Cell-division with libera-
tion of the new cells', 3. Free cell-forma-
tion.

1 . Cell-division is the process which occurs
in all reproduction of cells connected with
vegetative growth or increase of the mass of
existing structures. This is the manner in
which the cells are multiplied in the growth
of the thallus of the inferior plants, and in
the growth of the stems, leaves, roots, and
other organs of the higher plants. It occurs
also in the formation of the basidiospores or
sfylospores of Fungi, the spermatia of these
and Lichens, of gonidia in the Lichens and
conidia in the Fungi. The essential fact
observed in all the cases is, the division of
the primordial utricle of the parent-cell into
two distinct primordial utricles, each of which
secretes a layer of cellulose over its whole
surface ; and thus when the two are in appo-
sition, a partition is formed dividing the pa-
rent-cell into two parts. The form of the
daughter-cells depends of course on that of
the parent-cell at the time of division. In
the case of cellulose tissues, such as those in
the punctum vegetationis of the buds of the
higher plants, in cambium, &c., the division
is ordinarily into two halves, which respect-
ively grow until equal in size to the parent ;
and either both or only one of these divides
again in the same way, and so on, until the

whole structure is completed. It is evident
that the external forms of all cellular struc-
tures must depend greatly upon the laws of
division of the cells of plants ; for example,
supposing we start from a single square cell,
when this divides into two halves, and these
grow to equal the parent-cell, we have an
oblong figure ; if the half-cells divide again
in the same direction, we shall in time get a
long filament ; and if both new cells divide
again each time, the filament will grow much
longer in a given time than if only the end-
cell continually divided, leaving one new cell
behind it at each division. If the pair of
cells produced by the first halving divide at
right angles to the first division, a square
group of four cells results ; and if this law
continues to act, a flat plate of cellular tissue
will result. Further, if the cells also divide
by horizontal partitions (in the third direc-
tion of space), the mass of cells will gradually
acquire thickness or height as well as length
and breadth. Lastly, if the cells of particular
regions cease to divide sooner than others,
irregular or complex but definite structures
will be produced ; as those parts where the
cell-division goes on, will emerge from the
general mass, in the Cellular plants as lobes,
and in the higher plants as conical bodies
which are gradually developed under similar
laws into the organs. The diversities of
internal organization depend also to some
extent on the same laws, but less on these
than on the laws regulating the forms which
the cells acquire when full grown.

Cell- division may be observed most easily
in the lower Cellular plants, or in the simpler
structures (such as hairs) of the higher plants
(PL 38. figs. 8, 9). The Conferva? afford
exceedingly favourable opportunities, as do
also the filamentous or thalloid structures
of germinating Mosses, Ferns, microscopic
Fungi, &c. The behaviour of the parent-
cell before division exhibits some diversities.
If a simple filament is increasing by cell-
division, the cylindrical parent-cells merely
elongate a little before dividing transversely.
If the filament is to branch, the wall of the
parent-cell bulges out gradually at the point
where the branch is to appear ; the bulging
soon becomes a pouch, and this pouch is
soon shut off by the formation of a partition
at its base. Bead-like rows of cells likewise
divide by budding in this way, as may be
observed, for instance, in the Yeast-plant,
the new cell first appears as a little 'bubble'
on the side of the parent, with its cavity
continuous, and after it has acquired a cer-

CELL.

CELL.

tain size, its primordial utricle detaches itself
from that of the parent, and a partition is
formed at the point whence the second cell
emerged (PL 20. fig. 23).

Another point which must he noticed here,
is the question whether the parent primor-
dial utricle divides instantaneously, at a given
epoch, into the new utricle, or whether it
parts gradually, by a sort of constriction ad-
vancing from the surface towards the centre,
roughly comparable to what occurs when a
ligature is slowly drawn tight round an elastic
tube, or when a bar of soap is cut in two by
passing a string round it and gradually draw-
ing the loop tight. It seems probable that
the segmentation of the primordial utricle is
always gradual, and it is certain that it is so
in many cases. Its gradual constriction has
been observed in those Confervse where the
primordial utricle is a hollow sac, forming a
lining over the whole internal surface of the
parent-cell ; it may be traced in the larger
Conferva, in Spirogyra, &c., by keeping the
plants growing in water under the micro-
scope. It appears that the division is gene-
rally completed during the earlier hours of
the morning.

2. Cell-division with liberation of the new
cells. — The first step in this process is ana-
logous to what takes place at the outset in
the preceding set of cases; but we find much
more important modifications here. This is
the mode of development of spores of the
Ascomycetous Fungi, of the spores andtetra-
spores of the Algge, the spores of Lichens,
the spores of all the higher Cryptogamia,
the active gonidia or zoospores of the Algae,
the parent-cells of the spermatozoids or active
spiral filaments of the higher Cryptogamia,
and of the pollen grains of the Flowering
plants.

The general character is : Division of the
whole primordial utricle into segments,
which either acquire a cellulose coat within the
parent-cell before they are set free by its so-
lution or bursting, or escape from the parent-
cell without a cellulose coat, and secrete this
afterwards.

The following modifications occur : —

a. Division of a nearly solid primordial
utricle into four, either directly or by two
halvings. This occurs in the development
of pollen and of the spores of Mosses, Ferns,
&c. The parent-cells of the pollen or spores
become free in the interior of the anther or
sporange, by the solution of the walls and
septa of their parent-cells. The primordial
utricles of the free cells divide into four seg-

ments, entirely filling the cell. After this,
either partitions are formed between these
(pollen-cells), to be subsequently dissolved,
or they at once clothe themselves with a
cellular coat (Marchantia] . In either case, they
ultimately lie free in the parent-cell, which
is itself finally absorbed (PL 38. figs. 10-13).
It. Division of a homogeneous primordial
utricle into a large number of segments, each
of which acquires a cellulose coat, the whole
of the new cells lying closely packed but
free in the parent-cell. This occurs in the
antheridiaof the higher Cryptogamous plants,
in the formation of the parent-cells of the
spermatozoids, also in the formation of the
parent-cells of the spores and the elater-cells
of the Hepaticee. The formation of the
spores in the asci or theca? of the Ascomyce-
tous Fungi and the Lichens, belongs either
to this or the preceding case (PL 29. fig. 12).

c. Division of the homogeneous primordial
utricle into segments which do not acquire a
cellulose coat until after they are discharged
from the parent-cell. This occurs in the
development of the zoospores of many of the
Confervoideae ( Cladophora, Bryopsis, Achlya,
Ulothrix, &c.), where the primordial utricles
become free in the cavity of the parent-cell
when they divide, and break their way out
into the water, where they form a cellulose
coat after they have swum about freely for
some time by means of their cilia.

d. Division of a sac-like primordial utricle
into a number of portions, which appear at
first as papillae on the walls of the cell, and
finally become isolated in the cavity. This
occurs in the development of the gonidia
of Hydrodictyon, Botrydium, &c. These
last two cases are connected with a and b by
the circumstance that the zoospores or active
gonidia are replaced, under certain circum-
stances, by cells, that is, the bodies produced
in this way acquire a cellulose coat before
they leave the parent-cell.

Numerous intermediate conditions occur
which connect all these together, and the
last case, d, is closely related to what takes
place in the formation of the endosperm-cells,
placed under 3.

3. Free Cell-formation. — Here the new cell
is formed by a portion of the parent primor-
dial utricle separating itself from the rest of
the protoplasm, assuming a globular or oval
form, and secreting a cellulose membrane
upon its surface, so as to form a new cell
lying free in the cavity of the parent primor-
dial utricle. The most remarkable instance
of this case is the formation of the germinal

CELL.

[ 122 ]

CELL.

vesicles in the embryo-sac of the Flowering
plants(P1.38.figs.l-4). Other cells sometimes
occur, formed in the same way, at the oppo-
site end of the embryo-sac. The embryo-
sac also frequently becomes filled, after fer-
tilization, by a large increase of free cells
developed out of the layer of protoplasm or
primordial utricle lining the walls; these
accumulate in the sac, and sometimes be-
come consolidated into a tissue (albumen)
in which the embryo lies imbedded (Nuphar);
more frequently they are re-absorbed during
the growth of the embryo. The embryo
itself is developed from the germinal vesicle
by cell-division such as is described under § 1
(PI. 38. figs. 5, 6).

The notion of the independent origin of
cells from organic substances by generatio
equivoca seems to require no notice; but
allusion may be made to certain curious
phenomena which have been called ' abnor-
mal cell-formations/ occurring in some of the
Confervoids. The protoplasm of the Sipho-
neae is very apt to collect into globular masses
in injured filaments, and these globular
masses apparently acquire a cellulose coat in
some cases; they have been observed in
Vaucheria and Bryopsis ; a somewhat similar
phenomenon often occurs in the contents of
the cells of Spirogyra. It appears to be a
kind of gonidial reproduction, in which a
portion of the living contents are enabled to
save themselves from the general decompo-
sition.

Membrane. — In all young organs, in suc-
culent structures, and all the delicate tissues
of the higher plants, and in the majority of
the Cellular plants in almost the entire or-
ganization, the cellular membranes consist
of a thin structureless pellicle, possessing a
considerable degree of toughness and a cer-
tain amount of elasticity. (C. J. Agardh
has indeed lately asserted that cell-membrane
is composed of spiral fibrous structure, but
this doubtless is an error as regards the pri-
mary membrane.) It is readily permeable
by water, while no orifices of any kind can
be detected in it; but young and indeed soft
cell- membranes generally imbibe more or
less water, and swell to some extent, often be-
coming more or less gelatinous. It is stated by
Schleiden that the membranes of nascent cells
are soluble in water, but general experience
does not confirm this statement; the only ap-
proach to a corroboration of it that we have
met with, is the fact of the external membranes
of many of the filamentous and unicellular
Algae becoming gelatinous and gradually

dissolving away as the inner membranes are
successively deposited, forming a gelatinous
coat (ex. gr. Protococcus, Nostoc, Desmi-
diaceae, Diatomaceae,Zy#wewa, Oscillatorieae.
&c.); the same also taking place in the de-
velopment of spores and pollen grains, which
are set free by the parent-cell membranes
becoming dissolved. This, however, is
scarcely a direct solution in water, and comes
rather under the head of a decomposition.

Young and delicate cell-membranes are per-
fectly transparent and colourless, as is seen
in the Yeast plant, in the mycelium of Mil-
dews, in the cellular tissue of tuberous struc-
tures like the Potato, in piths (after the
mucilaginous cell-contents have been re-
moved). As they grow older, they often
become coloured, sometimes very deeply,
which is supposed, however, to depend on
the infiltration of foreign matters. In the
state of simple cell-membranes, when no in-
filtration of foreign matter has occurred, the
application of sulphuric acid of moderate
strength, with solution of iodine in solution
of iodide of potassium, brings out a bright
blue colour, and this is regarded as a test for
cellulose, the universal basis of vegetable
cell-membrane.

When the cell has attained a certain age,
new deposits of membranous substance take
place inside, and the membrane thus acquires
more or less thickness, together with a very
varied appearance, according to the character
of the deposits. The new layers are known
as SECONDARY LAYERS, and the term
Cell-wall is perhaps the most convenient
collective term which can be applied to the
various structures produced by the deposition
of new layers of cellulose upon the inside of
the primary cell-membrane. Although these
new deposits are thin layers of cellulose like
the primary membrane, they are rarely so
totally devoid of detail structure, and in
the majority of cases exhibit orifices and
irregularities of the most striking character.
Moreover, in one class of cases, they are not
deposited as a continuous coat, but as a
fibrous structure applied upon the primary
membrane, as in spiral-fibrous-cells ; and in
wood-cells they are formed one above an-
other to such a thickness that the cell-wall
loses its original membranous character, and
becomes a solid case, with the internal cavity
reduced to a comparatively small chamber in
the centre.

The simplest condition of a thickened cell-
wall is that met with in the unicellular and
filamentous Algse, where the primary mem-

CELL.

[ 123 ]

CELL.

brane becomes coated in the interior by suc-
cessive continuous layers of cellulose exactly
resembling itself, and which often indeed
can only be known to exist by comparing the
thickness of old and young cells, since no
lamellation can be detected; generally speak-
ing, however, the action of moderately di-
luted sulphuric acid swells up such mem-
branes, and renders the lamellae more or less
distinct (PL 38. fig. 24). The thickening
layers of the unicellular and filamentous
Algae are scarcely to be compared with those
of the cells of higher plants, since they are
rather to be regarded as the primary mem-
branes of new cells produced in the interior
of the older cells, in many cases set free by
the solution of the latter. These cell-walls
sometimes exhibit peculiar fibrous appear-
ances. See SPIRAL STRUCTURES.

These layers may be coloured blue by sul-
phuric acid and iodine when young, but
where they undergo solution into a kind of
jelty, as in filamentous Algae, this cellulose
reaction seems to fail ; at all events, it is so
uncertain in its behaviour, that although it
gives a positive result in successful cases, a
negative result is altogether inconclusive.

In the cells of the generality of plants of
higher organization, the secondary cell-mem-
branes exhibit a striking difference from the
primary, inasmuch as we find them con-
stantly perforated by holes, slits, or orifices
of some shape, so as to leave the primary
membrane bare, whence results a spotted
or streaked appearance of the cell-w7all, as
may be seen even in cells with the walls still
very thin, such as fully-formed pith-cells of
the* Elder.

The earlier anatomists regarded these
spots or dots as orifices through the cell-
wall, but they are in reality only pits open-
ing into the cavity of the cell, and closed at
the bottom by the original external mem-
brane of the cell. When the cell-wall be-
comes much thickened, as in cells of horny
albumen or wood-cells, the layers success-
ively deposited over the inside, mostly cor-
respond pretty exactly with the earliest
layers, and leave the spots always free, so
that these become gradually converted into
tubular canals running through the thick
cell-walls (PL 38. figs. 21-23 and 27). In the
majority of cases, if not in all, the spots or
pits in the cell-wall are opposite to similar
spots in the walls of the adjacent cells, so
that the cavities of the two contiguous cells
are only separated from each other by the
primary membrane of each, as at first, allow-

ing free permeation of fluid from one to the
other. In old cells these primary membranes
become destroyed, and thus the cavities com-
municate freely through these canals run-
ning out through their hard thickened walls.
The various complications of these pits are
spoken of under the head of PITT ED CELLS.

The secondary layers are further distin-
guished from the primary membrane by the
prevalence of a tendency to assume the cha-
racter of spiral bands or fibres winding upon
the original cell-wall. This may be detected
even in many cells which remain quite mem-
branous, as in some Conferva and many
hairs, also in pitted lignified cells, where the
thickening layer forms a general coat upon
the inside of the cell; for the liber-cells of
many plants exhibit a delicate spiral striation
of their walls, while some liber-cells display
it with especial distinctness. Some of these
cells give way in a spiral direction when torn
by pulling lengthways. In parenchymatous
cells this spiral structure is often very fully
developed in all its varieties ; but it is espe-
cially characteristic of the vessels and ducts,
while in certain woods, as in TAXUS, we
have a combination of the porous with the
spiral secondary deposits, the earlier thick-
ening layers leaving spots uncovered while
the later ones are deposited along a spiral
line coiling up the cell-wall from bottom to
top, and thus the cell appears to have a spi-
ral fibre lying upon its walls. These struc-
tures are spoken of at length under the head
of SPIRAL DEPOSITS and PITTED CELLS.

Cellulose is distinguished in vegetable
structures by the blue colour it assumes with
aqueous solution of iodine after treatment
with sulphuric acid. The nitrogenous pro-
toplasm is always coloured yellow-brown by
this means. It is sometimes difficult to
bring out the blue reaction in old cells;
various methods are had recourse to for this
purpose. In corky or other epidermal tis-
sues, the blue colour of cellulose may be
brought out by soaking the cells for twenty-
four hours or more in strong solution of
potash, washing it well, soaking in tincture
of iodine, drying, and then wetting with
water. Old wood-cells undergo the same
change by boiling in nitric acid, instead of
treating with caustic potash, and then adding
the iodine, &c. as above. All the solid
structures of cell-membranes yield to one or
other of these means, and exhibit the blue
colour with iodine, which if not indicative of
a composition of cellulose, points to a sub-
stance intermediate between this and starch,

CELL-CONTENTS.

[ 124 ]

CELLULAR TISSUE.

produced out of the cellulose by the chemical
action. (See CELLULOSE and CHEMICAL
REAGENTS.) Cell-membranes and their
modifications are examined of course in si-
milar preparations to those mentioned as dis-
playing the forms, &c. of cells.

BIBL.— General. Text-book of Structural
Botany, Mohl, Vegetable Cell, transl. by
Henfrey, 1853; Schacht, Die Pflanzenzelle,
Berlin, 1852; Meyen, Pftanzenphysiolooie,
Phytotomie ; Morren, Bulletin de V Acad. de
Bruxelles, v. No. 3. — Development. Two
works indispensable for the study of the
present state of this question, contain cita-
tions of most of the important authorities,
viz. Mohl, Vegetable Cell, and A. Braun,
Rejuvenescence, fyc., Ray Society's Publica-
tions, 1853. — Cell-Membrane. Mohl, On
Cellulose, Bot. Zeitung, v., transl. in Scien-
tific Memoirs, 2nd ser. (Nat. Hist.), vol. i.
90; Ueber die Zusammensetzung der Zell-
membran, Bot. Zeit. xi. 753 ; Harting, Mul-
der's Physiol. Chemistry, transl. by From-
berg, Edinburgh, 1849; Botan. Zeituno, v.
337; Kiitzing, Grundz. der Phil. Botanik,
pt. 1. 1852; J. G. Agardh, De Cellula vege-
tabili, &c., Lund. 1852; Caspary, Ueber
Streifung der Zellenwand, Bot. Zeit. xi. 801;
Criiger, Dieprimitif. Faser, Bot. Zeit. xii. 57.

CELL-CONTENTS.— This term (in Ger-
man Inhali) corresponds, in regard to vege-
tables, to the word endochrome as used by
Mr. Thwaites, Mr, Ralfs, and some of the
French botanists. It refers here most essen-
tially to the primordial utricle, as this is the
part effective in development, while the sub-
stances imbedded in or lying in the cavity of
this are variable according to age, stage of de-
velopment, &c. See PRIMORDIAL UTRICLE,

CELLULAR TISSUE, OF ANIMALS,
sometimes called fibro-ceHular, connective, or
areolar tissue. We shall use the term areo-
lar tissue (although fibro-areolar would be
the most appropriate) ; but as an account of
it would perhaps be looked for under the old
name, we have placed it under that head.

Areolar tissue is very generally diffused
throughout the bodies of vertebrate animals,
filling up the interspaces between the various
organs, and entering into the composition
of most of them.

It consists essentially of white fibrous tis -
sue, mostly containing the elements of the
yellow or elastic tissue. The most common
form of the white fibrous element is that of
minute, delicate, transparent fibres, called
fibrillBe, with pale outlines (PI. 40. fig. 41) ;
these are sometimes single, at others united

into bundles or fasciculi. The fibres as well
as the bundles sometimes pursue a straight
course, at others they are elegantly curved
and wavy, interlacing in all directions, and
leaving larger or smaller areolae or spaces
between them, the larger of which are visible
to the naked eye. The fibrillae are about
1-40,000 to 1-20,000", and the fasciculi about
1-7000 to 1-3000" in diameter. In the fas-
ciculi, they are connected by an amorphous,
transparent, gelatinous substance. When
treated with acetic acid, the fibres swell, be-
come paler, and lose their distinctness, the
bundles appearing as if fused into a gelati-
nous mass (fig. 31. p. 59), and round or
elliptical nuclei, with their long axes parallel
to the direction of the fibres, are brought
to view (PI. 40. fig. 42).

The yellow fibrous tissue occurs in the
form of fine fibres, with dark outlines ; these
sometimes run straight, at others they are
wavy, at others coiled or forming rings
around the bundles of the areolar tissue, or
running parallel with and between them.
They are best seen when the tissue has been
rendered transparent by the addition of ace-
tic acid.

These fibres cannot always be detected in
areolar tissue; sometimes it forms an almost
homogeneous, finely granular, or slightly
striated mass.

Areolar tissue consists chemically of gela-
tine, which may be obtained from it in solu-
tion by boiling.

The various complex structures into the
composition of which the white fibrous ele-
ment enters, as the mucous membranes, skin,
fatty tissue, &c., are noticed under the re-
spective heads.

Areolar tissue is met with in all classes of
vertebrate animals, and, as found in them, it
agrees essentially with that of man. It oc-
curs more rarely in the Invertebrata, and
when present, is rather homogeneous, rarely
fibrous, as in the Cephalopoda, the mantle
of the Mollusca, &c.

Areolar tissue is developed from the em-
bryonic corpuscles or cells (?). These be-
come elongated and fusiform; sometimes
the ends are branched. They unite with
each other, and the ends become longitudi-
nally split into the component fibrilla3 of the
future tissue. The substance of the cor-
puscle subsequently splits in the same man-
ner. But whether the corpuscle is a solid
body or protoplast, or whether it is a true
cell, and secondary deposition takes place
within it, the deposited substance subse-

CELLULAR TISSUE.

[ 125 ]

CEMENTS.

quently splitting to form the fibrils, does not
appear to have been determined. See FI-
BROUS TISSUES.

BIBL. Kolliker, Gewebelehre, fyc.; Paget,
Report, Sfc., Brit, and For. Med. Rev. 1842,
xiv.; Mulder (and Bonders), PhysioL Chem.;
Todd and Bowman, Phys. Anat. fyc. ; Drum-
mond, Ed. Monthly Journal, 1852 (these
contributions form models of the manner in
which the microscope and chemistry should
go hand in hand ; but the power used, 250
diameters, is too low).

CELLULAR TISSUE, OF PLANTS. See
TISSUES, Vegetable.

CELLULARIA, Lamk.— A genus of Po-
lypes, belonging to the order Bryozoa ( Po-
ly zoa).

Char. Polypidom calcareous or membrane-
calcareous, confervoid, divided dichoto-
mously, the divisions narrow, composed of
two or three alternating series of oblong
contiguous cells on a single plane, the aper-
tures lateral, oblique, and facing one way.
Polypes ascidian, with usually 14 tentacles ;
no gizzard.

Eight British species.

Two of the species are common on the
British coast, attached to other zoophytes,
the roots of fuci, &c.

C. reptans (PL 33. fig. 5). Creeping, di-
chotomous ; cells with an oblique, superior,
subterminal, oval aperture, armed with short
spines at the top.

C. scruposa. Creeping, dichotomous; cells
alternate, with a plain, superior, subterminal,
oval aperture, and a projecting angle on the
outer side of each.

BIBL. 3ohnston,Brit.Zooph.\847,i.', Reid,
Ann. Nat. Hist. xvi. p. 385 ; Van Beneden,
Nouv. Mem. de VAcad d. Brux. 1845. xviii.

CELLULOSE.— The proximate principle
of which the permanent cell-membranes of
plants are always composed, and occasionally
those of some structures of certain animals,
as the mantle of the Tunicata. (See TUNI-
CATA.) Its physical characters differ very
much in different cases ; sometimes it is ex-
ceedingly soft, acquires a blue colour with
iodine, and dissolves in sulphuric acid (amy-
loid ?). Usually it is more dense, and does not
become coloured blue with iodine until after
treatment with sulphuric acid, when it be-
comes more or less bright blue (the ordinary
test for cellulose). Occasionally this reaction
gives a purplish colour. In old, infiltrated,
or greatly consolidated cellulose structure,
this test gives only a yellow-brown colour ;
but boiling in nitric acid (for woody tissues)

or solution of potash (for epidermal tissues)
will generally bring the cellulose into a state
when, if wetted with tinct. of iodine, dried,
and then wetted with water, it turns blue.
Sulphuric acid is the most ready solvent of
cellulose ; solutions of potash and nitric acid
do not act so quickly, especially the latter.
Sulphuric acid always swells it before dis-
solving.

BIBL. See AMYLOID, CELL-MEM-
BRANES, and CHEMICAL REAGENTS. For
occurrence of cellulose in animal tissues, —
Schacht, MulLArchiv, 1851, Microsc. Journ.
1852, pp. 34 and 106 ; Huxley, Microsc.
Journ. 1852, p. 22 ; Schmidt, transl. in Tay-
lor's Scientific Memoirs, 5. p. 1; Kolliker
and Lowig, Ann. des Sc. nat. 3 ser. Zoologie,
1846. p. 193; Virchow, Comptes Rendus,
1853 (Ann. Nat. Hist. 2 ser. xii. p. 482);
Busk, Microsc. Journal, 1854.

CEMENTS.— These are used for closing
the cells in which microscopic objects are
placed for preservation, also for fastening
pieces of glass to each other, to form cells,
&c. Those, the method of making which
we have not described, can be procured at
any oil-shop.

1. Asphalte varnish consists of a solution
of asphalte in boiling linseed-oil, or oil of
turpentine, or in a mixture of the two.

2. Black Japan consists of asphalte, gum
animi, amber, linseed-oil, and oil of turpentine.

3. Brunswick black consists of asphalte,
drying linseed-oil, and oil of turpentine.

4. Canada Balsam; a. alone; b. digested
at a gentle heat with sufficient aether to ren-
der it slightly more fluid.

5. Electrical cement — a. is made by melt-
ing together 5 parts of rosin, 1 part of bees'-
wax, and 1 of red ochre, b. The addition of
2 parts of Canada balsam renders this ce-
ment much more strongly adhesive to glass.

6. Gold-size may be prepared by boiling
25 parts of linseed-oil for three hours with
1 part of red lead and £ of a part of umber ;
then pour off. Successive portions of a
finely powdered mixture of equal parts of
white lead and yellow ochre are then added
to the oil, being well rubbed and mixed with
it, until a tolerably thick liquid is formed ;
this must be once more thoroughly boiled.
It is also sold.

7- Gutta-percha cement is made by adding
15 parts of oil of turpentine to 1 part of
finely cut-up gutta-percha, and dissolving
by the aid of a continued heat and stirring.
The solution is then strained through a cloth.
In the strained solution 1 part of shell-lac is

CENANGIUM. [ 126 ]

then dissolved by heat and stirring. The
application of the heat is continued until a
drop of the solution let fall upon a cold sur-
face, becomes nearly hard. It can be ren-
dered thinner by the addition of more oil of
turpentine.

8. Marine glue consists of caoutchouc and
shell-lac dissolved in coal-naphtha by the
aid of heat. It is sold by the microscope-
makers and those who mount objects.

9. Sealing-wax varnish. Prepared by add-
ing enough spirit of wine to cover coarsely
powdered sealing-wax, and digesting at a
gentle heat.

10. Shell-lac varnish. Prepared in the
same manner as sealing-wax varnish, shell-
lac being substituted for the sealing-wax.

1 1 . White hard varnish consists of gum
sandarac dissolved in spirit of wine, and
mixed with turpentine varnish.

1 2. White lead mixed with drying linseed-
oil, and the addition of oil of turpentine
(white paint).

13. Wheat paste should have a few drops
of some essence added to it.

14. Gum-arabic dissolved in water, with a
small quantity of sugar-candy and a few
drops of essence.

The method of using these cements is
treated of under PRESERVATION.

The varnishes should be kept in wide-
mouthed capped bottles, or in bottles accu-
rately closed by a cork, in the under part of
which a camel's hair pencil is inserted.

A black colour may be imparted to any of
the varnishes, by mixing them with lamp-
black ; or any colour, by adding correspond-
ingly coloured sealing-wax.

They should all be old, or kept some time
before use.

CENANGIUM, Fries.— A genus of Pha-
cidiacei (Ascomycetous Fungi) growing upon
dead wood, twigs, bursting through the bark
in the form of little cups or hollow papilla.
Tulasne has recently made some interesting
observations upon this genus, and shown that
the plants present two or even three kinds
of reproductive bodies, asci with spores, and
also spermagonia or pycnidia with spermatia
or stylospores. In C. Cerasi, Fr. the pycnidia
are minute tubular bodies upon the same
stroma as the young cupules or asciferous
cups; they have been described as species
of Spharia and as imperfect cupules of C.
Cerasi, but their walls are lined with basidia,
producing shortly stalked stylospores, which
are linear and flexuose, and very large, viz.
about 1-500" long; they exhibit three trans-

CERAMIACE^E.

verse septa. In this species the pycnidia are
found in groups, and sometimes become
confluent. In C.Fraxini, Tul. (PI. 20. fig. 17),
the pycnidia contain not only stylospores at
the base of the cavity, but around the upper
part are found spermatia seated on branched
articulated filaments. These organs, how-
ever, are not regularly co-existent, but occa-
sionally occur alone in a pycnidium; and
sometimes the spermatia occur even in the
asciferous cupules. The asci in the cupules
of C. FrangulcB line the bottom of the cups,
and are mixed with paraphyses ; each ascus
or theca contains four spores. Several other
species are common in Britain.

BIBL. Berk. Hook. Er. Fl. ii. pt. 2. 211;
Ann. Nat. Hist. vi. 259. 2 ser. vii. 185 ;
Tulasne, Ann.desSc. nat. 3 ser. xx. 133. pi. 16.

CENOMYCE. See CLADONIA.

CEPHALOPODA.— An order of Mol-
lusca, containing the Nautilus, the Argonaut,
the Cuttle-fish (Sepia), &c., with the fossil
Belemnites, Ammonites and Nummulites.
The cartilage of the cuttle-fish is noticed
under CARTILAGE; the dorsal plate or se-
piostaire under SHELL.

The chromatoph ores or cutaneous pigment-
cells, and the cutaneous cellular (areolar)
tissue are interesting structures.

BIBL. Siebold, Vergleich. Anat. i.; Owen,
Hunterian Lectures, i. and Todd's Cycl.
Anat. and Phys. ; V. d. Hoeven, Handb. d.
Zoolog. ; Cuvier, Anim. Kingd. by Blyth,
Mudie, Johnston, Westwood and Carpenter;
Forbes and Hanley, Molluscous Animals, &c.

CEPHALOTRICHUM, Fr.— A genus of
Dematiei ( Hy phomycetous Fungi) . C. curium
is an extremely minute plant growing upon
the leaves of Sedges, with scattered, short,
brown, erect filaments, bearing somewhat
globular heads composed of tufts of forked
or ternate branches, with one or two short
acute branchlets, slightly scabrous, bearing
smooth spores.

BIBL. Berk. Ann. Nat. Hist. vi. 432.
pi. 12. fig. 13 ; Corda, Icones Fung. i. pi. 5.
tigs. 253-4.

CERAMIACE^E.— A family of Florideous
Algae. Rose-red or purple sea-weeds (one
freshwater?) with a filiform frond, consisting
of an articulated, branching filament, com-
posed of a single string of cells, sometimes
coated with a stratum of small cells. Fruc-
tification : l.favellfs; berry-like receptacles,
with a membranous coat, containing nume-
rous angular spores; 2. tetraspores, attached
to the ramuli or more or less immersed in
the substance of the branches, scattered ;

CERAMIUM.

[ 127 ]

CERCOMONAS.

3. antheridia, produced in the same situa-
tions as the spores. British genera :

I. Ptilota. Frond compressed, inarticulate,
distichous, pectinate-pinnate. Favellte pe-
dunculate, involucrate.

II. Microcladia. Frond filiform, inarti-
culate, dichotomous. Favellce sessile, invo-
lucrate.

III. Ceramium. Frond filiform, articulate,
dichotomous ; the joints opake. Favellce
sessile, mostly involucrate. Tetraspores
mostly immersed.

IV. Spyridia. Frond filiform, inarticu-
late ; the branches clothed with minute,
setiform, articulated ramelli. Favellce pe-
dunculate, involucrate. Tetraspores sessile
on the ramelli.

V. Griffithsia. Frond articulated, dicho-
tomous, or clothed with whorled, dichotomous
ramelli, rose-red. Favellce involucrate,
sessile or pedunculate. Tetraspores sessile,
on whorled ramelli.

VI. Wrangelia. Frond articulated, pin-
nate. Favellce terminal, involucrate, con-
taining tufts of pear-shaped spores. Tetra-
spores sessile, scattered on the ramelli.

VII. Seirospora. Frond articulated. Te-
traspores arranged in terminal, moniliform
strings.

VIII. Callithamnion. Frond, at least
the branches and ramuli, articulated, mostly
pinnated. Favellce terminal or lateral, sessile,
without involucre (except in C. Turneri).
Tetraspores sessile or pedicellate, scattered.

IX. Trentepohlia. Frond articulated,
branched, cells in single series. Favellcs (?)
in terminal corymbs.

BIBL. Harvey, Man. Brit. Marine Algce.
See also the Genera.

CERAMIUM, Roth.— A genus of Cera-
miaceae (Florideous Algae), containing a
number of species, mostly growing between

Fig. 118.

Ceramium Delongschampii.

Fragment of a frond showing one tetraspore in situ, and
two empty parent-cells. Magnified 50 diameters.

tide-marks, of which C. ciliatum is noted as
a beautiful object under a low magnifying
power. The][tetraspores are often only triple,
and arranged tetrahedrally and not in a row
(fig. 118).

BIBL. Harvey, Brit. Mar. Algce, pi. 22 C.;
PJiyc. Britann. pi. 139-41, &c.'&c.

CERATIDIUM, Ehr.— A genus of Infu-
soria, of the family Oxytrichina.

Char. Furnished with cilia, horns on the
fore-part of the body, but neither hooks nor
styles.

One species, C. cuneatum. Dujardin con-
siders this to have been a mutilated species
of Oxytricha. The appearance of horns
arises from the anterior part of the body
being deeply notched.

BIBL. Ehrenb. Infus. ; Dujardin, Infus.
p. 421.

CERATIUM, Alb. and Sch.— A genus of
Isariacei (Hyphomycetous Fungi), containing
an uncommon British plant, C. hydnoides,
which grows upon rotten wood as a tuft of
white prickle-like processes, bearing fila-
ments composed of strings of cells which
separate into conidia', large spores occur
among these, but their development is not
clear. The whole plant collapses ulti-
mately into a mucilaginous mass.

BIBL. Berk. Hook. Br. Flor. ii. pt. 2.
329 ; Grev. Sc. Crypt. Fl. pi. 168.

CERATIUM, Schrank.— Dujardin retains
this name for three species of Peridinium —
cornutum, tripos, sm&fusus.

CERATODON, Bridel.— A genus of Pot-
tiaceous Mosses.

Ceratodon purpureus, Brid. = Didym.
purpureus, H. and Tayl.

CERATONEIS, Ehr.— A genus of Dia-
tomaceae.

Mr. Smith places the British species in
other genera, thus :

C. arcus = Eunotia arcus ; C. closterium
= Nitzschia cl. ; C. fasciola = Gyrosigma
(Pleurosigma, Sin.) fasc. ; C. gracilis =
Nitzschia tcenia ; C. longissima = Nitzschia
Urostrata.

Kiitzing describes four other species ; but
they have not been satisfactorily examined.

BIBL. Ehr. Ber. d. Berlin Ak. 1839,
p. 123, 1840 et seq. ; Kiitz. Bacill. and Sp.
Alg. -, Smith, Brit. Diat.

CERATOPTERIS, Brongniart.— A genus
of Parkerieseous Ferns. Exotic. The in-
rolled margin of the leaf similates an indu-
sium.

CERCOMONAS. Duj — A genus of Infu-
soria, of the family Monadina.

CEREUS.

[ 128 J CERUMINOUS GLANDS.

Char. Body rounded or discoidal, tuber-
culated, with a variable posterior prolonga-
tion in the form of a tail, which is longer or
shorter and more or less filiform.

Dujardin remarks that the only absolute
difference between the Cercomonads and the
Monads consists in the presence of the posterior
prolongation, which is formed by the substance
of the body becoming agglutinated to the
slide, and more or less drawn out so as to form
sometimes merely a tubercle, at others an
elongated tail, or a filament almost as slender
as the anterior filament and susceptible of an
oscillating motion ; also that he thinks he
has frequently seen Monads gradually pass
into the state of Cercomonads. After this,
we may pass over the nine species.

BIBL. Duj. In/us, p. 287.

CEREUS. See CACTACE;E.

CERUMEN.— The so-called
'wax' of the ear.

Its morphological elements
are, — 1. Hairs; these exhibit very
beautifully the external layer of
epidermal scales. 2. Occasion-
ally, the Demodex folliculorum.
3. Numerous epidermal scales,
mostly compressed, shrunk, or so
altered as to resemble fibres, but
re solvable in to their original form
by warming with solution of pot-
ash and the subsequent addition
of water ; by this treatment they
are frequently rendered brown,
purplish, or almost black. 4.
Very numerous cells, filled with
pale fatty matter, of a rounded
or elongate, flattened, or irregu-
lar form ; these are derived from
the sebaceous follicles. 5. Nu-
merous free oil-globules of the
most varied sizes. 6. Yellow or
brown granules, and aggrega-
tions of them, mostly free, some-
times contained in cells. 7- Va-
rious elements derived from with-
out, as fibres of cotton, linen,
&c. See CERUMINOUS GLANDS,
and CHEMISTRY.

CERUMINOUS GLANDS.
— The glands which secrete the
'wax' of the ear. They are si-
tuated in the tube of the ear, or
the meatus auditorius externus
of anatomists. They closely re-
semble the sudoriparous ducts in
appearance, and exist only in
the cartilaginous portion of the

passage, where they are situated between
the skin and the cartilage, or the fibrous
mass which occupies its place. Each con-
sists of a simple tube coiled at one end, so
as to form a gland (fig. 119 d), the other
being continued in the form of a duct
(fig. 119 e) to the surface of the skin, upon
which it opens ; occasionally, however, into
the upper part of the hair-follicle.

The glands consist of an external coat of
areolar tissue, with scattered, somewhat
spindle-shaped nuclei, and very fine nuclear
fibres ; a layer of smooth, longitudinal, mus-
cular fibres, consisting of short fibre-cells
with elongated nuclei; and an inner single
layer of epithelium, composed of polygonal
cells, from 1-1800 to 1-1100" in diameter,
with roundish nuclei. These cells contain
round or irregularly-shaped yellowish-brown

Fig. 119.

Magnified 20 diameters.

Perpendicular section of the meatus auditorius externus. a. Corium ;
c, epidermis ; d, ceruminous glands ; e, their ducts ;
g, hair-follicle; h, sebaceous follicles; i, fatty

b, rete mucosum

/, their terminal orifices;

tissue.

CETOCHILUS.

129

CH.ETOMONAS.

granules, of very various sizes, as also glo-
bules of oil. The duct has a coat of areolar
tissue, and an epithelial coat, consisting of
several layers of small nucleated cells, not
containing fat or pigment-granules.

CETOCHILUS.— A genus of Entomo-
straca (Crustacea), belonging to the order
Copepoda, and family Cetochilidae.

Char. Head distinguishable from body,
but firmly articulated with the first ring of
the thorax, and furnished with two small
styliform prolongations; eyes 2; superior
antennae longer than the body, right only
furnished in the male with the swollen hinge-
joint; inferior antennae composed of two
nearly equal branches ; foot-jaws three pairs,
strongly developed, not branched ; thorax of
six, abdomen of four segments; legs five
pairs, last pair formed in the same manner
as the rest. Marine. 1 British species :

C. septentrionalis. Bright red; forms
part of the food of the whale and various
fishes; length 1-10".

BIBL. Baird, Brit. Entomos. p. 233.
CETRARIA, Ach.— A genus of Parme-
liaceae (Gymnocarpous Lichens), chiefly com-
posed of northern species, growing upon
trunks of trees, rocks, or on the ground in
heathy places. C. islandica, ' Iceland moss/
is found sparingly on the ground in exposed
places in Scotland.

BIBL. Hook. Br. Fl. ii. pt. 1. 224; Engl.
Botany, pi. 1330. 1036, &c.; Tulasne, Ann.
des Sc. not. 3 ser. xvii. pi. 10. fig. 1-3.

CEUTHOSPORA, Fr.— A genus of Me-
lanconiei (Coniomycetous Fungi) closely re-
lated to Phoma, one common species of which
( C. phacidioides} grows on holly -leaves ;
another occurs on the Cherry-laurel (C.
Lauri}. It is probable that these are only
forms belonging to some Ascomycetous ge-
nus.

1 . C. phacidioides, Grev. 3-5 cells in the
stroma, splitting into 3-5 plain short teeth.

2. C. Lauri, Sow. Unilocular, splitting
into 3-4 acute teeth.

BIBL. Berk. Hook. Br. Fl. ii. pt. 2. 283;
Grev. Sc. Crypt. FL pi. 253, 254.

CHJ3TOCERAS,Ehr.— A genus of Dia-
tomaceae.

Char. Frustules concatenate; valves equal, \
turgid, with two apertures (processes ?) on
each side, which, in the young state, are very
short and tubular, the two frustules being
contiguous, forming very long horns as the
frustules become remote ; the horns are sub-
sequently converted into very long, thin and
interwoven siliceous filaments. (The broken-

off horns might be regarded as Melosira.)
Marine and fossil.

Somewhat allied to Biddulphia. 5 spe-
cies : C. dichteta, tetrachceta, didymus, ba-
cillaria, and diploneis. None British.

BIBL. Ehrenb. Ber. de Berl. Akad. 1844.
p. 198 ; Kiitzing, Sp. Ala. p. 138.

CELETOGLENA, Ehr.— A genus of In-
fusoria, of the family Peridinaea.

Char. Carapace (siliceous?) hispid, or
studded with rigid hairs (? spines) ; no trans-
verse furrow; an eye-spot present. The
organ of motion is a flagelliform filament.

C. Volvocina (PL 23. fig. 24 a). Oval,
internal substance brownish-green ; eye-spot
red; length 1-1100". Aquatic. This ap-
pears to be the same as Trachelomonas vol-
vocina. See TRACHELOMONAS.

C. caudata. Oval, hispid, with a short
tail ; internal substance green ; eye-spot red;
margin of carapace urceolate and toothed ;
length 1-850"; aquatic.

BIBL. Ehr. In/us. ; id. Ber. d. Berl. Ak.
1840, p. 199; Dujardin, In/us, p. 329.

CH^TOMIUM, Kunze.— A genus of
Perisporacei (Ascomycetous Fungi), having a
filamentous mycelium bearing superficial,
roundish or ovate conceptacles clothed with
hairs, finally opening above and containing
clavate asci with paraphyses ; spores simple,
ovate. Br. species : —

1. C. elatum, Kunze. Conceptacle sub-
ovate, black or brown, more or less crusta-
ceous ; spores apiculate at each end. Gre-
ville, Sc. Crypt. Fl. pi. 230. On mouldering
straw, old matting, &c. Very common.

2. C. chartarum, Ehr. Conceptacles sub-
globose, black, surrounded by a bright yel-
low spot ; spores roundish. On paper.

BIBL. Hook. Br. Fl. ii. pt. 2. p. 328 ;
Kunze, Mycolog. Heft i. ; Fries, Syst. My-
col. iii. p. 254, 255.

CHJETOMONAS, Ehr.— A genus of In-
fusoria, of the family Cyclidisia.

Char. An oral vibratile organ (whether a
flagelliform filament or ring of cilia is un-
certain); movement of animal slow, but
leaping effected by means of non-vibratile
bristles situated upon the body.

In putrid animal and vegetable infusions, in
dead bodies of other infusoria, Closteria, &c.

C. globulus (PL 23. |ig. 25 a). Nearly
spherical, ash-coloured, setae numerous ;
length 1-2700".

C. constricta (PL 23. fig. 25 b). Oblong,
constricted in the middle, hyaline, setae two;
length 1-5400".

BIBL. Ehr. In/us, p. 248.

K

CH.ETOMORPHA.

[ 130 ]

CILETOTYPHLA.

CILETOMORPHA, Kiitz.=CoNFERVA
spec.

CH.ETONOTUS, Ehr.— A genus of mi-
croscopic aquatic animals, placed by Ehren-
berg among the Rotatoria (Rotifera), and by
Dujardin with the Infusoria.

Ehrenberg places it in the family Ichthy-
dina( which. see). Dujardin gives the follow-
ing characters :

Body oblong, convex, and furnished with
hairs or scales above ; flat and provided with
very minute vibratile cilia beneath ; termi-
nated in front by a rounded margin, near
which is a distinct mouth ; posteriorly bi-
furcate or terminated by two caudiform pro-
cesses.

The three or four species are found in
fresh water, amongst aquatic plants. Their
structure requires further investigation.

Chatonotus larus (PL 24. fig. 24). Length
1-710 to 1-220".

Dujardin appends Ichthydium, Ehr. to this
genus.

BIBL. Ehr. In/us, p. 389; Duj. In/us.
p. 568.

CH.ZETOPHORA, Schrank.— A genus of
Cha3tophorace8e(ConfervoidAlg8e),character-
ized likeDraparnaldiaby setigerous branched
filaments, but differing from the latter by
the filaments being imbedded in a gelatinous
matrix. The Chatophora are found in
fresh water, forming little green protuber-
ances on stones, sticks, &c., usually bright
green. The zoospores are formed singly in
the joints, and bear four cilia. The account
of the fructification given by Miiller (Flora,
1842. p. 513) seems to relate to Coleoch&te.

The membrane of the filaments is very
delicate, and the zoospores appear some-
times to escape by its solution. Br. species :

1. C. endimcefolia, Ag. Hassall, Br. Fr.
Alg. pi. 9. figs. 1, 2; Kiitz. Tab. Phyc. iii.
pi. 21 . fig. 3. Ulva incrassata, Eng. Bot. 967.
Common in streams.

2. C. tuberculosa, Hook. Hass. L c. pi. 9.
7, 8; Kiitz. L c. pi. 19 and 21. Rivularia
tuberculosa, Eng. Bot. 2366. Boggy pools.

3. C. elegans, Ag. Hass. 1. c. pi. 9. 3, 4;
Kiitz. /. c. pi. 20. Stagnant pools; com-
mon.

4. C. pisiformis, Ag. Hass. I. c. pi. 9. 5,
6 ; Greville, Crypt, t. 150 ; Kiitz., L c. pi. 18;
Thuret, Ann. des Sc. nat. 3 ser. xiv. pi. 19.
fig. 1-3. Subalpine lakes.

5. C. dilatata, Hass. L c. pi. 13. fig. 2.

6. C. longceva, Carm. A doubtful species.
Hook. Br. Flora, vol. ii. pt. 1.

BIBL. As above.

CILETOPHORACILE.— Afamily of Con-
fervoid Algae, growing in sea or fresh water,
invested with gelatine ; either filiform or (a
number of filaments being connected toge-
ther) expanded into gelatinous, branched,
definitely-formed or shapeless fronds or
masses. Filaments jointed, furnished with
bristle-like processes. Fructification con-
sisting of spores and four-ciliated zoospores,
formed out of the contents of the articula-
tions.

Synopsis of British Genera.

1. Draparnaldia. Filaments free, gelati-
nous, the primary nearly colourless, bearing
tufts of coloured ramuli at the joints ; zoo-
spores formed singly in the joints of the ra-
muli.

2. Chcetophora. Filaments aggregated
into shapeless, incrusting or branched gelati-
nous fronds, the joints bearing bristle-like
branches ; zoospores solitary in the articula-
tions ; the membranes of the filaments very
fugacious.

3. Bulbochcete. Filaments free, each joint
truncate at the apex, and bearing there either
an articulate deciduous bristle bulbous at the
base, or a sessile inflated cell crowned by a
bristle. Zoospores and spores formed in the
inflated cells or in the bulbs of the bristles.

4. Coleochcete. Frond disk-shaped or ir-
regularly expanded, adherent to leaves, &c.
of aquatic plants under water, formed of
jointed dichotomous filaments radiating from
a centre, more or less conjoined laterally ;
the joints producing from the back a trun-
cate open sheath, from which a long bristle
is exserted. Fructification : spores and zoo-
spores formed in the joints.

5. Ochlochcete. Frond discoid, appressed ;
filaments cylindrical, radiating from a centre,
irregularly branched, consisting of a single
series of cells, each of which is commonly
prolonged above into an inarticulate bristle.

Foreign genus. See APHANOCH^TE,
Kiitz.

BIBL. See the genera.
CH^TOPSIS, Greville=DEMATiUM.
CHJETOSTROMA, Corda. See VOLU-

TELLA.

CELETOTYPHLA, Ehr.— A genus of In-
fusoria, of the family Peridina3a.

Char. Carapace (siliceous?) hispid or co-
vered with rigid hairs ; no transverse furrow,
no eye-spot.

C. armata (PI. 23. fig. 26 : a, side-view,
b, posterior end view). Ovato-subglobose,
rounded at each end, hispid, with short setae,

CHALAZA.

[ 131 ]

CHALK.

posteriorly a ring of dark prickles ; length

C. aspera (PI. 24. fig. 26 c). Oblong,
rounded at each end, hispid with short setae;
posterior prickles scattered without order;
length 1-550".

C. ? pyritce. Oblong cylindrical, ends
rounded; setae slender and elongate; no
posterior prickles; length 1-1100", breadth
half the length. Fossil in flint. Ehrenberg
questions whether this is not a Xanthidium.

BIBL. Ehr. In/us, p. 250; Duj. In/us.
p. 328.

CHALAZA (in plants).— The term ap-
plied to the base of the nucleus of ovules,
vyhere the substance of the former is con-
tinuous with the coats, and where the vas-
cular cord derived from the placenta termi-
nates (fig. 120, ch}.

Fig. 120.

Section of an anatropous ovule. /, funiculus ; r, raphe ;
ch, chalaza; p, external coat or testa; s, internal coat or
tegmen; n, nucleus.

CHALIMUS, Burm.— A genus of Crus-
tacea, of the order Siphonostoma, and family
Caligidae.

Char. Fourth pair of feet slender, of only
one branch, and serving for walking; frontal
plate with a long and slender prehensile ap-
pendage arising from the middle of its ante-
rior surface.

C. scombri. Found upon the mackerel,
and upon species of Caligus, of which it has
been supposed to be the young; length
about 1-6*'.

BIBL. Burmeister, N.A,Acad. N. C.Bonn,
xvii. ; Baird, British Entomostraca, p. 278.

CHALK.— The earthy form of carbonate
of lime. The application of the microscope
to the examination of chalk brought to light
the interesting fact, that this substance has
not had its origin in chemical precipitation,
since it contains abundance of the inorganic
remains of marine animals and plants, princi-
pally the former.

Many of these remains are not micro-
scopic, as the remains of birds and reptiles,
the shells of Mollusca, Echinodermata, the
polypidoms of Zoophytes, &c., hence their
consideration does not come within our pro-
vince ; yet it must be remembered that their

microscopic structure is to a certain extent
characteristic, so that the class, order, or
even the more minute division of the animal
kingdom to which they belong may be dis-
covered. See BONE and SHELL.

The chief microscopic constituents of the
calcareous formations examined by M. Ehren-
berg, viz. chalk, chalk-marl, compact lime-
stone, and nummulitic limestone, were
found to be shells of Foraminifera, spicules
of Sponges, the valves of the Diatomaceae,
and peculiar bodies called crystalloids.

The Foraminifera found by M. Ehrenberg
in the Brighton chalk were — Rotalia glo-
bulosa* and turgida*, Textularia aciculata,
aspera*, globulosa and striata, and Turbinu-
linaitalica(t). The * denotes those most
common.

Those in the Gravesend chalk were —
Rotalia turgida*, Rosalina globularis, Ro-
talia globulosa*, Textularia aspera*, globu-
losa*, and striata.

M. D'Orbigny enumerates 22 species of
Foraminifera from the English chalk. The
Diatomaceae found by Ehrenberg in the cal-
careous formations belonged to the genera, —
Actinocyclus, Actinoptychus, Amphitetras,
Biddulphia, Cocconema, Coscinodiscus, Eu-
notia, Epithemia, Eupodiscus, Fragilaria,
Melosira, Grammatophora, Navicula, Stria-
tella, Synedra, Tessella, and Triceratium,
with four species of Dictyocha.

The cementing material of chalk consists
of very minute, numerous and remarkable
bodies, called crystalloids (PI. 19. fig. 15).
They are elliptical, or rounded and flattened,
from 1-10,000 to 1-2500" in length, the
most numerous perhaps 1-3000"; some of
them consist of a simple ring (a); in
others this is marked with pretty regular
transverse lines, so as to make it appear
jointed (6); in others, again, there is a
thinner central portion, often exhibiting one
or more granules (c). M. Ehrenberg re-
gards these as arising from the disintegra-
tion of the microscopic organisms forming
the chalk into much more minute calcareous
particles, and their reunion into regular ellip-
tical plates (or disks) by a peculiar process,
differing essentially from, and coarser than
that of crystallization, but comparable with
it ; one probably preceding all slow crystal •
line formation, and causing, but not alone,
the granular state of solid inorganic matter.
The best method of examining chalk for
Foraminifera is this : place a drop of water
upon a glass slide, and put into it as much
finely-scraped chalk as will cover the point of

K2

CHALK-STONES.

[ 132 ]

CHARACE^E.

a pen-knife; then diffuse it through the
water, and set it aside for a few seconds.
Next remove the finest particles which are
suspended in the water, together with most
of the water, and allow the remainder to
become perfectly dry. Moisten this re-
mainder with oil of turpentine, and warm it
over a spirit-lamp ; then add Canada balsam,
and digest it upon the tin-plate (iNTB.xxiv.),
but without its frothing. A preparation thus
made seldom fails ; and when magnified 300
diameters, the mass is seen to be chiefly
composedof minute well-preserved organisms.
As thus prepared, the cells of theForaminifera
first appear black, with a white central spot
(PI. 18. fig. 2), which is caused by air- bubbles
contained within the cells. The balsam gra-
dually penetrates into the cells, the black
rings of the air-bubbles disappear, and the
minute, frequently very elegant cells of the
Foraminifera become visible. See FLINT,
and FORAMINIFERA.

The crystalloids are best examined in
common whiting, or powdered chalk which
has been shaken with water and set aside.
A very minute quantity removed with a dip-
ping tube will exhibit them.

BIBL. The various works on geology, as
those of Lyell and Ansted ; Mantell, Won-
ders, fyc., Medals of Creation, and Ann. Nat.
Hist. 1845. xvi. p. 73 (Chalk and Flint of
S.E. of England}-, Bowerbank, Trans. Geol.
Soc. vi.; Ehrenberg, Ueb. d. Bild. d. Kreide-
fels. Sfc., Abh. d. Berlin. Akad. 1838 (or
Weaver's Abstract, Ann. Nat. Hist. 1841.
vii.); id. Ueber lebend. Thierart. d. Kreid.
Abh. d. Berl. Ak. 1840 (or Taylor's Scientific
Memoirs, iii. ; Morris, Catalogue of British
Fossils ; D'Orbigny, Bull, de la Soc. Geol. d.
France, iv. (or Weaver's Abst., Ann. Nat.
Hist. 1841. vii. p. 390).

CHALK-STONES.— This term is vul-
garly applied to the white concretions formed
around the joints in chronic gout, or, as it is
sometimes called, rheumatic gout. They
consist of very minute needles of urate of
soda (PL 8. fig. 12 6).

CHAM^NEMA, Kiitz.— A supposed ge-
nus of Leptotricheous Algae, consisting of
dusky-coloured jointed filaments, forming
flocks in various syrups. Doubtless the myce-
lia of some Fungi, such as PENICILLIUM.

BIBL. Kiitzing, Sp. Alg. 158.

CHANTRANSIA, Desv. See TRENTE-

POHLIA.

CHARA, L. See CHARACE.E.
CHARACE.E.— A family of plants for-
merly classed among the Algse, but which,

from the character of their reproductive or-
gans, evidently have a more elevated posi-
tion. They may be placed on the boundary
between the Algse and the Hepaticaceee.
They are remarkable for their well-known
' circulation,' first discovered by Corti. The
Characese are aquatic plants, of filamentous
structure, exhibiting elongated axes furnished
at intervals with whorls of branches (fig. 121).
In some species this axis is a simple tube
(fig. 128), sometimes a tube with a cortical
layer of smaller tubes surrounding it (figs.
122, 123). Some authors have divided the
species, on this and some other grounds, into
two genera, Nitella (simple tubes) and Char a
(corticated tubes); but, according to Al.
Braun, who has devoted great attention to
this family, the characters will not hold.
The mode of ramification of the simple tubes
is seen in figs. 128 & 129) ; that of the com-
pound axes is fundamentally the same, but
other cells arise from the branch cells at the
articulations, one above and one below each
branch (C. crinita}. Those on the upper
side of the branches grow up over the cen-
tral axis to meet those descending from the
under side of the branches of the whorl next
above, the ends becoming intercalated about
the middle of the internode ; in this course
of growth cell-division takes place, and the
primary cortical tubes are not only made up
of many lengths in each internode, but each is
perpendicularly divided into two, one large and
one smaller tube ( C. vulgaris), or produces a
secondary tube on each side (C. aspera] ; the
primary tubes stand out as ribs from the
surface. These cortical tubes describe a
spiral course around the internode. Fila-
mentous radical cells are also produced from
the whorls. The cells of the main axis and
its branches, and the primary cortical cells,
are those in which the circulation of their
contents may be best seen. The cell-wall is
lined by a close layer, like a pavement, of
chlorophyll-globules, arranged in a somewhat
spiral order; within them lies a thick layer
of semi-gelatinous consistence(the circulating
protoplasm), and the centre is filled up with a
watery fluid. The circulation in the ordinary
cells consists in the movement of the gelati-
nous protoplasmic sac, as one mass, slowly
up one side of the cell, across the ends, and
down the other side, not perpendicularly,
however, but in an oblique or spiral course,
as indicated in fig. 129. The fluid in the
centre does not circulate, but contains vesi-
cles, granules, or other bodies floating in it,
which are free, and when resting upon the

CHARACE.E.

[ 133 ]

CHARACE.E.

protoplasmic sac, are carried along by it and up
the side of the cell, until they fall down again
by gravitation. The young cells from which
the fruits are developed exhibit a circulation
of green vesicles ; the cortical filaments have
a circulating primordial utricle without chlo-
rophyll-globules.

The circulation is obscured in many Charce
by the existence of an incrustation of the
cell-wall by carbonate of lime, which may
often be found in rhomboidal crystals. In
C. (Nitella) translucens, flexilis, and other
species, this does not exist, and these
species without cortical tubes exhibit the
phenomenon more clearly than the others.
Those species, however, which are subject to
incrustation have comparatively little about
the tips of the shoots ; and if they are kept
growing for some time in a jar of water pretty
free from lime, new shoots may be obtained
very suitable for examination. When we
carefully examine the conical terminal cell of
a shoot, we find the following characters : —
The cell-membrane is distinctly laminated,
and thickened at the conical apex of the
cell ; when sulphuric acid and iodine are ap-
plied, the cell- wall exhibits a thick internal
layer of a blue colour, indicating its compo-
sition of cellulose, while a thin layer extend-
ing all over the outside becomes bright yellow,
and thus presents a resemblance to the cu-
ticular layer of the higher plants. The cell-
wall is lined by a thin layer of protoplasm,
in which are imbedded a vast number of
chlorophyll-globules, closely set and arranged
spirally, as above stated ; a clear line extends
obliquely up in this layer, bare of chloro-
phyll. The chlorophyll-globules have much
the appearance of vesicles here, and contain
starch-corpuscles, which cause the whole
layer to turn blue with iodine. (See CHLO-
ROPHYLL.) Within this motionless layer is
found the thick rotating layer of protoplasm,
in which again are imbedded numerous starch
and chlorophyll-globules, a vast number of
minute granules, and a number of globular
bodies of larger size, 1-1500", according to
Goppert and Cohn covered with rigid cilia.
The internal boundary of this layer is wavy
and irregular, and thus its rotation carries
along, to a certain extent, the watery juice
filling up the centre of the cell, in which lie
numerous transparent protoplasm-vesicles,
ciliated bodies and granular matters.

The fructification of Chara is very curious,
and its homologies are not yet satisfactorily
made out. Upon the branches are found
bodies of two kinds (either on the same or

on different branches, or on different plants^,
called the globule and the nucule. The glo-
bule (figs. 124, 125) is regarded as an anthe-
ridium ; it is a spherical body, of a red or
orange-colour when ripe, presenting a trans-
parent, thickish outer coat, enclosing an
inner wall of curious construction. This is

Fig. 121.

Fig. 122.

Fig. 124.

Fig. 123.

Fig. 121. Chara vulgaris. Natural size.
Fig. 122. Fragment of stem, magnified 15 diam.
howiner the rortical tubes.

fig. j^>.6. rrnmnuKmn vi octAii, m»gi*A.uvv»

showing the cortical tubes.

Fig. 123. A section of ditto, magnified 30 diam.
Fig. 124. Branch with nucule and globule, 10 diam.

CHARACE.E.

[ 134 ]

CHEESE-MOULD.

composed of eight triangular plates, each
composed of a number of long wedge-shaped
cells radiating from a central cell. The plates
have dentate margins, by which they fit into
one another (fig. 125). The cells contain a
red colouring matter. In the centre of each
plate, inside, rises an oblong cell, running in
toward the centre, where it meets its fellows
from the other plates, and they are united

Fig. 125.

Fig. 125. A globule, magnified 50 diam., showing the
triangular valves.

Fig. 126. A globule cut in half, to show the oblong
cells and the septate filaments in the centre, 50 diam.

Fig. 127. Portion of a septate filament, 200 diam., with
two biciliated spermatozoids, 400 diam.

Fig, 128. Chara translucens, showing its simple tubes
and nucules grouped in threes under the terminal glo-
bule.

Fig. 129, Diagram representing the course of the cir-
culation in the main tube and branches of Chara.

by a little collection of spherical cells; a
ninth cell, of similar form but larger size,
comes to join these in the centre, it being
the pedicle of the globule, arising from the
branch upon which it is seated, and entering
the globule between the lower four valves.
At the point where these nine cells meet in the
centre, a number of long septate filaments arise
(fig. 126). These are composed, when ma-
ture, of a large number of cells placed end
to end (figs. 126 & 127), each of which
finally discharges a ciliated spiral filament
(spermatozoid), which swims actively in the
water. The globule bursts, by the separation
of its triangular valves, when mature, and it
is after this that the spermatozoids are
emitted. The form of these spermatozoids
is very like that of those found in the Mosses,
and different from what is seen in the Ferns,
Lycopodiacea3, &c. (PI. 32. figs. 31-34).

'The nucule of the Charaj (figs. 124 & 128),
which is regarded by some authors as a pis-
tillidium, is an oval body coated by five cells
wound spirally around a central tough sac,
the five cells terminating above in five or ten
smaller cells, which project like teeth from
the summit, forming a kind of crown. The
cells of the crown separate from each other
at a particular period, leaving a canal leading
down to the central cell, which contains
protoplasm, oil, and starch-globules. Ulti-
mately the nucule falls off, germinates, and
becomes developed into a new plant.

The Chares also multiply by gemmae, pro-
duced at the articulations of the stem.

BIBL. Corti, Osservazioni, fyc. sulla Cir-
culazione, fyc. Lucca, 1774; Amici, Osserva-
zioni sulla Circulazione, fyc., Mem. di Societa
italiana, viii. vol. ii. Modena, 1818; Ann. des
Sc.nat. 1824; Dutrochet, Ann. des Sc. nat.
ser. 2. x. 349 ; Meyen, Pflanzen-physiologie,
ii. 206 ; Varley, Trans. Soc. of Arts. xlix. 1 833 ;
Trans. Microscop. Soc. ii. 93. 1849 ; Slack,
Trans. Soc. of Arts. xlix. ; Thuret, Ann. des
Sc. nat. ser. 2. xiv. 65 ; ser. 3. xvi. 18 ;
Treviranus, Physiologic der Gewachse, i. 1 839 ;
Kiitzing, Phyc. generalis, 313; C. Miiller,
Botanische Zeitung, 1845, transl. in Ann.
Nat. Hist. xvii. 254 et seq. ; Goppert and
Cohn, Botanische Zeit. vii. 665 et seq. 1849;
Al. Braun, Bericht Berlin. Akad. 1852-3;
Ann. Nat. Hist. ser. 2. xii. 297.

CHARACIUM, Al. Braun.— Apparently
the germinating gonidium of an GEdogonium
at once producing zoospores.

CHEESE-MITES. See ACARUS DO-

MESTICUS.

CHEESE-MOULD. See ASPERGILLUS.

CHEILOSCYPHUS.

[ 135 ]

CHILODON.

CHEILOSCYPHUS, Corda.— A genus
of Jungermanniese (Hepaticacece), founded
upon Jungermannia polyanthus, L., which is
not unfrequent in wet places.

BIBL. Hooker, Brit. Jungerm. pi. 62;
Corda, in Sturm, Dtshl. Flor. ii. 19, 20. p.
35. pi. 9.

CHEIROCEPHALUS. See BRANCHI-
PUS.

CHEIROSPORA, Fries.— A genus of
Melanconiei (Coniomycetous Fungi), grow-
ing upon the twigs of the beech. The myce-
lium spreads under the epidermis, and bursts
through in rounded or irregular, conical,
black pustules, 1-20" in diameter, which are
composed of a large number of fine filaments,
unequal in length and waved, each termina-
ting in a bunch of spores. The heads are
formed of chains of spores like a Penicillium,
when young, but crowded together more
densely as they become more fully developed
into a globular or oval head, about 1-700";
the spores about 1-4000". This genus cor-
responds to Stilbospora, Montague, Myrio-
cephalum. De Notaris, and, apparently, Hy-
peromyxa, Corda, but the latter is said to
have a mucous vesicle enclosing the head.

C. botryospora, Fr. On dead beech twigs.
Berk, and Broome, Ann. Nat. Hist. 2 ser. v.
455. (Fresenius finds a variety on the horn-
beam.)

BIBL. Cheirospora, Fries, Summa Veget.
508 ; Stilbospora, Fries, Syst. Mycolog. iii.
448 ; Montague, Ann. des Sc. nat. 2 ser. vi.
338. pi. 18. fig. 5 ; Hyperomyxa, Corda,
Icones Fung. iii. fig. 78 ; Montague, Ann.
des Sc. nat. 2 ser. xx. 378 ; Myriocephalum,
De Notaris, Mem. Acad. di Torino, ser. 2.
vii. ; Fresenius, Beitr. zur Mykologie, p. 39.
pi. 5. figs. 1-9 (2te Heft).

CHELIDONIUM, L.— A genus of Papa-
veraceous plants, remarkable for the yellow
juice contained inthelaticiferous canals. See
LATEX.

CHEMICAL REACTIONS. — INTRO-
DUCTION, p. xxxvii.

CH EMISTRY.— The following works may
be consulted when a more detailed account
of the chemical properties of substances is
required than that for which we have space
in this work.

General works ; large. — Berzelius, Lehrb.
d. Chem. ; Gmelin, Handbuch der Chemie
(translated in part by the Cavendish Society) ;
Brande, Manual, fyc. ; Graham, Manual, fyc. ;
Mitscherlich's Chemie.

Small. — Gregory, Outlines, <^c.; Lehmann,
Taschenbuch d. Theoret. Chem. ; quite ele-

mentary, Stockhardt, Experimental Analysis
(Bohn's series). Fresenius, Aril, z, Chem.
Analys. (translated by Bullock) ; Will, Anl.
z. Ch. An. (translated by Hofmann) ; Rose,
Analyt. Chem.

Organic chemistry in general. — Mulder,
Versuch, Sfc. (translated by Johnston) ;
Lowig, Chem. d. Organ. Verb. ; also the
above general works-
Animal chemistry. — Simon, Anthropo-
chemie (Sydenham Society) ; Lehmann,
Physiol. Chem. (Sydenham Society) ; Robin
and Verdeil, Traite d. Chim. Anat. et Phys. ;
Vogel, Anleit. z. Gebrauche d. Mikrosk.;
Heintz, Lehrbuch d. Zoochemie; Scherer,
Chem. und Mikrosk. Untersuch. fyc. ; Hofle,
Chem. und Mikrosk. am Krankenbette ; Gorup-
Besanez, Zoochem. Analyse; Schmidt, Ent-
wurf ein. allg. Untersuchungsmethode, 8fC. ;
Funke, Atlas d. Phys. Chemie.

Vegetable chemistry is treated in the
general works.

The progress of chemistry is reported in
the Chemical Gazette.

CHEYLETUS, Latr.— A genus of Arach-
nida, of the order Acarina, doubtfully referred
to the family Trombidina.

Char. Palpi thick, resembling arms, and
falciform at the ends ; antennal forceps
(mandibles ?) didactylous.

C. eruditus. Found in books and museums.
Acarus eruditus, Schrank, Enum. Insect.
Austria, no. 1058 ; Latreille, Hist. nat.
Crust, et Ins. viii. 54.

C. marginatus. Koch, Deutschl. Crust.,
Myriap. and Ins., copied by Guerin, Iconogr.
Regn. Anim., Arach. pi. 5. f. 8.

BIBL. Ut supra and Cuvier, Regne Animal,
the dateless edition (1853?); Gervais,
Walckenaer's Apteres, iii.

CHILODON, Ehr.— A genus of Infu-
soria, of the family Trachelina.

Char. Body covered with cilia; mouth
with teeth arranged in the form of a tube ;
fore part of the head produced into a broad
membranous or ear-like lip.

The cilia form longitudinal rows.

C. cucullulus (PI. 23. fig. 27 a). Depressed,
oblong, colourless, rounded at the ends,
slightly auriculate or beaked anteriorly on
the right side ; aquatic and marine ; length
1-1 120 to 1-140". ( PI. 23. fig. 27 b, side view.)
Contains a red globule (eye-spot ?).

C. uncinatus. Depressed, oblong, rounded
at the ends, colourless; narrowed and curved
anteriorly so as to appear hooked ; aquatic ;
length 1-430".

C. aureus. Ovato-conical, turgid, golden-

CHILOMONAS.

[ 136 J

CHLOROCOCCUM.

yellow, anterior end curved so as to form an
obtuse beak, posterior end narrowed; aquatic;
length 1-140".

C. ornatus. Ovato-cylindrical, golden-
yellow, ends rounded, a violet spot at the
neck; aquatic and marine ; length 1-174".

Dujardin admits only the first species ;
referring the others to the genus Nassula.

BIBL. Ehi*. Infusionsth. p. 336; Duj.
Infus. p. 490; Stein, In/us, fyc.

CHILOMONAS, Ehr.— A genus of Infu-
soria, of the family Monadina.

Char. No tail nor eye-spot; mouth oblique
or lateral, and surmounted by a lip; either
anterior cilia or one or two (?) very delicate
flagelliform filaments present.

C. volvox. Oval, narrowed and notched
in front, colourless and transparent, lip long ;
aquatic; length 1-1400".

C. paramecium. Oblong, keeled, trilateral,
colourless and opake, sometimes aggregated;
aquatic; length 1-1020".

C. destruens. Oblong, variable in form
from its softness, colourless or yellowish ;
aquatic and marine ; length 1-860".

Dujardin gives different characters : body
ovoid-oblong, obliquely notched in front,
with a very delicate filament arising from the
bottom of the notch. Movement by the
body revolving upon its centre from before
backwards,

C. granulosa (PI. 23. fig. 28). Oblong,
broader in front, colourless, filled with
granules which appear to project on the sur-
face ; length 1 -840". In an infusion of mosses.

C. obliqua. Ovoid or pyriform, nodular,
colourless, variable in form; length 1-2700".

BIBL. Ehrenb. Infus. p. 30; Duj. Inf.
p. 295.

CHIODECTON, Fee.— A genus of Endo-
carpeae (Angiocarpous Lichens), of which
one species, C. (Syncesia) albida, has been
found in Ireland.

BIBL. Leigh ton, Monogr. Br. Any. Li'

is, p. 24. pi. 8. fig. 4. 9. fig. 1 ; Tulasne,
Ann. des Sc. nat. 3 ser. xviii. pi. 10.

CHIOGRAPHA, Leight.— A genus of
Graphideae (Gymnocarpous Lichens) sepa-
rated from Opegrapha. C. Lyellii=O. Ly-
ellii, Sm.

BIBL. Leighton, Ann. Nat, Hist. 2 ser.
xiii. 388. pi. 7. fig. 24.

CHIONYPHE, Thienem.— A genus of
Mucorini (Hyphomycetous Fungi), found
growing upon melting snow.

BIBL. Thieneman, Nova ActaA.L. C. C.
xi. 1839 ; Ann. des Sc. nat. 2 ser. xiv. 63.

CHITINE is the horny substance which

gives firmness to the tegumentary system
and other parts of the Crustacea, Arachnida,
and Insects ; probably also the lorica of
the Rotatoria consists of it. It is left when
the above structures are exhausted success-
ively with alcohol, aether, water, acetic acid
and alkalies, retaining the original form of the
texture. Itisdissolvedby concentrated mineral
acids without the production of colour.
It is not dissolved by solution of potash, even
when boiling. Neither does it give the
characteristic reactions with Millon's or
Schultze's tests. It contains nitrogen.

BIBL. Odier, Mem. d. Mus. d'Hist. Nat.
i. p. 35 ; Lassaigne, Compt. Rend. xvi.
p. 1087; Schmidt, Zur Vergl. Phys. d. Wir-
bellos. Thiere (Taylor's Sclent. Mem. v.
p. 1); Payen, Compt. Rend. xvii. p. 227.

CHLAMIDOCOCCUS. See PROTO-
coccus.

CHLAMIDODON, Ehr.— A genus of
Infusoria, of the family Euplota.

Char. Furnished with cilia and a cylinder
of teeth, but neither styles nor hooks. (Oxy-
tricha with a lorica and teeth.)

C. Mnemosyne (PI. 23. fig. 29). Elliptical,
or the anterior end broader, hence ovate;
green or colourless, and containing rose-red
vesicles ; lorica projecting beyond the body ;
length 1-570 to 1-240"; marine.
BIBL. Ehr. Infus. p. 376.
CHLAMIDOMONAS (PI. 23. fig. 30, «,
b, c, d, e). See PROTOCOCCUS.

CHLORASTER, Ehr.— A genus of Infu-
soria, of the family Monadina.

Char. Single, mouth (?) terminal, a single
frontal eye-spot, no tail, middle of the body
with radiate warty processes. Allied to the
genera Glenomorum and Phacelomonas. Does
not admit coloured particles.

C. gyrans. Green, fusiform, acute at the
ends ; radiate processes in a whorl of four,
at first obtuse, then subacute ; flagelliform
filaments 4-5; length 1-1630"; aquatic.

It revolves rapidly upon its axis, and
undergoes spontaneous division.

BIBL. Ehr. Ber. d. Berl. Akad. 1848.
p. 236.

CHLORATE OF POTASH. See POTASH.
CHLORIDES. See the bases.
CHLOROCOCCUM, Grev.— A genus of
Palmellaceae (Confervoid Algae).

We have assigned to this the common
green pulverulent stratum which is found
upon every old trunk, on all old palings and
other exposed woodwork, &c. If this proves
to be really a distinct plant, and not an
accumulation of germinating gonidia of

CHLOROGONIUM.

[ 137 ]

CHLOROPHYLL.

Lichens (Lepraria), it will still differ from
the plants we have assembled under the
name of Protococcus, in its general habit,
especially in the absence of zoospores. This
point is, however, still open to inquiry, since
from recent investigations it appears that the
gonidia of the Lichens do divide into two,
four and eight, to form a pulverulent stra-
tum, which exactly represents Chlorococcum
and Protococcus.

Chi. vulgare, Grev. (PI. 3. fig. 1). A
collection of extremely minute cells, multi-
plying by division into twos and fours, no
gelatinous substratum, no zoospores. Dia-
meter of single cells 1-3000 to 1-4000"
(Protococcus viridis, l-200()to 1-3000"). Old
dry palings, bark of trees, &c., every-
where. Calculating from the known size of
the cells and the wide distribution, this, if a
species, would appear to be the most fecund
Alga in existence. There are 300 millions of
individuals on a square inch, in a layer 1-100"
thick, and such layers clothe almost every
piece of unpainted timber and old trunk we
meet with in the country. C. murorum, Gr. is
perhaps a Palmoglcea, Kiitz.

BIBL. Greville, Sc. Crypt. Fl. pi. 262;
Hassall, Br. Fr. Alga, pi. 81. fig. 5.

CHLOROGONIUM, Ehr.— A genus of
Infusoria, of the family Astasiaea.

Char. A red eye-spot, a tail, and two
anterior filaments. (Not attached by a fixed
pedicle.)

C. euchlorum (PI. 23. fig. 31). Spindle-
shaped, acute at each end, tail short ; length
1 - 1 1 50 to 1 -280 ''. Found in enormous numbers
in pools and puddles ; frequently as many as
10,000 in a single drop.

These organisms do not admit colouring
matter or foreign bodies ; hence they are
probably not Infusoria, but Algae. They
often adhere to each other in groups by the
so-called tails (PL 23. fig. 31, upper figure) ;
sometimes to foreign bodies (PI. 23. fig. 31,
lower figure, which exhibit them adhering to
a dead Vorticelld).

They undergo oblique spontaneous divi-
sion (PI. 41. fig. 1) ; this commences in the
internal substance, which is constricted before
the outer portion.

They also propagate by a process of
swarming, which takes place thus : the
internal substance first separates somewhat
from the transparent wall, subsequently
becoming irregularly constricted at various
parts. The constrictions deepening, the con-
stricted portions separate from each other as
independent vesicles (?), and the internal

substance acquires the appearance of a black-
berry or bunch of grapes; consisting of a
fusiform aggregation of uniform longish oval
granules. Up to this period, the parent
organism continues its movements; subse-
quently these cease. The granules have now
acquired independent vitality, and their fila-
ments become developed. The envelope
then breaks near its middle, and the swarm
of young ones escapes. In their somewhat
more developed stage they form Glenomorum
tingens, Ehr. See PROTOCOCCUS.

BIBL. Ehr. In/us, p. 113; Weise, Wieg-
mann's Archivf. Naturgesch. 1848. i. p. 65;
Stein, Die In/us, p. 188 et seq.

CHLOROPHYLL (leaf-green). — The
name applied to the green colouring matter
of plants. The nature of the bodies which
are understood under this term is still
somewhat questionable. It is ordinarily
stated that chlorophyll exists commonly
under the form of globules or granules, and oc-
casionally as an amorphous granular substance,
in either case more or less adherent to, or
imbedded in the primordial utricle of the
cell. It is, however, a contested point
whether the chlorophyll-corpuscles are semi-
solid, homogeneous globules, or vesicles
composed of a delicate membrane enclosing
a green liquid. Chlorophyll presents itself
in the form of distinct corpuscles (granules
of authors), in the cells of the flowering
plants generally, particularly the parenchyma
of leaves and the subepidermal parenchyma
of green stems and shoots. The granules are
especially large and distinct in certain water-
plants, and may be well seen lying scattered,
singly, imbedded in the circulating protoplasm
of the cells of the leaves of Vallisneria and
other water-plants. The corpuscles are
very clear in the cells of the prothallia of
Ferns, in the leaves of Selaginella, of Mosses
and Liverworts ; also in Chara, where they
are very abundant, and form a continuous
layer, or else numerous rows, imbedded in a
gelatinous stratum, between the cell-wall and
the circulating mass of protoplasm. In the
Confervoids the chlorophyll often appears
both formless and corpuscular in one and the
same cell, but usually more or less formless
in young cells, and more completely con-
verted into granules in the full-grown, as in
Vaucheria. In the Confervacese, such as Cla-
dophora, (Edogonium, it presents itself in a
granular stratum with numerous larger bright
corpuscles, and in Spirogyra, Zygnema, &c.,
the chlorophyll takes the form of the spiral
or annular band, to which it is adherent,

CHLOROPHYLL.

[ 138 ]

CHLOROPHYLL.

without large granulations in the general
mass, but with a number of distinct, large,
bright-looking corpuscles at intervals (PI. 5.
tig. 18). In Protococcus, in zoospores, and
in the individual ciliated bodies of the Volvo-
cinese, the chlorophyll appears to tinge the
general mass of granular protoplasm, leaving
the conical apex (beak) uncoloured (Plates
3 & 5), while more or less distinct corpuscles
or granules are scattered through the mass,
varying in number and size at different
periods. When any of these forms of chloro-
phyll are treated with aether or alcohol, the
colour is abstracted, while the organized forms,
the corpuscles, &c., remain, so that the true
chlorophyll is really only a soluble substance,
dyeing thebodies called chlorophyll- granules,
&c. It becomes a question then whether
these are homogeneous, semi-solid corpus-
cles, or vesicles containing the colouring
matter in sacs, from which it is extracted by
the a3ther, &c. Nageli and others assert the
vesicular character of the chlorophyll-cor-
puscles, and the appearances are sometimes
much in favour of this view, but in the many
cases in which we have obtained the appear-
ance of a double line around them, under
high magnifying powers, we have never been
able to divest ourselves of the impression
that this was an optical deception. Nageli
asserts that the corpuscles multiply by divi-
sion, which is probable, but does not prove
that they are vesicular structures. The
observation of Goppert and Cohn, of a chlo-
rophyll-corpuscle swelling up and bursting
through endosmose, may be explained with-
out supposing a regularly organized coat.
We are inclined to believe that the bodies
bearing the green colouring matter are struc-
tures belonging to the protoplasm, the green
colour being only an additional character,
produced by the action of light, superadded
to the ordinary character of the granular
structures occurring in the protoplasm or
nitrogenous cell-contents. See PROTOPLASM.
A very important point connected with
chlorophyll is its relation to starch. Thebodies
called starch-granules occur very commonly
with chlorophyll-corpuscles in the cells of
green parts of plants, and they become sub-
stituted for each other under varying circum-
stances. Some authors have imagined that
chlorophyll is produced by a chemical
decomposition of starch, while others think
that starch is developed from chlorophyll.
The chief ground for the latter view is the
fact, that starch-granules, one, or a group of
many, are often found in the centre of chlo-

rophyll-corpuscles, like a kind of nucleus. We
have traced, in Hepaticacese, the gradual
formation of a group of starch-granules in
the interior of a chlorophyll-corpuscle (where
they are readily detected by the application
of iodine), and this goes on in certain cases
until almost all the green colour is lost.
Starch occurs universally at a certain period
in the bright distinct chlorophyll-corpuscles
of Chara and of the Confervacese, Spirogyra,
&c., so that these are coloured blue by
iodine, although green before its application.
But this starch may disappear again in the
course of nature, for it always vanishes from
these corpuscles when they are about to
become organized into zoospores. In fact
the green chlorophyll is predominant during
active vegetation, and starch in periods of
rest or in full-grown structures. Moreover,
while chlorophyll may appear independently
in young cells, without being preceded by
starch, in green tissues, starch makes its
appearance without previous existence of
chlorophyll-corpuscles in subterraneous struc-
tures, as for example in the potato and other
tubers. The truth of the matter therefore
appears to be, that the chlorophyll struc-
tures, as above stated, are granular structures
belonging to the general protoplasm or nitro-
genous cell-contents ; that they become
coloured green in the light by a chemical
change connected with the vital processes ;
that in undergoing this change they do not
lose the power, which the or dinary protoplasm
possesses, of secreting starch, and decompo-
sing it again when required for the nutrition
of the plant. Starch-granules, when free
and uncoloured, appear to be produced ori-
ginally from granular or vesicular proto-
plasmic structures, only differing by absence
of colour from chlorophyll structures. For
example, the granular protoplasm around
the cell-nucleus in the cells of herbaceous
Monocotyledons (such as the Lily, Trades-
cantia, &c.) will sometimes become converted
into chlorophyll-granules (in superficial cells),
inside which starch may be subsequently
developed; but (in deeper-seated cells) the
granular protoplasm may give rise at once
to starch-granules (PI. 36. fig. 28 a) without
the previous existence of the green modifi-
cation of the protoplasm, i. e. chlorophyll.

Chlorophyll is turned yellow-brown by
tincture of iodine ; sulphuric acid gives it a
more or less deep blue colour; aether and
alcohol discharge the green tint. Prepara-
tions put up in chloride of calcium lose their
green colour ; those preserved in water will

CHOLERA.

sometimes preserve it a long time. The
green colouring matter extracted by alcohol
is a complex substance, containing a kind of
wax and a matter allied to indigo.

BIBL. Von Mohl, Vegetable Cell (London
Transl. 1852), p. 41 ; Vermischte Schriften,
p. 349; Nageli, Zeitschrift fur Wiss.Bot.iii.
110; Ray Soc. Vol. 184.9. p. 176; Mulder,
Physiological Chemistry, Edinb. Transl.
p. 266 ; Goppert and Cohn, Bot. Zeitung,
vii. 665 (1849); Schleiden, Grunzuge der
Wiss. Bot. 3rd ed. 196 ; Al. Braun, Verjun-
gung, (Ray Soc. Vol. 1853. p. 195); Morot,
Rech. sur la coloration des Vegetaux, Ann.
des Sc. nat. 3 ser. xiii. 1 60. A long list of
the older authors is given by Von Mohl, I. c.

CHOLERA.— The attempt has often been
made to discover some animalcule or minute
vegetable organism in the air, water, and the
intestinal and other animal liquids, during
the existence of cholera, which might explain
the origin of this fearful diseaaefc-; and state-
ments have been published announcing
success. None of these have, however, stood
the test of rigid investigation. When the
cholera prevailed at Berlin in 1832, the
renowned Professor Ehrenberg, who had
then been engaged in the study of microsco-
pic organisms for many years, declared after
special and careful examination, that neither
the air nor the water from various localities,
contained anything unusual. Repeated ex-
aminations of the air and water of in-
fected localities, made in 1849, and during
the more recent accessions of the cholera, have
afforded also conclusive negative evidence.

The view is no less unsupported by rea-
soning than by fact. Great reproductive
power is a general character of the more
minute organisms ; hence whenever they
are present, they are easily recognized. If
we examine a silk - worm affected with
muscardine, a fly with what may be termed
the muscardine of the fly (MuscA), a
portion of the crust of Favus, or a fragment
of an aphthous patch, the parts of the Fungi
are present in thousands; there is no need to
look for them twice. If they, or their ana-
logues, were present in cholera, the same
would surely be the case. There is, further,
no reason to believe that Fungi, when growing
in animal bodies, ever produce anything
more than a mechanical eifect, resulting from
their large numbers. The methods of
examining the air in regard to this point, are
described under AIR ; and they are far
superior to that of simply exposing slides
to the atmosphere. The use of glycerine in

9 ] CHONDRACANTHUS.

these experiments must be carefully avoided,
on account of its rendering minute and
delicate objects so transparent.

In regard to the supposed cholera-fungus
of 1849, one point requires special notice. It
was announced at the Microscopical Society,
that certain of the bodies detected (globular),
were spores of a true fungus (Uredo). It is
but justice, however, to Dr. Swayne to state
that this is incorrect ; although it has been
repeated in all works which have since
alluded to the subject.

BIBL. Swayne, Evacuations in Cholera,
fyc., Lancet, 1849, 368, 398; Obs. on College
Report, fyc., Lancet, 1849, 530; Brittan and
Budd, Medical Gazette, Sept. 1849 : Baly
and Gull, Rep. of Cholera Subcommittee, fyc.
of Roy. Coll. ofPhys., London, 1849 (Lancet,
1849, p. 493); Griffith, Medical Gazette,
Dec. 1849 ; Bennett and Robertson, Edinb.
Monthly Journal, Nov. 1849; Berkeley,
Medical Gazette, 1849. p .1035; Quain, Let-
ter, fyc., Lancet, Oct. 1849 ; Anonymous,
Cryptogamic Theory of Cholera, London Jour-
nal of Medicine, 1849, i. 1048-9; Robin, Vegt-
taux Parasites, ^c.,2nded. 1853. Appendice,
p. 676.

CHOLERA-FLY. See MUSCA.

BIBL. Knox, Lancet, 1853, ii. p. 479.

CHOLESTERINE, sometimes, but im-
properly termed, Cholestearine.

This substance exists naturally in most
animal liquids in a state of solution, also in
many animal solids ; as in the blood, the
bile, the meconium, the brain and spinal
cord. As an abnormal product, it occurs in
the crystalline form in the bile, biliary calculi,
various dropsical eflfusions, the contents of
cysts, pus, old tubercles, malignant tumours,
the excrements, expectoration of phthisis, &c.
It does not occur in the vegetable kingdom.

The crystals form thin pearly rhombic
plates (PL 9. fig. 21). The acute angles are
=79° 30', the obtuse =1 00° 30'. Sometimes
the angles are truncated.

Cholesterine is insoluble in water and
solution of potash, even when boiling ; but
soluble in aether and boiling alcohol, crystal-
lizing on cooling.

It is most easily procured from a gallstone
by boiling in alcohol; it falls on cooling.
The crystals thus obtained are usually thicker
than the natural plates.

BIBL. See CHEMISTRY, Animal.

CHONDRACANTHUS.— A genus of
Crustacea, of the order Siphonostoma, and
family Lernaeopoda.

C. Zei. Found upon the gills of Zeus

CHONDRIA.

[ 140 ]

CHORDA DORSALIS.

(the common Dory). The body is covered
with short reflexed spines. Length 4-5".

BIBL. Baird, Brit. Entomostr. p. 327.

CHONDRIA, Ag. See LAURENCIA.

CHONDRINE.— The gelatinous matter
of the permanent true cartilages.

Its solution differs from that of the gelatine
of bones, &c., in being precipitated by acetic
acid, acetate of lead, and alum. The acetic
precipitate is insoluble in excess.

It is coloured red by Millori's test ; but is
unaffected by that of Pettenkofer.

BIBL. See CHEMISTRY, Animal.

CHONDRUS, L.— A genus of Cryptone-
miaceae (Florideous Algae), composed of car-
tilaginous sea- weeds with flat, dichotomously-
divided fronds, the cellular structure of which
exhibits three layers ; a central of longitu-
dinal filaments, an intermediate of small
roundish cells, and an outer of vertical,
coloured and beaded rows of cells, the whole
imbedded in a tough " intercellular " matrix.
See INTERCELLULAR SUBSTANCE.

Fructification : spores contained in favel-
lidia immersed in the frond ; tetraspores
collected in imbedded sori,and "nemathecia,"
tubercles composed of radiating filaments
(antheridia ?). C. crispus becomes horny
when dry, and is the Irish moss or Carrigeen
of the shops.

BIBL. Harvey, Br. Mar. Alg. pi. 17 D. ;
Phyc. Brit. pi. 63 & 187 ; Greville, Alg.
Brit. pi. 15.

CHORDA, Stackh. — A genus of Lamina- -
riacese (Fucoid Algae), with fronds of a pecu-
liar, simple, cylindrical form ; two species,
C.filum and C. lomentaria, are found between
tide-marks on British coasts ; the former
grows from 1 to 20 or even 40 feet long, with
a greatest diameter at half its length of 1-4"
to 1-2". The cord-like frond is tubular, but
has at intervals thin diaphragms, formed by
interwoven transparent filaments. The wall
of the tube is composed of a number of layers
of very regular six-sided cells, upon which
are implanted little erect clavate cells which
coat the entire surface of the frond. These
present two forms, apparently constituting
oosporanges (spores, Harvey, paranemata, Ag.)
and trichosporanges (antheridia, Harvey,
spores, Ag.). The first are single sacs pro-
ducing a number of zoospores, the second
are filaments composed of about five joints,
each of which give birth to a zoospore.

BIBL. Harvey, Br. Mar. Alg. 31. pi. 3 B. ;
Phyc. Brit. p. 107, &c. ; Thuret, Ann. des
Sc. nat. 3 ser. xiv. p. 240. pi. 29. figs. 5-10 ;
Derbes and Solier, Ann. des Sc. nat.

3 ser. xiv. 268. pi. 33. figs. 7-10; Kiitzing,
Phyc. generalis, pis. 28 & 29.

CHORDA DORSALIS.— The embryonic
representative of the spinal column of the
Vertebrata ; the permanent spinal column of
the Cartilaginous Fishes. It sometimes forms
a spindle-shaped, transparent, gelatinous-
looking cord, with the broadest part near
the tail; at others it is cylindrical or conical,
rounded anteriorly and tapering posteriorly.

It usually consists of an outer compara-
tively thick and firm structureless membrane,
forming a sheath, and of pale nucleated cells,
which fill the sheath (fig. 130). In some

Fig. 130.

Magnified 350 diameters.

Portion of the chorda dorsalis of the embryo of a sheep,
rather more than 1-2" in length, a, sheath ; b, cells.

instances, however, its structure is fibrous,
and that of the sheath fibro-membranous.
The cells are mostly angular or polyhedral,
and closely crowded. Their size varies ; in
the embryo of a sheep rather more than 1-2"
in length, they measured about 1-1800".

The walls of the cells readily dissolve in solu-
tion of potash; but they yield neither gelatine
nor chondrine on boiling. The liquid within
the cells is not coagulated by boiling, but
the chorda itself becomes cloudy and granular.

In its earliest stage of development, the
chorda consists simply of alongitudinal band of
ordinary formative or embryonic cells ; the
sheath is subsequently formed. It appears that
the spinal column is not developed from the
chorda itself, but from a blastema secreted
by its component cells and effused around
them.

The chorda is most readily examined in
the larvae of frogs (tadpoles), of Tritons, or of
Fishes ; and may be separated by macerating
the dead animals for twenty-four hours in

CHORD ARIA.

CHYLAQUEOUS.

water. On cutting off the tail, it may then
be pressed out by gently scraping along its
course from the end of the tail, or from the
head towards the wound. It is a beautifully
delicate structure, and closely resembles in
appearance a piece of vegetable cellular tissue.

BIBL. Kolliker, Mikrosk. Anat. ii. p. 346;
Schwann, Ueber die Einstim., fyc. (Sydenh.
Soc.} ; Stannius, Vergl. Anat.

CHORDARIA, Ag.— A genus of Chorda-
riacese (Fucoid Algae), remarkable for the
solidity of the cellular texture of their fili-
form fronds. The axis and branches are
composed of a central mass of longitudinal
cells, upon which stand horizontal clavate
filaments, formed of a row of beaded cells,
constituting a distinct peripheral layer, which
gives a velvety texture and slimy character
to the surface. The so-called spores attached
to the horizontal filaments are oosporanges,
and discharge zoospores when mature ; tri-
chosporanges have not yet been observed.
C. flagelliformis, Mull., is common on rocks
and stones between tide-marks.

BIBL. Harvey, Br. Mar. Alg. pi. 10 A.;
Phyc. Brit. pi. Ill; Thuret, Ann. des Sc.
nat. 3 ser. xiv. 237.

CHORDARIACE^.— A family of Fucoid
Algae. Olive-coloured sea-weeds with a
gelatinous or cartilaginous, branching frond,
composed of vertical and horizontal filaments
interlaced together; the oosporanges andtri-
chosporanges attached to the filaments
forming the superficial layers of the frond.
Br. genera :

1. Chordaria. Axis cartilaginous, dense ;
filaments of the circumference unbrauched.

2. Mesogloia. Axis gelatinous, loose ;
filaments of the circumference branching.

BIBL. Harvey, Br. Marine Alga-, Thuret,
Ann. des Sc. nat. 3 ser. xvi. p. 5, &c. See
also the genera.

CHOROID MEMBRANE. See EYE.

CHROMATE OF LEAD (neutral).— Is
one of the best materials for colouring size
in injections. See INJECTION.

CHROMIC ACID.— May be prepared
b\ adding gradually from 120 to 150 parts, by
volume, of pure concentrated sulphuric acid
to 100 parts of a cold saturated solution of
bichromate of potash. The crystals of the
acid separate as the solution cools. The
mother-liquor should be poured off, and the
crystals dried upon a tile ; they may be
purified by re-crystallization from solution
in water. Or, by adding two parts of concen-
trated sulphuric acid to about one of dry
chromate of lead, and setting aside the thin

paste for twelve hours. On the addition of
water, the insoluble sulphate of lead subsides.
The supernatant liquid is poured off and
boiled down in a retort until the acid sepa-
rates on cooling. The crystals should be
dried on a tile and further purified as above.

Chromic acid is readily decomposed by
organic matter, as dust, &c., and should
therefore be preserved in a well-stoppered
bottle. Its aqueous solution, which should
be of a pale yellow colour, is used for
hardening and preserving nervous and mus-
cular tissues, &c. It should be prepared
when required.

CHROOCOCCUS, Nag. See PROTO-
coccus.

CHRYSIMENIA, J. Ag.— A genus of
Laurenciaceae (Florideous Algae).

C. clavellosa is a rare sea- weed 3 to 12"
high, forming a feathery frond, composed of
a branched, tubular, long, not constricted or
chambered cellular structure, filled with a
watery juice. The spores are angular, and
are contained in dense tufts in ceramidia
borne on the sides of the branchlets. The
tetraspores are 3-partite and immersed in
the brauchlets.

BIBL. Harvey, Br. Mar. Alg. pi. 13 A. ;
Phyc. Brit. pi. 114.

CHTHONOBLASTUS, Kiitz. See Mi-

CROCOLEUS.

CHYDORUS, Leach (Lynceus, Milll., in
part). A genus of Entomostraca, of the
order Cladocera, and family Lynceidse.

Char. Nearly spherical; beak very long
and sharp, curved downwards and forwards ;
inferior antennae very short.

C.spha>ricus(Pl.l5.fig. 7). Shell smooth ;
olive-green. Found in ponds and ditches.

C. globosus. Shell more rounded than in
the last, and nearly six times larger ; ante-
riorly reddish, with circular strife and nume-
rous black spots; aquatic; less common
than the former.

BIBL. Baird, Brit. Entom. p. 125.

CHYLAQUEOUS or chylo-aqueous liquid
and system.

In the Invertebrata, two distinct kinds of
nutrient liquids exist. In some classes of
this subkingdom, these two liquids coexist
in the same organism, though contained in
distinct systems of conduits; while in others
they become united into one. Dr. T. Wil-
liams distinguishes these two kinds of liquid
as the blood proper or true blood, and the
chylaqueous liquid. The former is always
contained in definitely organized (walled)
blood - vessels, and has a determinate

CHYLE.

C

circulatory movement. The latter, with
equal constancy, in chambers, irregular
cavities and cells communicating invariably
with the peritoneal cavity; not having a
determinate circulation, but a to-and-fro
movement, maintained by muscular and
ciliary agency. The true-blood system does
not exist under any form, even the most
rudimentary, below the Echinodermata; in
other words, the true-blood system begins at
the Echinodermata. Below the Echinoder-
mata, viz. in the Polypi and Acalephse, the
digestive and circulatory systems are identi-
fied, consequently the external medium is
admitted directly into the nutrient vessels.
This circumstance constitutes a fundamental
distinction between the chylaqueous system
and that of the true-blood; into which,
under no conditions, is the external inorganic
element directly introduced.

In every class in which the chylaqueous
liquid exists, it is charged more or less
abundantly with organized corpuscles. These
corpuscles are marked by distinctive charac-
ters, not in different classes and genera only,
but in different species, entitling these bodies
to great consideration in the establishment
of species. In those classes, as in the Echi-
nodermata, the Entozoa and Annelida, in
which, in the adult animal, these two orders
of liquids coexist, though distinct, in the
same individual, an inverse proportion
prevails between them, as respects their
magnitude or development. The system of
the chylaqueous liquid does not exist in the
adult, but only in the larval state of the
higher members of the articulated series,
as the Myriapoda, Insecta and the Crusta-
cea.

BIBL. Williams, Trans, and Proceed, of
Royal Society, 1852 (the former contains
figures of the corpuscles) ; id. Ann. Nat.
Hist., passim after 1852.

CHYLE.— The chyle consists of a liquid
which coagulates when removed from the
vessels, containing in suspension molecules,
nuclei, colourless corpuscles, and coloured
blood-corpuscles.

The molecules (PI. 41. fig. 12 a) are very
numerous, and probably consist of fatty
matter surrounded by a coat of a proteine-
compound ; to them is owing the milky
appearance which the chyle possesses during
active digestion. They form the molecular
base of Gulliver. The free nuclei (PI. 41.
fig. 26) have a somewhat homogeneous aspect;
they are not numerous, about 1-11,000 to
1-5600" in diameter, frequently appearing

2 ] CIBOTIUM.

cell-like and granular after the addition of
water. They are only met with at the
origins of the lacteals, in the mesentery, and
in the vasa efferentia of the mesenteric glands,
but never in the thoracic duct. The chyle-
corpuscles '(PI. 41. fig. 2 c), which are identical
with those of the lymph, are pale round
nucleated cells,l-4500 to l-2000"in diameter;
their contents become turbid when water is
added, and they are rendered very transparent
by the addition of acetic acid, the granular
nucleus becoming at the same tim e very distinct .
Sometimes they exhibit a number of Amoeba-
like processes (PI. 41. fig. 2 d). At the origins
of the lacteals the chyle-corpuscles are few
in number, or even absent ; near the mesen-
teric glands, they are met with undergoing
division. The coloured blood-corpuscles are
probably derived from without. Chemi-
cally, the chyle consists of a saline liquid,
containing albumen and fibrine in solution;
the latter when coagulated forming a soft and
loose clot.

BIBL. Kolliker, MikrosJc. Anat. ii. 561 ;
Wagner. Handwort. art. Chylus; ibid, Elem.
of Phys., by Willis; Gulliver, ibid, and
Gerber's Anat. ; Bennett, Edinb. Month.
Journ. 1852, 204; and the Bibl. of CHE-
MISTRY, Animal.

CHYLOCLADIA, Grev.— A genus of
Laurenciacese (Florideous Algae), containing
a few British species, with fronds of small
size, composed of a branched, cylindrical and
tubular structure, cut off into chambers
within by diaphragms at intervals, and filled
with a watery juice. The walls are com-
posed of small polygonal cells. Nageli has
given the minute anatomy of C. (Lomentaria)
kaliformis. The spores are wedge-shaped,
contained in tufts in ceramidia borne on the
branchlets. The tetraspores (3-partite) are
immersed in the branchlets.

BIBL. Harvey, Br. Mar. Alg. pi. 13 B.;
Phyc. Brit. pi. 145, &c.; Grev. Alg. Brit.
pi. 14; Nageli, Algen. Systeme, 246. pi. x.
figs. 13-21.

CHYTRIDIUM, A.Br.— Probably a form
analogous to CHARACIUM. It is described
as a balloon -shaped cell, attached by a root-
like base upon (Edogonia; the contents be-
come converted into ciliated zoospores, which
escape through dehiscence by a lid. It is
doubtless the spore of CEdogonium de-
scribed by Pringsheim.

BIBL. Al. Braun, Verjungung, fyc., Ray
Society's Translation, 1853. p. 185 ; Prings-
heim, Ann. Nat. Hist. ser. 2. xi. p. 297. pi. 9.

CIBOTIUM, Kaulfuss.— A genus of Cya-

CILIA.

CILIA.

thaese (Polypodiaceous Ferns),
valve indusium. Exotic.

Fig. 131.

With a bi-

" Cibotium macrocarpum.
A pinnule with sori. Magnified 10 diameters.

CILIA (plural of cilium) of ANIMALS. —
These are microscopic filaments attached by
one end to the surfaces of various parts of
animals, and exhibiting a vibratory or rota-
tory motion. They are usually rounded and
broadest at the base, tapering towards the
free end; sometimes they are flattened.
Their length is very variable, having been
estimated at 1-50,000 to 1-500"; probably
1-15,000 to 1-500" would include most of
them. The latter large size is attained by the
cilia existing on the point or angle of the gills
or branchial laminae of the whelk (Buccinum
undatum).

Numerous examples of animals furnished
with cilia, showing their appearance when at
rest, are figured in PI. 23, 24, 25, 34, & 35.
During life, and for some time after death,
they are usually in constant motion, giving
the parts of the field of the microscope in
which they are situated a tremulous appear-
ance when their motion is very rapid and the
cilia are very minute. When they are large,
as on the gills of the common sea-mussel
(MYTILUS), especially when their motion is
slackening, they are seen waving to and fro,
or lashing the water, and producing in it
strong currents, rendered visible by the mo-
tion of minute particles accidentally con-
tained in the water. The motion is mostly
uniform, or in one direction; occasionally,
however, it has been observed to cease for a
moment, and then to assume an opposite
direction to that previously exhibited. Du-
ring the motion, the whole filament is usually
more or less curved ; but in some instances
among the Infusoria, the basal portion of the
cilia remains rigid, whilst the terminal por-
tion vibrates ; under these circumstances,
the cilia are distinguished as flagelliform
filaments. Sometimes the cilia move around
an imaginary perpendicular axis, in a rotating
direction.

Cilia are found in all the Vertebrata and

the Invertebrata, excluding the Crustacea,
Arachnida, and Insecta. In Man, they
spring from epithelial cells; the localities
in which they are found are stated under
EPITHELIUM.

The uses of the cilia are of two kinds :
when the body to which they are attached is
of no great bulk or specific gravity, compared
with that of the medium in which they re-
side, the cilia become organs of locomotion,
as in the Rotatoria, Infusoria, the young
Acalephae, the ovum, &c. But if the inertia
of the body be too great to be overcome by
the feeble power of the cilia, they produce
motion in the surrounding medium, as on
gills of fishes, of young reptiles, and of the
Mollusca, the gill-tufts of the Annulata, and
the various mucous surfaces of the Vertebrata
upon which they exist, in which theyfavour re-
spiration and excretion. By the same agency
they also bring particles of food suspended
in the medium towards the mouth. It need
scarcely be remarked, that the motion of
cilia must be stronger in one direction than
the other, otherwise there could be no current.

The cause of the motion of cilia has long
formed a subject for discussion; it is un-
known. In some instances, as in the Infu-
soria, it appears to be voluntary. In some
cases it might be attributed to the action of
a contractile amorphous tissue, "such as that
composing the Am&bce. It would naturally
be attributed to muscular agency. But no
muscular tissue can be detected; in fact,
cilia are quite structureless. Moreover, they
are often of less breadth than the ultimate
fibrillae of muscle. Neither the most power-
ful poisons, as strychnine, prussic acid, opium
and belladonna, nor electricity, produce any
effect upon ciliary motion, provided the
structure upon which the cilia are situated
be not injured. It also lasts a long time
after death, having been observed in the
lower animals nineteen days after this occur-
rence, and when putrefaction was far ad-
vanced. The question has however lost its
interest in regard to its necessary dependence
upon muscular action, because cilia are com-
mon among the lower plants, where this is
out of the question.

The cilia and their motion may readily be
observed in the common Rotatoria and Infu-
soria, in a thin piece cut from the margin of
the gills of the oyster, or still better, the
sea-mussel ; in the latter, they form a most
beautiful and interesting object. Fresh-
water almost immediately arrests the motion
of the cilia in marine animals. In some cases,

CILIA.

CIMEX.

solution of potash excites the movement of
animal cilia after it has become languid.

The detection of the cilia is frequently of
great importance, as the characters of Infu-
soria, &c. are often based upon their num-
ber and arrangement. The means are either
indirect, as by the addition of moistened
particles of colouring matters, as indigo, &c.
to the living organism, and watching for
the movements of the particles ; or direct, by
examining the structures after the addition of
solution of iodine or bichloride of mercury,
or drying them at a gentle heat. Both me-
thods should be adopted to check each other,
for molecular movement has some resem-
blance to ciliary motion when feeble, although
there is absence of a definite current; and
fine hair-like Algae or Fungi attached to aqua-
tic organisms often resemble cilia, but are
deficient in the motion.

See INFUSORIA, MEMBRANES, UNDU-
LATING, and MOLECULAR MOTION.

BIBL. Purkiuje & Valentin, Comm. Phys.
fyc.-, Sharpey, Todd's Cycl. ofAnat. fy Phys.
i. 606 ; Valentin, Wagner' sHandw. d. Phys.
Sfc. i. 484 ; Virchow, ArcUv, vi. p. 133.

CILIA of VEGETABLES. — These minute
vibratile threads, apparently of the same
(unknown) nature as those of animals, are
in all cases met with in connexion with the
protoplasmic or nitrogenous structures of
plants, the structure bearing the closest re-
lation to animal organization. Cilia have as
yet been found only in Flowerless Plants,
viz. in all the higher or stem-forming Cryp-
togams, and in the Algae among the Thallo-
phytes. In the Marsileaceae, Lycopodiaceae,
Ferns, Equisetaceae, Mosses, Hepaticaceae,
and Characeae, they are found upon the ac-
tive filaments (spermatozoids) discharged
from the antheridia. In the Algae they oc-
cur upon the zoospores or active gonidia,
and on the fully-developed plants of the fa-
mily Volvocineae. They have been stated to
occur in certain other complete organisms,
as in Closterium, but this statement requires
further confirmation. Rigid filaments bearing
some resemblance to cilia occur occasionally
upon Diatomaceae and Oscillatoriae, but these
are not vibratile organs. The mode of ar-
rangement, &c. varies considerably among
the cases above cited. In spermatozoids
of the Marsileaceae, Lycopodiaceae, Ferns,
and Equisetaceae, they are set in considerable
number along a filament spirally or heliacally
coiled (PL 32. fig. 34). In the Muscaceae,
Hepaticacese, and Characeae, a pair of very
long cilia are attached at one end of the fila-

ment(fig.l27.p.!34). In zoospores they occur
in either a pair at the apex, as in Protococcus,
Conferva, Cladophora, Codium, &c., or there
are four in the same situation, as in Ulothrix,
Chcctophora, Ulva, &c.; while the large zoo-
spores of CEdogonium bear a crown of vibra-
tile cilia, and the great elliptical zoospore of
Vaucheria is clothed with them over its
whole surface. In the Volvocineae, there is
a pair of cilia attached, just like those of
zoospores, to each member of the family of
which the compound organism is made up,
and these project through orifices in the
common envelope, so as to render the per-
fect plant locomotive; while the cilia of
ordinary zoospores disappear when they be-
come encysted in a cellulose coat, prepara-
tory to germination. In the Fucaceae, as
in Fucus, Eciocarpus, Laminaria, &c., the
zoospores produced in the trichosporangia,
have a different arrangement of the cilia;
there are always two, but they are attached
on a reddish point on the side of the zoo-
spore, not at its apex, and one of the cilia is
directedforwards from the apex or beak, while
the other trails behind like a kind of rudder.

The mode in which these transitory cilia
are lost is variously stated; some authors
think they are retracted into the protoplasm ;
from what we have seen, we believe they are
thrown off entire. The cilia have the same
chemical reactions as the protoplasmic sub-
stances generally, and are apparently pro-
cesses of it; they are stained brown by
iodine, which also stops their motion and
renders them partly solid. The mode of
detecting and observing cilia is given in the
preceding article. Further particulars of
individual cases will be found under the
heads of the families and genera named above.

BIBL. Thuret, Rech. sur les Zoospores des
Algues, fye., Ann. des Sc. nat. 3 ser. vols. xiv.
& xvi.; Note sur les Antheridies des Fougeres,
Ann. des Sc. nat. 3 ser. xi. 5; Hofmeister,
Vergleichenden Untersuchungen, fyc. Leipsic,
1851 ; Unger, Die Pflanze in Moment e der
Thierwerdung, p. 34. Vienna, 1843; Al.
Braun, Verjungung, Sfc. (Rejuvenescence Sfc.,
Ray Soc. Vol. 1853) ; Cohn, Protococcus
pluvialis, Nova Acta A. L. C. C. xxii. 735
(Ray Soc.Vol. 1853. p. 352 etseq.} ; on Ste-
phanosphara, Siebold & Kolliker's Zeitschr.
iv. 77, transl. Ann. Nat. Hist. 2 ser. x. 321
et seq.; Henfrey, On Ferns, Linn. Trans, xxi.;
Focke, Physiologische Studien.

CILIARY PROCESSES. See EYE.

CIMEX, Linn. (Bug). — A genus of
Insects, of the order Hemiptera (Hete-

CINCHONINE.

[ 145 ]

CIRRIPEDIA.

roptera, Latr., Westw.), and family Cimi-
cidae.

Char. Antennae 4-jointed; labium 3-
jointed, the basal joint the longest ; thorax
sublunate, not transversely divided; abdo-
men much depressed, and more or less orbi-
cular; elytra reduced to a pair of short,
transverse, scale-like pieces; wings none; legs
moderately long and slender ; tarsi 3-jointed.

C. lectularius (the bed-bug). Ferruginous-
ochre ; thorax deeply emarginate, its sides
reflexed; abdomen suborbiculate, acute at
the apex, third joint of antennae longer than
the fourth ; rostrum inflected beneath the
thorax; labrum short, broad, subovate, tri-
gonate and ciliated.

The common bug appears to have only
three setae, one stouter than the rest, and
not toothed or serrated (PI. 26. fig. 27 a), and
two others extremely slender and very finely
serrated near the ends (PI. 26. fig. 27 b] ;
they are about 1-20,000" in breadth at the
serrated portion (hence about the l-20th
part of the breadth of the lancets of the flea).
The female is larger and more elongated
than the male. The eggs (PL 31. fig. 20)
are white, elongate-oval, elegantly pitted,
and terminated by a lid, which breaks off
when the young escape. The latter are very
small, white and transparent, and have a
much broader head, with shorter and thicker
antennae than the mature insect. They are
eleven weeks in attaining their full size.

C. columbarius (Bug of the pigeon). Fer-
ruginous-ochre; thorax deeply emarginate,
sides reflexed; abdomen orbicular, subacute
at the apex ; third joint of antennae slightly
longer than the fourth; length about 1-5".

C. hirundinis (Bug of the swallow). Fus-
co -ferruginous ; thorax slightly emarginate;
sides flat; abdomen ovate, subacute at apex;
antennae short, third and fourth joints nearly
equal; length about 1-7". Found in swal-
lows' nests.

C.pipistreUi (Bug of the bat). Ferrugi-
nous-ochre, shining ; thorax deeply emargi-
nate, sides slightly reflexed ; abdomen ovate,
posteriorly attenuate ; third joint of antennae
longer than the fourth; length 1-6". On
the common bat.

BIBL. De Geer, Mem. iii.; Dumeril, Cons,
gen. s. I. Ins.; Westwood, Introduction, Sfc.i
id. Brit. Cycl. Nat. Hist. i. 640; Jenyns,
Ann. Nat. Hist. iii. 1839. 241; Curtis, Brit.
Entom. xii. 569.

CINCHONINE. See ALKALOIDS. Cin-
chonine is insoluble in aether.

BIBL. See CHEMISTRY.

CINCLIDIUM, Swartz.— A genus of
Mniaceae (operculate Mosses arranged among
the Acrocarpi from prevailing habit), con-
taining two European species not yet re-
corded in Britain.

CIRCULAR CRYSTALS.— This term
has been applied to the flattened groups of
radiating crystalline needles formed by many
salts and other crystalline substances. The
term is, however, objectionable, as tending
to obscure their true nature. They form
beautiful polarizing objects. Among the
most interesting may be mentioned, boracic
acid, oxalurate of ammonia, salicine, and
sulphate of cadmium. They are further no-
ticed under their respective heads. Some
of them are figured in PI. 31. figs. 9-12.

See AMMONIA, OXALURATE OF, and
POLARIZATION.

BIBL. Brewster, Treatise on Optics, 1853.
p. 269.

CIRCULATION in ANIMALS. — The
movement in a temporarily or permanently
definite to-and-fro direction, of the nutritive
liquids of animals. We can only enumerate
here the articles in which will be found a
notice of the circulation, whether true or
spurious, as occurring in the most easily ac-
cessible or interesting organisms ; suffice it
to say, that circulation is produced either by
the agency of muscular or other contractile
tissue, or by the action of cilia. ASEL-
LUS, ARACHNIDA, ENTOMOSTRACA, IN-
FUSORIA, INSECTS (COCCINELLA, EPHE-
MERA, LARVAE, LIBELLULID^E), RANA,
TRITON.

CIRCULATION in PLANTS. See RO-
TATION and LATEX.

CIRRIPEDIA or CIRRHOPODA.—
An order of Crustacea. The barnacles or
acorn-shells.

Char. Marine animals, in the adult state
attached to other bodies ; enclosed in a mul-
tivalved shell or in a coriaceous involucre
furnished with calcareous points, the rudi-
ments of a shell; eyes none in the adult
state ; six pairs of feet, each with a short
fleshy peduncle, and two many-jointed horny
cirrhi ; mouth furnished with membranoso-
corneous mandibles and maxillae ; tail terete,
acuminate, reflexed between the legs ; body
not divided into segments, although there
are indications of them in the form of trans-
verse furrows on the dorsal surface. The
six pairs of arms or feet which are situated
on the ventral surface have each, supported
on a short peduncle, two long thin incurved
filaments, consisting of numerous joints, and

CLADOBOTRYUM.

[ 146 ]

CLADOSPOR1UM.

covered with hairs. The animals protrude
these filaments incessantly from the orifice
of the shell, and retract them, whereby wa-
ter for respiration, and, with the water, food
is brought into the shell. Cirripeds are
hermaphrodite .

The young Cirripeds, after leaving the
ovum, resemble some of the Entomostraca
(Cyclops, Cypris). They are unattached,
and possess eyes.

BIBL. Cuvier, Mem. du Mus. d'Hist. Nat.
ii. 1815; Saint-Ange, Mem. s. I. Cirrip.-,
Coldstream, Todd's Cycl. Anat. and Phys.,
art. Cirrhopoda ; Burmeister, Beit. z. Gesch.
d. Rankenfusser ; J. V. Thompson, Zool.
Researches, and Phil Trans. 1835, p. 355 ;
Darwin, Monograph of the Cirripedia, Ray
Society's Publ. 1851 and 1853; Bibl. of
ANIMAL KINGDOM.

CLADOBOTRYUM, Nees. See DAC-

TYLIUM.

CLADONIA, Fee.— A genus of Lecidineee
(Gymnocarpous Lichens), with a somewhat
shrubby thallus, abundant on moors and
heaths. The Rein-deer Moss ( C. ranaiferina)
is common in such localities.

BIBL. Hook. Brit. Fl. ii. pt. 1. 238;
Engl. Bot. pi. 173, 174, &c.

CLADOPHORA, Kiitz. — A genus of
Confervaceae(ConfervoidAlg8e),distmguished
by the branched habit of the attached fila-
ments. The Cladophorfe are interesting in
many respects, in particular for the thick,
laminated structure of the cell-wall, the spe-
cial projecting orifice in this by which the
zoospores are discharged, the large number
of the zoospores, and, lastly, by the favour-
able opportunity they afford of observing
cell-division in the growth of the branched
filaments. The filaments are composed of
cylindrical cells attached end to end, from
which the branches arise by the gradual pro-
trusion of a cylindrical pouch near the upper
end, which pouch, becoming shut off by a
septum, forms the first cell of the branch.
The cellulose wall acquires repeated layers
of thickening with age, and longitudinal and
transverse striae may be detected in these by
careful management. (See SPIRAL STRUC-
TURES.) The cellulose wall is lined by a
layer of protoplasm (primordial utricle), upon
the inside of which lies the chlorophyll, not,
however, really imbedded in it, as it is often
seen retracted from it in the centre of the
cell. At certain periods, numerous starch-
granules occur in the mass of chlorophyll,
but these disappear when the latter is about
to subdivide into zoospores. When this

takes place, the whole mass of chlorophyll is
contracted from the wall, and becomes broken
up, by a kind of segmentation, into a very
large number of 2-ciliated zoospores (these
sometimes occur in pairs, through imperfect
division). The zoospores, which are pro-
duced in all the cells, are discharged through
a special papilliform orifice in the cell-wall
(PI. 5. fig. 13); they have a distinct red
spot. Numerous supposed species inhabit
fresh, brackish, or sea-water in Britain;
some are very common and abundant ; but
it is difficult to draw out differential charac-
ters, as the habit appears to be very variable.
They are Conferva of older authors.

1. C. glomerata, Dillw., is 'of a dark green
colour, and grows commonly, in long drawn-
out skeins, in pure running water; but it
seems to be identical with the rarer C. cega-
gropila, L., which forms dense balls 2 to 4"
in diameter, in lakes, while there is also a
marine variety.

2. C. crispata, Sm., is perhaps not di-
stinct; it forms yellowish or dull green
strata, everywhere common in fresh water ;
frequent in" brackish water. It is the same
as C.flavescens, Roth. C.fracta, Fl. Dan.,
is probably a form of this.

The commonest marine species, which are
often found in large quantities on the sea-
shore, remarkable by their bright green tint,
are C. rupestris, L., Icetevirens, Dillw., al-
bida, Huds., lanosa, Roth., arcta, Dillw.,
and glaucescens, Griff. ; but some of these,
and of the rarer, appear doubtful. The species
require a careful study of fresh specimens in
all stages. Kiitzing (Sp. Alg.} has made an
inextricable mass of confusion of his species.

BIBL. Hassall, Br. Fr. Alga, p. 213. pi.
65-67; Harvey, Br. Mar. Alga, p. 199.
pi. 24 D ; Thuret, Rech. sur les Zoospores,
fyc., Ann. des Sc. nat. 3 ser. vol. xiv. p. 10.
pi. 16; Al. Braun, Verjungung, Sfc.(Rejuv.
in Nature, Ray Soc. Vol. 1853) passim-,
Mohl, Vermischte Schriften, p. 362. pi. 13.

CLADOPHYTUM, Leidy.— Probably the
mycelium of a fungus. Found in the intes-
tine of an lulus.

BIBL. See ARTHROMITUS.

CLADOSPORIUM, Link.— A genus of
Dematiei (Hyphomycetous Fungi). The
species C. herbarum is one of the commonest
moulds upon decaying substances of all sorts;
in this the mycelium spreads over the surface
as a dense or loose web of confluent tufts of
microscopic filaments, straight or curved,
more or less varicose, simple or branched ;
from these arise chains of spores, simple or

CLADOSTEPHUS.

CLAVICEPS.

with one or more septa, round, oval or long-
ish according to age, and finally becoming
detached from one another.

•1. Cl.herbarum, Lk. Tufts effused, at
first green, then black; spores olive, very
variable in habit. Everywhere common on
decaying substances. Corda, Ic. Fung. iii.
pi. 1. fig. 24 ; Fresenius, Beitr. zur Myk.
pi. 3. fig. 29; Dematium articulatum, Sowerby,
t. 400. fig. 8.

2. CL dendriticum, Wallr. On leaves of
pear-trees and hawthorn. C. pyrorum, Berk.
Gardn. Chronicle,} 848. 398. Helminthospo-
rium pyrorum, Desmaz. No. 1051. C. orbi-
culatum, Desm. Ann. des Sc. nat. 3 ser.
p. 2/5.

3. CL depressum, Berk. & Br. On living
leaves of Angelica. Ann. Nat. Hist. 2 ser,
vii. 97. pi. 5. fig, 8.

4. CL brachormium, Berk. & Br. On
leaves of Fumitory. Ibid.

5. CL lignicolum, Corda. On dead wood.
Corda, Icon. Fung. i. pi. 3. fig. 206.

6. CL nodulosum, Corda. On stems of
herbs. Corda, Icon. Fung. i. pi. 4. fig. 212.

CLADOSTEPHUS, Ag.— A genus of Ec-
tocarpaca3 (Fucoid Algae), containing two
common British species, C. verticlllatus and
C. sponyiosus, which grow on rocks and
stones, and form olive tufts a few inches
high, composed of rigid irregularly branched
cellular axes, clothed by whorls of short,
mostly simple, articulated branches. Harvey
states that the summer branches contain
dark grains in their withered tips, and are
deciduous, being replaced in winter by others
which bear numerous lateral stalked spores.
It is probable these represent respectively
the trichosporangia and oosporangia found
inEctocarpus, and that the so-called 'spores'
emit zoospores. See ECTOCARPUS.

BIBL. Harvey, Br. Mar. Alg. pi. 9 A;

130

Phyc. Brit. pi. 33 and 138.

CLADOTRICHUM,
Corda. — A genus of De-
matiei (Hyphomycetous
Fungi), forming dark floc-
culent points, or confluent
into powdery strata, on
dead stumps, &c. The
mycelium consists of rigid,
much - branched, septate
filaments, the upper joints
swollen; the spores in
chains together at the ends
of branches, and 2-, 3-sep-
tate, constricted in the

middle. Cladotrichum polysporum.

Magn. 200 diam.

1. CL triseptatum, Berk, and Broome.
Spores oblong, very obtuse, with three septa,
and constricted opposite the middle sep-
tum. Ann. Nat. Hist. ser. 2. vii. p. 98. pi. 5.
fig. 7- On a dead stump.

2. C. polysporum, Corda (fig. 132). Spores
2-septate. Corda, Icon. Fung. iv. pi. 6.
fig. 83; Prachtflora Eur. Schimmelbild.
(Polythrincium, Fries, Summ. Veg.)

CLAVARIA, Vaill.— A genus of Clavati
(Hymenomycetous Fungi), consisting of va-
riously branched fleshy fungi, growing mostly
on the ground, bearing their basidiosporous
fructification on the surface of the more or
less club-shaped branches. Some species 1"
high, others 1 foot.

BIBL. Hooker, Br. Flora, vol. ii. part 2.
p. 173.

CLAVATI.— A family of Hymenomyce-
tous Fungi, characterized by bearing basidio-
spores covering the tip and sides of branched
or simple club-shaped receptacles. See
BASIDIOSPORES, HYMENOMYCETES.

CLAVICEPS, Tulasne. — A genus of
Sphaeriacei (?) (Ascomycetous Fungi), con-
taining the plants which produce the ergot
of rye and other grasses. These plants have
recently been extricated from great confusion
by Tulasne, who appears to have placed their
history on a satisfactory basis.

The first sign of the attack upon the flower
of a grass is the appearance of the sphacelia
upon the outside of the nascent pistil; it
then enters into the outer part of the sub-
stance of the wall of the ovary, growing with
this until it forms a fungoid mass of the
same shape as an ovary, but obliterating the
cavity of the latter. At this time it is soft,
white, grooved on the. surface, and excavated
by irregular .cavities, which are connected
with the external folds or grooves ; the sur-
faces of these are all covered with parallel
linear cells, like a hymenium, and from the
extremities of these arise elongated, ellipsoid
or oval cells, about 1-5000" in length. These
become detached, and when they are placed
in water, germinate and emit filaments.
These bodies are spermatia, stylospores, or
perhaps conidia ; they exhibit no motion in
water, although they resemble the spermatia
of some other fungi. At this time Tulasne
calls the structure a spermagonium. At a
certain epoch a viscid fluid exudes from the
sphacelia, flowing over it and carrying about
multitudes of the spermatia or stylospores ;
but previously to this, a solid body, of a vio-
let colour on the surface and white within,
has originated at the base of the spermago-

L 2

CLEISTOGARPI.

[ 148 ]

CLOSTERIUM.

nium, and it gradually grows and rises out of
palese of the flowers, forming the spur or
ergot. This is not a metamorphosed seed
resulting from diseased conditions, but a real
new fungoid structure, the Sclerotium of
D.C. and others. When this ergot is sown
in the earth like a seed, it produces a num-
ber of little pedicles surmounted by thickened
heads, representing stalked Spharice (PI. 20.
fig. 18), and on these heads are ultimately
found fine points., which indicate the ostioles
of little conceptacles (fig. 19). The walls of
these conceptacles are lined with asci of
elongated clavate form (figs. 20, 21), with
linear, slightly clavate paraphyses. These
bodies are the Sphceria purpurea of Fries,
System. Myc.

Our space does not admit of our entering
further into detail; but it must be noted
that very varied opinions have hitherto pre-
vailed as to the nature of Ergot. Smith
and E. Quekett, as also Leveille, Phoebus,
Mougeot, and Fee, regarded the ergot as a
mere diseased form of the seed, associated
with a parasitic Fungus (Sphacelia, Lev., Fee,
Ergotcetia, Quekett).

The Sphacelia is often accompanied by a
Mucedinous fungus which is certainly not
the result of germination of the stylospores,
as might be imagined, but a distinct plant.

Tulasne describes three species :

1. C. purpurea, Tul. The ergot of grasses
—Sphceria entomorrhiza, Schum.; Sphceria
( Cordy ceps] purpurea, Fries; Kentrosporium
mitratum, Wallr.; Sphceropusfungorum,Gm-
bourt; Cordyceps purpurea, Fr. ; Cordyliceps
purpurea, Tulasne. On the flowers of
Grasses, such as rye, wheat, oats, and nu-
merous pasture grasses.

2. C. microcephala, Tul. Kentrosporium
microcephalum, Wallr. ; Sphceria microce-
phala, Wallr.; Sphceria Acus, Trog. ; Cordy-
ceps purpurea, var. Acus, Desm. On Phrag-
mites communis and Molinia ccerulea.

3. C. nigricans, Tul. On species of
Scirpus.

BIBL. Tulasne, Ann. des Sc. nat. 3 ser.
xx. p. 5-53. pi. 1-4, where all the other
literature is reviewed.

CLEISTOCARPI (Closed-fruited, i. e.
inoperculate). — An artificial division of the
Mosses. See MUSCACE^E.

CLENODON, Ehr.— A subgenus of No-
tommata, containing those species which
have only a single tooth in each jaw.

See NOTOMMATA.

CLIMACOSPHENIA, Ehr.— A genus
of Diatomacese.

Char. Frustules cuneate, divided into lo-
culi by transverse septa; valves obovato-
lanceolate, with moniliform vittse in the
front view. Marine.

C. australis. Very shortly stipitate ; sides
of the valves not (very faintly ?) striated.

On Algae from New Holland and South
Africa.

C. moniligera (PI. 19. fig. 9). Stipitate (?) ;
sides of the valves transversely striated
(a, front view ; b, side view).

In the Gulf of Mexico.

The nature of the stria? has not been de-
termined.

BIBL. Ehrenb. Abh. d. Eerl. Akad. 1841,
401 ; id. Bericht, 1843; Kiitzing, Eacillar.
123, and Sp.Alg. 114.

CLONOSTACHYS, Corda.— A genus of
Mucedines (Hyphomycetous Fungi), appa-
rently not distinct fromBotrytis. See B.vera.

BIBL. Corda, Prachtfl. europ. Schimmel-
bild. pi. 15.'

CLOSTERIUM, Nitzsch.— A genus of
Desmidiacese (Confervoid Algae).

Char. Cells single, elongated, attenuated
towards each end, entire ; mostly curved lu-
nately or arcuate ; junction of the segments
marked by a pale transverse band. Endo-
chrome green.

This beautiful genus is of great interest
to the scientific microscopic observer. Many
of the species are very common, so that
scarcely a drop can betaken from the bot-
tom of a clear pool without some of them
being contained in it.

Each cell is composed of two equal por-
tions, uniting at a transverse line occupying
the centre of the cell. The endochrome ex-
hibits longitudinal bands (PI. 10. fig. 40),
the number varying in different species, of a
darker green than the rest of the endochrome
(PL 10. fig. 40, 41, 43). Towards each end
of the cell is seen, in some, a circular
space (fig. 40), in which are a number of
moving molecules. In others, these mole-
cules appear to exist outside the endochrome,
or between it and the end of the cell. A
circulation is also visible between the cell-
wall and the surface of the endochrome ; the
motion of the liquid is irregular, but distinct
currents may be seen taking various direc-
tions. This circulation is quite distinct from
the molecular motion. It requires a high
power (400 diameters) to see it distinctly,
Focke attributes it to the action of cilia,
which he states to exist upon the internal
surface of the cell-wall ; the Rev. Mr.
Osborne has also recently described cilia upon

CLOSTERHM.

CLOSTERIUM.

the internal membrane. A number of trans-
parent vesicles are frequently visible in the
endochrome, sometimes scattered irregularly,
at others arranged in longitudinal series
(PI. 10. fig. 43).

The eudochrome consists of protoplasmic
substance coloured green (chlorophyll), and
at certain stages, starch is produced in this
as in the rest of the Algae. (See CHLORO-
PHYLL.)

The Closteria are reproduced in various
ways. The individuals divide, like the rest of
the Desmidiaeese, the separation taking place
transversely in the situation of the transpa-
rent space, where two new half-cells become
developed, subsequently separating. As
these new ' halves ' are often very small at
the epoch of separation, specimens occur
with the two portions very unequal. An-
other mode of reproduction is by conju-
gation. In this, a pair of individuals become
united somewhat in the same way as in the
Zygnemacese. Ordinarily, the individuals
conjugate by the convex side. The process
is described as follows: — The outer mem-
branes of the parents split circularly in the
situation of the central transverse space ; a
delicate internal membrane is protruded from
each, as a sac, and these meet and coalesce.
Sometimes the sacs are in pairs from each
parent-cell. (See CONJUGATION.) When
the cross process is complete, the contents
of both parent- cells pass into it and become
collected into a globular or squarish cell
(PI. 10. fig. 42 & 46). Different statements
are made with regard to the ultimate history
of this, and it is probably variable. Morren
states that it becomes a moving gonidium ;
while most authors state that it becomes a
resting spore with firm membranous coats.
Again, Morren describes the segmentation of
the green contents of this spore or gonidium
into a number of portions, each of which
becomes a perfect individual. Focke gives a
figure which seems to bear out this state-
ment, and it would find an analogy in the
mode of reproduction by active gonidia in
Pediastrum, described by Caspary and Al.
Braun. (See PEDIASTRUM.) Focke also
figures a condition of Closterium Lunula in
which the whole of the green contents of an
individual cell had become retracted from the
walls, and converted into a number of green
globular bodies, with proper coats, resem-
bling the resting spores found in many fila-
mentous Algae under certain conditions.
(See (EDOGONIUM and SPIROGYRA.)
The Closteria are capable of fixing them-

selves by one extremity to foreign bodies,
and Ehrenberg asserted the existence of a
footlike organ; but no such structure seems
to exist. The individuals also possess a
power of moving in water, but the nature of
this is inexplicable at present. The seg-
ments of the outer membrane separate from
each other when their contents decay, and
when they are dried. The membrane is co-
loured blue by sulphuric acid and iodine
(cellulose); in its natural condition it often
has a reddish tint, especially towards the
ends.

Analysis of species (British) : —

fCell suddenly narrowed at the ends r attenuatum,

l.<| into a conical point \ 1.1-57".

I Cell not suddenly narrowed 2

Cell striated, tapering into a beak at
ends, lower margin prominent at
middle 3

2. Cell very minute, beaked, straight,not f Griffithii*,

striated, nor lower margin promi- < 1. i-300 to

nent at middle I 1-450".

Cell not beaked; if striated, lower

margin not prominent at middle .. 6
f Beaks setaceous, as long as or longer

3. « than body 4

I Beaks linear, much shorter than body 5

f Beaks much longer than body { ^L^I Jgt/

4> \Beaks about as long as body {'if^JR

f Cells much inflated at middle, rapidly r Ralfsii,

I tapering at ends I 1. 1-79".

5'| Cell slightly inflated at middle, gra- f lineatum,

I dually tapering at ends 1 1. 1-48".

fCell minute, acicular; sporangium

fi ) cruciform 7

' 1 Cell not acicular ; sporangium orbi-

L cular 8

'Ends obtuse {"hTuO".

("Cell semilunate or semilanceolate,
lower margin inclined upwards at

_ ) ends 9

**1 Cell with either truncate ends, or
lower margin inclined downwards
I at ends 12

g J Vesicles numerous, scattered { j i^GO"

L Vesicles in a longitudinal row 10

f Ends of cell slightly curved upwards ; f turgidum,

10. J longitudinal striae distinct \ 1. 1-39".

| Ends of cell straight , striae none or

I indistinct 11

f Cell linear-lanceolate ; ends conical, ( acerosum §,

llJ obtuse il.l-70tol-58"

*-Cell semilanceolate; ends subacute -j a?Cf°g"//W7n'

f Cell not striated, crescent- shaped . . 13

12. < Cell either not orescent- shaped, or

I. else distinctly striated 17

r Vesicles numerous, scattered { j ''i!^'^"'

13. i Vesicles in longitudinal row 14

v Empty cell colourless, ends rounded 15

14. Empty cell usually reddish, ends

subacute 16

* PI. 10. figs. 57 & 58.

t PI. 10. figs. 45 & 46 (Conjugation).

J PI. 10. fig. 40.

$ PI. 10. figs. 41 & 42 (Conjugation).

COAL.

[ 150 ]

COAL.

15.

f Lower margin of cell inflated at middle { ff

V. l«l-/

\ Cell not inflated at middle { Je™ ^8

16.

f Cell inflated at middle

\l-90tol-l6o".

um,

1 Cell slender, not inflated at middle .. { ^"f

J Lower margin of cell inclined up-
wards at truncate ends ; longitudi- f didymotocum
i/ . , nal striae-none or indistinct ...... I 1. l-65"f.

I Ends of cell inclined downwards ; ) , a
I strise distinct .................. J 8

f Longitudinal strise 3 to 7, prominent 1 9
• 1 Longitudinal striae numerous, fine. . 20

f Cell semilunar or crescent-shaped . . { co

^"l«ni!

\, Cell hnear

20> C Cell narrowly linear, nearly straight {'ft
\ Cell tapering, curved .............. 21

{Longitudinal striae crowded, sutures r striolntum,
1 to 3 .......................... U.l-80tol-68".
Longitudinal strise not crowded, su- i intermedium
tures usually more than 3 ........ U.l-77tol-54//.

* PI. 10. fig. 43. t PL 10- fig. 44.

BIBL. Meneghini, Syn. Desmid. Linnaa,
xiv. 201 (1840); Lobarzewski, ibid. p. 2/8;
Ehrenb. Infus.-, Ralfs, Brit. Desmidiete-,
Dalrymple, Ann. Nat. Hist. 1840. v. 415 ;
Smith, ibid. 1850. v. 1 ; Meyen, Pflanzen-
physiologie, iii. 436, Sec.; Brebisson, Alg.
Falais.; Kiitzing, Spec. Alg. 163; Berkeley,
Ann. N. Hist. 2 ser. xiii. 256 ; Al. Braun,
Rejuvenescence, fyc., Ray Soc. Vol. 1853.
289, 292 ; Morren, Ann. des Sc. nat. 2 ser.
v. 257 ; Focke, Physiologische Studien, 1
Heft, 1847; Osborne, Quart. Journ. Mic. Sc.
iii. 54.

COAL. — This substance, although classed
from its mode of occurrence in nature in
the mineral kingdom, is in all cases of vege-
table origin. The degree, however, in which
traces of organic structure may be detected
in it vary extremely. Coal may be either
tolerably pure, containing but slight admix-
ture of earthy matters, or it may contain
large quantities of earthy substance, and
pass gradually into a carbonaceous impreg-
nation of an earthy basis, as in the various
modifications of bituminous shales. In the
next place the degree of metamorphosis of
the vegetable matter may be equally varied,
so that we have it still retaining its structure
very evidently, as in lignites, &c., or with
the structure greatly destroyed, or alto-
gether lost, as in much ordinary coal and
anthracite, which however are apparently of
somewhat different origin from the more
recent lignites. The old coal beds appear
to have been formed from deposits analogous
to our peat-bogs, and hence naturally consist
in great part of vegetables whose remains
soon became indistinguishable; but that arbo-

rescent vegetation was also present and
contributed to form the coal, seems proved
by the detection of woody structure like
that of the Coniferse in certain specimens of
coal. Sometimes the woody structure is even
evident to the naked eye in a charcoal-like
appearance of the fractured surface of coal.
In many lignites the coal consists of trunks
of trees converted into coal without much
alteration of the appearance of texture of
the wood, and in these the structure is very
readily made out by means of the micro-
scope. It would be out of place here to
enter upon the geological and chemical
questions connected with coal; the object
of applying the microscope to it is to ascertain
the existence or absence of organic structure.
For this purpose various methods are em-
ployed. That most in use is the preparation
of exceedingly thin slices in the manner
usually adopted for fossil structures, but the
brittle and opaque character of coal opposes
great difficulties here. Traces of structure
may be made out in some cases by grinding
coal to fine powder and examining the
fragments, but this plan is very unsatisfac-
tory. A third method is to burn the coal to
a white ash, and examine this under the
microscope; it often exhibits perfect skele-
tons of vegetable cells, but these are very
fragile and require great care in their
management. By imbuing them very cau-
tiously with turpentine and Canada balsam,
and placing on the covering glass wrhen the
latter has become rather firm, permanent
preparations may be often obtained. Schulze
recommends boiling in nitric acid before
incinerating the coal. The method which
has been attended with most success in our
hands is as follows. The coal is macerated
for about a week in a solution of carbonate
of potash ; at the end of that time it is
possible to cut tolerably thin slices with a
razor. These slices are then placed in a
watch-glass with strong nitric acid, covered
and gently heated; they soon turn brownish,
then yellow, when the process must be
arrested by dropping the whole into a saucer
of cold water, or else the coal would be
dissolved. The slices thus treated appear of
a darkish amber colour, very transparent, and
exhibit the structure, when existing, most
clearly. We have obtained longitudinal and
transverse sections of Coniferous wood from
various coals in this way. The specimens
are best preserved in glycerine, in cells ; we
find that spirit renders them opaque, and
even Canada balsam has the same defect.

COILEA.

[ 151 ]

COCCONEIS.

The proper identification of vegetable
structures in coal must of course depend
upon a sufficient knowledge of the characters
of vegetable tissues and organisms being
possessed by the observer.

BIBL. Witham, Internal Structure of
Fossil Vegetables, Edinb. 1833; Link, Ueb.
den Ursprung der Steinkohlen, fyc., Abhandl.
Berlin Akadem. 1838. p. 34; Goppert,
Preisschrift ueber Steinkohlen, Leiden, 1848;
Lindley and Hutton, Fossil Flora; Schleiden
and Schmidt, Geognost. Verhdltn. des Saal-
thales, Leipzig, 1846; Ehrenberg and Schulz,
Ber. Berlin Acad. Oct. 1844, Annals Nat.
Hist. xvi. p. 69 ; Bailey on Anthracite Coal,
Ann. Nat. Hist, xviii. p. 67 ; Unger, Genera
et Species Plant. Foss. 1850.

COB^EA, Cuv. — A climbing Dicotyledo-
nous plant, of the Nat. Order Polemoniaceae,
common in cultivation, remarkable for the
curious pyriform cells upon its seeds, con-
taining a spiral fibre (PI. 21. fig. 20). See
SPIRAL STRUCTURES.

COCCIDIUM.— A form of fructification
in the FLORIDE^E.

COCCINELLA, Linn. (Lady-bird). A
genus of Insects, of the order Coleoptera, and
family Coccinellidae.

C. septempunctata, the common lady-bird.
This insect exhibits the circulation through
the elytra. If one of these is separated
from the body without being detached, and
arranged in such manner that it may be
viewed as a transparent object, slow and
uniform continuous currents, one ascending
and the other descending, will be seen between
the laminae of which the elytrura consists.
On dividing the latter, an amber transparent
liquid containing colourless globules escapes.

BIBL. Nicolet, Ann. d. Sc. nat. 3rd ser.
7 ? ; Westwood, Introduction, SfC. ; Curtis,
Brit. Ent. 208 ; Stephens, Illustr. Brit.
Entom. ; Herrich-Schseffer, Synops. gen.
Coccinell., Deutschl. Ins. hft. 128.

COCCOCARPEJE. See CRYPTONEMI-

ACE^E.

COCCOCHLORIS, Sprengel (Palmo-
glcea, Kiitz.).— A genus of Palmellaceae
(Confervoid Algae), consisting of green mi-
croscopic cells, oval or globular, imbedded
in a gelatinous matrix, which is at first
definite in form(thus differing from Palmella},
and subsequently effused and shapeless. The
green cells are vesicles, filled with granular
colouring matter (chlorophyll) when in active
vegetation. They multiply by division, and
besides this, some of them grow much larger
than the rest, and have their contents con-

verted into a number of cells ; these large
cells become free from the general frond and
lay the foundation of a new one, originally
of definite form, which increases in size by
the division of the individuals within a per-
sistent gelatinous investment. Brebisson,
Ralfs and Al. Braun describe a process of
conjugation in C. Brebissonii. Two ordinary
cells come into contact, and their membranes
become fused ; the intermingled contents
then undergo a metamorphosis, brownish
oil-globules replacing the chlorophyll, and
the ' spore-cell ' thus produced passes through
a period of rest before resuming its vegeta-
tive development. Ralfs states that the
slender filamentous bodies sometimes found
in the frond are part of the organization of
the plant. We think there must be some
error here (see PALMELLACEAE). Several
British species are described :

1. C. protuberans, Spreng. Frond green,
irregularly lobed, spreading on the ground,
cells elliptical, about 1-3000", enlarged vesi-
cles 1-500 to 1-1000". Hassall, Br. Fr.
Alga, pi. 76. fig. 7, pi. 82. figs. 6-10 ; Pal-
mella protuberans, Grev. Sc. Crypt. Fl.
pi. 243. fig. 1.

2. C. muscicola, Meneghini. Hassall, I. c.
pi. 78. figs. 3 a, 3 b.

3. C. hyalina, Menegh. Aquatic. Hass.
1. c. pi. 78. figs. 2a,2b.

4. C. depressa, Menegh. Hass. 1. c. pi. 78.
4 a, 4 b.

5. C. Mooreana. Hass. I. c. pi. 78. \a,\b.

6. C. rivularis. Hass. I, c. pi. 78. 6 a, b.

7. C. Grevillei, Hass. Frond minute,
densely crowded, globose or somewhat lobed,
green. In heathy moist situations, frequent.
Hass. /. c. pi. 78. figs. 7 a, b and 8 ; Palmella
botryoides, Grev. Sc. Crypt. Fl. pi. 243.
fig. 2.

The plants are not yet satisfactorily under-
stood ; the relations to Palmella and Glceo-
capsa are confused.

BIBL. As above; also Meneghini, Monogr.
Nostochinearum ; Kiitzing, Phyc. generalis-,
Al. Braun, Rejuvenescence, fyc., Ray Soc.
Vol. 1853 (as Palmogleed) ; Ralfs, Ann. Nat.
Hist. ser. 2. vol. ii. p. 312 (as Palmella) ;
Nageli, Einzell. Algen. Zurich, 1849.

COCCONEIS, Ehr.— A genus of Diato-
maceae.

Char. Frustules single, depressed, adnate ;
valves elliptical, one of them with a median
line and central nodule.

The valves are mostly covered with dots
(minute depressions), appearing like lines
under a low power.

COCCONEMA.

[ 152 ]

CODIUM.

The upper valve differs from the adnate one
in not being furnished with the central no-
dule; under a low power it appears to have a
median line, as well as the adnate valve, but
this appearance, in some at least, arises from
the dots or markings at this part being more
closely in contact than elsewhere.

C. pediculus (PL 12. fig. 17). Frustules
very slightly arched (front view) ; valves
elliptical, striae longitudinal, faint ; length
1-1200 to 1-700"; aquatic.

C. placentula. Frustules flat; valves
elliptical; strise longitudinal, faint; length
1-760"; aquatic, common.

C. scuteUum (PL 12. fig. 18). Frustules
dorsally convex; valves ovato-elliptical, strise
transverse or slightly curved; length 1-700";
marine. /3. Nodule dilated into a stauros.

C. Thwaitesii (Achnanthidium flexellum,
Brebiss., Kiitz.). Ends of valves slightly
produced; aquatic; length 1-900".

C. Gremllii ~\ ,& -,1.x -»/r •

mith* Marme>

.

Many other foreign species.

BIBL. Ehrenb. Infus. ; Kiitzing, BacilL
and Sp Alg. p. 50; Smith, Brit. Diat. p. 21.

COCCONEMA, Ehr. - A genus of Diato-
maceae.

Char. .Frustules stipitate, navicular,
somewhat arched (side view) ; valves with a
submedian line, with central and terminal
nodules (= stipitate Cymbellai). Aquatic
(British).

The valves are transversely striated, the
striae being resolvable into dots (depressions).

C. lanceolatum (PL 12. figs. 19 & 20).
Front view of frustules lanceolate, truncate
at the ends ; valves semilanceolate, very
slightly inflated at the centre of the concave
margin; length 1-150''. Common. Stipes
dichotomous, jointed.

C. cymbiforme. Scarcely distinct from
the last (Sm.); stipites filiform, obsolete,
interwoven into a gelatinous mass; length
1-330".

C. cistula. Front view elliptic-oblong,
obtuse ; valves inflated on concave margin ;
stipes elongate, filiform, simple or subra-
mose; length 1-450"; common.

C. parvum (Sm.). Several other foreign
species.

BIBL. Ehr. Infus. ; Smith, Brit. Diat.',
Kiitz. BacilL and Sp. Alg. 59.

COCCUDINA, Duj.— A genus of Infu-
soria, of the family Plaesconina.

Char. Body oval, depressed or almost
discoid, often slightly sinuous at the margin;
convex, furrowed or granular and glabrous

above ; concave beneath, and furnished with
vibratile cilia and cirrhi or corniculate
appendages, serving as feet ; no mouth.

The species of this genus known to
Ehrenberg, are arranged among his Oxy-
trichina and Euplota.

C. costata (PL 41. fig. 3). Body obliquely
narrowed and sinuous in front, convex and
furrowed above, or with from five to six
very projecting tubercular ribs ; appendages
grouped at the two ends ; the anterior more
slender and vibratile; length 1-950"; in
marsh-water.

Three other species. Dujardin remarks that
Ehrenberg's genus Aspidisca belongs here.
BIBL. Dujardin, Infus. p. 445.
COCK-CHAFFER. See MELOLONTHA.
COCK-ROACH. See BLATTA.
COCOA-NUT. The seed of the Cocoa-nut
Palm, Cocos nucifera (Monocotyledon). Sec-
tions of the remarkably hard shell of this nut
afford good specimens of very greatly consoli-
dated woody tissue, while the fleshy contents
form an example of oily albumen, the soft,
thick-w7alled cells containing abundance of
drops of oil in their cavities. The husk of the
nut is composed of fibres analogous in their
structure to liber, and used for similar
purposes. See FIBROUS STRUCTURES.

CODIUM, Stackh .— A genus of Siphona-
ce8e(CoiifervoidAlgse). Marine. The species
have dark green spongy fronds of cylindrical,
flat, globular or crust-like form, composed
of interlacing continuous filaments devoid of
septa, terminating in radiant club-shaped
filaments at the surface (fig. 133). The spo-
Fig. 133.

Codium tomentosum.

Saccate cells arising from the filaments at the surface.
Magnified 10 diameters.

ranges (spores), are produced in lateral
branches from the clavate cells, forming
long elliptical sacs, the contents of which
are converted into a vast number of biciliated
zoospores, discharged when mature.

BIBL. Harvey, Br. Mar. Alg. pi. 24 A;
Phyc. Brit. pi. 93. 35 B. ; and Thuret, Ann.
des Sc. nat. 3 ser. xiv. 232. pi. 23. figs. 1 5,

CCELOCYSTIS.

COLEOCILETE.

CCELOCYSTIS, Kiitz. Probably a resting
form of EUGLENA.

CCELOSPFLERIUM, Nag. Probably the
same as COCCOCHLORIS.

CCENURUS, Rudolph!. — A supposed
genus of Entozoa, placed in the order Ste-
relmintha, and family Cystica.

Char. A simple vesicle, filled with an
albuminous liquid, upon the outer surface of
which a number of soft, short, retractile, cylin-
drical and rugose, rather than jointed bodies
are situated. The head of each resembles
that of a T'enia, having four disks and a
crown of hooks.

Recent researches have shown that the
single supposed species, C. cerebralis(P\.\6.
fig. 10), is the larva of a new species of Teenia,
allied to T. marginata.

It occurs in the brain of sheep, producing
the " staggers ; " sometimes also in that of
the Horse, the Ox and the Rabbit. The vesi-
cle is as large as the egg of a hen or a
pigeon. The bodies when extended are
about the 1-5 or 1-6" in length. When
retracted they appear to the naked eye as
opake white specks.

BIBL. Dujardin, Hist. nat. d'Helminthes,
p. 636; Kiichenmeister, Cosmos, iv. p.
388.

COFFEE.— The "berries," as they are
vulgarly called, of coffee, are the seeds of
Coffcea arabica, a Dicotyledonous plant, of
the Nat. Order Cinchonaceae. The bodies
consist chiefly of the hard homy albumen (see
ALBUMEN of plants), and this being com-
posed wholly of cellular tissue, it is possible
to ascertain the presence of adulterations
in ground coffee in many instances. Thus
chicory, parsnips, carrots and similar sub-
stances roasted and ground up with coffee,
may be detected by the presence of fragments
of the ducts and vessels of various characters
which occur in these roots.

COIR. — The term coir-rope is applied to
cordage manufactured from the fibrous tissue
of the husk of the cocoa-nut. See FIBROUS
SUBSTANCES.

COLACIUM, Ehr.— A genus of Infusoria,
of the family Astasiaea.

Char. Not clearly determined. A single
eye-spot (sometimes absent) ; body fixed by
a pedicle, which is either simple or branched.
Parasitic upon Entomostraca and Rota-
toria. A vibratory organ is present in front,
but whether consisting of a flagelliform
filament or a number of cilia is unknown.

C. vesiculosum (PI. 23. fig. 32). Ovato-
fusiform, variable, internal vesicles distinct,

pedicel very short, rarely branched ; bright
green; length 1-860".

C. stentorium. Cylindrical, conical or fun-
nel-shaped, variable, internal vesicles less
distinct, pedicel generally ramose; bright
green; length 1-1150".

BIBL. Ehr. Infus. 115.

COLEOCILETE, De Brebiss.— A genus
of Chaetophoracese (Confervoid Algae), of
which one species, C. scutata, is apparently
pretty common in freshwater pools, forming
minute green disks (fig. 134 ) adhering to
Fig. 134. Fig. 136.

Coleochaete scutata.

Fig. 134. A perfect plant. Magnified 25 diameters.

Fig. 135. Propagula from the back of the frond. Mag-
nified 50 diameters.

Fig. 136. Commencement of the development of a frond
from a propagulum. Magnified 10 diameters.

leaves, to the larger Confervae, sticks, &c.,
also to the sides of glass vessels in which
aquatic plants are kept growing. The disks
are formed of a number of dichotomous fila-
ments radiating from a central cell and
cohering laterally, the whole being closely
applied on the surface of support, so that
the discoid form is occasionally modified by
this (we have seen it forming a kind of cup
and irregular fan-like lobes, on the ends of
the articulations of Hydrodictyori). In cer-
tain cases the filaments are more or less free
from their lateral union. The contents of
the cells are as usual in this family ; Ralfs
was in error in stating that they are collected
in the centre; this is only the case when about
to be converted into zoospores, or when
dried. From the back of many of the cells
projects a long tubular process (fig. 134),
with a bulbous base ; this is at first closed,
but afterwards open and slightly everted at
the mouth, from whence emerges a very
slender bristle. The nature of this structure

COLEOSPORIUM.

[ 154 ]

COLEPINA.

is very obscure; it is best seen by drying the
specimens. The plants are reproduced
by zoospores and by spores. The former
are produced singly in the cells, from the
whole contents, bear two cilia, and break
out at the back of the cell in C. scutata,
from the side in C. pulvinata. The (resting)
spores are formed in cells near the margin, in
penultimate cells of the radiating filaments,
on the back, therefore, in C. scutata, at the
ends of the branches in C. pulvinata. A
curious process is described by Al. Braun,
as occurring in connexion with this in C. pul-
vinata : the cell about to become a sporange
enlarges, and while its contents become
converted into 5 to 8 resting spores,it acquires
a kind of cellular coat, through growth of
cellular branchletsfrom the preceding and the
surrounding cells, which branchlets meet and
enclose it. The bodies figured in the cut
(fig. 135) occur on the backs of the fronds,
according to De Brebisson, but he does not
state how they originate, perhaps they are
germinating zoospores which have come to
rest in this situation ; the young plant (fig.
136) appears to be formed from these by
cell-division.

C. scutata, De Breb. (Phyllactidium,
Kiitz., Phyc. gen.) (fig. 134). Fronds dis-
coid, sporanges on the back. On aquatic
plants, &c., common (?). A variety, /3 soluta,
occurs with the radiating filaments more or
less free.

C. pulvinata, A. Braun. Fronds com-
posed of tufted-branched, radiant, free fila-
ments, sporanges globose, at the ends of the
filaments. Chcetophora tuberculata, C. Mull,
according to Kiitzing. (This has not yet
been detected in Britain.)

BIBL. De Brebisson, Ann.des Sc.nat. 3ser.

1. p. 29. pi. 2; Ralfs, Ann. Nat. Hist. xvi.

p. 309. pi.

pi. 77; Al. Braun, Rejuvenescence, Ray Soc.

10; Hass. Brit. Fr. Alg. 217-

Vol. 1853, passim; Kiitzing, Species Alg.
424 ; Miiller, Regensb. " Flora," xxv. B. ii.
p. 513. pi. 3. 1842.

COLEOSPORIUM, Leveille'.— A genus
of Caeomacei (Coniomycetous Fungi), sepa-
rated by some authors from Uredo, but at
present not clearly shown to be distinct and
independentplants(seeUBEDo). Thesefungi,
which may be well observed in C. Senecionis,
Schlecht., and other common species, appear
as yellow, reddish or brownish pulveru-
lent spots upon the leaves of living plants.
Their mycelium, creeping in the intercellular
tissues of the plants upon which they are
parasitic, consists or delicate branched fila-

ments, which collect together at certain
points, become interwoven, at the same time
acquiring orange or yellow cell-contents, so
as to form a flat cushion-like body (clinode
or stroma}. From this arise vertical or
radiating, branched, club-shaped, sac-like
prolongations of some of the filaments, which
club-shaped sacs or tubes become the spo-
rangia ; the oldest are found in the centre,
the youngest at the circumference of the
group. The club-shaped sporanges, filled
with yellow or brown contents, become firmly
coherent laterally (at this stage they consti-
tute Uredo tremellosa). The first spore is
formed near the summit of the clavate spo-
range, leaving a little clear space at the tip ;
then a second spore below the first, and so
on to a third and fourth, occasionally to
a fifth; these increase in size so as to conceal
the existence of the sac in which they are
contained ; only the tips of all the laterally
coherent sacs or sporanges, left empty in
the spore-formation, form by their union a
transparent layer, presenting, when seen
from above, somewhat the appearance of the
corneae of the compound eye of an insect.
This lamella is burst open, with the epider-
mis of the infected plant, and the spores,
which grow into oval and globular forms,
become detached from one another and lie
loose, forming the yellow, red or brown
pulverulent spots above alluded to. The
spores have a granular cuticle and their coat
is double. British species (we cannot find
distinctive characters) :

1. C. synantherarum, Fries. On Colt's-
foot, &c., common. Ur. compransor, Schlecht,
(in part) ; U. tussilaginis, Pers.

2. C. senecionis, Fr. On Groundsel, com-
mon. U. senecionis, Schlecht.

3. C. campanulacearum, Lev. On Cam-
panula. U. campanula, Pers.

4. C. rhinanthacearum, Lev. On Eu-
phrasia, &c. U. rhinanthacearum, D.C.

5. C. pulsatillarum, Fr. U. pulsatillarum,
Strauss.

6. C. pinguis, Lev. On leaves, &c. of
roses, common. U. effusa, Strauss; Grev.
Sc. Crypt. Fl. t. 19.

BIBL. Leveille, Ann. des Sc-. nat. 3 ser.
viii. 369; De Bary, Brandpilze, Berlin, 1853,
p. 24. pi. 2; Fries, Summa Veget. p. 512;
Berk, in Hook. Br. Fl. ii. pt. 2. 377-9, &c.

COLEPINA, Ehr.— A family of Infusoria.

Char. Carapace barrel-shaped, traversed
longitudinally or transversely, or both, by
furrows, between which are situated minute
vibratile cilia ; truncate, and either smooth

COLEPS.

or dentate in front; posteriorly terminated
by from two to five points or teeth; aquatic.

Ehrenberg states that the oral and anal
orifices exist at the opposite ends of the
body. Tbe gastric sacculi are readily filled
with colouring matter. Motion that of revo-
lution upon the longitudinal axis.

A single genus : Coleps,

COLEPS, Ehr.— A genus of Infusoria, of
the family Colepina.

Char. Those of the family.

These animals are very voracious, and feed
freely upon the portions of the body of crushed
Entomostraca, which attract them as much
as sugar attracts flies.

C. hirtus (PL 23. fig. 33 a, Ehr.; fig. 33 b,
Duj.). Oval, white, carapace tabulate,
furrows transverse and longitudinal ; poste-
rior teeth three (two, Duj.) ; length 1-5/0
to 1-430".

/3 elongatus. Cylindrical, elongate, length
as in the last.

C. viridis. Ovate, furrows transverse and
longitudinal, green, posterior teeth three;
length 1-960 to 1-570".

C. amphacanthus. Ovate, carapace divided
by transverse furrows only, anterior teeth
unequal; posterior teeth three, large; length
1-280".

C. incurvus. Oblong, nearly cylindrical,
slightly curved, white, posterior teeth five ;
length 1-430".

BIBL. Ehr. Infus. 317 ; Duj. Infus. 365.

COLLEMA, Ach.— A genus of Colle-
maceee (Gymnocarpous Lichens), contain-
ing a number of indigenous species, remark-
able for the peculiar gelatinous character of
the frond and the beaded arrangement of
the gonidia, mostly growing on the ground
or among Mosses in damp places. Tulasne
has shown that they produce spermagonia,
with spermatia, which are generally imbedded
in the substance of the frond, opening by a
terminal pore (PL 29. fig. 13). The fronds
are mostly dark olive or blackish-green.

BIBL. "Hook. Brit. Flora, v. p. 1. 211.
See also under COLLEMACE.E.

COLLEMACE.E.— A family of Gymno-
carpous Lichens, known by the gelatinous
character of the (fresh) thallus, which is com-
posed of two kinds of filaments (see Li-
CHENES), some branched and cylindrical,
others (gonidial) moniliform (PL 26. fig. 13),
the former gradually combined into the ex-
cipula supporting the thecae and paraphyses,
constituting the apothecia. The spermagonia
are formed in a similar manner. Some authors
have imagined that the Nostochacese are

L 155 1 COLLOID MATTER.

early conditions of Collema, but this assump-
tion does not seem to be warranted. British
genus :

Collema. Thallus of uniform texture,
gelatinous when fresh, when dry generally
becoming hard and cartilaginous, polymor-
phous, granulated, foliaceous, lobed, lacini-
ated or branched. Apothecia circular, sessile,
rarely slightly elevated, bordered, formed of
the substance of the thallus, the disk some-
times coloured.

BIBL. Tulasne, Mem. sur les Lichens, Ann.
des Sc, nat. 3 ser. xvii. 29 & 202. pi. 6 & 7 ;
Fries, Summa Veget. 175; Itzigsohn, Botan.
Zeit. xii. p. 521. 1854.

COLLENCHYMA.— A peculiar kind of
thickening of cellular tissue in the subepi-
dermal layers of many herbaceous stems,
such as Rumex, Beta, Chenopodium, &c.,
which some have regarded as intercellular
substance, while others, more correctly, have
stated it to consist of metamorphosed second-
ary layers inside the cells. See for the dis-
cussion, INTERCELLULAR SUBSTANCE.

COLLETONEMA, Brebisson.— A genus
of Diatomacese.

Char. Frustules navicular, connate, ar-
ranged in rows, and immersed in a gelatinous
amorphous mucus, forming a filiform frond.
Aquatic.

C. viridulum. Frustules crowded and spi-
rally arranged ; front view linear-oblong,
truncate, slightly and gradually attenuate
towards the ends; valves lanceolate, obtusish,
not striated (?) ; length of frustules 1-610";
breadth of frond 1-670 to 1-450".

Doubtful species :

C. (?) amphioxys (Naunema amp., E.).
Mexico.

C. (?) americanum (Naun. amer., E.).
Hudson's River.

BIBL. Kiitzing, Sp. Alg. 105.

COLLOID MATTER, EXUDATION and
CORPUSCLES (animal).

The term colloid matter or exudation is
applied to a transparent, viscid, yellowish,
structureless or slightly granular matter,
resembling liquid gelatine. In a state of
greater consistence, it sometimes forms flakes
or irregular masses, which occasionally pos-
sess a laminated structure.

In a third form it constitutes spherical,
rounded or oval, sometims flattened micro-
scopic corpuscles — simple masses of sarcode
(PL 30. fig. 22 a). These are either homoge-
neous, or exhibit numerous laminae (concen-
tric colloid corpuscles) (PL 30. fig. 22 b) ;
sometimes a kind of nuclear body is present

COLLOMIA.

[ 156 ] COLOURING MATTERS.

(fig. 22 c), at others they contain carbonate
and phosphate of lime (fig. 22 d). Sometimes
they exhibit a radiate appearance (fig. 22 e).
In the liquid form, colloid exudation is
found within cysts in the thymus and thyroid
glands, the ovary, &c. ; and within the
enlarged areolse of areolar tissue around
these organs, &c. It is found in a free
state upon the surface of inflamed serous
membranes.

The colloid corpuscles are met with in the
hypertrophied heart, in the prostate (both
male and female), the thyroid and the thymus
glands, in the choroid membrane, in the
brain and spinal cord, and in the (waxy)
spleen, &c.

The liquid colloid matter generally consists
of a proteine- compound ; it becomes of a
gelatinous consistence, retaining its trans-
parency, or turbid and opake, by heat. The
colloid corpuscles do not, however, appear
to be uniform in composition; sometimes
they consist of a proteine-compound ; at
others, probably, of cellulose or amyloid, as
in the brain (true CORPORA AMYLACEA).
These bodies are further noticed under the
heads of the tissues and organs in which
they occur. See also TUMOURS (Colloid
cancer}.

BIBL. Rokitansky, Handb. d. Path.Anat.
bd. 1. p. 304; Wedl, Grundzuge d. Path.
Histol. ; Forster, Hand. d. Spec. Path. ;
Virchow, Arch. f. Path. Anat. v. ; Hassall,
Micr. Anat. &c.

COLLOMIA, Nutt.— A genus of Polemo-
niacese (Dicotyledons) remarkable for the
spiral structures produced in the epidermis
of the seeds (PI. 21. fig. 22) (see SPIRAL
STRUCTURES). The gummy substance in
which fibre is imbedded is soluble in water
and not in spirit, therefore the best way to
observe the elastic opening of the spiral
fibres is to make fine sections of the coat of
the seed and place them in a little spirit of
wine, upon a slider, with a covering glass :
to adjust the focus, and then to add water
carefully at the side of the covering glass so
as to wash away or dilute the spirit.

COLOSTRUM.— The first liquid secreted
by the mammary glands. See MILK.

COLOUR. See INTRODUCTION, p. xxix.

COLOURING MATTER, OF ANIMALS.
See PIGMENT.

COLOURING MATTERS, OF PLANTS.
The green colour of vegetables depends upon
the presence of CHLOROPHYLL, and is
spoken of under that head. The red and
yellow colours assumed by leaves and herba-

ceous shoots in autumn, depend upon a
chemical metamorphosis of the chlorophyll,
or on its absorption and the discoloration of
the cellular tissue. The red colour presented
by many of the lower Algae, such as some of
the Palmellacese, appear also to depend upon
a metamorphosis of the chlorophyll, con-
nected with the vital processes ; it is met
with also in the contents of the resting
spores of many of the filamentous Confer-
voids. We have found the protoplasm assu-
ming a reddish colour in the punctum
vegetationis of the buds of Monocotyledons
in the autumn, which probably depends upon
a similar cause. The bright colours of
flowers and other parts of the inflorescence
of plants, as also of the lower surface of
many leaves (Begonia, Victoria, &c.) and
herbaceous shoots, arises from the presence
of matters of a different kind, almost always
dissolved in the watery cell-sap. The colour
of petals is ordinarily found to depend upon
a certain number of the cells subjacent to
the epidermal layer being filled with a
coloured fluid ; and the depth of the colour
is proportionate to the number of superim-
posed layers of such cells, which act like so
many layers of a pigment. Each cell is
usually filled with one colour when fully
developed, but adjacent cells are often seen,
in variegated petals, to contain distinct
colours, the line of demarcation being accu-
rately fixed by the cell-walls, through which
the colours do not transude, unless the cells
are injured by pressure. In young tissues
the colour often has a granular appearance
in the cells, but this is a deception arising
from the mode in which the colour is deve-
loped. The colourless protoplasm originally
filling the cells becomes excavated, as it were,
by water bubbles, and the watery contents
of the excavations become coloured; they
gradually enlarge, as the protoplasm applies
itself more completely to the walls of the
cell, until they become confluent and the
coloured liquid fills the whole cell-cavity.
We have observed this pseudo-granular
appearance in the cells of the flowers of
Orchis Mono, in the cells of the lower
surface of the leaf of Victoria, and other
cases.

In some cases the liquid colouring matters
of flowers have been found to contain solid
corpuscles; the red colour-cells of Salvia
splendens, and the blue ones of Strelitzia
regina, contain globules, and according to
von Mohl, this is still more commonly the
case with the yellow colours ; in the yellow

COLPODA.

[ 1*7 ]

CONCRETIONS.

perigonial leaves of Strelitzia regina the
yellow colour is said to depend upon the
presence of crescentic and curled filaments
floating in the cell-sap.

The white patches upon variegated and
spotted leaves, such as those of Aucuba,
Holly, variegated Mint, Begonia argyrostig-
ma, &c., &c., arise from the absence of
chlorophyll in the cells subjacent to the
epidermis at those parts, which produces
the same effect as we see in leaves mined by
caterpillars.

COLPODA, Schrank, Ehr.— A genus of
Infusoria, of the family Colpodea.

Char. No eye-spot, tongue-like process
present, ventral surface ciliated, dorsal not.

Dujardin says : " Body sinuous or notched
on one side, sometimes reniform, surface
reticulated or marked with nodular obliquely
interlacing striae ; mouth lateral, situated at
the bottom of the notch, and furnished with
a projecting lip.

C. cucullus (PI. 24. fig. 25). Turgid,
slightly compressed, reniform, often nar-
rowed "in front; length 1-1720 to 1-280".
Common in vegetable infusions. Ecdysis
has been observed in this animalcule.

Stein describes the encysting process and
reproduction from spores as occurring in
this infusorium. There can be little question,
however, that his observations apply to
Paramecium chrysalis, E. (Pleuronema chr.,
Dm.)-

C. ? ren. Ovato-cylindrical, reniform,
rounded at the ends; aquatic; length 1-280".

C. ? cucullio (Loxodes cue., Duj.). Com-
pressed, flat, elliptical, slightly sinuous in
front; aquatic; length 1-900''.

BIBL. Ehr. In/us. 347; Duj. Infus. 478;
Stein, Infusionsth. 15, &c.

COLPODEA,Ehr.— A family of Infusoria.

Char. Gastric sacculi present; no cara-
pace ; oral and anal orifices distinct, neither
at the ends of the body.

Body usually covered with longitudinal
rows of cilia. The sacculi can be filled with
colouring matter.

Genera :

No eye-spot.
A tongue-like process.

No cilia on the dorsal surface . . Colpoda.

Cilia on every part Paramecium.

No tongue-like process.
Body narrowed and prolonged in

front(proboscis,E.),tailpresent Amphileptus.
Proboscis absent, tail present . . Uraglenu.
An eye-spot Ophryoglena.

BIBL. Ehrenb. Infus. 345.

COLURELLA, Bory, Duj. = Colurus,
Ehr.

COLURUS, Ehr. — A genus of Rotatoria,
of the family Euchlanidota.

Char. Two frontal eye-spots ; tail-like foot
forked ; carapace cylindrical or compressed.

Carapace openbeneath; cervical appendage
curved; jaws with 2 or 3 teeth each.

C. deflexus (PL 34. fig. 12, dorsal view;
13, ventral view; 14, teeth). Carapace ovate,
compressed, its posterior points long and
directed downwards ; terminal points of foot
(toes, E.) shorter than the foot itself; length
of carapace 1-240". Aquatic.

C. caudatus. Carapace ovate, compressed,
posterior points of carapace distinct, points
of foot longer than the foot itself; aquatic
and marine ; length 1-240".

C.? uncinatus and bicuspidatus are doubt-
ful species.

BIBL. Ehr. Infus. 475.

COMPRESSOR. INTRODUCTION, p.xx.

CONCEPTACLE.— A form of fructifica-
tion in the FLORIDE^E and FUCOIDE^E.
Also applied to the fructification of some
Fungi.

CONCRETIONSandCALCULL— These
terms are rather indefinite. A hard body
of considerable comparative size, formed
within an animal organism, would be called
a calculus; whilst a body of considerable
comparative size in which hardness was not
a marked feature, or a hard body of small or
microscopic dimensions, would be called a
concretion. Under the latter term, the no-
tion of a compound structure is usually
implied. Calculi generally consist of various
organic and inorganic substances entering
into the composition of tke secretions of the
body, which are precipitated from various
causes. Those found in the intestinal canal
are mostly composed of undigested vegetable
tissues derived from the food. Most, if not
all, calculi and concretions are mixed with
animal matter (proteine-compounds) derived
from the mucous cavities in which they are
contained, or simultaneously precipitated,
with their characteristic components, from
the secretions in the midst of which they are
formed. Hence when the proper calculous
matter is dissolved by a reagent which exerts
little or no action upon the animal matter, a
mass is left which exhibits the form of the
original body.

Calculi and concretions enlarge by the
deposition of new matter upon their outer
surface ; and as this deposition is not uni-
form and uninterrupted, either in regard to

CONDENSER.

[ 158 ]

CONFERVOIDE.E.

the nature or proportion of the respective
constituents, they mostly exhibit a laminated
structure. This is visible to the naked eye
in the larger ones, and evidenced in those
which are microscopic by the appearance of
concentric rings, and of a nucleus or nuclei.
These concentric rings and nuclei are dis-
tinguishable equally in concretions formed
artificially and in those occurring naturally.

It has been imagined that urinary concre-
tions and calculi owe their origin to a process
of cell-secretion. We believe this view to be
untenable.

BIBL. Taylor, Hunterian Catalogue, Cal-
culi-, Quekett,Mec?. Times, 1851. xxiv.p.551;
Griffith,Med. Times and Gaz.1852. xxv. p. 272;
and the Bibl. of CHEMISTRY, ANIMAL.

CONDENSER, ACHROMATIC.— IN-
TRODUCTION, p. xvi. We omitted to no-
tice that the "new condenser" mentioned at
p. xvii. is called after the inventor, "Gillett's
Condenser."

CONDENSER, BULL'S-EYE, &c.,
for opake objects. INTRODUCTION, p. xviii.

CONFERVA, Plin.— A genus of Confer-
vaceae(Confervoid Algae), which, as restricted
here, contains chiefly marine species ; but
we have thought it advisable to retain in it
the species separated by Kiitzing as Chteto-
morpha and Thuret as Microspora, so that
our Conferva corresponds to Hassall's pro-
posed genus Aplonema. The plants consist
of unbranched filaments, composed of cylin-
drical cells, the length and diameter of which
have a very variable relation in different spe-
cies. They are reproduced by zoospores
formed from the cell-contents. Al. Braun
says that C. bombycina produces four in a
cell. According to Thuret, C. area produces
large numbers, which escape by a lateral
orifice, while the species he describes as Mi-
crospora Jloccosa forms a number which
escape by a circular dehiscence breaking up
the filaments. The zoospores are 2-ciliated
in general, but sometimes bear four. The
spores have not been observed ; and hence
Kiitzing has suggested that C. bombycina,
and the other species of Conferva he ad-
mits, may be young states of (Edogonium,
but the true (Edogonia produce solitary zoo-
spores with a crown of cilia. British spe-
cies:

Freshwater.

1. C. bombycina, Ag. Filaments 1-360 to
1-180" in diameter, four or five times as long,
forming a yellow-green cloudy stratum.
Common in stagnant water. Dillw. Con-
fence, pi. 60.

2. C. jloccosa, Ag. (PI. 5. fig. 116). More

robust; articulations once or twice longer

than broad. Microspora jloccosa, Thuret,

Ann. des Sc. nat. 3 ser. xiv. pi. 17. fig. 6, 7.

Marine.

Thirteen species are described by Harvey
(Brit. Marine Algce), of which C. area, Dillw.
is one of the commonest, remarkable for the
large size of the tufted filaments, as thick as
hog's-bristles, growing 3 to 12" long, of a
yellow-green colour. C. Melagonium, Web.
and Mohr, has erect tufted filaments equally
thick, while C. Linum, Roth, has entangled
filaments twice as thick, deep glossy green,
and many feet long.

The cell- walls of these large marine species
present a curious striated appearance when
treated with acids, which has led J. Agardh,
apparently erroneously, to suppose they are
composed of spiral filaments. (See SPIRAL
STRUCTURES.)

BIBL. Harvey, loc. cit. Phyc. Britan. ;
Thuret, loc. cit.', Kiitzing, Species Alg.-,
Hassall, Brit. Freshw. Alg. 213 ; Al. Braun,
Rejuvenescence, fyc., Ray Soc. Vol. 1853.
p. 184.

CONFERVACE^E.— A family of Confer-
voideae. Marine or freshwater Algae ; com-
posed of articulated filaments, simple or
branched, without enveloping gelatine ; cells
cylindrical, shortish, not conjugating. Re-
production by zoospores and globular spores
produced from the cell-contents.

Synopsis of the British Genera.

1. Cladophora. Filaments tufted, much
branched. Sea and freshwater. Zoospores
minute, many in a cell.

2. Rhizoclonium. Filaments decumbent,
with small root-like branches. Zoospores
minute, numerous. Sea, brackish, and fresh-
water.

3. Conferva. Filaments unbranched.
Zoospores minute, numerous in the cells.
Sea, brackish, and freshwater.

4. (Edogonium. Filaments simple, with
very thick walls and mostly short joints,
often swollen to produce a spore or a zoo-
spore, and with annular striae near the cross
septa. Zoospores single, large, composed of
the entire contents of a cell, crowned with a
wreath of cilia. Freshwater.

BIBL. See the genera.

CONFERVOIDE^E or CHLOROPO-
RE^.— An order of Algae. The Chloro-
spores or Confervoids, the lowest order of
the Algse, display a preponderating number
of truly microscopical plants, and constitute

CONFERVOIDE.E.

[ 159 ]

CONFERVOIDE.E.

one of the favourite and most instructive
fields of microscopic research. As yet, how-
ever, the minute history of development is
wanting in a very large number, while the
facts already disclosed are so varied, that it
becomes a matter of difficulty to draw up a
sketch of their characteristics in a brief space.
The classification of the tribes standing on
the boundaries between the Coufervoids and
the Fucoids is in an unsettled condition, and
the real nature of the fructification of the
Lemanieae and Batrachospermeae may be
considered open to doubt. The detection by
Thuret of zoospores in so many of the true
Fucoids, takes away the ground on which
these two families have been included in that
order; and at present we prefer to leave them
among the Confervoids, where, however, it
is true they stand in rather an isolated posi-
tion ; but the forms of reproduction are
so varied here, that this seems of the less
consequence.

Among the Palmellaceae we find some of
the simplest forms of vegetable life, where
the organization is reduced to the condition
of a single microscopic membranous vesicle,
enclosing nitrogenous contents, ordinarily
tinged with chlorophyll, and containing
starch. Such we have in Chlorococcum vul-
gare, which forms the dryish green powder
upon palings, trunks of trees, &c. This
form appears to multiply only by the subdi-
visions of its cells into two or four new ones,
which separate and repeat the process. It
is a somewhat doubtful plant, but if a di-
stinct organism, it is the lowest of the Algae.
Advancing a step, we come to a number of
genera not yet well defined, in which the mem-
branes of the parent-cells soften into a kind
of gelatine, during the process of subdivision,
and hold the new cells together in groups of
definite or indefinite form ; among these are
Palmella, Glceocapsa, and others of like na-
ture, in which at present no zoospores have
been discovered. In Coccochloris a process
of conjugation occurs. Side by side with
Chlorococcum,^ regards organization, stands
the genus Protococcus, in which, in addition
to the vegetative growth by subdivision
going on in damp air (the cells being held
together more or less firmly into a gelatinous
crust), the contents of the individual cells
are set free by solution of the membranes
when placed in water, and emerge as ciliated
zoospores, endowed with active motion.
These genera also exhibit a resting form,
characterized by the increased thickness of
the membrane of the cell, and a change of

the green contents into a brownish, reddish,
or even crimson colour.

The Ulvaceas are not widely separated
from the Palmellacese, but the conjunc-
tion of the cells into a definite membrane
indicates a higher organization. In other
respects, however, they hardly differ more
from some of the more perfect genera of
Palmellaceae than those do from Protococcus ;
and therefore, although more conspicuous
and extensively developed than the Nosto-
chaceae and Desmidiaceae, it seems natural to
place the Ulvaceae near the Palmellaceae, espe-
cially as the reproduction by cell-division and
by zoospores is analogous in all respects to
what is seen in Protococcus, of which they
would appear to be the permanently aquatic
representatives. Prasiola and Schizogonium,
however, differ from the other Ulvaceae in the
absence of zoospores, the contents (homo-
geneous, not granular) of the cells being
discharged as motionless spore-like bodies,
from which new fronds grow up. Some
authors separate these genera, but we are
hardly in a position to determine the exact
place of these plants at present.

The Nostochaceae exhibit but a slight
advance in the organization over the Palmel-
laceae. They are composed of linear series of
cells, mostly inflated, so as to give the fila-
ments a beaded appearance ; the linear series
increase in length by transverse division,
and also in some stages subdivide laterally ;
larger globular (spermatic) cells occur at
intervals in the lines, with others devoid of en-
dochrome (vesicular cells, Thwaites). During
the increase, the older external membranes
soften into a gelatinous coat. In Nostoc, where
the filaments accumulate in large quan-
tity, they lie elegantly curled and entwined
in masses of this jelly, which exhibit a more
or less definite, lobed, external form, appear-
ing to the naked eye as gelatinous crusts or
globular masses, as they lie upon damp
ground or among mosses. No other mode
of increase but by subdivision has yet been
observed here, but it is not improbable
that some different kind may be detected
hereafter.

Nearly allied to Protococcus stand a
family which until recently have been re-
garded by most authors as animals, namely
the Volvocineae, which consist essentially of
groups of organisms identical with the cili-
ated zoospores, held together in a definite
form by a common membranous envelope,
through which the cilia penetrate, so that
the entire full-grown plant moves freely in

CONFERVOIDE^l.

[ 160 ]

CONFERVOIDE^.

the water, as in Volvox, Gonium, Syncrypta,
&c. The vegetable nature of these seems
beyond doubt.

The Desmidiaceae form another tribe of
very simple organization, where the indivi-
dual plant is composed of a single cell ; but
here the coat or enclosing membrane is pe-
culiarly characterized by the assumption of
remarkable forms unlike any other vegetable
structures, presenting angular and escalloped
outlines or elegant processes projecting from
the wall, but always so as to exhibit a bilateral
symmetry. Thesecells areisolated,orarranged
in linear series or beautiful, complicated star-
like groups, enclosed at first in a common
gelatinous envelope, but readily breaking up
into isolated frustules. They are further
remarkable for exhibiting the process of
conjugation with great distinctness, resulting
in the production of peculiarly formed bodies
with rigid external membranes, which are
generally regarded, probably correctly, as
sporanges. They are also reproduced by
zoospores.

The Diatomaceae are nearly related in
many respects to the Desmidiaceae, but, on
the other hand, diverge from the ordinary
characters of plants so much in other re-
spects, that some authors place them in the
animal kingdom. Like the Desmidiaceae,
they are microscopic simple cells, isolated or
coherent in groups, and either free or im-
bedded in a definitely or indefinitely formed
mucous nidus. They differ, however, from
the Desmidiacese by possessing when free a
more active power of locomotion, and also
by being often attached by a kind of foot,
and this either singly or in large polypiform
families. Their great distinctive character
is the presence of a siliceous coat to the cell,
which preserves the form of the organism
when the soft parts are removed by fire or
acids. The cell-contents of the Diatomaceae
are usually of a dirty yellow colour, and this
appears to depend upon a modification of
chlorophyll. The reproduction is by division
and by conjugation, analogous to that of the
Desmidiaceae.

The Oscillatoriaceae are truly filamentous
plants, the component parts of which, though
readily separating under external influences,
are organically combined into complex
cells in their normal state. The filaments of
this group are mostly very minute, and ex-
hibit transverse markings, which in some
cases are so delicate that they cannot be re-
garded as actual divisions of the cell-contents
by septa; yet the filaments break readily

across in these places, and the fragments go
on growing. In the larger forms the articu-
lations of the cell-contents are more distinct,
but even here the filaments look like rows of
individual masses of cell-contents contained
in a common tube. The tube is often large
and gelatinous, forming a kind of sheath,
and in some genera the filaments are con-
tained in bundles in these sheaths. The
most remarkable point about this tribe is
the occurrence of the peculiar kind of motion
in the typical genus Oscillatoria, whence
they derive their name ; the filaments wave
backwards and forwards, and the broken
fragments oscillate like the beam of a ba-
lance, from what cause or by what means is
still unknown. The Oscillatoriaceae are also
curious from the rapidity of their growth,
which may be readily traced under the mi-
croscope.

The Siphonaceae are plants of larger dimen-
sions and higher organization than any of the
preceding, and, indeed, they are placed
among the lower Fucoids by some authors.
They seem to us to be more in place here.
They are composed of tubular cells of much
larger size than those of any other Confer-
voids, the entire plant often consisting of
one undivided tube, while in other cases
the branches arise from true articulations.
In Botrydium a very curious structure is
exhibited: the plant consists of a tough
membranous globule, filled with green mat-
ter, rising from a branched, colourless, root-
like portion spreading in the damp ground,
the whole consisting only of one very large
undivided cell. In Vaucheria and Bryopsis
the tubular cell grows into a long filament,
more or less branched, but not divided. In
Hydrodictyon, which from its general struc-
ture appears referable here, the plant is
a large net with meshes half an inch broad,
the net itself being composed of large tubes
rounded at both ends, articulated at the in-
tersections of the meshes. In Codium, the
filaments are closely combined into a spongy
mass. The fructification of these genera is
very varied, so that the group appears
scarcely natural ; but the plants are all more
or less anomalous, and have affinities with
very different tribes, while the comparatively
enormous cells of which they are composed
are peculiar to them among the filamentous
Confer voids. Vaucheria is reproduced by
very large oval spores covered with innumer-
able vibratile cilia, by means of which they
swim actively in water ; the spores are de-
veloped from the contents of the ends of the

CONFERVOIDE.E.

[ 161 ]

CONFERVO1DE.E.

filaments ; another mode of reproduction is
also stated to exist, in which a process of
conjugation is said to occur ; this is spoken
of elsewhere. In Hydrodictyon the repro-
duction takes place by the conversion of the
contents of the cells into numerous zoo-
spores, which * swarm' inside the cell, and,
never escaping, arrange themselves on the
walls in the form of a network, acquire mem-
branes, and, by the solution of the cell-wall,
emerge as new, perfect, net-like fronds, like
the parent. In Bryopsis the contents of the
ends of the filaments are developed into nu-
merous small zoospores,with two or four cilia,
like those of the Confervaceae ; these escape
and germinate, and produce filaments. In
C odium, the ovoid lateral sacs, ordinarily re-
garded as spores, also produce numerous
zoospores with two cilia, which escape and
germinate in like manner. In the anomalous
genus Achlya, which, from the colourless
condition of the contents and the parasitic
habit, is almost like a Fungus, the reproduc-
tion resembles that of Bryopsis, zoospores
being developed and emitted from the ends
of the tubes, germinating and growing into
filaments with great rapidity.

The Confervaceae and Zygnemacese are in-
teresting families of this order, known as the
Silk-weeds so abundant in ponds, ditches,
and running fresh water, and also occurring
in brackish water and the sea. They are
simple plants, composed of cylindrical cells,
flattened at the top and bottom, of variable
length in proportion to their diameter, ar-
ranged in lines so as to form long threads,
which are simple or give off lateral branches
of like structure. They are not very evi-
dently gelatinous, but they are often slip-
pery to the touch, and the microscope mostly
detects a delicate gelatinous coat investing
the filaments, which consists in reality of the
softened older external walls in course of
solution. The cells or joints are filled with
contents, usually of green, but occasionally
of brown or purple colour, either lining the
walls equally or arranged in various patterns,
such as spiral coils, reticulations, &c. upon
them. They are reproduced by spores and
by zoospores, and in the production of the
former a very curious process takes place in the
Zygnemaceae; in Zygnema (fig. 137, page 166)
and others the filaments become coupled by
cross tubes, produced by the inosculation of
branches sent from two cells of adjacent
filaments; the contents then become inter-
mixed and produce a spore, which acquires
a thick coat, and remains at rest for some

time, then germinates, and forms a new fila-
ment. In CEdogonium, spores are formed
in certain stages from the entire contents of
joints, apparently without conjugation ; these
sometimes acquire a red colour. The zoo-
spores vary in different genera; in CEdogo-
nium they are very large, being formed
from the entire contents of the cell, and
instead of a pair of cilia, or four, they bear a
crown of cilia at the apex. In most cases,
however, they are produced in large numbers
in each cell, and are small, pear-shaped, and
furnished with two cilia, as in Cladophora,
Conferva, Chcetomorpha, &c. They certainly
occur in some cases in the Zygnernaceae, and
from what is seen in CEdogonium, it seems
probable that they are normal there. They
escape either by orifices formed in the cell-
wall (Chcetomorpha], by an annular dehis-
cence of this ((Edoaonium), or by the fila-
ments breaking up entirely (Conferva).

The Chaetophoraceae differ from the Con-
fervaceae principally in their habit and mode of
branching. They occur in the sea and in
fresh water, and are characterized by the
presence of a jelly enveloping the filaments,
or branched, round, or shapeless masses
composed of filaments ; by the cells consti-
tuting the joints of the filaments bearing
slender bristle-like branches ; and frequently
by the collection of the green contents in
the middle of the cells. They are repro-
duced by zoospores, either numerous or soli-
tary in the cells, bearing four cilia.

The Batrachospermeae exhibit a greater
complexity of structure, consisting of jointed
moniliform filaments, composed of rows of
cells, branched and bearing whorls of ramuli;
the filaments of the whorls dense, dichoto-
mous, and beaded, some of them growing
down over the central filament, and forming
a sheath round it. The fructification con-
sists of spore-like bodies borne on the fila-
ments of the whorls, but their true nature
has not yet been investigated. The plants
are brownish-green or purplish, and occur
in fresh water.

The Lemaneeae are freshwater Algae, by
some supposed to bear a close relation to
the lower Fucoids, occurring in rapid rivers,
attached to stones. The fronds are branched
and of leathery texture, consisting of tubes
composed of cellular tissue, the superficial
layers small, polygonal, and firmly conjoined,
the deeper layers bounding the cavity of the
tubes lax and spherical. The fructification
consists of beaded filaments arising from the
internal cells, and growing out freely in the

M

CONFERVOIDE.E.

cavity of the tube, finally breaking up into
the component bead-like cells (spores),
which reproduce the plant. The genus
Lemanea deserves further investigation.

Synopsis of the Families.

1. LEMANEE.E. Frond filamentous, in-
articulate, cartilaginous-leathery, hollow,
furnished at irregular distances with whorls
of warts, or necklace-shaped. Fructification :
tufted, simple or branched, necklace-shaped
filaments, attached to the inner surface of
the tubular frond, and finally breaking up into
elliptical spores. Growing in fresh uater.

2. BATRACHOSPERME^. Plants fila-
mentous, articulated, invested with gelatine.
Frond composed of aggregated, articulate,
longitudinal cells, whorled at intervals with
short, horizontal, cylindrical, or beaded,
jointed ramuli. Fructification : ovate spores
attached to the lateral ramuli, which consist
of minute, radiating, dichotomous, beaded
filaments. Freshwater plants.

3. CH^TOPHORACE^E. Plants growing
in the sea or fresh water, coated by gelati-
nous substance, either filiform, or (a number
of filaments being collected together) formed
into gelatinous, branched, definitely formed
or shapeless fronds or masses. Filaments
jointed ; articulations colourless at each end,
coloured in the middle. Fructification :
zoospores produced from the cell-contents
of the filaments.

4. CONFERVACE^E. Plants growing in
the sea or in fresh water, filamentous, jointed,
without evident gelatine (forming merely a
delicate coat around the separate filaments).
Filaments very variable in appearance, simple
or branched ; the cells constituting the arti-
culations of the filaments more or less filled
with green or very rarely brown or purple
granular matter, sometimes arranged in
peculiar patterns on the walls, and con-
vertible into spores or zoospores. Not con-
jugating.

5. ZYGNEMACE^E. Freshwater filamen-
tous plants, without evident gelatine, com-
posed of series of cylindrical cells, straight
or curved. Cell-contents often arranged in
elegant patterns on the walls. "Reproduction
resulting from conjugation, followed by the
development of a true spore, in some genera
dividing into four sporules before germina-
tion. Zoospores have been observed.

6. SIPHONACE^E. Plants found in the
sea, fresh water, or on damp ground ; of a
membranous or horny, hyaline substance,
filled with green granular matter. Fronds

[ 162 1 CONFERVOIDE.E.

consisting of continuous tubular filaments,
either free or collected into spongy masses of
various shapes, either crustaceous, globular,
cylindrical or flat. Fructification'. (1) vesicles
(coniocysts) external, often stalked, giving
birth to large spores or numbers of zoospores;
(2) ciliated spores produced from the con-
tents of the apex of the tubes; (3) conversion
of the whole contents into spores or zoospores.

7. OSCILLATORIACE^E. Plants growing
either in the sea, in fresh water, or on damp
ground, of a gelatinous substance and fila-
mentous structure. Filaments very slender,
tubular, continuous, filled with coloured,
granular, transversely striate substance ;
seldom branched, though often cohering to-
gether so as to appear branched, usually
massed together in broad, floating, or sessile
strata, of very gelatinous nature ; occasion-
ally erect and tufted, and still more rarely
collected into radiating series bound together
by firm gelatine, and then forming globose,
lobed or flat crustaceous fronds. Fructifica-
tion (where known to exist) : the internal
mass, or " contents," divided by transverse
septa, finally separating into roundish or
lenticular spores (?).

8. NOSTOCHACE.E. Gelatinous plants
growing in fresh water or in damp situations
among mosses, &c.; of soft or almost leathery
substance, consisting of variously curled or
twisted necklace-shaped filaments, colourless
or green, composed of simple (or in some
stages double) rows of cells, contained in a
gelatinous matrix of definite form, or heaped
together without order in a gelatinous mass.
Some of the cells enlarged, and then form-
ing either vesicular empty cells or densely
filled spermatic cells. Reproduction : only
the breaking up of the filaments known.
The enlarged spermatic cells regarded as
sporanges.

9. ULVACE^B. Marine or freshwater Algre,
consisting of membranous, flat and expanded,
tubular or saccate fronds composed of poly-
gonal cells firmly conjoined by their sides.
Reproduced by zoospores formed from the
cell-contents and breaking out from the sur-
face, or by motionless spores formed from
the whole contents of a cell.

10. PALMELLACE^E. Plants forming ge-
latinous or pulverulent crusts on damp sur-
faces of stone, wood, &c., or more or less
regular masses of gelatinous substance, or
delicate pseudo-membranous expansions or
fronds, of flat, globular, or tubular form, in
fresh water or on damp ground; composed
of one or many, sometimes innumerable

CONFERVOIDE^E.

[ 163 ]

CONIFERS.

cells with green, red, or yellowish contents,
spherical or elliptical form; the simplest
being isolated cells (found in groups of two,
four, eight, &c. in course of multiplication) ;
others permanently formed of some multiple
of four ; the highest of compact, numerous,
more or less closely conjoined cells. In-
creased by division, or by zoospores bearing
two cilia, formed from the coloured cell-
contents, set free by the solution of the jelly
in water. The zoospores devoid of a mem-
brane, at first moving actively, then coming
to rest, and acquiring a membranous coat.
Some species green and red in different
stages.

11. DESMIDIACE.E. Microscopic, gela-
tinous plants, of a green colour, growing in
fresh water, composed of cells, devoid of a
siliceous coat, of peculiar forms, such as
oval, crescentic, shortly cylindrical, or cylin-
dric-oblong, &c., with variously-formed rays
or lobes, giving a more or less stellate form,
presenting a bi-lateral symmetry, the junc-
tion of the halves being marked by a division
of the green contents; the individual cells
either free, or arranged in linear series, col-
lected into faggot-like bundles, or in elegant
star-like groups, which are imbedded in a
common gelatinous coat. Multiplied by
division and by spores produced in sporangia
formed after the conjugation of two cells
and union of their contents, and by zoo-
spores.

12. DIATOMACE^. Microscopic cellular
bodies, growing in fresh, brackish, and sea
water ; free or attached, single or imbedded
in gelatinous tubes, the individual cells
(frustuks) with yellowish or brownish con-
tents, and provided with a siliceous coat
(lorica) composed of two usually symmetrical
valves, variously marked, with a connecting
band or hoop at the suture. Multiplied by
division and by the formation of new larger
individuals out of the contents of conjugated
cells ; perhaps also by spores and zoospores.

13. VOLVOCINE^E. Microscopic, cellular,
freshwater plants, composed of groups
of bodies resembling zoospores, connected
into a definite form by their enveloping
membranes. The plants (families) areformed
either of assemblages of coated zoospores
united in a definite form by the cohesion of
their membranes, or of assemblages of naked
zoospores enclosed in a large common invest-
ing membrane. The individual, zoospore-
like bodies with two cilia throughout life,
perforating the membranous coats, and by
their conjoined action, causing a free move-

ment of the entire group. Reproduction :
by direct division or by spores, which are
thin-coated and active, or thick-coated and
motionless, according to external condi-
tions.

BIBL. See under the Families.

CONIDIA.— The name applied by Fries
to the stalked spores or reproductive cells
produced directly from the mycelium of
many Fungi : characteristic of the Coniomy-
cetes. Late discoveries have rendered the
term of somewhat equivocal value, and it is
not yet sufficiently distinguished from the
organs called STYLOSPORES and SPERMA-
TIA. Physiologically, they are regarded as
equivalent to the gonidia of Lichens.

CONIFER^.— A class of Gymnosper-
mous plants, so called from the peculiar
form of the female inflorescence, in which
the flowers are collected into imbricated
cones ; this is the case at least in the Abie-
tineae and Cupressineae ; in the Taxinese,
which are separated by some authors, the
female flowers are solitary. These plants
are remarkable in many respects. The pro-
cesses occurring in the fertilization of the
ovules are quite different from those in the
Angiospermous flowering plants, and form
a link with the conditions in the higher
Flowerless plants. (See GYMNOSPERMIA.)
The pollen is of a remarkable form in the
Abietineae. The most striking point, how-
ever, in relation to the microscopic structure,
is the condition of the stems of these plants.
The wood is entirely composed of prosen-
chymatous cells, of large size, without inter-
mixture of ducts or vessels, and those walls
of the cells parallel with the medullary rays
(very rarely those at right angles) are marked
with one or more rows of the peculiar bor-
dered pits, which have been wrongly called
glands (PL 1. fig. 4). The structure of
these is explained under the head of PITTED
STRUCTURES. It must be understood,
however, that the peculiarity of Coniferous
wood does not depend on the presence of
these, which are common, but on the simul-
taneous absence of ducts. The wood of the
Yew presents in addition a spiral fibre, be-
tween the coils of which the pits lie. (See
TAXUS.) These peculiar conditions of the
wood render it possible to identify it in mi-
croscopic sections in a recent, and, if toler-
ably well preserved, even in a fossil state ;
the Coniferous structure may be readily de-
tected in silicified wood, in which almost all
trace of organic matter is lost, the silica
forming complete casts of the microscopic

M 2

CONIFERS.

[ 164 ]

CONIOMYCETES.

structures. This is beautifully seen in some
silicified wood which has been brought from
Australia by Dr. Hooker, parts of which are
so friable, that microscopic sections may be
obtained by splitting it with a knife (PL 19.
fig. 33). With solid silicified wood, sections
made by the lapidary are required. We have
also readily detected the structure in COAL by
the process we have given under that head.

The only case of a structure approaching
near enough to that of the Coniferous wood
to lead to misconception, appears to be that
of the wood of certain Magnoliaceae, such as
Drimys,Sph(Erostema, and Tasmannia, where
there is likewise absence of ducts and ves-
sels, while the prosenchymatous cells have
bordered pits: but the wood differs consider
ably in the character of the medullary rays,
and in the number and arrangement of the
pits on the walls of the cells. (See WIN-
TERED )

The wood of many of the Conifers is tra-
versed by turpentine-canals, which are large
intercellular passages bounded by thin-walled
cells ; in others these occur only in the bark,
while in Taxus and Torrega both are devoid
of them; where none occur in the wood,
there are generally isolated rows of cells
filled with secretions, but not even these
occur in the wood of Abies pectinata.

The following analysis of the structure of
the wood of some of the most important, is
modified slightty from Hartig : —

A. Cells of the pith with thin walls.

a. Liber-cells in cross-section broad"}
and mostly short, isolated, in scat- I .
tered groups, or in bands of several f AI
rows, or wanting .............. J

*Wood with turpentine-canals.
fMedullary rays with varying pits . . Pinu-s.
ffMedullary rays with uniform pits.
J Cords of secretion- cells at the
outer limit of the annual rings

§ Outer wood-cells of the annual ) n ,
rings smooth within ........ f Learus-

§§ Outer wood-cells of the annual T

rings with an obscure spiral > Larix.
fibre ...................... J

it Wood without isolated rows of ) D.
secretion-cells .............. }Picen.

**Wood without turpentine-canals.
fMedullary rays with distant pits.

J Wood-cells with distant pits, 1 or\ ,,. 0
2 rows in pairs .............. / AOte*'

JJWood-cells with crowded pits,
1 — 5 rows, in spiral arrange-

*

Cunninghamia.

tfMedullary rays with crowded pits Dammara.

b. Liber-cells with square or oblong~\
cross-section, in concentric rows, I TAXINEJE and
alternating with parenchymatous \ PODOCARPE^.
cells .......................... J

*Pith with thick-coated liber-cells .... Sallsburia.
**Pith without thick-coated liber-cells.

t Wood-cells with openly - coiled \ „,
spiral fibre ........ ..... ....... / Taxus.

tfWood-cells smooth within.

fLiber-layers with thick-coated \ D ,

cells .. ...................... } Podocarpus.

JJ Liber - layers without thick- \ „

coated cells .............. / Dacrydium.

B. Cells of the pith with thick walls, \
liber-cells square /

*Liber-cells without pit-canals.

fPith with a roundish cross-section, 1 „,

bark without turpentine-canals . . / Taxodmm.
ft Pith with quadrangular cross-sec- 1 ™,

tion, bark with turpentine-canals / TfluJa-
**Liber-cells with pit-canals.
fWood-cells smooth inside.
JPith 3-angled ........... Juninerus

ttPith 2- or 4-angled ............ Cup?e™'.

BIBL. Goppert, De Coniferarum Struc-
tura, Vratisl. 1841; Anat. Magnoliac. Lin-
nsea, xvi. p. 135, Ann. des Sc. nat. 2 ser.
xviii.; Hartig, EotanischeZeitung, vi. p. 123
1848; Schacht, Die Pjlanzenzelle, Berlin,
1852, p. 435.

CONIOCARPON, B.C. (Spiloma, Hook.
Br. F/.).— A genus of Graphideae (Gymno-
carpous Lichens) closely related to Arthonia,
but distinguished by the upper surface of the
apothecia breaking up into powder.

BIBL. Leighton, Ann. Nat. Hist. 2 ser
xiii. 443. pi. 8.

CONIOMYCETES.— An order of Fungi
composed of microscopic forms, for the most
part parasitical upon plants, growing beneath
the epidermis, or overgrowing decaying ve-
getables, and then more or less imbedded in
the matrix. The fructification consists of
groups of sessile or stalked spores (conidia,
Fries, and stylospores, Tulasne) arising from
the filamentous mycelium. In the simplest
forms the mycelium consists of short fila-
ments, which are more or less completely
converted into spores ; or it forms an irre-
gular flocculent patch in decaying matter or
under the epidermis of plants, in which the
spores are found intermingled, breaking out
on the surface of the epidermis in the para-
sites; but in the more complete forms the
mycelium becomes organized into firm struc-
tures of definite form (conceptacles) which
are hollow, the walls being lined with short
filaments terminatirg in spores. These
conceptacles are either produced on the

CONIOMYCETES.

[ 165 ]

CONIOPHYTUM.

surface of the epidermis of the plant infested,
or they are formed internally, and are
exposed by breaking their way through to
the surface of the epidermal structures in
which they are imbedded.

We must not omit, in giving a description
of this order as it stands in systematic works,
to notice that recent observations go to
prove that it rests upon a very insecure
basis, and that certain supposed genera
belonging to it appear to be merely forms of
genera which exhibit at other stages of
growth, or even at the same time, asciferous
structures which have formed the bases of
Ascomycetous genera. These cases are
referred to in the introductory notice of the
Fungi, and a few of the instances must be
mentioned here, and also under the head of
the Ascomycetes, as guides to the directions
in which much new investigation is requisite.
M. Tulasne has found that the forms repre-
senting the genera Septoria and Cytispora
(Sphaeronemei), are produced in the earlier
stages of the growth of species of Sphceria ;
that the majority of the Tubercularice are the
stromas of species of Sphceria; that some
species of Sphceria (S. Laburni) exhibit
three forms of spores, namely thecaspores,
others like a Sporocadus, and others repre-
senting a Cytispora. Dothidea Ribesii has
spores like the Xylarice, and others like the
Septoriee. Mr. Berkeley has found Asteroma
Ulmi a precursor to Dothidea Ulmi, Stilbo-
spora macrosperma growing on the same
stroma or conceptacle as Sphceria inquinans,
&c. Further observations will be found
under SPH.ERONEMEI, MELANCONIEI, and
other heads there referred to.

Again, the heterogeneous assemblage of
genera collected under the heads of Puc-
CINEI and C^EOMACEI (which we associate
under the latter title), seem really to be As-
comycetous Fungi, and some of the Pucci-
neous and Caeomaceous genera to be even
merely representatives of dimorphous species.
Certain Uredines, for example, being only
different stages or forms of certain Puccinice.
(See UREDO.) JEcidium, with Rozstelia
again, are closely related to those forms
scattered between Coniomycetes and Asco-
mycetes, which have both asciferous spo-
ranges and spermagonia. (See

Synopsis of the Tribes.

1. SPH^ERONEMEI. Conceptacles rising
from microscopic mycelium growing on the
surface of leaves, bark, stems, &c., contain-
ing a chamber lined with filaments bearing

single, often septate spores, and bursting by
a pore at the summit to emit the elongated
spores, in a gelatinous ball. (Many are
spermagon ous form s of Ascomycetous genera. )

2. MELANCONIEI. Conceptacles as in
the preceding, but bursting irregularly at
the summit, and often ultimately wart-like ;
spores elongated. (Many are spermagonous
forms of Ascomycetous genera.)

3. PHRAGMOTRICHACE.<E. Conceptacles
horny, breaking through the epidermis of
leaves, &c., at first closed, afterwards burst-
ing longitudinally; spores septate, and in
chain-like series, intermixed with paraphyses
on the internal walls of the Conceptacles.

4. TORULACEI. Mycelium filamentous,
overgrowing decayed vegetables, bearing
erect filaments, terminating in rows of
simple or compound spores.

5. C^EOMACEI. Mycelium a filamen-
tous mass growing in the interior of living
vegetable structures, finally breaking out on
the surface in patches, margined or naked,
and bearing simple or compound spores,
single or in beaded series.

BIBL. Berkeley and Broome, Hooker's
London Journal of Botany, iii. p. 320 ;
Tulasne, Comptes Rendus, March 1851 ;
transl. Ann. Nat. Hist. N. S. viii. p. 114;
Ann. des Sc. nat. 3 ser. xv. 370; ibid. xx. 129;
Botan. Zeit. xi. 49 et seq.', Comptes Rendus,
1854 (Ann. Nat. Hist. 2 ser. xiv. 76) ; Fries,
Syst. My col. ; De Bary, Brand-pilze, Berlin,
1853.

CONIOPHYTUM, Hassall (Dolichosper-
mum, Ralfs). — A genus of Nostochaceae
(Confervoid Algae), consisting of one species
colouring large sheets of water of a deep
coppery green, by its minute fronds, each
composed of a number of filaments variously
curled and interwoven, densely in the centre,
and more loosely towards the circumference ;
these fronds being free look like a pulveru-
lent or granular accumulation in the water,
when viewed by the naked eye. This genus
differs from its allies in the relative positions
of the spermatic and vesicular cells, the
former being either next to, or at a distance
from the latter. This fact seems to throw
some doubt on the value of this character as
a distinctive mark.

Coniophytum (Thompsoni),R&\fs. Fronds
minute, visible to the naked eye, granular-
pulverulent, filaments brittle, not imbedded
in mucoid matter, much curled, and inter-
woven, rarely spiral; spermatic cells cylin-
drical, somewhat curved or reniform, usually
solitary, sometimes in pairs. Dolichosper-

CONIOTHECIUM.

[ 166 ]

CONJUGATION.

mum Thompsoni, Ralfs, Ann. Nat. Hist. 2 ser.
vol. v. 336. pi. 9. 3. Anabaina Flos-aquce,
Harvey, Brit. Algee, ed. 1 ; Hassall, Brit.
Fr. Algce, t. 75. f. 2. For further details,
see Hassall, On the Coloration of the Ser-
pentine, Botanical Gazette, no. 20, Aug.
1850.

CONIOTHECIUM, Corda.— A genus of
Torulacei (Coniomycetous Fungi), apparently
somewhat doubtful plants. Berkeley and
Broome name three of Corda's species as
occurring in Britain.

BIBL. Berk, and Broome, Ann. Nat. Hist.
2 ser. v. 460; Corda, Icones Fung. i. figs. 21,
25, 26 ; Fries, Summa Veget. 523.

CONIOTHYRIUM, Corda.— A genus of
Sepedonei (Coniomycetous Fungi).

C. glomeratum, Corda, recorded by
Berkeley and Broome as British, is said by
Fries to belong to his genus Clisosporum.
It is a microscopic plant growing in the
cracks of dead wood (elm), composed of
minute free membranous peridia enclosing
numerous spores, which escape by the burst-
ing of the apex.

BIBL. Berk, and Broome, Ann. Nat. Hist.
2 ser. xiii. 460; Corda, iv. f. 208; Fries,
Summa Veget. 522; see also Montagne, Ann.
des Sc. nat. 3 ser. xii. 304.

CONJUGATION. — A process occurring
among some of the lower plants and animals,
in which the substance of two distinct orga-
nisms comes into contact and becomes fused
into a single mass. This operation is always
connected with reproduction in plants, and
probably also in animals.

In the vegetable kingdom it has been
observed in the Algae, viz. in the Zygnema-
ceae, the Desmidiacea?, the Diatomacese, the
Palmellacea3, and doubtfully in the Sipho-
nacea3, and in one genus of Fungi, viz. Sizy-
yites. In all these cases it consists essen-
tially in the blending together of the contents
of two distinct cells, either by the complete
fusion of two free cells, by the passage of
the contents of one cell into the cavity of
another, or by the emission of the contents
of both cellsinto a space between them, where
the mixed contents become enclosed in a
special envelope.

The conjugation earliest discovered was
that of the Zygnemacese, in which the cells
of distinct filaments lying parallel with one
another, become united by lateral inoscula-
tion or by cross branches, formed by the
budding out of the walls of the cells opposite
to each other, the protruded processes
coming into contact, cohering and becoming

Fig. 138.

confluent by the ab- Fig. 137.

sorption of the surfaces

of contact (fig. 137).

The cavities of the two

cells being thus freely

opened into one

another, the contents

become mixed ; in Spi-

rogyra and Zygnema

the contents of one of

the cells usually travel

across into the cavity

of the other (PI. 5.

fig. 18) ; in Zygogo-

nium the Contents of Zygnema cruciata.
both Cells Collect in the Conjugating filaments

cross-piece, this is the M mfied 250 diameters.
case also in Meso-
carpus (fig. 138) and Staurocarpus, in the
latter of which the
cross-piece becomes
greatly enlarged. The
contents in all these
cases become retracted
from the cell-wall, and,
secreting special coats,
become spores, which
escape by the rupture
of the conjugated cells.
In Mougeotia (fig. 139)
there is no cross branch.
The filaments become
angularly bent and in-
osculate at the angles.
A spore is said to be
formed in each cell here. Ma^fied 200 diameters.
(See ZYGNEMACESE.)

In the Desmidiacese the process presents
a number of modifications. In the filamen-
tous forms, such as Hyalotheca and Didy-
moprium, conjugation does not usually take

Fig. 139.

Mougeotia genuflexa.

Conjugating filaments.

Magnified 100 diameters.

place until the single cells of the filaments

CONJUGATION.

[ 167 ]

CONJUGATION.

have become separated, but in some cases,
as in D. Borreri, conjugation of the filamen-
tous groups has been observed ; perhaps
this occurs in Desmidium also. In Closte-
rium, Penium, Tetmemorus, Cosmarium, &c.,
the free cells conjugate in pairs. In almost
all these cases the mode of union appears
to be different from that which is seen in
Zygnemaceae, for the external membrane
dehisces more or less completely, so as to
separate the parent-cells into two valves,
while a delicate internal membrane previ-
ously lining this is protruded as a sac, to
meet its fellow from the corresponding con-
jugating individual ; these sac-like processes
coalesce, and thus the contents of the cells
are enabled to mix. In Hyalotheca dissiliens
and Penium Brebissonii, there is said to be
union of the primary or outer cell-coat, as in
Zygnema. The resulting spore or gonidium
is mostly formed in the connecting piece
(Closterium, Cosmarium, Tetmemorus, Hya-
lothecd)(P\. 6. figs. 1-3), or in one of the cells
(Didymoprium Grevillii, and perhaps in
Desmidium). In Closterium lineatum it has
been observed that the conjugating cells
divide completely by constriction of their
delicate internal membrane, just before con-
jugation, so that the dehiscent primary
membranes emit from each parent individual
a pair of little sacs in close apposition, and
these meeting their fellows, a double or twin
conjugation takes place, and a pair of spores
or gonidia is formed. A gelatinous invest-
ment is secreted around the conjugating sac-
like processes, and the spore is generally at
first imbedded in an abundant gelatinous
coat. (See DESMIDIACE.E.)

In the Diatomacese there does not appear
to be any delicate internal membrane, like
that of the Desmidiacese, concerned in the
conjugation. The two conjugating indi-
viduals, lying near together, become con-
nected together by the excretion of a collec-
tion of gelatinous substance, the siliceous
coats then dehisce, and the contents of the
parent-cells, escaping from the valves, meet
between them to unite into a globular mass,
which does not become a spore, but gradually
acquires the form of the parent. There is
no connecting tube here ; only the investing
gelatinous matter. In Himantidium and
Surirella, one new individual is formed in
the conjugation (PI. 6. fig. 4) ; in Eunotia,
Cocconema, Gomphonema and Schizonema,
the contents of the parent-cells appear to
divide transversely before extrusion, and
thus form a pair of new individuals in the

conjugation (PI. 6. fig. 5) (as in the case of
the spores of Closterium lineatum). A pecu-
liar condition occurs in other genera, Cyclo-
tella, Melosira, &c., which is supposed to
be a conjugation of the divided contents of
one frustule. (See DIATOMACE^S.)

Among the Palmellaceae, conjugation has
been observed in Coccochloris Brebissonii
(Palmoglaa macrococca, A. Braun), where a
pair of vegetative cells become completely
fused, membrane and contents, to form a
spore which acquires a firm coat and oily
contents, and passes through a stage of rest
before recommencing vegetative develop-
ment (PI. 3. fig. 6 c, rf).

Conjugation is stated by some authors
to take place also in Vaucheria. Nageli,
and still more distinctly Karsten state that
the hook-like branchlets conjugate with the
inflated lateral branches in which spores are
produced (distinct from the gonidia in the
ends of the filaments). This point is not yet
quite settled (see VAUCHERIA). Phseno-
mena bearing some analogy to this are
described also by Al. Braun in Achlya and
in COLEOCH^ETE. The supposed conjuga-
tion of adjacent cells of a filament in (Edo-
yonium and Bulboch&te appears to have no
reality.

The only known case of conjugation in
the Fungi, that described by Ehrenberg in
SIZYGITES, a genus of Mildew Fungi, is
described under that head.

The conjugation observed in the animal
kingdom, consists in the direct union, by a
more or less extensive fusion of the substance
of two distinct individuals. luDiplozoon para-
doxum the two individuals become united by
a cross branch, and the remarkable result is
that sexual organs become developed on both
bodies after this. Conjugation takes place
also in ACTINOPHRYS, ACINETA, GREGA-
RINA and PODOPHRYA. The results have
not been observed (see under the heads of
these genera).

BIBL. Vegetables. Vaucher, Hist, des
Conferves', Meyen, Pflanzen-physiologie, iii.
413; Hassall, Brit. Freshw. Algce; Kiitzing,
Phyc. generalise Ralfs, Brit. Desmidiece ;
Morren, Ann. des Sc. nat. 2 ser. v. 257 ;
Smith, Ann. Nat. Hist. 2 ser. v. 1.; Thwaites,
Ann. Nat. Hist. xx. and ser. 2. i. and iii. ;
Al. Braun, Rejuvenescence in Nature, Ray
Society's Volume, 1853, p. 283 et seq.-,
Focke, Physiolog. Studien. Heft ii. 1854;
Nageli, Algen-systeme, p. 175 ; Karsten,
Botan. Zeitung, x. p. 89 (1852); Ehrenberg,
Verhandl. Naturf. Freund. i. 98 (1829).

CONJUNCTIVA.

CORALLINES.

Animals. Kolliker, Siebold and Kolliker's
Zeitschr. i. pp. 1. 198 (Quarterly Journal of
Microscopic Science, i. p. 98) ; Siebold, Sieb.
and Kolliker's Zeitschr. i. p. 270. iii. p. 62 ;
Stein, ,Die Infusionsthiere, 1854; Wiegmann' 's
Archiv, 1849. p. 147; Nordmann, Mikr.
Beitrdge, Sfc. Heft i. p. 56; Allen Thompson,
Todd's Cyclop, art. Ovum.

CONJUNCTIVA. See EYE.

CONOCEPHALUS, Hill. See FEGA-

TELLA.

CONOCHILUS, Ehr.— A genus of Ro-
tatoria, of the family CEcistina.

Char. Animals aggregated around a cen-
tral gelatinous nucleus, and forming a re-
volving sphere ; two persistent frontal eye-
spots.

From ten to forty in each sphere. The
nucleus is sometimes green, from the pre-
sence of parasitic monads. Four thick co-
nical papillae arise from the middle of the
frontal surface, eachhaving abristle at its apex.

C. volvox (PI. 34. figs. 15-17). Carapace
and body white, gelatinous, and hyaline;
length 1-60", breadth of sphere 1-8". Aquatic.

BIBL. Ehr. Infus. p. 393.

CONOSTOMUM, Sw.— A genus of Bar-
tramiaceous Mosses, with one British spe-
cies : Conostomum boreale, Sw.

COPPER.— Crystals of metallic copper
exist in artificial AVANTURINE. The
acetate of copper is noticed under ACETIC
ACID.

CORAL. — A term applied in general to
the calcareous polypidom or skeleton of Po-
lypes or Zoophytes, and in particular to that
of CORALLIUM.

CORALLINA, Linn. — A genus of Coral-
Fig. 140. Fig. 141.

Corallina officinalis.

Fig. 140. A branch of the frond. Natural size.

Fig. 141. A section of the end of a branch terminating
in a ceramidium, containing spores. Magnified 10 dia-
meters.

linaceae (Florideous Algae), of stony charac-
ter, looking like corals. The common spe-
cies, C. officinalis, grows everywhere between
tide-marks, on rocks, &c., and presents a
branched, mostly pinnate tuft of articulated
filaments evenly coated with carbonate of
lime. The spores are borne in tufts in cera-
midia (fig. 141 ), usually at the apices of the
branches (being the last joints transformed),
or they occur laterally (fig. 140), sometimes
in pairs and sometimes irregularly over the
whole frond ; they open by a small terminal
pore (fig. 141).

The structure may be examined in these
plants by keeping them for some time in
vinegar or dilute muriatic acid, which will
remove the lime and allow of the substance
being sliced in the same way as other Algae.

BIBL. Harvey, Br. Mar. Alg. pi. 13 C.;
Phyc. Brit. pi. 222 ; Decaisne, Ann. des Sc.
nat. ser. 2. xvii. pi. 17. fig. 1. xviii. p. 119.

CORALLINACE^.— A family of Flori-
deae. Rigid, articulated, or crustaceous,
mostly calcareous sea-weeds, purple when
fresh, fading, on exposure, to milk-white;
composed of closely-packed elongated cells
or filaments, in which carbonate of lime is
deposited in an organized form. Tetraspores
tufted, contained in ovate or spherical con-
ceptacles (ceramidia, Harvey), furnished with
a terminal pore. British genera :

* Frond filiform, articulated (Corallineae).

I. Corallina. Frond pinnated. Ceramidia
terminal, simple.

II. Jania. Frond dichotomous. Cera-
midia tipped with two horn-like ramuli.

** Frond crust aceous or foliaceous, opake,
not articulated (Nulliporese).

III. Melobesia. Frond stony, forming
either a crustaceous expansion, or a folia-
ceous or a shrub- like body.

IV. Hildebrandtia. Frond cartilaginous,
not stony, forming a crustaceous expan-
sion.

*** Frond plane, hyaline, composed of cells
radiating from a centre. Fructification
unknown (Lithocysteae).

V. Lithocystis (a minute parasite).

CORALLINES. — The Corallinacese, a
family of Algae, were formerly imagined to
be of animal nature, and were classed among
the Zoophytes. On the other hand, Ellis
applied the term Coralline more extensively,
including under it Bryozoa, and Sertularian

CORALLIUM.

[ 169 ]

CORN.

and similar Zoophytes (Polypes) ; the name
is still often vulgarly used in this sense.
Dr. Johnston (Brit. Sponges and Litho-
phytes) properly restricts the term to the
family to which the genus Corallina gives
the name. See CORALLINACE^ and PO-
LYPI.

CORALLIUM, Lam.— A genus of Po-
5, of the order Anthozoa.

red coral of commerce is the internal
skeleton of the Corallium rubrum, Lam.
(Isis nobilis, Lin.) (PI. 33. fig. 6 c). A por-
tion of the dried animal matter is usually
found adhering to its surface, and contains
abundance of spicula (PI. 33. fig. 7).

The furrows seen upon the outer surface
of unprepared coral, are the impressions of
vessels which traverse the cortical substance
and form a medium of communication be-
tween the various polypes.

The structure of coral is rather obscure.
The transverse section (PL 33. fig. 8 «) ex-
hibits somewhat undefined lines, some of
which are semiconcentric with the marginal
furrows, and appear to be lines of growth ;
these are intersected by darker and narrower
lines, apparently canals. The orifices of
larger canals are also visible. The longitu-
dinal section (PL 33. fig. 8 b) exhibits longi-
tudinal lines, probably those of growth, with
an indistinct intermediate structure. When
treated with acid, the residue is soft and
easily folded so as to produce a lined appear-
ance ; and in parts the organic skeletons of
spicula may be distinguished. Hence it
probably consists of spicula, aggregated and
ultimately consolidated, so that their struc-
ture is no longer distinguishable.

BIBL. Cuvier, Regne Animal, dateless ed.
(1853?), Zoophytes, pi. 80.

CORDYCEPS, Fries. — See SPH^ERIA
and CLAVICEPS.

CORDYLOPHORA, Allman.— A genus
of Polypes, of the order Anthozoa. Aquatic.

Char. Polypidom horny, branched, rooted
by a creeping tubular fibre; branches tubular;
polypes existing at the extremities of the
branches, ovoid, the mouth at the distal
extremity, and furnished with scattered fili-
form tentacula.

C. lacustris, the only species.

BIBL, Allman, Ann. Nat. Hist. xiii. p.
330; Johnston, Brit. Zoophytes, p. 44.

COREMIUM, Link.— A genus of Muce-
dines (Hyphomycetous Fungi), perhaps not
really distinct from Penicillium, but differing
from the characteristic form of that genus in
having the erect fertile filaments compacted

into a kind of cellular pedicle to bear the
Fig. 142.

Coremium niveum, Corda.
Magnified 200 diameters.

strings of spores (fig. 142). Brit, species :

C. leucopus, Pers. Filaments white,
spores green. Not uncommon on decaying
fruits, &c. Floccaria glauca, Grev. Sc. Crypt.
Fl. t. 301. Penicillium crustaceum /3, Fries.

C. candidum, Nees. Filaments and
spores white. On decaying substances.
Penicillium candidum j3, Fries.

BIBL. Hook. Brit. Fl. v. pt. 2. 344 ;
Fries, Syst. My col. iii. 408 ; Greville, loc.cit.;
Corda, Icones Fung. ii. pi. 11. fig. 73; Pracht-
flora, pi. 25.

CORK. — Ordinarily the outer layer of
bark of the Cork Oak (Quercus Suber), for
the development of which, see BARK. Ho-
rizontal and transverse sections of the large
light-coloured cells of cork are shown in
PL 38. figs. 16 & 17. The term cork is
applied generally to excessive developments
of the suberous layer of barks.

CORN. — The general name applied to
the seeds, or rather the fruits of the various
plants furnishing the ordinary materials for
bread. These all belong to the Monocoty-
ledonous family, Graminacea3 (Grasses), for
Buck-wheats cannot be considered as true
corns. The grains of the Grasses are enve-
loped in the adherent pericarp, which is dry
and smooth ; the seed which this encloses is
characterized by the presence of a compara-
tively large mealy albumen, composed of
thin- walled parenchyma, more or less densely

CORNICULARIA.

CORYNEUM.

filled with starch, which makes up the great
body of the grain ; a few layers of cells sub-
jacent to the surface, however, contain little
starch, but abundance of nitrogenous proto-
plasmic matter, or gluten. These layers
containing the greater proportion of the
gluten, together with epidermis, are removed
from fine flour in grinding, as the bran and
pollard, the fine white flour consisting chiefly
of the starch. The forms of the starch-grains
differ considerably, as also their condition in
the cell. In Wheat (Triticum), the starch-
grains are lenticular (PI. 36. fig. 8), and lie
loose in the cells; in Barley (Hordeum),
they are somewhat discoidal, with a thicker
rim (PI. 36. fig. 9) ; in Oats (Avena), poly-
gonal, but compacted together into roundish
masses (PI. 36. fig. 10), in both cases also
free in the cells ; in Rice ( Oryza), the starch-
grains are very small, and packed so closely
together that they press upon one another,
thus acquiring a parenchymatous form (PL
36. figs. 12 & 13); and then, as they adhere
firmly together, the contents of the cells ap-
pear like one solid mass ; hence the horny
character of the grains of rice, and the grit-
tiness of rice-flour. In Maize (Zea), the
outer part of the grain is horny from the
same cause as rice, and presents a similar
appearance (PI. 36. fig. 3), but in the centre
the cells are often less densely filled, and the
grains lie more or less loose (PI. 36. fig. 5).
For further particulars of the characters of
the starch-grains, see STARCH.

CORNICULARIA, Ach.— A genus of
Parmeliacese (Gymnocarpous Lichens) com-
posed of rigid tufted plants, the lobes of the
thallus standing up in forked horn-like pro-
cesses. Most of the species occur on the
ground or rocks on high mountains.

BIBL. Hook. Br. FL ii. pt. 1. 232; Engl.
Botany, pi. 452. 846. 720, &c.

CORNS — consist of thickened epidermis,
the scales being increased in number, much
flattened, and closely aggregated from pres-
sure. This is the structure in their simplest
form. When larger, they represent an ordi-
nary blister, conjoined with the thickening
of the epidermis ; hence the origin of the
cavity in the centre of many of them. The
papilla3 of the cutis are generally hypertro-
phied. The epidermic scales may be ren-
dered distinct by digestion with acetic acid
or solution of potash.

CORPORA AMYLACEA.— These are
microscopic rounded bodies, exhibiting a
number of concentric rings, and somewhat
resembling starch-grains in appearance (PI.

30. fig. 23). They are found in the fornix,
the septum lucidum, the walls of the ventri-
cles, and the cortical substance of the brain,
the medullary substance of the spinal cord,
the waxy spleen, &c. They are but little
acted upon by dilute acids ; caustic alkalies
render them more transparent, and gradually
dissolve them. Solution of iodine gives them
a bluish tinge, and the subsequent addition
of sulphuric acid produces the bluish-violet
colour seen when cellulose is treated with
these reagents. The reaction is best seen
when the action of the acid takes place
slowly. Hence these bodies have been re-
garded as consisting of cellulose. It has
been objected, that as cholesterine gives si-
milar reactions, arid occurs in those places
where the corpora amylacea are met with,
the reactions might arise from the presence
of this substance. The former view is, how-
ever, probably correct.

The corpora amylacea must be distin-
guished from the concretions forming 'brain-
sand,' or the acervulus cerebri. These are
also rounded, single, or aggregated, usually
exhibiting the concentric rings, sometimes
forming cylindrical, ramified, or reticular
fibres. They are met with in the choroid
plexuses, the pineal gland, the arachnoid
membrane, and sometimes in the walls of
the ventricles. These consist of an organic
(proteine) skeleton, containing carbonate
and phosphate of lime. When treated with
acids, the latter are dissolved, the former
being left, and retaining the original form of
the concretions.

The relation of the corpora amylacea and
the acervulus cerebri to the colloid cor-
puscles, if any exist, has not been deter-
mined.

BIBL. Purkinje, Mutter's Archiv, 1836 &
1845; Kolliker, Mikr. Anat. ii. pt. 2. 501 ;
Virchow, Archw f. Path. Anat. fyc. p. 135,
268, 416, and Ann. Nat. Hist. xii. p. 481.

CORPUSCULA, of the Conifers. See
GYMNOSPERMIA.

CORROSIVE SUBLIMATE. See MER-
CURY, BICHLORIDE OF. — A saturated solu-
tion of this salt is very useful in rendering
very transparent bodies consisting of pro-
teine-compounds more opake and distinct,
as the bodies and cilia of Infusoria, &c.

CORYNEUM, Kunze.— A genus of Me-
lanconiei (Coniomycetous Fungi), consisting
of parasitic plants growing upon dead twigs,
bursting out as convex solid pustules from
beneath the epidermis. A vertical section
of half of one of these pustules is shown

COSCINODISCUS.

[ 171 ]

COTHURNIA.

Coryneum disciforme.
Vertical section of half

a pustule.
Magnified 200 diams.

in fig. 143 ; the cellular stroma is covered

by stalked multiseptate

spores. Five species Flg- l43-

are recorded as British.

The species figured, C.

disciforme, Kze., grows

on dead twigs of birch.

It is not improbable
that this genus is con-
nected with some Asco-
mycetous form.

BIBL. Hook. Brit.
Fl. v. pt. 2. p. 355;
Berk. & Broome, Ann.
Nat. Hist. 2 ser. \.458-,
Corda, Icones Fung.

COSCINODISCUS, Ehr.— A genus of
Diatom aceae.

Char. Frustules free, single, disk-shaped;
valves circular, flat, or slightly convex, ex-
hibiting a cellular or areolar appearance.
(No internal septa nor lateral processes.)

The cellular appearance arises from the
existence of depressions, which are of differ-
ent sizes. The valves form beautiful objects.

Kiitzing enumerates forty -one species,
which are either marine or fossil. Smith
admits four British species :

C. minor, E. Depressions irregular and
crowded (circular, Sm.); margin of valves
smooth; aquatic and marine ; diam. 1-1200
to 1-500".

C. radiatus, E. (PI. 18. fig. 32). Depres-
sions obscurely radiating, marginal ones
smallest; margin of valves smooth; marine
and fossil; diam. 1-550 to 1-180" (a, side
view ; b, front view).

C. eccentricus, E. Depressions arranged
in curved lines, with the convexity towards
the centre; marine and fossil; diam. 1-400
to 1-200".

C. craspedodiscus, K. = Craspedodiscus
elegans, E. (PL 19. figs. 7 & 8). Margin of
valves tumid, elegantly sculptured, central
markings (depressions) radiating; an umbili-
cal star formed of 5 to6 oblong larger cells(?) ;
diam. 1-120". Bermuda.

BIBL. Ehr. Abhandl. d. Berl. ATcad. 1838
and 1839 ; id. Ber. d. Berl. Akad., 1840 et
seq.; Kiitzing, Bacillarien, and Sp. Alg.-,
Smith, Brit. Diat. 1.

COSMARIUM, Corda.— A genus of Des-
midiacese.

Char. Cells single, constricted at the
middle; segments as broad as or broader
than long, neither serrated nor spinous.

Ralfs admits thirty-three British species.
Among the most common are, —

C. pyramidatum (PI. 10. fig. 18, 19 empty
cell). Oval, with depressed and truncate
ends, deeply constricted ; end view elliptical ;
segments punctate, entire ; length 1-470 to
1-260".

C. bioculatum. Smooth, depressed, con-
striction producing a gaping notch on each
side ; end view elliptical ; segments sub-
elliptic, entire; sporangium orbicular, spi-
nous; length 1-1410".

C. crenatum (PI. 10. fig. 20). Punctate,
deeply constricted ; segments crenate at the
margin, depressed at the end; end view
elliptical ; spines of sporangium very short ;
length 1-470".

C. tetrophthalmum (PI. 10. fig. 22).
Deeply constricted; segments semicircular;
end view elliptical ; rough with pearly gra-
nules, which give a crenate appearance to
the margin; length 1-230".

C. margaritiferum (PI. 10. fig. 21). Rough
with pearly granules, which are as broad as
long; end view elliptic; segments semicir-
cular or reniform; length 1-560 to 1-300".

C. ornatum. Segments twice as long as
broad, rough with granules giving a dentate
appearance to the margin ; end view with a
truncate projection on each side; length
1-610".

C. cucurbita. Punctate, constriction slight,
ends rounded; transverse view circular;
length 1-580".

BIBL. Ralfs, Brit. Desmid. pp. 91 & 212.

COTHURNIA, Ehr.— A genus of Infu-
soria, of the family Ophrydina.

Char. Solitary; carapace urceolate,
stalked.

An anterior ring of cilia is present. The
body contracts suddenly, like that of Vorti-
cella.

Dujardin unites this genus with Vagini-
cola.

C. imberbis, E. (PI. 25. fig. 20). Stalk
much shorter than the hyaline carapace;
body yellowish ; aquatic; length of carapace
1-280". Found upon Cyclops quadricornis.

C. maritima, E. Stalk much shorter than
the carapace ; body whitish, hyaline; length
of carapace 1-570' , On Ceramium.

C. havniensis, E. Stalk much longer
than the carapace ; body whitish ; length of
carapace without the stalk 1-280", stalk
twice this length. On Sertularite, &c.

Stein adds three species, C. Sieboldii,
C. astaci, and C. curva ; found upon Astacus
flumatilis (the Cray-fish).

BIBL. Ehr. Infus. p. 297; Duj. Infus.
p. 564 ; Stein, Die Infus.

COTTON.

[ 172 ]

CRIBRARIA.

COTTON.— The hairs from the epidermis
of the seeds of various species of Gossypium
(Malvaceae, Dicotyledons). These hairs are
readily distinguished, under the microscope,
from the various textile fibres consisting of
liber structures. From the absence of the
regular thickening layers, the cells of the
cotton-hairs become collapsed when dry,
appearing like a flat band with thickened
borders, while liber-cells of all kinds remain
cylindrical, and taper to a point at each end
(PI. 21. fig. 1). See FIBROUS STRUC-
TURES).

COVERS. See INTRODUCTION, p. xxi.

CRASPEDODISCUS, E.— A genus of
Diatomaceae. Fossil.

C. coscinodiscus, J?i.=:Pyxidicula coscino-
discus, E.= Coscinodiscus pyxidicula, Kg.

C. elegans, E. = Coscinodiscus craspedo-
discus, Kg.

BIBL. Ehr. Ber. d. Berl. Ak. 1844. p.
261-266; Kiitzing, Sp.Alg. p. 126.

CRATERIUM, Trent.— A genus of Myxo-
gastres (Gasteromycetous Fungi), consisting
of minute yellow or brown cup-like bodies,
of papery consistence, closed by a deciduous
operculum (fig. 144), arising from an evanes-

Fig. 144.

cent filamentous
mycelium, grow-
ing over moss,
leaves, bark, &c.
Most of the spe-
cies are common.
The black spores
contained within

these Cups are Craterium pyriforme.

intermixed with Magnified 10 diameters.

crowded, obscurely articulated filaments
(destitute of spiral fibres), which do not
anastomose, and are at length erect. Five
species are described as British.

BIBL. Hook. Brit. Fl. v. pt. 2. p. 316;
Sowerby, Fungi, t. 239 (C. minutum, as
Cyathus minutus).

CREATINEor KREATINE.— Occurs in
the juice of the flesh of Mammals, Birds,
Amphibia and Fishes ; also in human urine.
It crystallizes from an aqueous solution in
transparent, highly refractive, oblique rhom-
bic prisms and needles (PI. 7- fig- 22) belong-
ing to the oblique rhombic prismatic
system.

BIBL. See CHEMISTRY, Animal (Leh-
mann, Gorup-Besanez, Funke).

CREATININE or KREATININE.—
Occurs in the juice of the flesh of Man and
Mammals ; probably in the amniotic liquid ;
also in human urine. The crystals form

colourless prisms belonging to the oblique
rhombic prismatic system (PI. /. fig- 23).

Creatinine forms a crystalline compound
with chloride of zinc (PI. 7- fig- 24). This
is very difficultly soluble in water, and not
at all in alcohol or aether.

BIBL. See CREATINE.

CREMIDARIA, Presl.— A genus of Cya-

Fig. 145.

Fig. 146.

Cremidaria horrida.

Fig. 145. Fragment of a pinnule, the son covered by
indusia. Magnified 5 diameters.

Fig. 146. A sorus with indusium destroyed.

Fig. 147. The same, side view, showing the fragment
of the indusium at the base.

Fig. 148. Vertical section of a sorus.

Figs. 146-8 magnified 25 diameters.

thaeese (Polypodiaceous Ferns), with an in-
dusium bursting irregularly, and leaving the
numerous sporanges almost bare. Exotic.

CRIBRARIA, Schrad.— A genus of Myxo-
gastres (Gasteromycetous Fungi), consisting
of minute stalked capsules growing upon rot-
ten wood, &c. The capsules (peridia) are
membranous ; the upper part falls or decays
off when the spores are mature, and the
anastomosing filaments (capillitium) which
are contained in the interior rise out and
form a persistent spherical cage or network
(fig. 150), from the meshes of which the

Fig. 149.

Cribraria aurantiaca.
Natural size.

spores escape. The only species we find

CRICKET.

[ 173 ]

CRUSTACEA.

recorded as British is C. intermedia, Berk.,
Fig. 150.

Cribraria aurantiaca.

Peridium burst, with the capillitium exserted.
Magnified 25 diameters.

intermediate between C. vulgaris and C. au-
rantiaca. The peridium is yellow with a
white stalk ; the spores yellow. (Figured as
Sphaerocarpus semitrichioides by Sowerby,
t. 400. fig. 5.)

BIBL. Hook. Brit. Fl. v. pt. 2. 318; Fries,
Syst. Mycolog. iii. 168 ; Corda, Icon. Fung.
v. pi. 3. fig. 35.

CRICKET. See ACHETA.

CRISTATELLA, Cuv.— A genus of Po-
lypi, of the order Bryozoa.

Char. Polypidom free, disk-shaped, poly-
piferous at the margin ; tentacles numerous,
pectinate upon two arms. Aquatic.

C. mucedo (Plate 33. fig. 9). Three, four
or more polypes arise from the locomotive
polypidom. Ova in the young state enclosed
in a ciliated membrane, disk-shaped, fur-
nished with marginal spines which are hooked
at the end (fig. 10), and opening with a lid.
They are occasionally found in large num-
bers in the holes made by the feet of cattle
around ponds.

BIBL. Cuvier, Regne Animal, 1817, iv. p.
68 ; Turpin, Ann. d. Sc. nat. 2 ser. vii. p. 65;
Gervais, ibid. vii. p. 77 ; Johnston, Brit.
Zooph. p. 387 ; Vaiiey, Lond. Phys. Journ.
iii. p. 3/.

CRONARTIUM, Fries. — A genus of
Cseomacei (Coniomycetous Fungi). See
C^EOMACEI and UREDO.

CROUANIA, J. Agardh.— A genus of
Cryptonemiaceae (Florideous Algae). C. at-

tenuata is a very rare plant, which has been
found epiphytic on Cladostephus spongiosus.
Its frond consists of a single-tubed filament,
with the joints clothed with dense whorls of
minute dichotomously multiplied branchlets,
somewhat beaded. The favellidia are stated
to occur near the tips of the branchlets ; the
tetraspores (large) are affixed to the bases of
the latter.

BIBL. Harvey, Br. Mar. Alg. pi. 21 D ;
Phyc. Brit. pi. 106; J. Agardh, Alg. Medit.
83 ; Agardh, Sp. Alg. ii. 136 (as Griffithsia
nodulosa)', Kiitzing, Sp. Alg. 651 (Calli-
thamnion).

CRUMENULA, Duj.— A genus of In-
fusoria, of the family Thecamonadina.

Char. Oval, depressed, with a resisting,
obliquely striated or reticulated tegument,
from a notch in the fore part of which a long
flagelliform filament issues ; a red eye-spot.
Movement slow.

C. testa (PL 23. fig. 34). Green ; aquatic ;
length 1-510". Filament three times as long
as the body.

Dujardin appends Prorocentrum, E. to this
genus.

BIBL. Dujardin, Infus. p. 339.

CRUORIA, Fries.— A genus of Crypto-
nemiaceae (Florideous Algae). C. pellita is
common on exposed rocks and stones be-
tween tide-marks, forming a glossy purplish
skin, between gelatinous and leathery, upon
smooth surfaces, in patches 2 to 3 in dia-
meter. This 'skin' is formed of vertical tufts
of simple articulated filaments imbedded in
a gelatinous matrix. One of the cells of each
filament is larger than the rest. The tetra-
spores occur at the bases of the filaments.

BIBL. Harvey, Br. Mar. Alg. pi. 20 C ;
Phyc.Brit.pl. 117.

CRUSTACEA.— A class of Invertebrate,
Articulate animals.

Char. Apterous ; no tracheae ; respiration
aquatic (branchial), or effected by the skin :
legs jointed. (A dorsal vessel, ventricle, or
heart ; integument composed partly of chi-
tine).

The integument of the Crustacea usually
forms a hard calcareous shell, sometimes, how-
ever, being leathery or horny ; it constitutes
an external skeleton. In its most complex
condition four layers are distinguishable. An
outermost, very thin, transparent and struc-
tureless or cellular, — the epidermis ; beneath
this, a layer of pigment-cells to which the
colour is owing, but sometimes the pigment
is not contained within cells ; under this is
a thick layer, forming the greater part of

CRUSTACEA.

[ 174 ]

CRYPTOGLENA.

the substance of the integument, impregnated
with calcareous salts, and frequently fur-
nished with direct prolongations in the form
of tubercles, spinous appendages, or hairs.
See SHELL. The innermost layer consists of
a delicate fibrous coat, corresponding to an
internal periosteum or true skin ; it plays an
important part in the moulting process (ec-
dysis) which the Crustacea undergo, proba-
bly secreting the new layers of the integument.

The higher Crustacea (the Decapoda) have
mostly two pairs of antennae.

The oral organs consist of a transverse
labrum or upper lip, beneath which is a pair
of powerful toothed mandibles, acting late-
rally, and furnished with palpi. Next come
two pairs of maxillae ; the first are membra-
nous and hairy at the margin, but without
palpi ; the second are also membranous and
hairy, and correspond to the labium of In-
sects. Between the mandibles and the first
pair of maxillae is sometimes situated a soft,
tongue-like, sometimes cleft appendage.
The oral organs undergo various modifica-
tions in the lower Crustacea; these will be
considered under the respective heads. Be-
hind these are three pairs of secondary or
auxiliary jaws, or rather feet converted into
jaws, and comparable to the six legs of In-
sects; these are furnished externally with
palpi. Next follow five pairs of true thoracic
legs, behind which are five pairs of false or
abdominal legs.

The voluntary muscles of the Crustacea are
transversely striated.

The eyes are either simple : consisting of a
convex cornea, behind which is a rounded
refracting body or lens ; this lies in a cup-
shaped mass of pigment, perforated by the
optic nerves ; — compound without facets :
consisting of a smooth cornea, behind which
a number of closely-placed eyes are situated ;
sometimes a modification of this form occurs,
in the existence of a smooth outer and an
inner faceted cornea ; — or compound faceted :
as in the eyes of insects. The facets are
frequently four-sided, but sometimes six-
sided. In some of the eyes a conical vitreous
body is situated behind the lens. The eyes
are sometimes sessile, at others stalked.

The alimentary -canal is usually short and
nearly straight, sometimes curved or coiled.
Its wall consists of three or four layers — the
outermost, more or less fibrous, representing
a peritoneal coat ; the innermost, a transpa-
rent, structureless, epithelial coat, furnished
at the part corresponding to the stomach
with calcareous teeth, scales, or hairs, and

which is thrown off during the ecdysis. Be-
tween these two coats is a layer of smooth
muscular fibres.

The liver exists either in the form of sim-
ple follicles surrounding the alimentary ca-
nal ; of branched caeca situated at its upper
end, sometimes with short ducts ; or as two
glandular tufts or branches, consisting of
more or lessj-amified and closely-connected
caeca, with short ducts.

In many of the Crustacea the walls of the
alimentary canal are surrounded by cells
containing a bright orange-yellow or blue
fatty matter ; these are either scattered or
arranged in the form of lobules. They cor-
respond to the fatty body of Insects.

The Crustacea undergo remarkable meta-
morphoses, the adult form frequently differ-
ing strikingly from that of the embryo.

See ASELLUS, CIRRIPEDIA, ENTOMO-
STRACA, GAMMARUS, ONISCUS, and Si-

PHONOSTOMA.

BIBL. That of ANIMAL KINGDOM, and
the Bibl. of the works there cited.

CRYPTOCOCCE.E.— One of Kiitzing's
families of Algae, including his genera Cryp-
tococcus, Ulvina, and Splicer otilus, all of
which appear to be forms of the mycelia
(conidia?)of Mildew Fungi; they consist
of masses of extremely minute colourless
globules, found floating in aromatic waters,
vinegar, &c.

CRYPTOCOCCUS, Kiitz. See CRYP-

TOCOCCE^E.

CRYPTOGAMIA.— This term was ap-
plied by Linnaeus to his 24th Class, which
included all plants in which no true flowers
exist; the name signifying that the sexual
organs are hidden. In Natural Arrangements
of the Vegetable Kingdom the term is often
used in the same sense, but in this case as
one of two great divisions, being opposed
to Phanerogamia or Phaenogamia, which are
plants with the sexual organs conspicuous.
See VEGETABLE KINGDOM.

CRYPTOGLENA, Ehr.— A genus of In-
fusoria, of the family Cryptomonadina.

Char. A red eye-spot ; carapace a scutel-
lum, rolled in at the margins, without a
neck. Aquatic.

C. cornea (PI. 23. fig. 35 a). Conical,
expanded, and truncate in front, posteriorly
subacute; bluish-green; length 1-1150".
Two flagelliform filaments.

C. niyra (PL 23. fig. 25 6). Ovato-sub-

flobose, emarginate in front ; green ; length
-1150". Motion slow; no cilia distin-
guished.

CRYPTOMONADINA.

[ 175 J

CRYPTONEMIACE^E.

C. ccerulescens. Elliptic, depressed, emar-
ginate in front; bluish-green ; length I -6000".
Motion rapid ; no cilia distinguished.

These organisms require further examina-
tion.

BIBL. Ehr. In/us, p. 46; Duj. In/us, p.
333

CRYPTOMONADINA, Ehr.— A family
of Infusoria.

Char. An envelope or carapace, either soft
or hard ; no appendages (organs of motion,
D.) except anterior cilia, or one or more fla-
gelliform filaments; form constant. (Envelope
insoluble in potash ?)

These organisms do not admit colouring
matters, hence they should probably be re-
ferred to the Algae. One or more cilia or
flagelliform filaments have been detected in
all the genera but one (Lagenella).

The family corresponds very nearly with
the Thecamonadina of Dujardin.

No eye-spot.

Carapace with a distinct tooth in front Prorocentrum.
Carapace without a tooth Cryptomonas.

Eye-spot present.

Carapace with a neck Lagenella.

Carapace without a neck

Carapace a scutellum Cryptoglena.

Carapace not a scutellum Trachelomonas.

Dujardin adds the genera Phacus, D. (in-
cluding Euglena, E. in part), Crumenula, D.,
Diselmis,D., Chlamidomonas, E., Plceotia, D.,
Anisonema, D. (including Bodo grandis, E.,
and Oxyrrhis, D.=Prorocentrum? E.) ; and
appends doubtfully Ch(Btoglena,E., and Chce-
totyphla, E.

See THECAMONADINA, OPHIDOMONAS,
and PROTOCOCCUS.

BIBL. Ehrenb. In/us, p. 38 ; Duj. Infus.
p. 323.

CRYPTOMONAS, E.— A genus of Infu-
soria, of the family Cryptomonadina.

Char. No eye-spot ; carapace without an
anterior tooth. Dujardin says : Globular
or slightly depressed ; secreting a membra-
nous flexible carapace, and furnished with a
very delicate flagelliform filament.

The species are not well characterized.
Ehrenberg admits seven, and to these Du-
jardin adds two.

C. ovata, E. (PL 23. fig. 36 a) ; length
1-570"; aquatic.

C. lenticularis, E. (PI. 23. fig. 36 6);
length 1-1730"; aquatic.

C.fusca, E. (PI. 23. fig. 36 c); length
1-1500"; aquatic.

C. globulus, D. (PI. 23. fig. 36 d] ; length
1-2500"; aquatic.

C. inaqualis, D. (PI. 23. fig. 36 e); length
1-2506"; marine.

Dujardin appends Cryptoglena, E. and
Lagenella, E. to this genus.

BIBL. Ehr. Infus. p. 40; Dujardin, Infus.
p. 329.

CRYPTONEMIACE^. — A family of
Florideae. Purplish or rose-red sea-weeds,
with a filiform or (rarely) expanded, gelati-
nous or cartilaginous frond, composed wholly
or in part of cylindrical cells connected to-
gether into filaments. Axis formed of verti-
cal, periphery of horizontal radiating fila-
ments. FRUCTIFICATION : — 1. Conceptacles
(favellidia), globose masses of spores im-
mersed in the frond or in swellings of the
branches. 2. Tetraspores variously dis-
persed. 3. Antheridia (Nemaleon).

Subtribe 1. COCCOCARPE^E. Frond solid,
dense, cartilaginous or horny. Favellidia
contained in semi-external tubercles or swel-
lings of the frond.

I. Grateloupia. Frond pinnated, flat, nar-
row, membranaceo-cartilaginous, of very
dense texture. Favellidia immersed in the
branches, communicating with the surface
by a pore. Tetraspores scattered.

II. Gelidium. Frond pinnated, com-
pressed, narrow, horny, of very dense struc-
ture. Favellidia immersed in swollen ramuli.
Tetraspores forming sub-defined sori in the
ramuli.

III. Gigartina. Frond cartilaginous, cy-
lindrical or compressed, its flesh composed
of anastomosing filaments, lying apart in
firm gelatine. Favellidia contained within
external tubercles. Tetraspores massed to-
gether in dense sori, sunk in the frond.

Subtribe 2. SPONGIOCARPE^E. Frond
solid, dense, cartilaginous or horny. Favel-
lidia of several imperfectly known. Wart-
like swellings composed of filaments, some-
times containing tetraspores, sometimes
spores.

IV. Chondrus. Frond fan-shaped, dicho-
tomously cleft, cartilaginous, of very dense
texture. Tetraspores collected into sori,
immersed in the substance of the frond.

V. Phyllophora. Frond stalked, rigid,
membranaceous, proliferous from the disk,
of very dense structure. Tetraspores in
distinct superficial sori or in special leaflet-
like lobes.

VI. Peyssonelia. Frond depressed, ex-
panded, rooting by the under surface, con-
centrically zoned, membranous or leathery.
Tetraspores contained in superficial warts.

VII. Gymnogongrus. Frond filiform, di-

CRYPTONEMIACE.E.

[ 176 ]

CRYSTALLOGRAPHY.

chotomous, horny, of very dense structure.
Tetraspores strung together, contained in
superficial wart-like sori.

VIII. Polyides. Root scutate. Frond
cylindrical, dichotomous, cartilaginous. Fa-
vellcB contained in spongy external warts.
Tetraspores scattered through the peripheric
stratum of the frond, cruciate.

IX. Furcellaria. Root branching.
Frond cylindrical, dichotomous, cartilagi-
nous. Favellce unknown. Tetraspores deeply
imbedded among the filaments of the peri-
phery, in the swollen pod-like upper branches
of the frond, transversely zoned.

Subtribe 3. GASTROCARPE.E. Frond
gelatinously membranaceous or fleshy, often
of lax structure internally. Favellidia im-
mersed in the central substance of the frond,
very numerous.

X. Dumontia. Frond cylindrical, tubular,
membranaceous. Tufts of spores attached
to the wall of the tube inside.

XI. Halymenia. Frond compressed or
flat, gelatinoso-membranaceous, the mem-
branous surfaces separated by a few slender,
anastomosing filaments. Masses of spores
attached to the inner face of the membra-
nous wall.

XII. Ginannia. Frond cylindrical, dicho-
tomous, traversed by a fibrous axis; the
walls membranaceous. Masses of spores
attached to the inner face of the membra-
nous wall.

XIII. Kallymenia. Frond expanded, leaf-
like, fleshy -membranous, solid, of dense
structure. Favellidia like pimples, half im-
mersed in the frond, and scattered over its
surface.

XIV. Iridcea. Frond expanded, leaf-like,
thick, fleshy-leathery, solid, of dense struc-
ture. Favellidia wholly immersed, densely
crowded.

XV. Catenella. Frond filiform, branched,
constricted at intervals into oblong articula-
tions ; the tube filled with lax filaments.

Subtribe 4. GLOIOCLADIE^E. Frond
loosely gelatinous, the filaments of which it is
composed lying apart from one another, sur-
rounded by a copious gelatine. Favellidia
immersed among the filaments of the peri-
phery.

XVI. Cruoria. Frowrfcrustaceous, skin-like.

XVII. Naccaria. Frond filiform, solid,
cellular ; the ramuli only composed of radi-
ating free filaments.

XVIII. Gloiosiphonia. Frond tubular,
hollow ; the walls of the tube composed of
radiating filaments.

XIX. Nemaleon. Frond filiform, solid,
elastic, filamentous; the axis composed of
closely-packed filaments; the periphery of
moniliform free filaments.

XX. Dudresnaia. Frond filiform, solid,
gelatinous, filamentous; the axis composed
of a network of anastomosing filaments ; the
periphery of moniliform free filaments.

XXI. Crouania. Frond filiform, consist-
ing of a jointed filament, whorled at the
joints with minute, multifid, gelatinous ra-
muli.

BIBL. Harvey, Marine Alga-, Derbes et
Solier, Ann. des Sc. nat 3 ser. xiv. 273.
See also the Genera.

CRYPTOSPORIUM, Kze.— A genus of
Sphaeronemei (Coniomycetous Fungi). Mi-
croscopic Fungi growing upon bark and
leaves, producing spindle-shaped spores, at
first conglutinated beneath the epidermis of
the nurse-plant. Two species have been re-
corded as British.

1. C. Caricis, Corda. Heaps of spores
punctiform ; spores slightly curved, dark
brown and pellucid. On leaves of various
sedges. Corda, apud Sturm, Deutschl. Flor.
t. 1.

2. C. vulgare, Fries. Heaps confluent ;
spores curved, black (subhyaline). On dead
twigs of birch, hazel, alder, &c. Corda, I.e.
t. li. (Mr. Berkeley thinks this not con-
generic with C. Caricis.)

BIBL. Berkeley and Broome, Ann. of Nat.
Hist. 2 ser. v. p. 3/1 ; Fries, Syst. Myc. iii.
p. 481.

CRYSTALLINE, or CRYSTALLINE
LENS. See EYE.

CRYSTALLOGRAPHY.— The laws of
crystallography teach us that in perfectly
formed crystals, each peculiar chemical com-
bination corresponds to a distinct relation of
all the angles which can possibly arise from
the primary form ; hence by ascertaining the
latter, we can infer the former. It was our
intention to have given a sketch of the me-
thod of determining the primary forms of
the most common microscopic crystals, and
the systems to which they belong ; but our
space is far too limited for this purpose, so
that we must rest satisfied with a reference
to works specially devoted to the subject.

The angular inclination of the facets of
small crystals is in many cases easily deter-
mined, by viewing the crystals in all posi-
tions, and measuring the angles with the
GONIOMETER. When possible, the crystals
should be held by the forceps, or fixed to
them by the aid of melted wax, or Canada

CRYSTALLOIDS.

[ 177 ]

CULICID.E.

balsam ; where this cannot be effected, the
crystals should be immersed in liquid, and
made to assume the required positions by
moving the cover with the mounted needle.
BIBL. Schmidt, Entw. ein. allg. Untersuch.
fyc. ; Robin and Verdeil, Traite de Chimie
Anatom. fyc.; Phillips, Elementary Introduct.
to Mineral. (Brooke and Miller); Dana, Syst.
of Mineral.-, Naumann, Element, d. Mineral.-,
Nicol, Man. of Mineralogy ; Rammelsberg,
Lehrbuch d. Krystallkunde.

CRYSTALLOIDS.— These bodies have
been noticed under CHALK. Ehrenberg's
explanation of their nature appears doubtful;
at all events, we do not recollect having ob-
served any such bodies among the varied
forms assumed by imperfectly crystallized
substances. It would be interesting to de-
termine whether similar bodies are met with
in calcareous strata now in progress of for-
mation.

BIBL. Ehrenberg, Abh. d. Berlin Akad.
1848 ; id. Mikro-Geologie.

CRYSTALS.— Crystals are constantly
being met with in the examination of animal
and vegetable products, and the determina-
tion of their nature or composition is always
of great importance.

There are three methods of determining
this : 1, by ascertaining the atomic weight of
the substance, or by its quantitative analysis ;
2, by the study of its crystallographic pro-
perties ; and 3, by its qualitative analysis.

The first belongs to the domain of che-
mistry, and requires an appreciable quantity
of substance.

The second requires well-formed crystals,
and a knowledge of crystallography. As the
latter is an exceedingly difficult science, re-
course is generally had to the third method,
upon which some remarks have already been
made in the INTRODUCTION, p. xxxvii.

The forms of crystals vary according to
the conditions under which they are pro-
duced, but there can be no doubt that under
absolutely the same conditions, their forms
would be relatively constant. In many ani-
mal and other liquids, the forms assumed by
the crystals deposited are tolerably charac-
teristic, so that their composition may be
inferred ; but where accuracy is required, it
is always well to use chemical reagents.

Crystals, when rapidly formed, constitute
beautiful microscopic objects; the arbores-
cent, radiating, and other appearances which
they present are well known; and a more
exquisitely curious and interesting sight can-
not be witnessed than the very formation

itself taking place under the microscope.
This may be readily seen in a drop of any
saline solution spontaneously evaporating
upon a slide. See URIC ACID and POLAR-
IZATION; and for crystals in plants, RA-
PHIDES.

BIBL. See CHEMISTRY, and the Bibl. of
that article; also CRYSTALLOGRAPHY.

CUCULLANUS, Mull.— A genus of En-
tozoa, belonging to the order Coelelmintha,
and family Nematoidea.

Char. Body elongate, posteriorly attenu-
ate ; head broad, with a bivalve manducatory
apparatus ; mouth anterior, terminal, form-
ing a long vertical fissure.

C. elegans. Found in the intestine, sto-
mach, and pyloric appendages of the perch
and other freshwater fishes. Almost all the
other species of this genus live also in the
intestines of fishes. Length 1-6 to 1-3".
Colour, reddish-yellow.

BIBL. Dujardin, Hist. nat. d. Helminthes,
p. 245.

CUCURBITARIA, Grev. SeeSpn^RiA.
CULEX, Linn. — A genus of Dipterous
Insects, of the family Culicidae.

Char. Palpi longer than the proboscis in
the male, very short in the female.

Twenty species. C. pipiens, the common
gnat. See CULICIDAE.

CULICID^.— A family of Dipterous In-
sects, as the type of which the common gnat
(Culex pipiens) may be examined.

The parts of the mouth are produced into
a slender, elongated rostrum or proboscis,
which is nearly half the entire length of the
insect, and slightly thickened at the tip.
This proboscis, simple as it appears, in reality
consists of seven pieces in the females, be-
sides a pair of many -jointed palpi, which are
as long as, or even longer than the rostrum
in some of the males, and very hairy at the
extremity ; in the females, however, they are
generally very short. The head is small.
The antennae are slender and filiform, as
long as, or longer than the thorax, and
14-jointed in both sexes ; but they are plu-
mose in the males (PI. 26. fig. 21) and pilose
in the females (PI. 26. fig. 30 a) ; the basal
joint is subglobose and tubercular in form.
The eyes are lunate; the ocelli obsolete.
The thorax is oblong-oval. The abdomen is
long and slender, upon which the wings are
incumbent when at rest ; the latter have the
veins furnished with scales (PI. 27. fig. 22).
The legs are very long and slender.

The proboscis of the female is composed
of the following parts : — 1. An outer tubular

N

CULICID.E.

[ 178 ]

CUSCUTA.

canal (PI. 26. figs. 30 & 31 e), representing
the labrum, forming the most robust part of
the mouth, except the labium. 2. A pair of
slender needle-like pieces, the mandibles,
serrated on the inside near the tip (PL 26.
figs. 30 & 3 1/), thickened at the back, like
a scythe, and transversely striated. 3. A
second pair of very delicate and slender or-
gans (PI. 26. figs. 30 & 31 g\ dilated at the
base, to which the palpi are attached, repre-
senting the maxillae. 4. A slender needle-
like instrument, lanceolate at the end, tra-
versed by a narrow canal (PI. 26. figs. 30 &
31 d), the analogue of the tongue. 5. The
outer tubular canal (PL 26. fig. 30 »), in
which the others are lodged when at rest,
and representing the labium. The labrum
and labium are each traversed by a longitu-
dinal slit throughout their length.

It appears that in the males the labrum
and tongue are absent. It has been sup-
posed that when the lancets of the female
gnat are introduced into the skin, a veno-
mous liquid is simultaneously instilled into
the wound, and that the great irritation pro-
duced may thus be accounted for. It is
more probable, however, that this arises from
the deeper penetration of the lancets into
the skin, for they are of great comparative
length, — about four times that of the lancets
of the flea.

The eggs are deposited in a small boat-
shaped mass, which floats upon the surface
of the water. They are oval, with a small
narrow knot at the top, and are arranged
side by side, and closely packed.

The larvse inhabit standing waters, and
may be observed frequently, during the
spring and summer, jerking themselves about
with great agility, or suspending themselves,
for the purpose of respiration, immediately
below the surface of the water, with the
head downwards. The head (PL 28. fig. 1)
is distinct, large, rounded, and furnished
with two unjointed antennae, and several
ciliated appendages, which serve for obtain-
ing nourishment. The thorax is furnished
with bundles of feathery hairs ; the abdomen
is long, nearly cylindrical, much narrower
than the front parts of the body, and divided
into ten segments, the eighth of which is
furnished with a long respiratory air-tube
terminated by a small star; the last joint is
terminated by setae, and by five conical slen-
der plates.

After several moultings, the larvae are
transformed into pupae, which also move
about with agility by means of the tail anc

wo terminal swimming organs. In this
state they take no food ; and the position in
which they suspend themselves in the water
s the reverse of that previously assumed,
i. e. the head is upwards. The respiratory
organs consist of two air-tubes placed upon
;he thorax, and the body is much curved.
The final transformation takes place in three
or four weeks, the exuviae of the pupa serving
as a raft, upon which the insect remains un-
til its wings are extended.

BIBL. Westwood,/n£rod^c^'ow,<^c.p.507;
Robineau Desvoidy, Mem. Soc. d'Hist. nat.
iii. 1827, p. 390; Stephens, ZooL Journ. 1 ;
Curtis, Brit. Entomol. xii. 537.

CUPRESSINE^.— A suborder of Coni-
ferae (Gymnospermous Flowering Plants),
distinguished from the Abietineae by the
erect ovules and spheroidal pollen-grains.
The pollen-grains of the Cupressinese divide
into two unequal cells, the larger of which pro-
trudes as the pollen-tube, while the smaller
remains unchanged. Further particulars will
be found under CONIFERS and WOOD.

CUPRESSUS, Tournefort.— A genus of
Cupressineae, of which the Cypress, C. sem-
pervirens, is an example. See CONIFERS.
CURCULIO, Linn.— A genus of Coleop-
terous Insects, of the family Curculionidae
(weevils).

Curculio imperialis, the diamond-beetle,
is well known on account of the splendid
colours which it exhibits. Many other mem-
bers of this family present colours almost
equally brilliant. These colours are pro-
duced mainly by the action of minute scales
upon the incident light. See SCALES OF
INSECTS.

The oral organs of the Curculionidae are
curiously placed at the end of an elongated
rostrum which represents the head, and to
the sides of which the antennae are attached.
BIBL. Westwood, Introduction, 8fC.; Ste-
phens, British Beetles.

CURCUMA, L.— A genus of Zingiberaceae
(Monocotyledons), remarkable on account of
the tuberous rhizomes. Those of C. long a
form the substance called turmeric, and
the starch from the cells of the young tubers
forms one of the kinds of East Indian arrow-
root. The tubers of other species yield very
pure starch, and furnish East Indian arrow-
roots. The grains of an unknown Curcuma
imported under that name are represented
in fig. 19 of Plate 36.

CUSCUTA, Tournefort.— A curious genus
of Convolvulacese (Dicotyledons), consisting
of parasitical, leafless plants, annual or per-

CUTICLE.

[ 179 ]

ennial, nourished by short radical processes,
which they usually send into the interior of
the stems of the plants upon which they live,
although they sometimes affix themselves to
leaves also (C.Epithymum). C. Epilinum,
which grows in cultivated fields of flax, and
C. Trifolii, parasitical on clover, twine round
the stems like a fine red string, and produce
root-processes in rows on the side next the
nurse-plant, never on the free side. By
making careful sections, it may be seen that
the woody structure of the roots of the para-
site penetrates the cambium (or even into the
pith) of the nurse-plant, and becomes com-
pletely grafted on it. In the perennial kinds
(C. verrucosa), the roots become imbedded
in the annual rings. The embryo of Cuscuta
is curious, being filiform, and coiled up like
a watch-spring in the seed.

BIBL. Wheeler, Phytologist, i. 753 (Nov.
1843); Brandt, Linncea, xxii. 81(1849);
Schacht, Beitrdge z. Anat. und Phys. 1854.
p. 167.

CUTICLE OF ANIMALS. See SKIN.

CUTICLE OF PLANTS. See EPIDER-
MIS.

CUTLERIA.— A genus of Cutleriaceae
(Fucoid Algae) represented in Britain by C.

Fig. 151.

muUifida, which has a
" rooting," fan-shaped,
irregularly laciniated
frond from 2 to 8" long,
the lacinia? riband-like,
between cartilaginous
and membranous, olive,
with scattered sori, bear-
ing on some plants
(which have an orange
tint) antheridia, and in
others oosporanges (fig.
151).

The oosporanges (fig.
152) occur at the bases
of tufted hairs, and are
oblong, stalked bodies,
divided by perpendicu-
lar and transverse septa
into (usually) 8 cham-
bers, each of which gives birth to a zoospore
capable of germination. The antheridia occur
in an analogous condition on distinct plants;
they are more sausage-shaped, and divided
into a greater number of minute chambers,
from which the spermatozoids or anthero-
zoids are expelled when mature ; these have
never been seen to germinate.

BIBL. Harvey, Brit. Mar. Alg. 36. pi. 6 A;
Phyc. Brit. pi. 75 ; Greville, Brit. Alg. pl.10;

Cutleria dichotoma.
Fragment of a frond.
Nat. size.

Thuret, Ann. des Sc. nat. 3 ser. xiv. 241.
pi. 31. xvi. 12. pi. 1 ; Kiitzing, Phyc. gene-
ralis, pi. 25. fig. 2.

Fig. 152.

Cutleria dichotoma.

Fig. 152. Section of a lacinia of a frond, showing the
stalked eight-chambered oosporanges growing in tufts
with intercalated hairs. Magnified 50 diameters.

CUTLERIACE.E.— A family of Fucoid
Algae. Olive-coloured inarticulate sea-weeds,
with the fructification consisting of stalked
eight-celled oosporanges and many-celled
antheridia, arranged in definite spots or lines
(sori) on the surface; the root-like portion
coated with woolly fibres. Remarkable for
producing both zoospores, or active germina-
tive gonidia, and antherozoids. British
genus :

Cutleria. Frond ribless, irregularly cleft.
Oosporanges on short stalks. Antheridia on
different plants, in similar situations to the
oosporanges.

CUTTLE-FISH. See SEPIA.

C YATH,EE,E.-- A tribe of Polypodiaceous
Ferns, distinguished by the insertion of the
sporanges on a projecting axis, the annulus
of the sporanges being vertical (fig. 154).

Genera.
A. Sori without indusia.

I. Alsophila. Sori globose, naked, regu-
larly arranged. Indusium absent. Sporanges
inserted on a globose axis, and imbricated.
Veins pinnate.

II. Trichopteris. Sori globose, naked,
regularly arranged, without an indusium.

N 2

[ 180 ]

CYCADACE.E.

Sporanges on a globose axis, areolate and
crinite with long hairs. Veins pinnate.

III. Metaxya. Sori globose, naked, irre-
gularly scattered. Indusium wanting. Spo-
rangia inserted on a globose axis, beset with
long articulated hairs. Veins pinnate.

.B. Sori indusiate.

IV. Hemitelia. Sorus globose, indusiate,
each solitary, on a pinnule. Indusium an
ovate, concave, torn scale, situated at the
lower side of the base.

V. Hypoderris. Sori globose, indusiate,
regularly arranged. Indusium cup-shaped,
reticulated, fringed at the margin. Spo-
rangia inserted on an almost obsolete axis.
Veins anastomosing.

VI. Cremidaria. Sori globose, indusiate,
regularly arranged. Indusium forming an
involucre, at length irregularly torn or par-
tite. Sporangia inserted on a globose axis.
Veins pinnate.

VII. Diacalpe. Sori globose, indusiate,
regularly arranged. Indusium sessile, sphe-
rical, at first closed, at length irregularly
burst at the summit. Sporangia inserted on
a punctiform, scarcely elevated axis.

VIII. Thyrsopteris. Sori globose, indu-
siate, pedunculate on stalks, which are divi-
sions of a bi- tri-pinnate fertile leaf. Indu-
sium globose-hemispherical, with an open
mouth; margin almost entire. Sporangia
inserted on a convex axis. Veins pinnate.

IX. Woodsia. Sori globose, indusiate,
regularly arranged. Indusium cup-shaped,
open, hairy at the margin. Sporangia in-
serted at the bottom of the indusium, pedi-
cellate. Veins pinnate.

X. Clbotium. Sori depressed-globose, in-
dusiate, regularly arranged. Indusium bi-
valve ; valves unequal, or almost equal.
Sporangia inserted on a convex axis. Veins
pinnate.

XI. Dicksonia. Sori globose, indusiate,
regularly arranged. Indusium bivalve,
arched-semilunar on each side. Sporangia
inserted on a transverse, linear, crest-like
axis. Veins pinnate.

XII. Deparia. Sori hemispherical, indu-
siate, marginal, exserted. Indusium goblet-
shaped, with an open mouth, torn. Spor-
angia stalked, on a small axis. Veins pinnate.

XIII. Cyathea. Sori hemispherical, indu-
siate, regularly arranged. Indusium at first
closed, at length bursting in a circumscissile
manner, and cup-shaped. Sporanges in-
serted on a subglobose axis. Veins pinnate.

XIV. Matonia. Sori globose, indusiate,
solitary, arising from the points of confluence

of most of the venules, Indusium orbicu-
late, peltate ; the margin distinctly reflexed,
subglobose-hemispherical, umbonate in the
middle, stipitate. Sporanges about six, in-
serted at the base of the stalk. Veins ana-
stomosing.

CYATHEA, Smith.— A genus of Cya-
thseese (Polypodiaceous Ferns), many of
which are arborescent. They have a cup-
like indusium, whence the name. Exotic
(figs. 153-4).

Fig. 153.

Fig. 154.

Cyathea elegans.
Fig. 153. Pinnule with son. Magnified 5 diameters.
Fig. 154. Vertical section of a sorus in a cup-like indu-
sium. Magnified 25 diameters.

CYATHUS, Hall. See NIDULARIACEI.

CYCADACE.E.— A family of Gymno-
spermous Flowering Plants, consisting of
remarkable exotic trees, having somewhat
the aspect of Palms, but most nearly related
to the Coniferae. The microscopic structure
of the wood is analogous to that of the Co-
nifers, and the mode of fertilization of the
ovules is similar. (See GYMNOSPERMIA.)
Species of Cycas, Zamia, &c. are commonly
cultivated in botanical gardens. They offer
interesting subjects of microscopic investiga-
tion. The parenchymatous tissue, in the
form of pith, large medullary rays, and in
Cycas of concentric rings alternating with
those of the wood, is remarkable for the
quantity of starch contained in it at cer-
tain periods. This is extracted and used as
arrowroot or sago. Cycas circinalis fur-
nishes a kind of sago (its starch-grains are
represented in fig. 17. PI. 36). Dion edule
yields a kind of arrow-root in Mexico. Ence-
phalartos yields Caftre-bread at the Cape, &c.
The wood is composed, in Cycas and Zamia,
almost wholly of large dotted tubes, somewhat
like those of Araucaria (with many rows of
bordered pits) (PI. 39. fig. 20), but a medul-
lary sheath exists, composed of unreliable
spiral vessels, with tubes of varied character,
reticulate, annular or other fibrous forms, as
in the Dicotvledons, and in Zamia the dotted

CYCAS.

CYCLOPS.

tubes are said to be unreliable in some cases
into spiral ribands. In Zamia and Ence-
phalartos there does not appear to be a di-
stinction of concentric rings of wood, but in
Cycas these exist, separated by layers of
cellular tissue. The rings, however, are
not "annual," only five or six existing in
large old trunks. The leaves of the Cyca-
dacese possess a remarkably solid epidermal
structure, and in Cycas the upper thickened
walls of the epidermal cells exhibit pore-
canals or deep pits running from the cavity
of the cell toward the outer surface, as well
as towards the contiguous cells (PL 38. fig.
28). See EPIDERMIS. The pollen of the
Cycadaceae is angular, collected in masses
and transparent ; it is contained in anthers
of peculiar form seated on the lower surface
of the scales of the male cones.

BIBL. Don, Ann. Nat. History, v. 48;
Linn. Trans, xvii. ; Brongniart, Ann. des
Sc. nat. xvi. 589 ; Mohl, Vermischt. Schrift.
195 ; Link, Icon. Select, fasc. ii. t. ix. & xv.;
Miquel, Linneea, xviii. 125. and pi. 4, 5, 6
(tr&nsl. Ann. des S. nat. 3 ser. v. 11). Also
the works referred to under GYMNOSPER-
MIA.

CYCAS, L. See CYCADACE^S.

CYCLIDINA, Ehr.— A family of Infu-
soria.

Char. No carapace ; a single alimentary
orifice; appendages in the form of cilia or
bristles.

dT r cm* .

uritiii Rounded, cilia scattered Pantotrichum.

th Ibristles ...................... Chcetomonas.

BIBL. Ehr. Infus. p. 244.

CYCLIDIUM, Hill, Ehr.— A genus of
Infusoria, of the family Cyclidina.

Char. Body compressed ; organs of loco-
motion a circle of abdominal cilia-like feet.

The gastric sacculi will admit coloured
particles.

C. glaucoma (PI. 23. fig. 37 c, side view;
d, dorsal view). Oblong, elliptical, entire ;
circle of cilia large ; dorsal lines very fine ;
aquatic; length 1-2880 to 1-1150".

C. margaritaceum. Orbicular - elliptic,
slightly emarginate posteriorly; cilia obso-
lete; pearly; aquatic; length 1-2100 to
1-1000''.

Two doubtful species, — C. planum and
lentiforme.

Dujardin includes his species of Cyclidium,
the relation of which to those of Ehrenberg
is doubtful, in the family Monadina; with
the characters :

Body disk- shaped, depressed or lamelli-
form, but little variable in form, with a single
flagelliform filament. Four species :

C. nodulosum. With series of nodules and
vacuoles ; motion extremely slow ; aquatic ;
length 1-530".

C, abscissum (PI. 23. fig. 37 b). Lamelli-
form, oval, truncated posteriorly; motion
slow; aquatic; length 1-920".

C. distortum (PI. 23. fig. 37 a). Oval,
nodular, irregularly twisted ; margin thick-
ened; aquatic; length 1-1800".

C. crassum. Aquatic; length 1-1800 to
1-1100".

BIBL. Ehr. Infus. p. 245; Duj. Infus.
p. 286.

CYCLODIUM, Presl.— A genus of Aspi-
dieae (Polypodiaceous Ferns). Exotic.

CYCLOGLENA, Ehr.— A genus of Rota-
toria, of the family Hydatinaea.

Char. Eyes more than three, forming a
cervical group ; foot forked.

Pharyngeal jaws with one or perhaps three
teeth !

C. lupus (PI. 34. fig. 18). Body ovate-
oblong or conical, not auricled; foot and
toes short; aquatic; length 1-144 to 1-120".

C.? elegans. In Egypt.

BIBL. Ehr. Infus. p. 453.

CYCLOPS, Miiller.— A genus of Ento-
mostraca, of the order Copepoda, and family
Cyclopidae.

Char. Foot-jaws large and strong, branched;
eye single, frontal; inferior antennae simple;
external ovaries two. (Both superior antennae
in the male furnished with the swelling and
hinge -joint).

C. quadricornis (PI. 15. figs. 8-15). The
only species. Variable in colour ; aquatic ;
length 7-12 to 9-12".

Char. Those of the genus.

Thorax composed of four, and abdomen
(apparently the tail) of six segments ; head
consolidated with the first and largest joint
of the thorax; last joint of abdomen con-
sisting of two separate lobes.

Superior antennae (figs. 8, 9 a) composed of
many joints (twenty-six, Baird), from each
of which one or more setae arise; in the
male, each superior antenna exhibits a swel-
ling at about its middle (fig. 8 6) followed by
a sudden contraction, the first articulation of
which forms a hinge- joint; inferior antennae
(fig. 9 b] four-jointed, each joint with setae,
the terminal with six of unequal length.
The mandibles (fig. 11) consist of an ovate
body (a), narrowed and twisted above, and
terminating in a number of brownish teeth,

CYCLOPS.

[ 182 ]

CYLINDROSPERMUM.

with a marginal serrated seta (6); each man-
dible has also a palpus, consisting of one
segment and two long filaments.

Behind the mandibles, the first pair of
foot-jaws (fig. 12) are situated; each consists
of a body, convex externally, concave inter-
nally, furnished at the end with two or three
strong teeth, and with a single-jointed palp-
like organ terminated by setae.

The second pair of foot-jaws (fig. 13 a b)
are divided to the base into two portions :
an internal (6) smaller, and consisting of
four joints, each with one or more setigerous
spines, the last with three ; and an external
(a) composed of three joints, to the base of
the first of which the internal portion is at-
tached; this first joint is the longest, and
furnished on its inner side with two tuber-
cles, each with one or two setigerous spines,
a longer jointed spine arising from near its
distal extremity; the second joint is fur-
nished with two strong claws, of nearly equal
size ; and to its upper edge is attached the
third joint, smaller than the second, also
furnished with two claws ; some of the spines
are themselves setigerous.

There are five pairs of legs or feet, four of
which are branchial, uniform, and arise from
the thoracic segments. Each of these feet
(fig. 14) is composed of two branches arising
from a common base ; each branch is three-
jointed, and each joint is furnished with ele-
gantly plumose setae, the last having six or
seven. The fifth pair of feet (fig. 15) are
rudimentary, and arise from the first and
smallest segment of the abdomen ; they are
two-jointed in the female, and three-jointed
in the male.

The external ovary (fig. 9 o) communicates
directly with the internal by means of a
small canal on each side between the first
and second segments of the abdomen.

The tail consists of two lobes, each termi-
nated by four variously setigerous filaments,
the two intermediate being the longest, and
jointed near their origin; sometimes there
are two joints to each, and the outer ones
are also jointed.

Scarcely a pool of water can be found in
which this animal may not be seen darting
about in various directions. It varies greatly
in structure and appearance, according to
age, locality, sex, &c., and these varieties
have been admitted as so many species by
some authors.

PI. 15. fig. 16 represents a recently hatched
Cyclops.

The individuals are frequently covered

with Vorticellce and other parasitic Infu-
soria.

BIBL. Baird, British Entomostr. p. 198;
Koch, Deutschl. Crustac. &c.

CYCLOTELLA, Kiitz.— A genus of Dia-
tomaceae.

Char. Frustules free or adherent to other
bodies, disk-shaped, mostly solitary ; valves
circular, flat, convex, depressed or undulated,
striated ; striae radiating.

The frustules of some of the species are
immersed in an amorphous gelatinous sub-
stance.

When the valves of (all ?) the species of
Cyclotella are examined under an object-
glass of large aperture, with the central stop
(!NTR. p. xvi. et seq.), the surface is found
to be marked with dots or depressions
arranged in radiating rows, as in some spe-
cies of Coscinodiscus ; hence these two ge-
nera should probably be united. Some of
the species (?) appear to represent the frus-
tules of Melosira seen in end view.

C. operculata, K. (Pyxidicula operculata,
£., Discoplea Kutzingii, E.) (PI. 12. fig. 21 ;
a, side view; b, front view). Angles of frus-
tules in front view rounded ; striae obscure,
very short, giving the margin a punctate
appearance;, aquatic; diameter attaining
1-1000".

/3 rectangula, K. (C. Kutzingiana, S.)
(PI. 12. fig. 22). Angles of front view not
rounded; striae more distinct.

C.Meneghiniana. Valves plane, distinctly
striated at the margin; aquatic; length
1-1440".

/3 major. Twice as broad.

C. antiqua,$.(Discoplcea atmospherical.}.
Valves convex; striae broad, reaching nei-
ther the centre nor the margin; aquatic;
diam. 1-760".

Kiitzing characterizes three marine spe-
cies, with the valves free from striae, and
seventeen doubtful species, marine and fos-
sil, belonging to the genera Actinocyclus,
Discoplea (?), and Hyalodiscus of Ehren-
berg.

BIBL. Kiitzing, Syn. Diat., Bacill. p. 50,
and Sp. Alg. p. 18 ; Ehrenberg, Ber. d.
Berl. Akad., passim-, id. Infus., and Mikro-
geologie, fyc. ; Smith, Brit. Diat. p. 27 ;
Thwaites, Ann. Nat. Hist. 1848. i. p.
169.

CYLINDROSPERMUM, Kiitzing (Ana-
baina, Bory and others). — A genus of Nos-
tochaceae (Confervoid Algae), with the fila-
ments radiating less than in the allied Sphee-
rozyga ; distinguished under the microscope

CYLINDROSPORUM.

[ 183 ]

CYNIPS.

by the resemblance of the filaments to an
annulose animal, the ordinary cells looking
like a long, jointed body, the large elliptic
spermatic cell like a thorax, and the termi-
nal vesicular cell often bearing fine hairs, like
a head. Br. species :

1. C. ca*ewato,Ralfs(P1.5.fig.4). Fila-
ments moniliform ; ordinary cells orbicular ;
vesicular cells oval; spermatic cells oval,
catenate. (Ralfs, Ann. Nat. Hist. ser. 2. vol.
v. pi. 9. fig. 14.) Forming a bluish stratum,
containing very delicate, elongated, straight
or slightly flexuose, generally parallel fila-
ments.

The remaining British species are not de-
scribed by Mr. Ralfs, but the following are
noticed as British by Kiitzing( Species Alga-
rum} under the head of Cylindrospermum.

2. C. macrospermum, Kiitzing. Fila-
ments thick, equal; ordinary cells oblong,
1- 700th of a line in diameter; sper-
matic cells oblong, turgid, firm, fuscous,
1-100 to 1-60"' long, 1-300 to 1-200'" thick.
Kutzing, Sp. Algarum, 293; Tab. Phyc.
vol. i. pi. 98. fig. 4. Anabaina impalpebralis,
Hassall, Br. Fr. Algce, pi. 75. fig. 3. Stand-
ing water; forming an aeruginous green
stratum.

3. C. mesoleptum, Kutzing. Filaments
densely entangled, unequal, 1-800 to 1-650'"
thick; spermatic cells oblong, 1-180 to
1-1 50'" long, 1-350 to 1-300"' broad, slightly
constricted in the middle. Kutzing, Sp.Alg.
Tab. Phyc. vol. i. pi. 98. fig. 5. Anabaina
constricta, Hassall, Br. Fr. Alga, pi. 75.
fig. 9. JSruginous green; in brackish
marshes.

Excluded Species of Kutzing.

Cylindrospermum elongatum = Spheerozyga elastica,

Ag. (Ralfs).
„ leptospermum = Sph<erozygfi lepto-

sperma (Ralfs).
„ Carmichaelii = Spheerozyga Carmi-

chaelii (Harvey).
„ Ralfsii = Dolichospermum

Ralfsii (Ralfs).
,, II assail ii = ConiophytumThomp-

soni (Hassall).

BIBL. Ralfs on Nostochinece, Ann. of Nat.
Hist. ser. 2. vol. v. p. 321 ; Kutzing, Sp. Alg.

CYLINDROSPORUM, Grev.— A genus
of parasitic Fungi of uncertain place.

C. concentricum, Grev.— Uredo cylindro-
spora, Hook. Br. FL Grows upon the leaves
of cabbages ; distinct from Cystopus.

BIBL. Grev. Sc. Crypt. FL t. xxix.; Berke-
ley, Hort. Trans, iii. 265.

CYMATOPLEURA, Smith. SeeSpmNC-

TOCYSTIS.

The former name was proposed to desig-

nate the genus Sphinctocystis, previously
founded by Hassall : it cannot, therefore, be
retained. See the laws upon the subject of
Nomenclature in the Annals of Natural
History, 1843. xi. p. 259.

BIBL. Smith, Ann. Nat. Hist. 1851,
vii.

CYMBELLA, Ag.— A genus of Diato-
maceae.

Char. Frastules solitary, free; valves
cymbiform, unsymmetrical, with a subcentral
and two terminal nodules, a submedian lon-
gitudinal line, and transverse or slightly
radiating stria?. Aquatic and fossil.

Frustules sometimes immersed in an amor-
phous gelatinous mass.

C. Ehrenbergii, K. (PI. 13. fig. 31; a, front
view; b, side view). Broadly lanceolate,
apices slightly produced, somewhat obtuse ;
striae distinct (resolvable into dots) ; length
1-200". (Fossil in San Fiore deposit.)

Five other British species, and several
more foreign, differing from each other by
slight characters.

BIBL. Smith, Brit. Diatomacece, p. 17;
Kutzing, Bacillar. p. 79, and Sp. Alg.
p. 57.

CYMBOSIRA, Kiitz.— A genus of Diato-
macese.

Char. Frustules resembling those ofAch-
nanthes; solitary or binate, stipitate, at-
tached end to end, and thus concatenate.
Marine.

C. Agardhii (PL 14. fig. 18). Frustules
linear, slightly arcuate, finely striated,
rounded at ends; valves oblong - linear,
slightly dilated in the middle, apices ob-
tusely rounded. Length 1-960 to 1-280".
Not British (?).

BIBL. Kutzing, Bacill p. 77, and Sp.
Alg. p. 57.

CYNIPS, Linn.— A genus of Hymenop-
terous Insects, of the family Cynipidse (gall-
flies).

The species, as well as those of other
genera of this family, are particularly interest-
ing on account of the females being fur-
nished with a boring apparatus at the end of
the abdomen, by means of which various
partsof plants are pierced to allow of the depo-
sition of the eggs in a situation where the
larvae can obtain food when hatched. The
irritation arising from the presence of the
gives rise to the formation of various
among which we may mention the
alls of commerce, the bedeguar or red
fibrous gall of the rose, the oak-spangles,
&c. The apparatus itself requires further

CYPHELLA.

CYPRIS.

examination; but it appears to consist of
a sheath, channelled on its under side for
the reception of two equal and very slender
bristles, the whole protected by two valve-
like sheaths, and contained in a canal
traversing the last segment of the abdomen.

BIBL. Westwood, Introduction, &c.

CYPHELLA, Fries. — A genus of Auricu-
larini (Hymenomycetous Fungi), forming

Fig. 155.

Fig. 156.

Cyphella Taxi.

Fig. 155. Entire plant, magnified 10 diameters.
Fig. 156. Horizontal section of the wall of the cup,
showing the basidiospores, magnified 250 diameters.

somewhat membranous minute cups, sessile
or stalked upon branches of trees or upon
mosses; bearing basidiospores on a layer
forming a kind of lining to the cup; the
spores ultimately separating as a powder in
the interior.

BIBL. Fries,%s£..%c.ii.p.201; Leveille,
Ann. des Sc. nat. 2 se'r. xvi. 23?.

CYPHIDIUM, Ehr.— A genus of Infu-
soria, of the family Arcellina.

Char. Carapace urceolate, tuberculated ;
expansion variable, broad, single and entire.

The carapace is combustible, and resembles
a small cube, with a short pedicle.

C. aureolum (PL 23. fig. 38). Cubical,
gibbous, expansion (fig. 38 b) hyaline; aqua-
tic ; length 1-570 to 1-432".

BIBL. Ehr. In/us, p. 135.

CYPHODERIA, Schlumb.— A genus of
Infusoria, of the family Arcellina.

Char. Carapace membranous, resisting,
ovoid, elongated in front, recurved and
constricted in the form of a neck and marked
with oblique rows of projections ; orifice
circular, oblique ; expansions very long,
filiform, very slender at the end, simple or
branched.

Agrees with Difflugia enchelys, E. (Tri-
nema, Duj.), in the oblique orifice, the
oblique rows of markings, and the nature of
the expansions, but differs from it in the
presence of the anterior neck-like constric-
tion.

C. margaritacea. Carapace yellowish,
expansions twice its length ; aquatic ; length
1-380 to 1-180".

Schlumberger remarks that the form of

the carapace is very variable, that the neck
is sometimes quite rudimentary, and that in
other individuals the posterior part instead
of being broad and round, is suddenly nar-
rowed into a truncated point.

The foundation of a genus upon an incon-
stant character must be regarded as a very
questionable proceeding. Perhaps Cypho-
deria is the adult form of Difflugia enchelys.
BIBL. Schlumberger, Ann. des Sc. nat.
3 ser. iii. 1845.

CYPHONAUTES, Ehr.— A genus of
Rotatoria, of the family Megalotrochsea.
Char. Eyes absent ; no teeth.
C. compressus (PI. 34. fig. 19, side view ;
fig. 20, view from above). Compressed,
obtusely triangular, truncate in front, sub-
acutely gibbous at the back; marine; length
1-180".

BIBL. Ehrenb. In fits. p. 395.
CYPRIDINA, Edwards.— A genus of
Entomostraca, of the order Ostracoda, and
family Cypridinadae.

Char. Eyes two, stalked ; antennae two
pairs, both pediform ; feet two pairs ; one
pair always enclosed within the shell, long,
slender, cylindrical, twisted, divided into
numerous short joints, and furnished near
the upper third of their length with several
sharp, stout serrated spines; abdomen ter-
minated by a broad lamellar plate, armed
with strong claws and hooked spines.
Marine.

C. Mac Andrei.
C. Erenda.

BIBL. Baird, Brit. Entom. p. 1?6 ; M.-
Edwards, Hist. Nat. Crust, iii. 409.

CYPRIS, Miiller.— A genus of Ento-
mostraca, of the order Ostracoda, and family
Cypridae.

Char. Eye single ; inferior antennae with
a tuft or pencil of long filaments arising
from the last joint but one ; animal swim-
ming freely.

Body enclosed within a bivalve carapace
or shell. Superior antennae (PL 15. fig. 18)
seven-jointed, with pretty long, mostly
feathery filaments, arising from three or four
last joints. Inferior antennae (fig. 19) foot-
like, five-jointed, giving off the tuft of
usually feathery filaments, the last joint ter-
minated by several strong curved claws.
Labrum composed of a somewhat hood-
shaped piece, projecting between the two
inferior antennae ; labium or lower lip elon-
gated and triangular. Mandibles (fig. 20)
large, pointed at one end, with five teeth at
the other, and furnished with a three-jointed

CYSTIC OXIDE.

[ 185 ]

CYSTOPTERIS.

setigerous palp, the basal joint of which has
a small branchial joint with five terminal
digitations. First pair of jaws (fig. 21) con-
sisting of a large basal plate (a), with four
finger-like processes at its anterior extremity,
one of which is two-jointed, and all termi-
nated by several long filaments ; from the
outer edge of this plate arises a large elon-
gated branchial lamina (b), giving off from
its crescentic margin nineteen long pectinate
spines. Second pair of jaws (fig. 22) small,
and composed of two flattened joints, the
terminal one having several rigid hairs at the
end, and a lateral palp-like process. First
pair of feet (fig. 23) slender and five-jointed,
the last joint with a strong hook. Second
pair of feet (fig. 24) four-jointed, the last
joint terminated by two short hooks and a
spur-like posterior filament. Abdomen
(fig. 25) consisting of two long portions,
each with two terminal hooks, and a third at
its upper edge.

C. tristriata (PI. 15. figs. 17-25). Shell
oval and somewhat reniform, posteriorly
exhibiting three narrow oblique streaks or
dark bands ; valves convex, green, and
covered with dense short hairs. Near the
centre of each valve are about seven small
clear spots. Aquatic.

C. vidua. Shell oval, slightly sinuated
beneath, and with dense, short, marginal
hairs ; dull white ; valves marked with three
black, somewhat waved bands, running
transversely across the shell at unequal
distances, the most anterior being the smal-
lest ; posterior margin rather narrower than
the anterior. Aquatic.

Twelve other British species, but none
very well characterized.

BIBL. Baird, Brit. Entomostraca,ip. 161;
Straus, Mem. d. Mus. d. Hist. nat. vii. 1821 ;
Edwards, Hist. Nat. Crust, iii.

CYSTIC OXIDE or CYSTINE.— A
very rare component or constituent of uri-
nary calculi in man and the dog. It also
occurs in the urine, in solution and as a
crystalline deposit.

Cystine is insoluble in water and alcohol ;
soluble in mineral acids, but not in acetic
acid ; also soluble in solutions of fixed
alkalies, their carbonates, and in solution of
ammonia. It is precipitated from its solu-
tion by acetic acid.

Its crystals form colourless, regular six-
sided plates or prisms (PI. 9. group 5) ; the
larger crystals usually exhibit a number of
smaller hexagonal tables irregularly arranged
upon them; sometimes rectangular plates

are met with. The crystals usually exhibit
but little colour with polarized light. Cystine
is most readily obtained in crystals from a
calculus, by solution in ammonia and spon-
taneous evaporation.

Some of the forms of lithic acid prepared
artificially, resemble those of cystine (PL 8.
group 8 6) ; they may be distinguished by
the addition of ammonia, which dissolves the
cystine, but has little or no action upon the
uric acid.

Carbonate of potash also somewhat resem-
bles cystine in the form of its crystals (PL 6.
fig. 13) ; but water or acetic acid will at once
distinguish them.

BIBL. See the BIBL. of CHEMISTRY,
Animal.

CYSTICERCUS, Rud. — A supposed
genus of Entozoa, of the order Sterelmintha,
and family Cystica.

Char. Individuals existing singly in a cyst,
and composed of a short body of a Ttenia
with a double crown of hooks, and termi-
nated posteriorly by a larger or smaller
vesicle.

Head with four suctorial disks. Dujardin
admits five species.

Recent researches have shown that the
species of Cysticercus are larval T^ENI^E.

C. celluloses (PL 16. fig. 3). Head almost
tetragonal ; neck very short ; body cylin-
drical, longer than the vesicle; breadth of
cyst half an inch; length of body 1-6 to 2-5"
(or 1" when extended). Occurs in the
anterior chamber and upon the conjunctiva of
the eye, also in the voluntary muscles and
brain of man ; in the cellular tissue of the
pig, producing the peculiar appearance of
" measly pork ; " also in the ape, the dog,
the ox, the rat, &c.

C.fasciolaris (PL 16. fig. 3 b, head of).

Occurs in the liver of the rat, the mouse, &c.

BIBL. Dujardin, Hist. d. Helminth, p. 632;

Beneden, Cosmos, iv. and Les Vers Cestoides,

&c., 1850.

CYSTINE. See CYSTIC OXIDE.
CYSTOCOCCUS,Nag.=PROTococcus.
CYSTOPTERIDEJS. — A subtribe of
Polypoda3ous Ferns, with indusiate son.

I. Cystopteris. Sori globose. Indusium
subacuminate, fixed by a sublateral basilar
point. Veins scarcely anastomosing.

II. Onoclea. Sori globose, one on the
middle of each primary vein. Indusium thin,
hood-like, lateral, fixed by its lower side, free
on the upper. Margins of the fertile leaves
rolled up in the form of berries.

CYSTOPTERIS, Bernhardi.— A genus of

CYSTOPUS.

[ 186 ]

CYTHERE.

Cystopterideae (Polypodaeous Ferns), con-
Fig. 157.

•y

Cystopteris fragilis.

A pinnule with the sori covered by the indusia.
Magnified 10 diameters.

taining several elegant little indigenous
species (fig. 157).

CYSTOPUS, Leveille. — A genus of
Caeomacei (Coniomycetous Fungi), of which
the ' white rust ' common on cabbages and
other Cruciferous plants is a good example,
appearing in white pustules, eventually
bursting and destroying the epidermis of the
leaves, stalks, flowers and seed-vessels of
the infected plants. When fine slices of
these pustules are examined under the
microscope, the mycelium is found, creep-
ing among the cells of the parenchyma,
composed of inarticulate, tubular, branched
filaments, with a colourless membrane and
whitish granular contents. Numerous rami-
fications spread out in the plane of the
epidermis, while others spring up in tufts of
two to seven, or rarely singly, perpendi-
cular to the former, to produce spores.
These erect branches are at first mere
pouches projecting from the horizontal fila-
ments ; they gradually swell into ovate-
cylindrical or club-shaped sacs. The con-
tents in the summit of each such sac become
organized into a spore, which at length
quite fills up the top of the sac (sporange).
Then the sac or sporange becomes con-
stricted under this first spore, and the for-
mation of a second commences under the
constriction. This is repeated until a neck-
lace-like chain of spores is produced, the
spores subsequently becoming somewhat
cylindrical or cubical. The number appears
indefinite ; five and seven spores have been
found in a chain ; they are united by the
constricted portions of the sporange; and
even when they have fallen apart, these
connecting pieces are seen projecting on them

like parts of a stalk from which they have
been broken off. Both the adherent spo-
rangial membrane and the smooth proper
coat of the spores are colourless, the contents
granular and whitish. Tulasne has recently
discovered another form of spore, spheroidal
or trigonal, and of a yellow colour, only one
or two of which are formed from the end of
a fertile filament. See UREDINE^E. Br.
species :

C. candidus, Lev. Very common on
Cruciferae, producing great distortion in the
growth. Uredo Candida, Pers., Grev. So.
Crypt. Fl. t. 251.

BIBL. Leveille, Ann. des Sc.nat. 3 ser. viii.
369; Berkeley, Hort. Transact, iii. 265
(figs.) ; De Bary, Brandpilze, Berlin, 1853,
p. 20. pi. 2. figs. 3-7 ; Tulasne, Ann. des
Sc. nat. 4 ser. ii. 108, 171.

CYSTOSEIRA, Ag.— A genus of Fucaceaj
(Fucoid Algae), of much branched habit,
some species of which are common on rocks
in tide-pools or between tide-marks. The
gradually attenuated branches contain in-
flated air-sacs, at intervals along their length,
within their substance. The conceptacles
are immersed in the ends of the branches,
which are pierced by their numerous pores.
They contain both spores and antheridia,
but not mixed ; the spores occur at the bot-
tom of the cavity, the antheridia above, near
the pore. The antheridia have only a single
coat. The antherozoids are expelled in a
mass, and soon after begin to move, turning
rapidly upon their axes. They are oval or
spherical in one direction, and rather com-
pressed in the other. They have two cilia
inserted on a red granule ; the long cilium
in front moves rapidly, while the posterior
short one is motionless. See FUCACE^E.

BIBL. Harvey, Br. Mar. Ala. pi. 1 B ;
Phyc. Brit. 133, &c. ; Thuret, Ann. des Sc.
nat. 3 ser. xvi. pp. 7 & 10.

CYSTOTRICHA, Berk, and Broome.— A
genus of Phragmotrichacei (?) (Coniomyce-
tous Fungi). Minute fungi forming dots or
lines upon wood from which the bark has
been stripped. Only one species is de-
scribed.

C. striola, Berk. & Br. Perithecia black,
with a reddish tinge, opening by a reddish
disk.

BIBL. Berk. & Br. Ann. Nat. Hist. 2 ser.
v. 457. pi. 12. fig. 10.

CYTHERE, Miill.— A genus of Entomo-
straca, of the order Ostracoda, and family
Cytheridae.

Char. Eye single ; superior antennae sim-

CYTISPORA.

[ 187 ]

DACRYMYCES.

pie, setigerous, but without a tuft or pencil
of long filaments ; inferior antennae with one
tolerably long, curved and three-jointed fila-
ment; feet three pairs, none enclosed within
the shell; abdomen short; last four joints
of superior antennas with one or two setae at
the base, the last terminated by several ra-
ther larger hairs ; inferior antennas with five
joints ; feet five-jointed, second joint largest,
the last terminated by one or two long curved
hooks directed forwards.

Fifteen'British species, all marine but one,
viz.

C. inopinator (PI. 15. fig. 26). Shell ob-
long-ovate, nearly of equal size at each end,
white, with a slightly orange mark on the
upper edge, transparent, smooth and shining,
with a few short spinous projections on the
lower margin of the posterior extremity;
each valve with a gibbous external projection
at about the middle; superior antennae
five(?)-jointed, and with rather short setae ;
size, "very small" !

BIBL. Baird, Brit. Entomostraca, p. 163.

CYTHEREIS, Jones.— A genus of Ento-
mostraca.

Char. Animals unknown. Valves of the
carapace almost regularly oblong; surface
very irregular, being wrinkled, ridged, and
beset with tubercles, andcrenulated or strongly
toothed on the margins.

Three British species. Found in sea-
sand.

Do they consist of valves of Entomostraca
partially converted into calcareous crystal-
loids, or upon which crystalloids are depo-
sited ?

BIBL. Baird, Brit. Entomostr. p. 174.

CYTISPORA, Ehrenb.— A genus of Me-
lauconiacei (Coniomycetous Fungi), remark-
able for emitting the minute bodies formerly
regarded as spores, agglutinated together
into a more or less gelatinous mass, in the
form of a tendril. The relationship between
the forms called Cytispora and various spe-
cies of Sphferia has long been noticed, and
Fries stated that he had seen C. leucostoma
pass into S. leucostoma. C.fugax was stated
by Berkeley to be exactly analogous to S. sa~
licina. Recent researches seem to prove
that the present genus, with Septoria and
others, are really only forms belonging to
various Ascomycetous Fungi, and that they
bear the same relationship to the latter as
the spermagonia of LICHENS do to the the-
ciferous fructification. Hence the so-called
spores of Cytispora, &c. would in reality be
the spermatia or stylospores of the Sphcerice.

As these questions are not yet clearly worked
out, we retain the names of these pseudo-
genera and species in the present work.
More minute details on the subject are given
under SPH^RIA, and the works of Tulasne
and Messrs. Berkeley and Broome below
cited should be consulted.

1. Cytispora rubescens, Fr. Disk dirty
brown; spores (?) reddish. On Rosaceae.

2. C. chrysosperma, Pers. Disk black;
spores yellow. On Poplar bark.

3. C. carphosperma, Fr. Disk dingy;
spores straw-coloured. On Hawthorn and
other Rosaceae.

4. C. leucosperma, Pers. Disk dirty white;
spores white. On various trees. Common.
Nemasporum Rosarum, Grev. Scot. Crypt.
Fl. t. 20.

5. C. fugax, Bull. Disk dirty brown ;
spores pale. On willow branches. Very
common.

6. C. orbicularis, Berk. Disk yellowish ;
spores pale vinous red. Upon small orange
gourds. Berkeley, Ann. Nat. Hist. i. pi. /•
fig. 6.

7- C. Hendersoni, Berk. & Broome. Disks
whitish ; spores large, dirty white. On Dog-
rose. Berk. & Br. Ann. Nat. Hist. 2 ser.
v. 379.

C. pulveracea, Berk. Br. Flora=Ceutko-
spora Phacidioides, Desm.

BIBL. Berkeley, Brit. Flor. vol. ii.pt. 2.
p. 281, and loc. supra cit. ; Berk. & Broome,
Hooker's Journal of Botany, iii. 319; Tu-
lasne, Ann. des Sc. nat. 3 ser. xv. p. 375
(transl. in Ann. Nat. Hist. 2nd ser. viii. 114);
Ann, des Sc. nat. xx. p. 129 ; Botanische
Zeitung, xi. 49 (1853).

CYTOBLAST. See NUCLEUS.

CYTOBLASTEMA, OF ANIMALS, or, for
brevity, BLASTEMA. — The amorphous pro-
teine-substance in which animal and vege-
table cells are formed, or of which they are
wholly composed. See CELLS.

CYTOBLASTEMA, OF VEGETABLES.
See PROTOPLASM.

D.

DACRYMYCES, Fries.— A genus of Tre-
mellini (Hymenomycetous Fungi), consisting
of lobulated gelatinous bodies growing upon
wood. D. stillatus, a common species, is
yellow or red, turning brown when dried.
Tulasne has recently published some curious
observations on this genus, showing that the
spores produced on the basidia of the exter-
nal hymenial layer, are of two kinds, and

DACTYLIUM.

[ 188 ]

DAPHNIA.

Fig. 158.

Dactylum fumo-
sum.

Magn. 200 diams.

while one kind germinates, the other kind
produces minute stalked bodies, one from
each chamber of the septate spore, destitute
of germinative power (spermatial).

BIBL. Berkeley in Hook. Brit. Fl. v. pt. 2.
p. 219; Greville, Sc. Crypt. Fl. pi. 159;
Tulasne, Ann. des Sc. not. 3 ser. xix. 211.
pi. 12 & 13.

DACTYLIUM, Nees.— A genus of Muce-
dines (Hyphomycetous Fungi), nearly allied
to Botrytis, consisting of
moulds growing over de-
caying plants. Fries refers
Corda's species of Dacty-
lium to Dendryphium. One
species ,Dacty Hum oogenum,
Montagne, is remarkable
for its place of occurrence :
it grows upon the surface of
the membrane within the
shell of the eggs of fowls
and other birds. It does
not appear to have been
observed in this country,
but several foreign writers
have investigated it; and
from the experiments made
by Spring and Wittich, it
appears that the spores pass
through orifices existing in the shell, and
germinate in the interior, often in the air-
chamber. A full account of this plant and
of the literature, is given by Ch. Robin.
British species :

1. D. pyriferum, Fr. On mouldering
stems of herbaceous plants.

2. D. macrosporum, Fr. On rotten wood,
leaves, and fungi.

3. D. dendroides, Fr. On decaying aga-
rics, &c. Very common. Grev. Sc. Crypt.
Fl. pi. 126. fig. 1.

4. D. obovatum, Berk. On willow twigs,
in damp. Ann. Nat. Hist. vi. pi. 14. fig. 26*.

5. D. sphcerocephalum, Berk. On dead
ivy-twigs, I. c. fig. 27.

6. D. tenellum, Fr. On moss.

BIBL. Berk, in Hook. Brit. Fl. v. pt. 2.
p. 345 ; Ann. Nat. Hist, ut supr. ; Berk. &
Broome, Ann. Nat. Hist. 2 ser. vii. p. 102;
Ch. Robin, Vegctaux Parasites, 2nd ed. 543.
pi. 2. figs. 5 & 6; Fries, Syst. Myc. iii. p.414;
Summa Veget. 491.

DACTYLOCOCCUS, Nag. See PAL-

MELLACE.E.

DALTONIA, Hook, and Tayl.— A genus
of Pleurocarpous Mosses, the species given
being restored here on account of the struc-
ture of the leaf, while D. heteromalla of

Hooker goes to Hypnum on the same
ground.

Daltonia splanchnoides, Hook, and T.=
Hookeria splanchnoides, Hook.

DAM^EUS, Koch. See BELBA.

DAN^A, Smith. — A genus of Marattia-

Fig. 159.

Dansea.

Part of a pinnule with sori.
Magnified 5 diameters.

ceous Ferns, whence the family are some-
times called also Danasaceas. Exotic.

DAPHNE, L. See THYMELEACE.E.

DAPHNELLA, Baird.— A genus of En-
tomostraca, of the order Cladocera, and fa-
mily Daphniadse.

Char. Inferior antennae very large, each
branch consisting of two joints only.

In Dr. Baird' s figures there are indications
of a third joint in the anterior branch of the
inferior antennas ; hence the single species,
D. Winyii (PI. 15. fig. 27), is only a Daphnia
or Sida. Aquatic.

BIBL. Baird, Brit. Entomostraca, p. 109.

DAPHNIA, Mull.— A genus of Entomo-
straca, of the order Cladocera, and family
Daphniadse.

Char. Head produced into a more or less
prominent beak ; superior antennas situated
beneath the beak, either one-jointed or con-
sisting of a minute tubercle with a tuft of
short filaments ; inferior antennas large and
powerful, two-branched, one branch three-
jointed, the other four-jointed ; five pairs of
feet.

Valves of the carapace reticulated, mostly
four, terminated below by a longer or shorter
serrated spine. Anterior branch of inferior
antennas (PI. 15. fig. 28 b] four-jointed, first
joint very short ; from the end of the third
a long filament arises, and the fourth joint
is terminated by three others; posterior
branch three-jointed, the first and second
joints sending off a long filament, the third
terminated by three of them ; the filaments
are jointed near the middle, and usually
feathery. Eye spherical, with about twenty

DAPHNIA.

[ 189 ]

DAVALLIE.E.

lenses. Labrum (PI. 15. fig. 35) flattened, and
with a large hairy lobule at the end. Man-
dibles (PI. 15. fig. 34) consisting of a fleshy-
looking body, bent inwards near the end,
and terminated by numerous minute teeth.
Jaws (PL 15. fig. 36) composed of a strong
body terminated by four horny spines, three
of which are curved inwards. Legs five
pairs, those of the first pair in the female
(PI. 15. fig. 29) three-jointed; upon the
outer edge of the second joint are three small
projections, each with four or five long jointed
setae ; terminal joint very small, and with
one or two similar setae ; the setae not plu-
mose. In the male they are more slender,
with a strong claw at the end of the second
joint, while the seta arising from the termi-
nal joint is very long, nearly the length of
the body, and floats outside the shells.

The second (PI. 15. fig. 30), third (fig. 31)
and fourth (fig. 32) pairs of legs are bran-
chial and somewhat similar, the joints fur-
nished with jointed and mostly plumose setae,
and a branchial plate also giving off numerous
plumose setae. The fifth pair of feet (fig. 33)
are three -jointed, the portion corresponding
to the branchial plate rounded and without
filaments; above this is a curved, jointed,
and plumose spine, the third and fourth
joints forming finger-like processes springing
from the lower end of the foot, with two or
three plumose setae. The branchial feet are
constantly in motion during life, and this
gives rise to the quivering appearance seen
in the Daphnue with the naked eye or a sim-
ple lens.

The ova on their escape from the body
become lodged between the back of the ani-
mal and the shell, where they remain until
completely hatched ; but at certain seasons
of the year epiphippial or winter-ova (PI. 15.
fig. 37) are produced (ENTOMOSTRACA).

Seven British species of Daphnia are re-
cognized : some of them may be found in
almost every collection of water, which they
frequently colour.

D.pulex (PI. 15. fig. 28) (common water-
flea). Valves oval, their dorsal margin not
serrated ; head large, rounded above and in
front ; superior antennae (PL 15. fig. 28 a)
very small; filaments of inferior antennae
plumose ; posterior portion of abdomen with
four projections at its curve, the first pro-
longed and bent upwards ; below these are
two jointed filaments ; the end portion has
two dentate arches, and terminates in two
strong hooks.

Some other species are common, but their

Fig. 160.

Dasya Kutzingiana.
Magnified 50 diams.

essential characters have not been briefly
expressed.

BIBL. Baird, Brit. Entom. p. 89.

DASYA, Ag. — A genus of Rhodomelaceae
(Florideous Algae), con-
sisting of tufted filamen-
tous sea-weeds, of a red,
brown, or purple colour,
growing on rocks near
low - water mark. The
principal filaments are
stoutish, branched, and
clothed with branched ra-
mules, upon which are
borne the stichidia con-
taining tetraspores (fig.
160), or ceramidia con-
taining spores, on di-
stinct plants. Four British
species are recorded, of
which D. coccinea and D.
Arbuscula are the com-
monest. The wood-cut
(from Kiitzing) represents
a branched raumle bear-
ing a stichidium with two
rows of tetraspores, from
an Italian species.

BIBL. Harvey, Brit.
Alga, 93. pi. 12 B ; PJiyc. Brit. pi. 40. 224,
225 & 253\

DASYDYTES, Gosse.— A genus of Rota-
toria, of the family Ichthydina.

Char. Eyes absent ; body furnished with
bristle-like hairs; tail simple, truncate.

D. yoniathrice. Hairs long, each hair bent
at an abrupt angle; neck constricted;
length 1-146"; aquatic.

D. antenniger. Hair short, downy; a
pencil of long hairs at each angle of the
posterior extremity of the body ; head with
two club-shaped organs resembling antennae;
length 1-170".

BIBL. Gosse, Ann. Nat. Hist. viii. 1851.
p. 198.

DASYGL^EA, Thwaites (in Kiitzing).— A
genus of Oscillatoriaceae (Confer void Algae),
forming a shapeless gelatinous stratum in
marshy places. One species is described.

D.amorpAa,Berk.(Pl. 3. fig.ll). Filaments
free at the tips, curled and entangled, sheaths
very large, 1-220 to 1-50".

BIBL. Kutzing, SpeciesAlg. p. 272 ; Tab.
Phycol. Cent. i. pi. 72. fig. 2.

DAVALLIA, Sm. See DAVALLIE.E.

DAVALLIEJ3.— A subtribe of Polypo-
daeous Ferns, with indusiate sori, containing
one genus :

DEGENERATION, FATTY. [ 190

Davallia. Sori globose, infra-marginal;
indusium somewhat urn- or cup-shaped, the
mouth truncated (figs. 161 and 162). Veins
pinnate.

Fig. 161. Fig. 162.

Davallia pyxidata.

A pinnule with sori. A sorus with the

Magn. 5 diams. indusium cut open.

Magn. 15 diams.

DEGENERATION, FATTY.— The ab-
normal deposition of free fatty matter in the
histological elements of animal bodies.

When, from whatever cause, the normal
functions of the morphological elements of
a tissue — cells, or the secondary deposits
formed in them — become languid or inter-
rupted, free globules of fat or oil become
visible in them ; and as the deposition of
this fatty matter increases in amount, the
tissue loses to a greater or less extent its
natural vital and physical properties ; hence
it is said to be in a state of fatty degenera-
tion. The discovery of the fatty degenera-
tion of tissues is probably one of the most
valuable fruits of microscopic study in regard
to medical science ; for it has shown us that
maladies supposed formerly to arise from too
great abundance of the circulating fluid, have
really had their origin in a decayed state of
the tubes or vessels in which the fluid was
contained ; and that the natural process of
human decay, as it is called, is a morbid pro-
cess or disease, probably to a certain extent
as remediable or preventible as many other
diseases to which man is naturally liable.
Here is indeed a matter of deep interest.

In addition to the deposition of fat within
the elements of a tissue undergoing fatty
degeneration, amorphous finely granular pro-
teine-matters are sometimes found; occa-
sionally also brown, yellow, red, or black
granular pigment is met with, together with
amorphous or crystalline calcareous salts, as
the carbonate and phosphate of lime, &c.;
sometimes the fatty matter is crystalline ; it
then generally consists of cholesterine.

Fatty degeneration of cells is well seen in
those of the liver when undergoing this
change. In the normal state, these, as well

DEGENERATION, FATTY.

as most cells, except those of true fatty tis-
sue, contain merely one or two very minute
or no globules of fat ; whilst in the degene-
rated tissue they contain a considerable
number of larger or smaller globules (fig.
163). At the same time, the cell-walls and

Fig. 163.

Cells of the human liver : a, nearly normal cells ; b, cells
with pigment-granules ; c, cells containing fatty matter.

Magnified 400 diameters.

nuclei become thinner and paler, or atro-
phied. A similar state to that which is
abnormal in man is normal in the lower ani-
mals. Sometimes the substance intervening
between cells becomes degenerated, and thus
we have intercellular fatty degeneration (PI.
30. fig. 15). Other instances of fatty dege-
neration are noticed under the respective
heads of the tissues, &c., as the Graafian
vesicles and the cells of the corpora lutea
(OVARY), the epithelia of the mucous and
serous membranes, and of the various glands,
the vessels, the exudation-corpuscles of in-
flammation, the muscles, &c.

The fatty degeneration of the capillaries is
represented in PL 30. fig. 13. In the larger
blood-vessels, when reaching a more advanced
degree, it forms atheroma.

It might appear paradoxical to regard the
presence of numerous fat-globules, in such
instances as the cells of cancer, and the
exudation-cells of inflammation, where the
vital processes are so evidently augmented,
as indicating a state of degeneration. But in
these, as in other instances, thefunctions of the
cells, after the latter have attained their full
development, cease, and the cells undergo
degeneration and decay.

The free fatty matter is probably derived in
general from the liberation of that previously
dissolved in the contents of the cell ; but it
may be produced by the formation of fatty
matter from the proteine or other consti-

DELESSERIA.

DEMATIEI.

Fig. 164.

tuents of the cell-contents. It is curious
that portions of the flesh and other proteine-
components of one animal, when kept in the
peritoneal cavity of another living animal,
will undergo fatty degeneration. The for-
mation of adipocire is probably an instance
of post-mortem fatty degeneration. See FAT.
BIBL. Virchow, Archiv, 1847. i. p-94;
Burdach, ibid. vi. p. 103; Wedl, Grundz'uge d.
Path. Hist. -, Forster, Handb. d. Spec. Path.
Anat. ; Wagner, Nachr. d. Ges. d. Wiss. z.
Gb'ttingen; May. 1851 (Chem. Gaz. ix. p.
309).

DELESSERIA,. Lamx.— A genus of De-
Iesseriacea3 (Florideous Algae), consisting of
sea- weeds with a flat, membranaceous, rose-
coloured frond, having a percurrent midrib,
growing on rocks or on other larger Alga?,
mostly from 2 to 8 inches high. Six species
are described as British, most of them com-
mon. The leaf-like lobes of the frond arise
from a kind of stalk, or from the midribs of
older lobes. The tex-
ture is densely paren-
chymatous throughout.
D. sanguined ripens its
fruit in the winter, and
then the membranous
part of the fronds de-
cays, leaving the midribs
clothed with tufts of the
sporophylls or leafy
lobes containing the te-
traspores (fig. 164), and
stalked coccidia con-
taining the spores. The
fructification is some-
what similar in D.alata, Delesseria sanguinea.
while in D. sinuosa the Midribs of fronds in winter
coccidiaare immersed in bearing 8Por°Phylls-
the frond, and the tetra-
spores in cilia-like processes fringing its
margin ; and in D. Hypoglossum the coccidia
are seated on the midrib, and the tetraspores
arranged in longitudinal linear rows like sori
on each side of the midrib.

BIBL. Harvey, Brit. Mar. Ala. p. 113.
pi. 15 A; Phyc. Brit. pis. 2. 26. 83. 151.
247. 259 ; Greville, Alg. Brit. pi. 72-74, 76.
DELESSERIACEJE.— A family of Flo-
rideae. Rosy or purplish-red, or blood-red
sea-weeds, with a leafy, or rarely filiform,
areolated, inarticulate frond, composed of
polygonal cells. Lobes of the frond deli-
cately membranous. Fructification double :
1. Conceptacles (coccidia) external, or half-
immersed, hemispherical, usually imperfo-
rate, containing beneath a membranous peri-

carp a tuft of dichotomous filaments, whose
articulations are finally changed into spores.
2. Tetraspores in distinctly definite sori,
either scattered through the frond or placed
in proper fruit-lobes or sporophylls.

Synopsis of the British Genera.

I. Delesseria. Frond leafy, of definite
form, with a percurrent midrib.

II. Nitophyllum. Frondleafy, of indefinite
form, without a midrib (sometimes traversed
by vague, vanishing nerves).

III. Plocamium. Frond linear or filiform,
compressed, much branched, distichous;
ramuli pectinate, secund.

BIBL. See the genera.

DEMATIEL— AfamilyofHyphomycetous
Fungi, growing on the dry parts of plants,
and characterized by the mostly septate
spores being attached to rigid thick-walled
filaments, which are continuous or septate.

Synopsis of British Genera.

I. Cephalotrichum. Fertile filaments
stalk-like, erect, septate, terminating in a
globose capitule, formed by radiating forked
or ternate branches bearing globular spores
at their tips.

II. Rhopalomyces. Fertile filaments erect,
continuous, simple, terminating in a globular
head of spores, which are seated on a cellular
capitule; the cells of this are hexangular,
with a cup-like depression in the middle,
and each with a wart-like apiculus in the
middle, bearing a spore.

III. Sporocybe. Filaments rather fibrous,
subulate, capitate, bearing simple spores
conglobated into a terminal head.

IV. (Edemium. Filaments rigid, erect, al-
most continuous, or annulated, bearing at
the sides globular masses of spores.

V. Myxotrichum. Filaments erect, scarcely
septate, fertile branches crowned by globule's
of heterogeneous conglutinated spores.

VI. Helminthosporium. Filaments erect,
simple, septate; spores transversely septate.

VII. Bolacotricha. Filaments simple, uni-
formly articulate at the apex; spores con-
glomerated, large, globular, shortly stalked,
contents distinctly granular.

VIII. Triposporium. Filaments erect, sep-
tate, sterile branches solitary, more or less
spreading ; fertile branches shorter, bearing
at the tips solitary, stellate, mostly very
shortly stalked spores.

IX. Helicosporium. Filaments erect, subu-
late, closely septate, continuous and dia-
phanous at the summit ; spores thread-like,

DEMATIUM.

DEMODEX.

septate, spirally coiled, then expanding them-
selves with elasticity.

X. Cladotrichum. Filaments erect, sep-
tate, branched; branches and branchlets
bearing uniseptate spores at their tips.

XI. Dematium. Filaments erect, septate,
with verticillate branchlets below, simple
and whip-like above ; spores crowded on the
apices of the ramules.

XII. Cladosporium. Filaments erect, sep-
tate above, bearing the spores arranged in
rows forming short monilifonn branchlets.

XIII. Macrosporium. Filaments suberect,
septate, delicate, evanescent, bearing erect,
stipitate spores, with many transverse and
usually some longitudinal septa.

XIV. Arthrinium. Filaments tufted, sub-
erect, annulate with opaque thickish septa ;
spores fusiform, septate, large.

XV. Camptoum. Filaments as in the
preceding; spores ovate, curved, small.

XVI. Glenospora. Mycelium widely ex-
panded, the filaments fasciculate within a
common membrane, the apices of the fila-
ments free, and producing fertile branches
below their tips, on which are borne large
spores, often in pairs.

Allied Genera not hitherto found in Britain.

Mystrosporium. Pedicels erect, very sim-
ple, septate ; spores cellular, terminal.

Leptotrichum. Pedicels erect, simple,
continuous; spore didymous.

Blast otrichum. Pedicels ascending or
floating, very much branched, continuous ;
spores oblong, transversely septate.

Stachyobotrys. Pedicels branched, sep-
tate; branches crowned at the tips with
whorls of mammillary, very short branchlets,
forming a capitulum ; spores didymous.

Helicotrichum. Filaments creeping,
branched, septate only at the tips; spores
spirally curled, somewhat septate.

DEMATIUM, Pers.— A genus of Dema-

Fig. 165. Fig. 166. Fig. 167.

Dematium griseum. Magnified 200 diameters.

tiei (Hyphomycetous Fungi), growing upon
dry leaves, bark, &c., distinguished by the
sporiferous branchlets arising closely toge-
ther near the base of the erect filaments.
British species :

1. D. griseum, Pers. (figs. 165-7). On
rotten hazel-stumps. Cheetopsis Waughii,
Grev. Sc. Crypt. Fl. pi. 236. See SPORO-
DUM and ECHINOBOTRYUM.

BIBL. Berk. Hook. Br. FL v. pt. 2. p. 338;
Ann. Nat. Hist. i. 260. vi. 435 ; Grev. /. c. ;
Fries, Summa Veg. 499 ; Corda, Icon. Fung.
i. pi. 4. figs. 242, 243.

DEMODEX, Owen (Simonia, Gerv.).— A
genus of Arachnida, the exact systematic
position of which is doubtful, although usu-
ally placed in the family Acarina.

Char. Feet terminated by four or five
claws, no acetabula ; abdomen annulose.

D. folliculorum (PI. 2. fig. 42), the Ica-
rus , Simonia , or Entozoon follicu-
lorum of some authors, inhabits the seba-
ceous and hair-follicles of the human skin.
Its structure has not been satisfactorily de-
termined, the minute size of the various
parts rendering it extremely difficult to iso-
late them. It varies in length from about
1-150 to 1-50".

At the anterior part of the body are two
two-jointed organs (PI. 2. fig. 43 a), the basal
joint longest, the distal smallest, and proba-
bly terminated like the feet by claws ; these
appear to represent palpi. Between these
are two narrow, elongated organs (fig. 43 b],
the nature of which is doubtful; by some
they are regarded as forming a suctorial
rostrum, by others as constituting maxillse
or mandibles. Above these is a triangular
labrum (fig. 43 c) ; a labium has also been
described.

Above or upon the basal joint of the palpi
are two minute tubercles, one on each side
(fig. 43 d). Similar tubercles are seen upon
the dorsal surface of the thorax, between the
second and third, and the third and fourth
pairs of legs.

On each side of the thorax are four pairs
of very short conical legs; these are appa-
rently three -jointed, and marked by irregular
fine transverse striae, and terminated by four
or five minute hooks.

The abdomen is longer than the thorax,
tapers posteriorly, and exhibits indications
of transverse rings, in the form of numerous
delicate transverse lines.

These animals may be obtained by press-
ing out the contents of the follicles existing
upon the sides and alee of the nose, especially

DENDROCOMETES.

[ 193 ]

DEPARIA.

when these appear enlarged, whitish, and
exhibit a terminal black spot. A drop of oil
should then be added to the secretion, and
the whole allowed to macerate for some
hours at a gentle heat. Or the secretion
may be digested in a mixture of alcohol and
aether, to dissolve the fatty matter, and then
treated with solution of potash.

The secretion contains the ova, the young
animals, and the exuviae. When contained
in the follicles, the tail is directed towards
their orifice.

A species of Demodex was found by Top-
ping in the pustules of the skin of a dog
affected with the "mange." This appears
to agree in structure with D.folliculoruni',
but its average size is less, amounting to
1-150 to 1-100" in length. It does not ap-
pear to constitute a distinct species, for
Gruby found that by inoculating the dog
with the human parasite, a disease resem-
bling, if not identical with the mange, was
produced.

BIBL. Simon, Mutter's Archiv, 1842. p.
218; Owen, Hunterian Lectures, i. p. 251 ;
Gervais, Walckenaer's Apteres, iii. p. 282 ;
Wilson, Trans. Royal Soc. 1844. p. 305 ;
Tulk, Ann. Nat. Hist. 1844. xiii. p. 75 ;
Gruby, Ed. Month. Journ. 184?. vii. p. 333;
Wedl. Grundz. d. Path. Hist. p. 803.

DENDROCOMETES, Stein. — A sup-
posed new genus of Acinetina. The single
species, D. paradoxus (PI. 25. fig. 36), has
since been found by Stein to constitute the
resting stage or Acineta-form. of Sjnrochona
gemmipara. It represents an Acineta or
Actinophrys with branched arms or tentacles,
and is found upon the gill-plates of Gam-
marus pulex.

BIBL. Stein, Siebold and Kolliker's
Zeitsckrift f. Wissens. Zool. 1852. iii. p.492;
id., Die Infus. p. 205.

DENDROSOMA, Ehr.— A genus of Infu-
soria, of the family Acinetina.

Char. Consists of a thick branched pedicle,
fixed at its base, the branches supporting at
their ends numerous bodies, each resembling
an Actinophrys.

D. radians. Bodies conical, thick, soft
and smooth, alternately branched, branches
incrassate and tentaculate at the ends. Size
1-96". Aquatic.

BIBL. Ehrenberg, Infus. p. 316; id. Ber.
d. Berl Akad. 1840. p. 199.

DENDRYPHIUM, Wallr.— A genus of
Mucedines (Hyphomycetous Fungi), consist-
ing of moulds growing over dead herbaceous
plants, nearly related to Dactylium, but there

Fi

are often several spores chained together at
the tips of the branches ; perhaps not di-
stinct from Brachycladium,
Corda, whose species of Dac-
tylium (fig. 168) are brought
under this genus by Fries.
British species :

1. D. curtum, Berk, and
Br. On dead stems. Ann.
Nat. Hist. 2 ser. vii. pi. 6.
fig. 9.

2. D. laxum, Berk, and Br.
On dead stems. L. c. fig.
10.

3. D. griseum, Berk, and

Br. On dead steins. L. c. Demlryphium

fig. 11. atrum.

BIBL. Berkeley & Broome, A fertile filament

i -i"£ t £ Tf • witnseptate spores

/. C. p. 1/6. pi. 6; Fries, upon its bran^hes.

Summa Veget. 504. Magn. 200 diams.

DENTICELLA, Ehr. See BIDDULPHIA.

DENTICULA, Kiitz.— A genus of Diato-
maceae.

Char. Frustules free, single or binate,
prismatic and rectangular, oblong or linear
in front view; valves transversely striated.
Aquatic.

Striae mostly coarse, not resolvable into
dots ; valves without a median line or no-
dules ; ends of the striae visible at the mar-
gins of the front view of the frustules ; no
internal septa.

Kiitzing describes seven species.

D. obtusa (PI. 12. fig. 25; d, front view;
c, valve). Valves lanceolate, obtuse at the
ends; length 1-330".

The other species differ principally in size.

BIBL. Kiitzing, Bacillar. p. 43; id. Sp.
Ah.-o.ll.

DEPARIA, Hooker.— A genus of Cya-
Fig. 169.

Deparia prolifera.

Sorus enclosed in the stalked indusium.
Magnified 25 diameters.

thaeous Ferns, with stalked indusia shaped
like ancient flat goblets (fig. 169). Exotic.

DEPAZEA.

DESMIDIACEJS.

DEPAZEA, Fries.— See SPH^RIA.
DEPOSITS, URINARY. See URINE.
DERMANYSSUS, Duges.— A genus of
Arachnida, of the order Acarina, and family
Gamasea.

Char. Body soft ; palpi free, filiform, the
fifth (last) joint smallest ; labium acute;
mandibles: of the male chelate, external
finger very long ; of the female, ensiform ;
coxae approximate; anterior legs longest;
last joint of legs terminated by a bilobed
caruncle and two claws.

D. avium (PI. 2. fig. 24). Found in the
cages of tame singing birds. Body ovate-
oblong, depressed, slightly broader, and
sometimes emarginate posteriorly. The sixth
joint of the legs (c) is the longest. Mouth
forming a kind of moveable head attached to
the under part of the anterior margin of the
body; it consists of — 1, a triangular labium,
pointed in front, and with two palpi ; 2, the
palpi (fig. 24 «t)» the second joint largest,
the fifth smallest and accompanied by a large
but short, moveable, external seta ; and 3,
the two mandibles (b, of female ; af of male).
Red or reddish-brown.

D. vespertilionis. Found upon the mouse-
coloured bat (V. murinus). Rostrum or
labium nearly as long as the palpi, broad or
oval at the base, narrowed in front, cleft
longitudinally above, and containing the two
long and slender mandibles.

D. pipistrellcB. On the common bat ( V.
pipistrellus).

D. hirundinis. In the nest of the swallow.

D. gallincB. On the common fowl.

Other species are found on the noctule
bat ( V. noctula), the merlin, the turkey, the
common snail (H. pomatia), serpents, &c.

Two doubtful species are described as oc-
curring upon the human body, one of them
in ulcers.

BIBL. Duges, Ann. d. Sc. nat. 2 ser. ii.
p. 19; Gervais, Walckenaer's Arachn. iii. p.
222 ; Busk, Micr. Journ. 1842. ii. p. 65.

DERMESTES, Linn.— A genus of Cole-
opterous Insects, of the family Dermestidae.

Char. Maxillary palpi shorter than the
maxillae ; antennae short, club large, three-
jointed.

D. lardarius (the bacon-beetle). Black ;
base of the elytra with a gray transverse
band with black points. Length about 1-3".

The larva is about half an inch in length,
gradually narrowed towards the end of the
body, and terminated by a truncated cone
with a fleshy lobe at its tip, which is em-
ployed as a proleg; the segments of the

body are clothed with long, scattered brown
hairs (PI. 1. fig, 1), and protected above by
a coriaceous plate, the last segment having
a pair of short, curved, horny spines; the
head is scaly, with six small ocelli on each
side, and two short three-jointed antennae.
The hairs of the larva are used as test-objects.
See HAIRS and TEST-OBJECTS.

BIBL. Westwood, Introduction, fyc. ;
Curtis, Brit. Insects, 682.

DERMESTID.E.— A family of Coleop-
terous Insects.

Char. Antennae short, clavate, not elbowed;
labrum very short, with a membranous tip ;
mandibles short, thick, toothed at the tip, and
concealed beneath the labrum ; legs partially
contractile, the five-jointed tarsi not folded
under the tibiae when at rest, the latter
long and narrow ; body ovoid or oblong,
thick, rounded at each end, and clothed with
hairs or scales ; head short, deeply immersed
in the cavity of the thorax, which is trapezoid
and broadest behind.

The larvae of these insects create great
ravages amongst dried skins, furs, &c.; they
also feed upon feathers, bacon, books, paper,
mummies, &c. They are particularly inter-
esting to the microscopist, on account of the
peculiar and beautiful structure of the hairs
existing upon their bodies.

There are five British genera : Anthrenus,
Attagenus, Megatoma, Tiresias and Der-
mestes.

See DERMESTES.

BIBL. Westwood, Introduction, fyc.

DESMARESTIA, Lamx.—A genus of
Sporochnaceae (Fucoid Algae), consisting of
olive or brownish sea-weeds, with repeatedly
pinnate, feathery fronds, from one to several
feet long, growing chiefly between tide-
marks or in deep water. The characters of
the reproductive structures have not yet been
made out, as the species rarely fruit on our
coast, although the plants are common.

BIBL. Harvey, Brit. Mar.Alg. 23. pi. 5D.;
Phyc. Brit. 49. 115; Greville, Ala. Brit.
pi. 5. figs. 1 to 6.

DESMIDIACE.E (PI. 10).— A family of
Confervoid Algae, consisting entirely of mi-
croscopic flexible organisms inhabiting fresh
water,scarcely a specimen of which can be found
that does not contain some of them. They
occur in greatest abundance in clear pools in
open exposed situations, the larger species
being generally found nearest the bottom.
Sometimes they adhere in large quantities to
aquatic plants, forming green films investing
these ; at others they rest as a thick coating

DESMIDIACE^E.

[ 195 ]

DESMIDIACE.E.

at the bottom of the water, or lie intermin-
gled amongst Confervas, &c.

They are most striking objects under the
microscope, from the peculiarity, beauty,
and variety of their forms, and their external
markings and appendages; that which is
most distinctive in their appearance is the
bilateral symmetry, indicative of the tendency
to divide into two valves or segments. Each
frustule is in reality a single cell, as is shown
by the fact that the entire contents escape
when an orifice is made ; but in the gene-
rality of the forms, a constriction, or more or
less deep notch, or a kind of suture, exists
in the middle of the external cellulose coat.
In a few instances, such as Scenedesmus,
the symmetrical form is absent ; in Pedias-
trum (PL 10. figs. 48, 49) it is only indi-
cated by a notch on the outer side ; but a
graduated series may be formed from those
genera in which this character is inconspi-
cuous, to those in which it is fully developed.
Thus in Closterium (figs. 40 to 45) and some
species of Penium, there is no constriction ;
in Tetmemorus (fig. 33), some Cosmaria (fig.
22), and Hyalotheca (fig. 1), it is quite evi-
dent, although but slight ; in Didymoprium
and Desmidium (fig. 7) it is denoted by a
notch at each angle ; while in Spheerozosma,
Micrasterias(fi.g. 11), and some other genera,
the constriction is very deep, the connecting
portion forming a mere isthmus between
the segments, which appear like distinct
cells.

The cells frequently exhibit external warty
or spinous processes (PI. 10. fig. 23), and the
cellulose coat (coloured blue by means of
iodine and sulphuric acid) presents minute
markings which, unlike those on the siliceous
envelope of the Diatomaceae, are always ele-
vations. The cells are surrounded by a more
or less perfect and distinct sheath, of gelati-
nous consistence, and very transparent. In
Hyalotheca, Didymoprium, Spheerozosma, &c.
this is very well defined (PL 10. figs. 1 to 6),
but in other genera it is more attenuated,
and the fact of its existence can only be dis-
covered by its preventing the contact of the
cells. The sheath of Hyalotheca often pre-
sents delicate dark striae, which, if the gela-
tinous sheath is not clearly seen, look like
rigid cilia standing upon the surface of the
cell-wall ; these appear to be either fissures
in the gelatinous sheath, connected with the
breaking up of the filamentous groups into
single cells, or they are related to a fibrous
disintegration of the gelatinous sheaths, such
as occurs in manv OSCILLATORIACE^.

The contents of the cells of the Desmi-
diacese appear to be somewhat similar to
that of the green Confervoids generally, viz.
a mass of protoplasm coloured green by
chlorophyll, and entirely enclosed in a pri-
mordial utricle, which does not appear to be
adherent to the cellulose coat in mature
specimens. The contents of the cells con-
tain minute starch-granules in certain stages,
as in the other Confervoids, namely in the
full-grown condition, and in the sporanges
formed after conjugation.

It was stated some years ago by Focke,
that the internal surface of the outer coat of
Closterium was ciliated, and the Rev. Mr.
Osborne has recently declared that the mem-
brane of the endochrome (primordial utricle)
is ciliated both on its inner and outer sur-
face. This is a point which deserves fuller
investigation, as it is importantly connected
with the circulation observed in this genus.
The particulars of this phsenomenon will be
found under CLOSTERIUM. The Desmi-
diaceae, at all events many of them, have the
power of fixing themselves to external ob-
jects, and possess a feeble power of locomo-
tion, which is not produced by the aid of
cilia, and cannot be explained, unless on the
same principles which have been assumed to
account for the same phaenomenon in the
DIATOMACEAE. It enables the Desmidiaceae,
when mixed with mud, to make their way to
the surface ; and they will be found to travel
and fix themselves to that side of a glass
vessel next the light. In some instances,
also, they retire beneath the surface of the
mud of pools, &c. before this dries up.

The Desmidiaceae, like other green plants,
evolve oxygen when exposed to the sun's
light.

The reproduction of this family exhibits a
number of very interesting and varied phae-
nomena. No less than four modes have
been observed, and many points connected
with the subject still remain to be cleared
up.

The simplest kind of reproduction is by
cell-division, where each frustule divides into
two. The manner in which this takes place
differs to some extent in its details in the
various genera, according to the form. Thus
in Closterium the parent-cell acquires a con-
stricted appearance in the middle, probably
not by actual constriction, but by the two
halves retreating from each other, while a
new hour-glass-shaped prolongation of the
membrane is formed in the middle. It ap-
pears probable also that the primordial utricle

o2

DESMIDIACE.E.

[ 196 ]

DESMIDIACE.E.

first becomes constricted, since specimens
are met with in which this appears divided
into two portions in the line of the division.
The constriction of the outer cell-wall at
length becomes complete, the halves sepa-
rate, and the truncated new end of each then
grows out so as to restore the symmetry of
the new frustule. In such forms as Desmi-
dium, Didymoprium, &c., the, division takes
place in a manner apparently resembling
that occurring in the filamentous Confervae.
Here there is no necessity for the subsequent
restoration of symmetry, as in Closterium.
In those forms where hairs, globular or ellip-
tical, or angular lobes are united by a narrow
neck (bipartite forms), the process of divi-
sion is very curious, and displays itself very
clearly. To produce two new symmetrical
frustules out of one, it is evident that two
new half-frustules must be formed, as in
Closterium; but in the present cases the
foundations of the new halves are laid, and
their development often far advanced, before
the division of the parent is completed. The
central region of the isthmus expands and
displays two globular enlargements, separated
from each other and from each half of the
parent by a neck. These two enlargements
are the rudiments of the new ' half-frustules/
and they increase in size (PL 10. fig. 11),
gradually pushing the halves of the parent-
cell apart, until they form two complete half-
frustules, back to back, connected by a short
neck, at which point they are sooner or later
detached from one another. In SphcBrozosma
the cells thus produced remain connected in
rows in a gelatinous sheath, and this mode
of division is well illustrated by the cells in va-
rious stages sometimes seen in such filaments;
in Euastrum, Cosmarium, Staurastrum, &c.,
the new cells separate, the old * half-frus-
tules' taking away each their new 'halves'
as new bipartite individuals. The membrane
of the nascent ' halves ' is very delicate, and
at first devoid of the characteristic markings
and processes, and it often happens that
these are not completely formed before the
division is complete.

A second mode of reproduction has been
described by Caspary, and more fully by A.
Braun, in Pediastrum. The contents of the
parent-cells become retracted from their
walls, and the whole transformed into a
number of active ciliated zoospores, which
are discharged within a delicate sac from the
parent, and after some time come to rest
and arrange themselves within this sac (PI. 6.
fig. 11) into a colony having the regular

pattern of the species, each zoospore be-
coming one of the notched frustules of the
group (see PEDIASTRUM).

A third process, analogous to this, has
been observed by Pringsheim in the genus
Ccelastrum (Nageli), likewise composed of
grouped families : here the contents of each
cell are divided into a number of portions,
as if for the formation of zoospores, but no
motion takes place ; they acquire cellulose
coats, arrange themselves within the parent
according to the typical pattern, and then
the wall of the parent- cell splits and peels
off, leaving them as the foundation of a new
group. This process bears the same relation
to the preceding as the formation of the
small resting-spores (without conjugation)
does to that of zoospores in GEdogonium, &c.,
or the winter-spores to the moving young in
Volvox. Connected with this is a pheno-
menon which has been observed and figured
in Closterium by Focke, where the entire
green contents were wholly retracted from
the walls, and broken up into a number of
green encysted globules (PI. 6. fig. 3 B), closely
resembling the above-named resting- spores or
winter-spores of Volvox (PL 3. figs. 26, 34), &c.
The fourth mode of reproduction is by
what is called conjugation, where two parent-
cells contract an organic union, their cavities
becoming continuous, and their contents be-
coming blended to form the substance of a
spore. The details of this process will be
found under CONJUGATION, and also under
CLOSTERIUM and other genera of this fa-
mily; here we have merely to add some
observations respecting the sporanges or
spores, whichever they may be, formed after
conjugation. These are at first cellulose
vesicles filled with green and granular con-
tents ; by degrees the latter become brown
or red, and the coats become thickened. In
some genera the coats remain smooth, in
others they acquire a granular, tuberculated
or even spinous surface (PL 10. fig. 12),
these spines being either simple or forked.
(Bodies exactly resembling these are found
fossil in flint, and are regarded as of the
same nature by Ralfs and others ; Ehrenberg
described them as species of XANTHIDIUM.)
The ultimate history of the sporanges is at
present obscure. In regard to those of Clo-
sterium,some information exists; both Jenner
and Focke describe and figure a globular
gelatinous mass, apparently produced from
a sporange, in which were imbedded a num-
ber of minute frustules(P1.6.fig.3A,c?). Per-
haps the conditions may vary here, as they

DESMIDIACE.E.

J

DESMIDIUM.

appear to do in SPIROGYRA, where the body
produced after conjugation usually germi-
nates at once into a filament, but sometimes
breaks up into zoospores or minute resting-
spores, such as are met with in unconjugated
cells. The reproduction of the Desmidiacea?
still offers a wide field for investigation.

The Desmidiacea3 may be collected in the
same manner as is recommended for the
DiATOMACEvE. Their preservation is a
somewhat difficult matter, as almost all the
preservative liquids alter them more or less.
Those producing the smallest amount of
change are Thwaites's liquid, Ralfs's liquid,
or simple camphor-water. A few of them,
for example Pediastrum, are unchanged by
concentrated solution of chloride of calcium,
except that the colour becomes rather paler.
We believe, moreover, that the cell-mem-
brane, upon the forms of which the charac-
ters mainly depend, remains unaltered in all
the kinds when kept in this solution. See
MOUNTING and PRESERVATIVE LIQUIDS.

Analysis of the Tribes and Genera.
(PL 10).

I. CLOSTERIE.E. Cells single, elongated,
never spinous, frequently not constricted
in the middle (sporangia smooth).

1. Closterium. Cell crescent-shaped or
arcuate, or much attenuated at the ends, not
constricted in the middle (figs. 40 to 45,
57, 58).

2. Penium. Cell straight, not or very
slightly constricted in the middle, rounded
at the ends (fig. 36).

3. Tetmemorus. Cell straight, constricted
in the middle, notched at the ends (figs. 33,
34).

4. Docidium. Cell straight, constricted in
the middle, truncate at the ends (figs. 38, 39).

5. Spirotania. Cell straight, not con-
stricted ; endochrome spiral (fig. 59).

II. COSMARIE^:. Cells single, distinctly
constricted in the middle ; segments seldom
longer than broad (sporangia spinous or
tuberculated, rarely if ever smooth).

6. Micrasterias. Lobes of the segments
incised or bidentate (fig. 13).

7. Euastrum. Segments sinuated, gene-
rally notched at the ends, and with inflated
protuberances (figs. 14 to 17)'

8. Cosmarium. Segments neither notched
nor sinuated, end view elliptic, circular, or
cruciform (figs. 18 to 22).

9. Xanthidium. Segments compressed,
entire, spinous (figs. 23 to 25).

10. Arthrodesmus. Segments compressed,
each with only two spines (fig. 27).

11. Staurastrum. End view angular, ra-
diate, or with elongated processes, which are
never in pairs (figs. 26, 28 to 31).

12. Didymocladon. End view angular,
each angle with two processes, one inferior
and parallel with the similar one of the
other segment, the other superior and diver-
gent (figs. 32, 56).

III. DESMIDIE.E. Cells united into an elon-
gated jointed filament (sporangia spherical,
smooth).

13. Hyalotheca. Filament cylindrical
(figs. 1, 2).

14. Didymoprium. Filament cylindrical
or subcylindrical ; cells with two opposite
bidentate projections (figs. 5, 6).

15. Desmidium. Filament triangular or
quadrangular; cells with two opposite bi-
dentate projections (figs. 7» 8).

16. Aptogonum. Filament triangular or
plane, with foramina between the joints
(figs. 55. 52).

17. Sphcerozosma. Filament plane, mar-
gins incised or sinuated ; joints with junc-
tion-glands (figs. 9, 10).

(The genus Eucampia, Ehr. is placed near
Desmidium by Kiitzing. It is not a Diatoma-
cean, as it shrinks in drying (seeEucAMPiA)).

IV. ANKISTRODESMI^S. Cells elongated, en-
tire, small, grouped in faggot-like bundles.

18. Ankistrodesmus (fig. 47).

V. PEDIASTRE.E. Cells grouped in the form
of a disk or star, or placed side by side in
one or two short rows.

19. Pediastrum. Cells forming a disk or
star, the outer margins bidentate (fig. 48).

20. Scenedesmus. Cells placed side by
side in one or two rows (figs. 50, 51, 53, 54).

BIBL. Ralfs, British Desmidiece ; Ehren-
berg, Infusionsth. ; Pritchard, Infusoria ;
Hassall, Brit. Freshwater Alga; Nageli,
Einzell. Alg. Zurich, 1849 ; A. Braun, Ver-
jungung, fyc. (Ray Soc. Vol. 1853) ; Focke,
Physiologische Studien, Heft i. 1848 ; Cas-
pary, Bot.Zeitung, viii. 786 (1850); Prings-
heim, Flora, 1852, p. 486. See also the Bibl.
of Closterium and other genera.

DESMIDIUM, Ag.— A genus of Desmi-
diaceae.

Char. Cells united into a brittle, regularly
twisted, triangular or quadrangular filament,
and two- toothed at the angles.

The filaments exhibit one or two dark,

DEUTZIA.

[ 198 ]

DIATOMA.

oblique, wavy lines, arising from their being
twisted. In the side view of the cells, the
endochrome exhibits thick, frequently cleft
rays, corresponding in numberwiththe angles.

D. Swartzii (PI. 10. fig. 7 ; fig. 8, side
view of separate cell). Filament triangular.
Length of joint 1-2000 to 1-1660"; breadth
of filament 1-630". Not uncommon. Spo-
rangia round or oblong.

D. quadrangulatum. Filaments quadran-
gular. Length of joint 1-1240"; breadth of
filament 1-600 to 1-450".

BIBL. Ralfs, Brit. Desmid. p. 60; Kiitz-
ing, Sp. Alg. p. 190.

DEUTZIA, Thunberg. — A genus of Phila-
delphaceae (Dicotyledonous Plants) remark-
able for the stellate hairs upon their foliage
(PI. 21. fig. 26), and the reticulated mem-
brane covering the seeds, both of which struc-
tures form interesting microscopic objects.
See HAIRS and SEEDS. Fig. 170.

DIACALPE, Bl.
— A genus of Cya-
thaeous Ferns, with
globular indusia,
splitting open at the
top (fig. 170), and
containing spor-
anges inserted on a
punctiform recepta-
cle rising from the
middle of the vein.
Herbaceous; leaves
tripinnate, membra- Diacalpe aspienoides.

AT ? „ T Part of a pinnule with son.

nous. Nativeof Java. Magnified 10 diams.

DIACH^EA, Fries.— A genus Fig. 171.
of Myxogastres (Gasteromyce-
tous Fungi), consisting of pe-
rishable little plants, growing
over either living or dead plants,
with an elongated membranous
peridium, which falls off like a
cap, and displays a white reticu-
lated capillitium furnished with
a floccose central column, with
interspersed blackish-red spores.

Diachaa differs from Stemo-
nitis in the peridium, the colu-
mella, and the habit of growth.

D. elegans, Fr. (Stemonitis,
Trentep.), the only species, has
been found in England, upon
the living leaves of the Lily of
the Valley, &c. (fig. 171).

BIBL. Fries, Syst. My col. iii.
p. 155; Berk. Ann. Nat. Hist.
i. p. 257 ; Corda, Ic. Fung.

pi. 3. fig. 38. Magn. 25 diams.

DIADESMIS, Kiitz.— A genus of Diato-
maceae.

Char. Frustules riavicular, closely united
into elongated biconvex filaments; valves
with a median and terminal nodules. Aqua-
tic. (Not British?.)

The markings have not been satisfactorily
investigated.

D. confervacea (PI. 12. fig. 27). Breadth
of frustules (in front view) about half the
length ; valves unstriated (under ordinary
illumination?), lanceolate, acuminate and
acute at the ends; length of frustules 1-960".

Three fossil species.

BIBL. Kiitzing, Bacill. p. 199, and Sp.
Alg. p. 95.

DIAMOND-BEETLE. See CURCULIO.

DIAPTOMUS, Westw.— A genus of Ento-
mostraca, of the order Copepoda, and family
Diaptomidae.

Char. Head distinct from thorax ; inferior
antennae two-branched ; thorax and abdomen
each of five segments ; foot-jaws unbranched;
legs five pairs, the first pair with two branches,
one three- the other two-jointed; three suc-
ceeding pairs with each branch three-jointed ;
external ovary single, large, lying across the
abdomen.

D. castor (PI. 15. fig. 38). Found in ponds
and slowly running water ; common in spring
and autumn. Length about 1-8".

BIBL. Westwood, Entomologist's Text-
book ; Baird, Brit. Entom. ; M.-Edwards,
Hist. Nat. Crust, iii. 427.

DIATOMA, Dec.— A genus of Diato-
macea3.

Char. Frustules (in front view) linear,
sometimes cuneate ; at first united into flat
filaments, afterwards partly separating so as
to remain connected by the generally alter-
nate angles only, and thus forming a zigzag
chain.

Filaments either free or fixed by a stipes.
Frustules prismatic, without vitta3; valves
with transverse continuous striae (not resol-
vable into dots ?), not always visible by direct
light ; ends of the striae extending into the
front view.

D. vulgare (PI. 12. fig. 26; a, side view;
b, front view). Fixed by an inconspicuous
stipes ; frustules rectangular, oblong ; valves
contracted and obtuse at the ends striae
evident; length of frustules 1-430". Aquatic.

D. tenue. Stipitate; valves lanceolate,
striae evident; length of frustules 1-660".
In fresh or brackish water. Very variable in
the form (front-view) of the frustules ; some-
times cuneate.

DIATOMACE.E.

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DIATOMACE^E.

D. elongatum. Frustules very slender,
slightty attenuated towards the middle ;
valves linear, evidently striated, tumid and
rounded at the ends; length 1-280". Aquatic.

D. pectinale. Front view square or ob-
long ; valves acutely lanceolate ; unstriated
(under ordinary illumination); length 1-720".
Aquatic.

Six other species (Kiitzing).

BIBL. Ralfs, Ann. Nat. Hist. 1843. xi.
p. 449 ; Kiitzing, Bacill. p. 47 ', Spec. Alg.
p. 16.

DIATOMACE^.— Afamily of Confervoid
Algae, of very peculiar character, consisting of
microscopic, brittle organisms, found in almost
all fresh, brackish, or salt water ; sometimes
forming a uniform yellowish-brown layer on
the bottom of the water, at others adhering
to various water-plants, decaying stems,
stones, &c., or scattered between the fila-
ments of Confervas, &c. They also occur
among Mosses, Oscillatorice, and on damp
ground.

The individual cells of the Diatomacese
are called frustules or testules, and are fur-
nished with an external coat of silica. This
consists of two usually symmetrical portions
or valves, comparable to those of a bivalve
shell, but are in contact at their margins
with an intermediate piece (the hoop), vari-
able in breadth according to age. When this
is very narrow, it forms a mere junction line,
and is called the line of suture ; and that
aspect of the frustules in which this is turned
towards the observer forms the front or front
view (primary side, Kutzing, secondary side,
Rabenh.) (PI. 11. fig. 7. j PI. 12. figs. 9 a,
30 6). That aspect of the frustules in which
the surface of the valves is turned towards
the observer, forms the side or side view of
the frastule (secondary side, Kiitz., primary
side, Rabenh.) (Pl.ll.fig.6; P1.12.fig.30a).

The separate valves are of various forms,
circular, oblong, elliptical, linear, saddle-
shaped, boat-shaped (navicular), undulate,
sigmoid, &c. (PI. 11, 12, 13); and their broad
surfaces exhibit various more or less delicate
sculpturings and markings, in the form of
bands, lines either parallel, radiate, or cross-
ing each other, and dots, or a cellular ap-
pearance.

These markings are in general not well
seen, and in some cases cannot be seen at all,
until the valves have been properly prepared.
They are of special interest, not only on ac-
count of their extremely beautiful symmetry,
but because they are used as test-objects for
the quality of the object-glasses in regard to

angular aperture. The nature of the mark-
ings is described under the individual genera.
The modes of viewing them will be spoken
of further on.

During the process of multiplication by
division, which is almost always going on,
the annular, siliceous, narrower or broader
band, or hoop, undergoes an increase of
width, and thus removes the two valves to
some distance apart (PI. 11. figs. 7 «, 11 ;
PI. 12. fig. 1). The hoop is sometimes fur-
nished with the markings, at others not.
Some of the valves are furnished with pro-
cesses, called cornua or tubuli (PI. 12. fig.
30 b) ; at others their surfaces are undulate,
producing the appearance of dark, curved or
wavy lines (PL 12. figs. 22, 23, 24) ; some-
times curiously arranged lines (vittae) indicate
imperfect internal septa (PI. 12. fig. 35).

In the young state of these organisms, the
endochrome is uniformly distributed, but
after a certain time the colouring matter be-
comes accumulated into various, usually very
regular and often elegant forms, and minute
granular globules are formed, transparent ve-
sicles become visible, drops of oil, and vesicles
filled with granules, which at first are mo-
tionless, but afterwards move about as in the
swarming motion of the Algae. Frequently
a considerable nuclear-looking body is pre-
sent in the middle of the frustule (PI. 11.
fig. 33 a). As we have seen it, delicate pro-
cesses were visible arising from it.

The frustules of the Diatomaceae are some-
times surrounded by a transparent gelatinous
sheath, frequently of great delicacy ; in some
genera they are attached by a stipes or stalk
to water-plants, &c.

Those Diatomaceae which are not fixed by
a stipes, and especially such as are linear or
spindle-shaped, are capable of spontaneous
motion ; they may be constantly seen slowly
moving across the field, or now and then
starting somewhat suddenly forwards, moving
mostly in the direction of their length, some-
times receding, sometimes performing a ro-
tatory movement on their axis. Those which
are contained in numbers in a gelatinous fila-
ment, like Encyonema, are capable of moving
backwards and forwards in this; and Mr.
Thwaites described a curious movement of
the frustules of Bacillaria paradoxa, where
the frustules, united in a band, slid back-
wards and forwards over one another.

The cause of these motions is very ob-
scure. They have been supposed to be pro-
duced by the endosmotic changes connected
with the nutrition of the organisms, but this

DIATOMACE.E.

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DIATOMACE.E.

is very improbable, otherwise they would be
met with frequently in other minute unicel-
lular organisms. No true vibratile cilia have
yet been detected upon the Diatomaceae,
although Mr. Thwaites imagined, from the
appearance of currents in the water, that
they exist on Bacillaria. Some are not un-
frequently found bearing tufts of or fringed
with rigid cilia, like those often seen at the
ends of the filaments of Oscillatorioe ; these
would seem to be formed like the fringes met
with in the Desmidiaceae, by a modification
of the gelatinous envelope ; they never ex-
hibit motion.

In the foregoing paragraphs the Diato-
maceae have been treated in reference chiefly
to their own peculiar characters. We
must not, however, pass over the physiolo-
gical relations of these organisms to other
families, nor omit to remark upon the un-
philosophical treatment they have received
at the hands of systematic naturalists.

In placing the Diatomaceae among plants,
we assume an agreement between the frus-
tule of a Diatomacean and an individual cell
of any undoubted vegetable, such as Proto-
coccus, and between the series of frustules
such as we find in Fragilaria (PI. 12. fig. 33),
or Melosira (PL 13. fig. 5 a), with the cellu-
lar filament of a Conferva or a Zygnema.
This agreement does undoubtedly exist, and
the siliceous shell is really only a result of
the incrustation or permeation by silica of a
true vegetable cell-membrane, just in the
same way as takes place in the epidermis of
Equisetum. It is not yet ascertained in
either case whether the silica is outside or
in the substance of the cell-membrane ; cer-
tainly it is not inside, as that would be in-
compatible with the known phaenomena of
division. It may be removed by hydrofluoric
acid, leaving the basement-membrane in
situ ; but this proves nothing. The proba-
bilities are that the substance of the mem-
brane is imbued with it. The application of
the term "epiderm" to the membrane (Smith)
is altogether inadmissible, as there is no ho-
mology whatever ; and the supposition that
the reticulations on the valves of some ge-
nera denote a compound cellular tissue, is at
once without foundation in fact, and contrary
to what the general character of such or-
ganisms would lead us to expect, since we
find spores, pollen-grains, the outer walls of
epidermal cells, the membranes of the Des-
midiaceae, &c., generally exhibiting patterns
of some kind dependent upon the mode of
development of the simple membrane form-

ing their external coat. The cell-contents
of the Diatomaceae require far more careful
study than they have yet received. It is
most probable that there exists a layer of
protoplasm, forming a primordial utricle, in-
side the cell-membrane, and enclosing the
rest of the contents ; the coloured substance
constituting the mass of the endochrome
appears to be a modification of chlorophyll ;
it takes a green or greenish-blue tint with
sulphuric acid, and also often by drying.
Oil-globules, soluble in aether, are also found,
sometimes of large size, in particular stages of
growth, probably representing here the starch-
grains found in other Confervoids, or indeed
the oil which occurs in them and other plants
in seasons of rest. (No starch has been de-
tected in this family.) A transparent rounded
body is often observed in the centre of the
contents, and has been called a nucleus.
Schmidt found in Frustulia salina, after re-
moving the oil by aether and the protoplasm
by potash, a substance identical in composi-
tion with the cellulose of Lichens. This was
probably derived from the organic matter of
the silicified membranes of the frustules.

The ordinary mode of increase of the cells
of the Diatomaceae is, like that of all other
vegetable cells, a process of division. In
Melosira, Isthmia, &c. this bears a close re-
semblance to the process which occurs in
Spirogyra, and it is only a modified form of
the same process that is found in the free
Diatomaceans. It may be briefly described
thus : — the primordial utricle, enclosing the
contents, divided into two portions which
separate from one another in a plane parallel
with the sides of the individual frustules;
the two valves of the parent-cell gradually
separate from one another, remaining con-
nected by the simultaneous gradual widening
of the "hoop." In the space thus afforded,
the two segments of contents secrete each a
new layer of membrane (ultimately silicified)
over the surfaces where they are in contact,
which layers of membrane constitute two
new half-frustules, back to back, corre-
sponding to and conjoined with the two half-
frustules of the parent, to form two new in-
dividuals. The history and ultimate fate of
the "hoop" seems to be variable. Some-
times it becomes solidly silicified, but not
much expanded in breadth, and falls off
when the two frustules are complete, allow-
ing them to separate; this is the case in
Gyrosigma, and probably all the allied forms;
these "hoops" are often to be found in large
numbers in the settlings of water in which

DIATOMACE.E.

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DIATOMACE.E.

Diatomacese have been kept a long time.
Perhaps the most remarkable development
of the silicified hoop occurs in Biddulphia
(PL 14. fig. 9), Isthmia, and similar forms;
the new half-frustules formed inside the
" hoop " of these genera slip out from it
like the inner tubes from the outer case of
a telescope. In Melosira (PL 6. fig. 8) the
hoops appear to keep the new frustules
united together for some time. It seems
probable that the " hoop"-structure is not
always silicified, but that it is the source
from which, by softening and swelling up, is
derived the gelatinous envelope of some
kinds, as is the case with the gelatinous
sheath of Hyalotkeca, &c. among the Des-
midiaceae, and Nostoc, &c. among the fila-
mentous Confervoids. The hoop appears
to be a provision for the protection of the
nascent half-frustules, which probably do not
become silicified until full-grown, and would
thus be liable to be injured or disturbed by
the movements of the rigid and heavy parent
half-frustules, if the centre of the frustule in
process of division was naked as in the Des-
midiaceae.

The development of the stipes upon which
the frustules of many genera are attached, is
at present altogether a mystery.

The only mode of reproduction (besides
the division) known certainly to exist in the
Diatomaceae, is one in which the operation
of conjugation takes place. This has been
observed in a number of genera, and presents
considerable variation in its details. In Fra-
gilaria (PL 6. fig. 4) and Surirella (PL 6.
fig. 5) the conjugation takes place between
two free frustules lying near together, each
of which opens at the suture and extrudes
its contents in a mass (probably enclosed in
the primordial utricle) ; the masses of con-
tents coalesce, the whole meanwhile beco-
ming involved in a mass of gelatinous sub-
stance. After a while, the body resulting
from the conjugation is seen to assume the
form of a frustule, of larger size than the
parents, which the discoverer, Mr. Thwaites,
called a sporangial frustule. In the majority
of cases, however, as in Eunotia (PL 6. fig.
6), Gomphonema, Cocconema, &c., the con-
jugation is double, as is the case in Closte-
rium lineatum (CONJUGATION); the con-
tents of the parent-frustules apparently divide
into two portions (as if for cell-division)
before conjugating, and then there is a col-
lateral conjugation of the two pairs, two
sporangial frustules being the result. In
Melosira (PL 6. fig. 8) and Orthosira (PL 6.

fig. 9) the conditions are different, and even
more curious, if the received view be correct.
The appearances presented seem to indicate
that the conjugation takes place between
two segments of a frustule which have sepa-
rated as if for ordinary cell-division, but
instead of forming new half-frustules, have
coalesced again and secreted a coat over the
entire surface, thus constituting one new
independent " sporangial" frustule of larger
size. In Melosira (PL 6. fig. S) this has
been observed to increase by cell- division,
and form a new filament of far greater dia-
meter than that to which it owed its birth.
The "sporangial" frustules of the free forms
doubtless increase by cell-division in the
usual way. (See CONJUGATION.)

A great difficulty meets us here. The
necessary consequence of the conjugation
just described is, that every species in which
it occurs must be represented by two forms,
one small and the other large, between which
a gap exists, over wrhich we have at present
no means of bridging, except by supposing
that the two new halves formed in cell-divi-
sion need not always be equal, and that by
a dwindling away through a succession of
steps of this kind, the progeny of the spo-
rangial frustules may be reduced to the
original size. The size of the frustules is said
also to vary with the depth of the sea, in
marine species. The effect of all this seems to
have been disregarded in systematic treatises
on the Diatomacese. Some of the book-species
appear to produce other book-species by
conjugation; according to Focke, Surirella
splendida produces /S. bifrons, a very di-
stinct form, and it is not improbable that
S. splendida is produced by the conjugation
of S. Microcora (Focke). There is great
probability, however, that the observations
recently made by Focke upon the contents
of certain species will lead to the discovery
of another mode of increase, a reproduction
by gonidia, either active or quiescent, such
as occurs in the Desmidiaceas and the other
Confervoids. Indeed the contents of the
cells of Melosira have been observed to
display a motion like 'swarming.' Such
spores or gonidia discharged from the large
' sporangial ' frustules might reproduce the
small form, just as the young filaments deve-
loped from the zoospores of Cheetophora, &c.,
are very slender compared with those of full-
grown filaments. Focke describes and figures
appearances on the contents of the frustules
of Pinnularia viridis, Surirella bifrons, and
others, very like what occur occasionally in

DIATOMACE.E.

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DIATOMACE.E.

the cell-contents of Closterium, namely en-
cysted globules (PI. 6. fig. 10) resembling the
resting -spores of Volvox and the filamentous
Confervse ((EDOGONIUM), and he considers
that such bodies produced in S. bifrons may
probably reproduce S. Microcora. In some
of Mr. Thwaites's figures of conjugating
Diatomacese (PI. 6. fig. 6), there are appear-
ances which would lead to the idea that spores
were occasionally produced in this process.

The principal attraction of the Diatoma-
cese to microscopists lies, however, at present
in the structure of the siliceous coats, and we
must devote some considerable space to that
part of the subject.

Some remarks upon the method of render-
ing the markings visible have been made in
the INTRODUCTION, p. xxv (Illumination) ;
and upon the cause of their becoming visible
under proper illumination in the article
ANGULAR APERTURE. The grounds for
the belief that most of the markings are
depressions, have also been mentioned (IN-
TRODUCTION p. xxxiii, /.). Different views
of the nature of the markings from those
entertained by us have been proposed by
other authors ; but these appear based upon
no kind of evidence whatever, and may be
regarded as mere statements without attempt
at proof. The last we have met with is that
of Schacht, who compares them to the striae
upon the liber-fibres of Vinca ; it would be
difficult to find a more hasty generalization.
We shall not dwell upon these debates, but
proceed to some further instructions for
observing the objects.

Preparation of the valves, to render them
as distinct as possible, is essential. This may
be effected in two ways : — 1. By incinerating
them upon a very thin plate of mica over
the flame of a spirit-lamp. This is the
quickest method, but it has the disadvan-
tages of the valves often becoming semi-
fused or agglutinated to each other by the
effects of the heat in the presence of the
alkaline salts contained in all organic matters,
especially those which are of marine origin.
2. Boiling with strong nitric acid. This is
the best method. The water containing the
Diatomacege is allowed to settle for twenty-
four hours, the supernatant liquid poured
off and the deposit dried in a porcelain dish.
Strong nitric acid is then added, the whole
mixed with a feather or glass brush, and
poured into a flask or test-tube and boiled
for some time; a portion being removed
occasionally with a dip-tube to determine
when the valves are perfectly clean. When

this is the case, distilled water is added to
the mixture, and the whole allowed to settle.
The supernatant liquid is then carefully
decanted, more water added, and the mixture
again allowed to settle, poured off, and these
operations repeated until a drop of the liquid
containing the valves, when evaporated on a
slide, leaves no film (of calcareous salts) at
the margins of the drop. This is a some-
what tedious process, but it is essential that
it should be thoroughly carried out. If the
valves be not thoroughly washed, the film of
nitrate of lime remaining upon the slide will
absorb water from the atmosphere, and the
whole will be spoiled.

The appearance of the valves thus prepared
will vary according to their structure, and the
manner in which they are examined. In
some cases the valves appear colourless, and
the markings perfectly distinct with the
ordinary direct light of the mirror, provided
the power be sufficient (PI. 13. fig. 2; PI. 18.
figs. 32, 43, 45). In others (PI. 11), the
valves appear coloured when viewed by the
ordinary light. But when the mirror is
brought to one side, and the light is thus
thrown upon the object obliquely, one or
two sets of fine parallel lines are seen traver-
sing the valves (PI. 1. figs. 17, 18; PL 11.
figs. 10, 12, 15, &c.). And when an object-
glass of considerable aperture is used, with
the condenser and central stop exactly cen-
trical (INTRODUCTION, p. xvi), the lines
are replaced entirely or in part by a series of
dots (PI. 1. fig. 16; PI. 11. figs. 39, 40, &c.);
these, under a high eye-piece, have di-
stinctly angular forms, sometimes appear-
ing regularly hexagonal (PI. 11. figs. 41, 48).
If the condenser and stop be not exactly
centrical, or the surface of the valve be not
flat, the true form of the dots will be replaced
by some other; thus hexagonal dots may be
made to appear triangular, quadrangular, &c.,
and those dots which cannot be conceived to
be really hexagonal (PL 1 1. fig. 39) may be
made to appear so.

Those who do not possess object-glasses of
considerable aperture, may render evident
the lines or dots upon many of the common
and formerly considered difficult valves, by
using a central stop in both the condenser
and the object-glass (INTRODUCTION, p. xvi).

There can be but little doubt that the
valves of all the Diatomaceae are furnished
with markings, although in some of them
they have not yet been detected. In the
most difficultly resolvable of those at present
known, lines only can be rendered evident,

DIATOMACE.E.

[ 203 ]

DIATOMACE^E.

although these probably consist of rows of
dots ; these very difficult valves require the
use of an Amici's prism (INTRODUCTION,
p. xviii).

We have already stated (INTRODUCTION,
j). xxiii, /.) that the dots consist of depres-
sions. In reviewing the considerations
establishing this point, we may divide the
valves into those which exhibit the dots by
ordinary light, and those which require ob-
lique light and the use of stops.

In those^isible with ordinary light (PI. 13.
fig. 29; PI. 18. fig. 32, &c.), the valves are
thinner and weaker at the parts occupied by
the dots, so that the line of fracture corre-
sponds to these parts; and the depressions
are distinctly visible at the edges of the
curved portions of the valves (PI. 13. fig. 2 b).
In those requiring the use of oblique light
and stops, the line of fracture also corresponds
to the rows of dots, provided the light be
equally oblique on all sides; and the same
appearances are presented by the dots in
both cases, beginning with those in which
they are very large (as in Isthmia], to those
of moderate and small size (as in the species
of Coscinodiscus], down to those in which
they are extremely minute (as in Gyrosigma,
&c.). Moreover, analogy aifords a strong
confirmatory ground, for the Diatomaceae
form a very natural family ; and if the dots
are depressions in some genera, we might
expect them to be so in the others.

The explanation of the manner in which
oblique light renders the dots visible, has
been given under ANGULAR APERTURE.
Some objections have been made to a part of
that explanation, but as they are founded on
a want of acquaintance with the subject, we
have not considered it requisite to notice them.

The method of determining the structure
of the frustules of the Diatomacea3 is the
same as that of microscopic bodies in general,
and has been laid down in the INTRODUC-
TION, p. xxxii. The presence or absence of
a gelatinous envelope or a stipes should first
be determined. The general form of the
frustules, both in the front and side view, is
next examined, which should be done while
they are immersed in water; the frustules
being made to roll over by gently moving
the glass cover with the point of the mounted
needle, the eye being kept upon the object,
and a somewhat low power used. The frus-
tules should then be prepared, and examined
when dry as to their markings. Perhaps
these may be visible by ordinary light; if
not, the mirror should be turned on one side

as much as possible to obtain the effects of
oblique light. If lines then become visible,
it does not follow that the valves are marked
with lined structures such as grooves or
ridges ; because the shadows of rows of dots
may become extended into lines under
oblique illumination, in any direction in
which the dots will form a linear series. This
point must, however, be decided by exami-
nation with the aid of the condenser, stops,
&c. ; and if the valve be much curved, it
must be crushed, so as to obtain a fragment
as flat as possible. The markings upon the
most difficult valves can only be brought
out by using extremely oblique light, reflected
either from the mirror brought as close be-
neath and as much on one side of the stage as
possible, or from the Amici's prism. The field
will then appear black or nearly so, the valve
having frequently a bluish appearance ; this
extreme obliquity of the rays of light being
essential, to allow of one set being thrown
out of the field (see ANGULAR APERTURE).

In using very oblique unilateral light,
spurious rows of parallel lines are often seen,
not only upon the valves of the Diatomaceas,
but upon objects not possessing a lined
structure, as many crystals, &c. These can
only be distinguished from those connected
with the presence of dots, by their not being
resolvable into dots, their greater coarseness
and their variability in number (in a given
space) under different kinds of illumination.

If the direction of the lines changes with
the variation of the position of the valve to
that of the incident light, it may be pretty
surely predicted that the lines are spurious,
and that the condenser and stops will effect
their resolution into dots.

The prepared valves of the Diatomaceae
frequently appear coloured when dry, the
colour vanishing when they are moistened.
This colour arises from iridescence, and not
from the presence of pigment or other
colouring matter (INTRODUCTION, p.xxx,3).

Collection. In collecting the Diatomacea3,
a number of phials (1 to 2 oz.), with wide
mouths and furnished with corks, must be
provided, in which they may be brought
home. The mouth of the bottle being closed
with the thumb and brought as closely as
possible to the masses of them in the water,
on removing the thumb, the water will enter
and carry the Diatomacese with it into the
bottle. A spoon is frequently of use in
removing layers of them from the bottom of
the water, or from pieces of woodwork, &c.
immersed in the water. Many of them are

DIATOMACE^E.

[ 204 ]

DIATOMACE^E.

entangled in the meshes of Confervae and
other Algae, or on the submersed stems of
the higher plants; these, if fixed to the stems,
can only be removed with them; if, however,
the masses of Diatomaceae are merely en-
tangled in the meshes of their stems, they
may be detached and collected in the " ring-
net" (INTRODUCTION, p.xliv), and the pieces
of muslin placed in the bottles. A stick
with a loop of string at the end, is often
useful in procuring those which would be
otherwise beyond reach; the neck of the
bottle being engaged in the loop, and the
mouth kept downwards when immersed in
the water until opposite and close to the
masses of Diatomaceae, it is then inclined
upwards and filled. On exposing the bottles
to the light for some hours, the Diatomaceae
will collect on the surface of the mud or
other matters, and can then be removed with
a dipping-tube. It is often difficult to free
them from minute particles of sand; this
may, however, generally be done by diffusing
the deposit through distilled water, allowing
the mixture to stand for a short time, and
then pouring off the uppermost portions ;
the sand being the heaviest, will subside first.
The deep-sea species may be obtained by
dredging, or by treating the alimentary canal
of fishes, mollusca, &c., with strong nitric
acid as above directed.

The Diatomaceae are often found fossil
(forming the fossil Infusoria of geologists) ;
occurring in vast numbers in aquatic and
marine geological deposits, forming hills,
rocks and various strata ; also in peat-beds,
fossil polishing powders, as tripoli, &c. The
deposits from San Fiore (Tuscany), Bermuda,
Lough Morne (Ireland), &c., are well known
as containing many of the most beautiful
species, and are sold by the dealers in micro-
scopic objects and apparatus.

Preservation. The Diatomaceae may be
preserved either in the dry state, immersed
in balsam, in water, or dilute spirit (one to
six) (see PRESERVATION). For exhibiting
the delicate markings,they should be mounted
in the dry state, placed upon and covered by
the thinnest glass which can be obtained.

The mounted sable-hair or bristle will be
essential in isolating single valves (INTRO-
DUCTION, p. xxii) for mounting.

With regard to the systematic arrangement
of the Diatomaceae, the following table must
be regarded merely as an aid to finding the
genera scattered through the work ; the
structure of the frustules of many genera is
so imperfectly known, that it would be im-

possible at present to institute a correct
systematic division. Those genera which are
fossil, or are not known to occur in Great
Britain, are appended after the line ( ).

Tribe 1. Striata. Frustules transversely
striated ; neither vittate, nor areolate.
Subtribe 1 . Astomaticae. Valves without a
median nodule or aperture.

Cohort 1. EUNOTI^E. Epithemia(Pl.\2.
fig. 32), Eunotia (PI. 18. fig. 30), Hi-
mantidium (PI. 12. fig. 36).

Coh. 2. MERIDIEM. Meridian (PI. 12.
fig. 28; PI. 13. fig. 7). Oncosphenia.

Coh. 3. FRAGILARI^E. Diatoma (PI. 12.
fig. 26), Fragilaria (PI. 12. fig. 33), Den-
ticula(Pl. 12.fig.25), Odontidium(Pl 13.
fig. 14).

Coh. 4. MELOSIRE.E. Cyclotella (PI. 12.
figs. 21, 22), Melosira (PL 13. figs. 5, 6),
Orthosira (PI. 13. fig. 15), Pyxidicula

(PI. 19. fig. 13). Dicladia, Gonio-

thecium, Hercotheca, Insilella, Masto-
gonia, Periptera, Pododiscus (PI. 13.
fig. 16), Podosira(Pl. 14. fig. 27), Rhi-
zoselenia, Stephanodiscus, Stephanogo-
nia, Syringidium.

Coh. 5. SURIRELLE.E. Bacillaria (PL 12.
fig. 14), Campylodiscus (PL 12. fig. 16;
P1.18.fig.44),Don/^ora(PL12.fig.29),
Nitzschia (PL 13. figs. 9-13), SpMncto-
cystis (PL 12. figs. 23, 24), Surirella
(PL 13, figs. 21, 22), Synedra (PL 13.
figs. 23-25), Tryblionella (PL 13. figs. 30-
32). Rhaphoneis.

Subtribe 2. Stomaticse. Valves with a me-
dian nodule or aperture.

Coh. 6. COCCONEID^B. Cocconeis(Pl.l2.
figs. 17, 18).

Coh. 7- ACHNANTHE^E. AchnantUdium
(PL 12. figs. 5, 6), Achnanthes (PL 12.
figs. 1-4), Dickieia (PL 14. fig. 16),
Cymbosira (PL 14. fig. 18).

Coh. 8. CYMBELLE.E. Cymbetta(Pl 18.
fig. 31), Cocconema (PL 12. figs. 19, 20),

Encyonema (PL 14. fig. 10). Syncy-

clia (PL 14. fig. 14).

Coh. 9. GOMPHONEME^E. Gomphonema
(PL 12. fig. 34), Sphenella (PL 14.
fig. 19), Sphenosira (PL 13. fig. 26).

Coh. 10. NAVICULE^E. Amphiprora (PL
12. fig. 8), Amphora (PL 12. figs. 10,
11), Pinnularia (PL 11. fig. 1-5), Navi-
cula(P\.ll.figs.6-9),Gyrosiffma (PL 11.
figs. 10-38), Stauroneis (PL 11. figs. 43,
46), Diadesmis (PL 12. fig. 27), Schizo-
nema (PL 14. fig. 12). Colletonema,

DIATOMACE^E.

C 205 ]

DICKIEIA.

Frustulia (PL 14. fig. 17), Homfeocladia
(PL 14. fig. \5},Micromega(P\. 13. fig. 8),
Phlyct<enia,Rhaphidogl<Ba(P\.\4.fig.U).
Coh. 11. AMPHIPLEURE.E. Amphipleura
(PL 12. fig. 7), Berkeleyia (PL 14. tig. 8).

Tribe II. Vitiates. Frustules with vittae
(in front view) ; valves not areolate.

Subtribe. 1. Astomaticae. Valves without a
median nodule.

Coh. 12. LICMOPHORE^. Licmophora
(PL IS. fig. 3), Podosphenia (PL 13.
fig. 17), Rhipidophora (PL 13. fig. 19).
Climacosphenia.

Coh.lS.STRIATELLE^. &TMfeIfo (P1.13.

fig. 20), Tessella (PL 14. fig. 11).

Hyalosira (PL 13. fig. 1), Pleurodes-
mium, Rhabdonema (PL 13. fig. 18).

Subtribe 2. Stomaticae. Valves with a median

nodule.

Coh. 14. TABELLARIE.E. Grammato-
phora (PL 12. fig.35), Tabellaria (PL 13.
fig. 27), Tetracyclus (PL 13. fig. 28).

Anaulus, Biblarium, Stylobiblium,

Terpsinoe (PL 19. fig. 10).

Tribe III. Areolatce. Valves with cell-like
markings, often visible by direct (not oblique)
light.

Subtribe. 1. Disciformes. Valves equal;
without appendages or processes.

Coh. 15. COSCINODISCE^E. Actinocy-
clus (PL 18. fig. 43), Coscinodiscus

(PL 18. fig. 32 ; PL 19. fig. 7). Ac-

tinoptychus (PL 18. fig. 45), Arachnoi-
discus (PL 12. fig. 12), Asterolampra
(PL 19. fig. 5), Asteromphalos (PL 19.
fig.2),Halionyx,Heliopelta(Pl.l9.&gA),
Odontodiscus, Omphalopelta, Symbolo-
phora (PL 19. fig. 6), Systephania.

Coh. 16. ANGULIFER.E. Amphitetras

(PL 12. fig. 9). Amphipentas(P\. 19.

fig. 11), Lithodesmium (PL 13. fig. 4).

Subtribe. 2. Appendiculatse. Valves with

processes or appendages.
Coh. 17. EUPODISCE.E. Eupodiscus

(PL 12. figs. 30, 31).
Coh. 18. BIDDULPHI.E. Biddulphia

(PL 12. fig. 15; PL 14. fig. 9), Isthmia,

(PL 13. fig. 2). Chatoceras, Hemi-

aulus (PL 19. fig. 3), ZygocerostPl. 14.

fig. 13).
Coh. 19. ANGULAT^E. Triceratium

(PL 13. fig. 29). Syndendrium.

Coh. 20. ACTINISCI^E. Actiniscus,

Mesocena (PL 19. fig. 1).

BIBL. Ralfs, Ann. Nat. Hist. 1843. xi.
p. 447, xii. pp. 104. 2/1. 346. 457; Thwaites,
Ann. Nat. Hist. 1847. xix. p. 200, xx. pp. 9.
343. 1848. 2nd ser. p. 161 ; Dickie, 1848,
2nd ser. ii. pp. 93. 153; Smith, Brit. Diatom.;
id. Ann. N. H. 1850. 2nd ser. v. p. 121,
Microscopic Journal, part 10. 1854 ; Bailey,
Silliman's Journ. xli. xlii. ; id. Ann. N. H.
1851. viii. p. 157; Ehrenberg, Infusionsthier-
chen; id. Abhandl. d. Berl. Akad. 1839.
1840; id. Bericht d. Berl. Akad. passim;
id. Mikrogeologie ; Brebisson, Considera-
tions sur les Diatomees; Rabenhorst, Die
Siisswasser Diatom. ; Kiitzing, Bacillar. and
Species Algarum ; Pritchard, Infusorial Ani-
malcules; Alex. Braun, Verjungung (Ray
Soc. Vol. 1853); Nageli, Einzell. Algen. p. 9;
Focke, Physiologisch. Studien, Heft ii. 1853;
Meneghini, Suit. Animalit. &c. (Ray Soc.
Fo/.1853); Gregory, Mic. Journ.pt. 10. 1854.

DICELLA, Werneck.— A genus of Infu-
soria, of the family Trachelina (?), Ehr.

Char. Those of Bursaria, with two im-
moveable setaceous appendages.

B. appendieulata.

DICHROISM (double colour) is the
term applied to the property possessed by
many doubly refracting crystalline substances,
of exhibiting two colours when light is trans-
mitted through them in different positions.
It may be observed under the microscope in
crystals of the tourmaline, the acetate of
copper, the chloride of palladium, and the
oxalate of chromium and potash, or of chro-
mium and ammonia.

Dichroism depends upon the absorption of
some of the coloured rays of the polarized
light in the passage through the crystal, this
absorption varying with the different relative
positions of the planes of primitive polariza-
tion of these rays, to the axis of double
refraction of the crystals, so that the two
pencils formed by double refraction are
differently coloured.

In the acetate of copper, the two colours
are deep blue and yellowish-green; in the
chloride of palladium, they are red and green ;
in the oxalate of chromium and potash they
are blue and green, and hi the tourmaline
they are not always the same. The variation
in colour is entirely independent of the
thickness of the crystal.

BIBL. Brewster, Phil. Trans. 1819, and
Optics, p. 353; Herschel, Encyc. Metrop.
art. Light, p. 1064.

DICKIEIA, Berkeley and Ralfs.— A genus
of Diatomaceae.

DICKSONIA.

[ 206 ]

DICRANACEvE.

Char. Frustules resembling those of Ach-
nanthes, irregularly scattered through a flat
undulate frond or subgelatinous layer, nar-
rowed at the base so as to appear substipi-
tate.

D. ulvacea (PL 14. fig. 16; a, frond, nat.
size ; b, portion magnified ; c, prepared
frustule, front view ; d, valve). Stipes very
short, capillary ; frond oblong, irregularly
lobed or crenulate; frustules (front view)
oblong, obtuse-angled, truncate at the ends ;
valves narrowly linear ; length of frond 1 to
H"; of frustules, 1-1000 to 1-720"; marine.

Frond very pale purplish white. Recent
frustules with a round colourless spot at each
of the four angles (in the front view). Found
in shallow pools between high and low-water
mark.

D. Danseii. Frond indefinite, mammillate ;
valves oval. The frustules of this species
appear also to resemble those of Achnanthes ;
but the form and structure of the frond do
not correspond with the characters of the
genus Dickieia, hence either the generic
characters must be altered, or this species
placed in a new genus.

BIBL. Berkeley and Ralfs, Ann. Nat. Hist.
1844, xiv. p. 328; Kiitzing, Bacitt. p. 119,
Sp. Alg. p. 109 ; Thwaites, Ann. Nat. Hist.
1848.1. p. 171.

DICKSONIA, L'Heritier.— A genus of
Cyathseous Ferns. Exotic.

DICLADIA, Ehr.— A genus of Diatoma-
eeae.

Char. Frustules single ; valves unequal,
one turgid and simple, the other two-horned,
the horns sometimes branched. Marine and
fossil.

Closely allied to Rhizoselenia.

Frustules siliceous, bivalve ; minute struc-
ture of valves undetermined.

Four species, none British.

BIBL. Ehrenb. Ber. d. Berl Akad. 1844.
p. 73 ; Kiitzing, Sp. Alg. p. 24.

DICOTYLEDONS. — One of the two
great divisions of the Angiospermous Flow-
ering Plants, synonymous with the Exogens
of Decandolle, and opposed to Monocotyle-
dons, the name being derived from the con-
dition of the embryo prevailing throughout
the vast majority of plants included in this
assemblage. As in all other natural groups,
instances occur wherein the particular cha-
racter from which the name is derived, the
presence of a pair of cotyledons in the
embryo, is absent, as in Orobanche, &c. (like
the Orchidacese and other plants among the
Monocotyledons), but in these cases the

plants agree with Dicotyledons in general in
all the rest of the prominent characters, such
as the structure of stem, leaves, plan of
flower, &c. See VEGETABLE KINGDOM
and SEED.

DICRANACE.E.— A family of Apocar-
pous operculate Mosses, branching by inno-
vations, or with the tops of the fertile branches
several times divided. Leaves lanceolate or
subulate, channeled-concave, with a nerve
mostly dilated and flattened, rarely slender,
scarcely cylindrical. The cells prosenchyma-
tous, often mingled with parenchymatous,
rarely papillose, mostly empty, often thick-
ened upwards, thereby rounded or elliptical ;
the basilar cells arranged in a curved manner
at the margins of the leaves, distinctly
diverse ; parenchymatous, lax, thick, large,
flat or with a more or less thick and patelli-
form front, delicate or robust, hyaline, fuscous,
brown or purple, ultimately marcescent,
mostly very conspicuous (alar cells). Cap-
sule oval or cylindrical, arched or straight,
apophysate or strumose at the base, with a
subulate operculum. Peristome, if present,
purple, teeth trabeculate.

British Genera.

I. BLINDIA. Calyptra dimidiate, hood-
shaped, peristome wanting or simple, then of
sixteen equidistant, lanceolate, distantly arti-
culated, smooth, slender teeth, slightly tra-
beculate within, purple, cartilaginous.
Capsule exannulate.

II. DICRANUM. Calyptra dimidiate. Pe-
ristome simple, teeth connate at the base into
a more or less emergent membrane, or equi-
distant and arising below the orifice of the
capsule, split more or less deeply, even in
some cases to the base, into two or rarely
more free arms, purple below, traberculate
nodose above (figs. 172 & 173).

Fig. 172.

Fig. 173.

Dicranum palustre.

Fig. 172. Mouth of the capsule with the peristome
everted. Magnified 40 diameters.

Fig. 173. Portion of the peristome. Magnified 100
diameters.

DICRANUM.

[ 207 ]

PICTYOSPH^RIUM.

Fig. 174.

DICRANUM, Hedw.— A genus of Apo-
carpous operculate Mosses.
Dicranum undulatum, Turn.
D. spurium, Hedw.
D. scoparium, Hedw.
D. majus, Sm.=D. scoparium, Hedw.
D.falcatum, Hedw.
D. Starkii, Web. and Mohr.
D.fulvellum, Sm.

D. hyperboreum, Sm.=D.fulvellum, Grev.
ex p.

D. longifolium, Ehrh.
D. montanum, Hedw. = D. Scottianum,
var. montanum, Hook.
D.flagellum, Hedw.
D. Scottianum, Turn.
D. turfaceum, C. Miill. = D. flexuosum,
Auct. ex p.

D.flexuosum, Hedw.

D. denudatum, Er'u[.=Didymodon longi-
rostris, W. and Mohr.
See LEUCOBRYUM.
DICTYDIUM, Schrad.— A
genus of Myxogastres (Gaste-
romycetous Fungi), exceed-
ingly elegant little plants,
growing upon rotten wood.
The peridium is excessively
delicate and the peculiar capil-
litium adherent to it, so that
when the spores are expelled,
the transparent case appears
like a cage, formed of the veins
alone. There are no filaments
mingled with the spores. D.
umbilicatum (fig. 174) is a
British species ; it is of a
brownish-purple colour until Dictydium umbi-
the spores are discharged, then licatum.
hyaline ; it is gregarious in its Ma^n- 25 diam-
habit of growth.

BIBL. Berk, in Hook. Brit. Flora, v.
pt. 2. p. 317; Greville, Sc. Crypt. Fl. pi. 153;
Fries, Syst. Myc. iii. p. 164; Schrad. Nov.
Gen. p. 11, &c.; Corda, Icon. Fung. v. pi. 3.
fig. 36.

DICTYOCHA, Ehr.— The nature of the
curious bodies, of which the genus Dictyocha
consists, is unknown. They consist of a
single piece, hence they are not Diatomaceae.
This piece is siliceous and loosely reticular
or stellate. Perhaps they are spicula of
Echinoderinata ?. They are both marine and
fossil.

Kiitzing enumerates twenty-nine species (?);
distinguished principally by the number of
external spines and internal areolae; they
vary in diameter from 1-1150 to 1-370".

D. gracilis (PI. 18. fig. 46; a, perspective
view ; b, side view ; c, view from above).

BIBL. Ehrenberg, Abh. d. Berl. Akad.
1838. 1839. 1840, and Eer. d. Berl. Akad.
1844. 1845; Kutzing, Bacill. p. 140, Sp.
Alg. p. 142.

DICTYOLAMPRA, Ehr.— A genus of
Diatomaceae.

Char. Frustules single; no internal septa;
valves equal, cellular (apparently) in the
middle, the smooth margin radiate.

D. stella. The only species. Probably a
Cyclotella ? Found among Polycystina from
Barbadoes.

BIBL. Ehr. Eer. d. Berl. Akad. 1847- p. 54.

DIPTYOPTERIS, Presl.— A genus of

Polypodieae (Ferns), deriving their name

from the reticulated arrangement of the

veins.

DICTYOPYXIS, Ehr.— A genus of Dia-
tomaceae.

The species are referred by Kutzing to the
genera Pyxidicula and Coscinodiscus.

BIBL. Ehr. Eer. d. Berl. Akad. 1844.
p. 267 ; Kiitz. Sp. Alg. p. 125.

DICTYOSIPHON, Grev.— A genus of
Dictyosiphonaceae (Fucoid Algae), represented
in Britain by a common branched filamentous
sea-weed (D. f&niculaceus), with the frond
growing from one to several feet long, of an
olive or rusty-brown colour. The fructifica-
tion at present known consists of ovoid
sporanges, imbedded in the cellular tissue of
the branches, lying lengthways ; they open
by a pore at the surface.

BIBL. Harvey,Br. Mar. Alg.y. 40. pi. 7 D;
Greville, Alg. Brit. pi. 8 ; Thuret, Ann. des
Sc. nat. 3 ser. xiv. p. 238.

DICTYOSIPHONACEJE,— A family of
Fucoideae. Olive- coloured sea- weeds with
cylindrical branched fronds, the oosporanges
imbedded lengthways in the substance of
the frond, opening by a pore on the sur-
face.

Synopsis of British Genera.

I. Dictyosiphon. Root a minute naked
disk; frond cylindrical, branched; oospo-
ranges scattered irregularly, solitary or in
dot-like sori.

II. Striaria. Root a minute naked disk;
frond cylindrical, branched; oosporanges
arranged in transverse lines on the surface of
the frond.

BIBL. See the genera.
DICTYOSPH^RIUM, Nageli. See
PALMELLACE.E.

DICTYOSPORIUM.

[ 208 ]

DIDYMIUM.

Fig. 1/5.

DICTYOSPORIUM, Corda.— A genus of
Torulacei (Coniomycetous Fungi) containing
one species, D. eleyans
(fig. 1/6), a minute fun-
gus growing upon oak
which has been stripped
of its bark ; very remark-
able for the reticulated
character of its spores Dictyosporium ele&ans.

BIBL, Berk, and Br. Spy Js magnifieSd
Ann. Nat. Hist. 2ser. v. 1000 diameters.
p. 460 ; Corda,/cow. Fung.
li. pi. 8. fig. 29.

DICTYOTA, Lamx.— A genus of Dictyo-
tacese (Fucoid Algae), containing one British
species, D. dichotoma, common between
tide-marks, on rocks, &c., remarkable for
its dichotomously dividedmembranous frond,
of olive-green colour, 3 to 12" long, which
produces spores in two ways (on different
individuals), either collected in sori or scat-
tered. These spores appear to require fur-
ther examination.

BIBL. Harvey, Brit. Alg. p. 39. pi. 7 A ;
Phyc. Brit. pi. 103; Greville, Alg. Brit.
pi. 10.

DICTYOTACE^E.— AfamilyofFucoidese.
Olive-coloured inarticulate sea-weeds, with
large spores like those of Fucaceae, superfi-
cial, in definite spots or lines (sori}, or
scattered. Root coated with woolly fibres.
Frond flat.

Many other genera are included in this
family by most authors; but Thuret has
pointed out that the genera here named pro-
duce spores, while the structures described
as such in the others are sporanges. PADINA
presents some interesting points of micro-
scopic structure. All the genera are formed
of very regular muriform parenchyma.

Synopsis of the British genera.

I. Haliseris. Frond dichotomous, with a
midrib.

II. Padina. Frond ribless, fan-shaped,
concentrically streaked. Sori linear, con-
centric, bursting through the epidermis.

III. Zonaria. Frond ribless, lobed, con-
centrically striate. Sori roundish, contain-
ing spores and jointed threads.

IV. Taonia. Frond ribless, irregularly
cleft, somewhat fan-shaped. Sori linear,
concentric, superficial; alternating with scat-
tered spores.

V. Dictyota. Frond ribless, dichotomous.
Sori roundish, scattered, bursting through
the epidermis, or (on distinct individuals)
scattered spores.

For other genera often included here,
see SPOROCHNACE^E, PUNCTARIACE^E,
DICTYOSIPHONACE.E, and CUTLERIACE^E.

BIBL. See the genera.

DICTYOXYPHIUM, Hooker.— A genus
of Lindsaeese (Polypodaeous Ferns). Exotic.

DIDERMA, Pers.— A genus of Myxo-
gastres (Gasteromycetous Fungi), consisting
of minute epiphytic plants, of tolerably per-
sistent structure (fig. 1/6). -pis 176
The peculiar character re-
sides in the double layer of
the peridium, the outer being
smooth and crust-like, fragile
and dehiscent, while the in-
ner is very delicate and eva-
nescent. The spores, among Diderma lePidotum-
which are found filaments Ma&n- 25 diams-
adherent either toward the base or to a colu-
mella, are at first compacted together into a
ball, which, after the absorption of the inner
layeroftheperidium,lieslooseintheoutercase.
The species vary in habit, being either stipitate
with the stalk more (Leangium, Lk.) or less
(Leocarpus, Lk.) distinct in different cases,
and sessile. A dozen species are recorded as
British, of which the sessile D. globosum,
and the obscurely stalked D. vernicosum,
appear the commonest.

BIBL. Berk, in Hook. Brit. Flor. v. pt. 2.
p. 310; Ann. Nat. Hist. i. 257; Fries, Syst.
Myc. iii. 96; SummdVeg.450; Greville, Sc.
Crypt. Fl. pis. 3. 122 & 132 ; Corda,Ic. Fung.

DIDYMIUM, Schrad.— A genus of Myxo-
gastres (Gasteromycetous Fungi), consisting
of minute plants growing upon leaves, bark,
rotten wood, &c. (fig. 177), distinguished by
its double peridium, of which, however, the
inner membranous layer is the true case
(bursting irregularly), while
the outer forms a kind of
bark, which breaks up into
little scales or mealy down.
Filaments exist twiningamong
the spores adherent to the pe-
ridium. Sixteen species are
recorded as British, several of
which are not uncommon. Magn. 25 diams.
They vary in habit, like the
Didermce, being either stalked, sessile, or
adnate to their support. D.farinaceum is
figured (pi. 240) by Sowerby as Trichia
sphterocephala.

BIBL. Berk. Hook. Br.Fl. v. pt. 2. p. 312,
Ann. Nat. Hist. i. p. 257. 2 ser. v. p. 365,
xiii. p. 459; Fries, Syst. Myc. iii. p. 113;
Summa Veg. 451 ; Sowerby, Fungi, pis. 12.
240. 412; Corda, Icon. Fung.

Fig. 177.

Didymium
liquidum.

DIDYMOCHLJ2NA.

[ 209 ]

DIDYMOPRIUM.

DIDYMOCHL.ENA,

Desv. — A genus of Di-
plasieae ( Polypodseous
Ferns), with a curious
elliptical indusium open-
ing on each side (figs.
178 & 179). Exotic.

Fig. 179.

Didymochlaena sinuosa.

Fig. 178. A sorus from above. Magn. 20 diams.
Fig. 179. Transverse vertical section of ditto.

DIDYMOCLADON, Ralfs.— A genus of
Desmidiaceae.

Char. Cells single, constricted at the mid-
dle, end view tri- or quadrangular; each
angle with two processes, one lateral and in
the front view nearly parallel with the corre-
sponding one of the other segment, the other
superior and divergent.

The two processes distinguish this genus
from Staurastrum.

D. furcigerus (PI. 10. fig. 32, front view;
fig. 56, end view).

a, end view triangular.

/3, end view quadrangular.

Length, including processes, 1-330".

BIBL. Ralfs, Brit. Desmid. p. 144.

DIDYMOHELIX, Griffith.— A genus of
Oscillatoriacese (Confervoid Algae), with the
threads consisting of pairs of microscopic, in-
terlacing, flattened, ferruginous, spiral fila-
ments. (Probably surrounded by gelatine.)

D. ferruginea (Gallionella ferrug., Ehr.,
Glceotila ochracea, Kiitz.).

Found in ferruginous bog-water.

The structure of the compound filaments
of which this beautiful and curious or-
ganism consists, requires great care to elicit,
both on account of their minute size and
their peculiar form. The breadth of the
filaments is from 1-5000 to 1-30,000", the
average 1-10,000 to 1-20,000". The fila-
ments are imbued with peroxide of iron, but
they contain no silica, or at least not more
than a mere trace, such as is naturally inva-
riably associated with the peroxide. When
treated with hydrosulphuret of ammonia,
they become black. When acted upon slowly
with dilute muriatic acid, the colour gradu-
ally vanishes, a very transparent colourless
cast of the original being left. If the com-
pound filaments be macerated for some time

in distilled water, the filaments will separate
(PL 1. fig. lOd). When examined with a
£-inch object-glass, the filaments present
the appearance represented in PI. 1. fig. 10 a.
When a higher power is used, they appear
as in fig. 106, which represents them as seen
when too much liquid is contained between
the slide and the cover, or when the proper
correction is not made for the thickness of
the glass cover and of the liquid, or when
they are lying edgewise. When lying flat
upon the slide, and the correction is perfect,
they appear as in PI. 1. fig. lOc.

Ehrenberg considered them as represent-
ing Polygastric Infusoria, — Kiitzing as con-
sisting of cells. These views, however, are
based upon inaccurate observation, or the
substitution of analogy for observation, and
need no consideration.

In the natural state, a quantity of yellow-
ish-brown gelatinous matter is always found
in the water containing the filaments. Eh-
renberg supposed that they are formed in or
from this. We have always found in this
ferruginous gelatine some fibres of a very
minute Nostochaceous plant (probably Ana-
baina subtilissima, Kiitz.). Perhaps the pre-
sence of the Nostoc is accidental, because a
proper soil is present in the ferruginous
water for its growth.

The Didymohelix is by no means common,
even in waters which contain a very copious
ferruginous deposit.

Didymohelix may be preserved either in
the dry state, in chloride of calcium, or in
balsam; perhaps the chloride is the best.
Balsam renders it very transparent.

We have enumerated this as a test-object
for the general excellence of a high-power
object-glass ; also of the observer's manage-
ment of the microscope. See TEST-OB-
JECTS.

BIBL. Ehr. In/us.', Kiitzing, Sp. Alg. p.
363 ; Ralfs, Ann. Nat. Hist. 1843. xii. p. 351;
Grif. Ann. Nat. Hist. 1853. xii. p. 438.

DIDYMOPRIUM, Kiitz.— A genus of
Desmidiaceae.

Char. Cells with a bidentate or bicrenate
process on each side, united into an elon-
gated, fragile, cylindrical, and regularly
twisted filament. (Sheath either present,
wanting or indistinct.)

Differs from Desmidium in having only
two processes, and not being angular, and in
the number of rays of the endochrome in
the side view not depending upon the num-
ber of angles.

D. Borreri (PI. 1 . fig. 1 1 ) . Joints inflated,

DIDYMOSPORIUM.

[ 210 ]

DINEMASPORIUM.

barrel-shaped, longer than broad ; side view
circular ; angles bicrenate. (Sheath wanting
or indistinct.)

The delicate longitudinal lines have been
proposed by Mr. Jenner as a test-object for
the power of the microscope ; they are best
seen in the empty cells when dried. Breadth
of filament, including teeth, 1-1030".

D. Gremllii (PI. 10. fig. 5; fig. 6, side
view). Joints broader than long, with a
thickened border at their junction ; side view
broadly elliptic ; angles bidentate. (Sheath
distinct.) Breadth of filament 1-470".

BIBL. Ralfs, Brit. Desmid. p. 55.

DIDYMOSPORIUM, Nees.— A genus of
Melanconiei (Coniomycetous Fungi), grow-
ing upon shoots of trees. The only British
species, D.profusum, Grev., has very minute,
oblong, uniseptate spores, at first glued to-
gether like a depressed conical nucleus, be-
neath the epidermis, afterwards bursting
through, and becoming free. D.elevatum,
Jjk.—Melanconium bicolor, Nees.

BIBL. Berk., Hook. Brit. Flor. v. pt. 2.
p. 357 ; Ann. Nat. Hist. vi. p. 438 ; Greville,
Sc. Crypt. Fl. pi. 212. fig. 1 (as Stilbospora).

DIFFLUGIA, Leclerc.— A genus of Infu-
soria, of the family Arcellina.

Char. Contained in a spherical or oblong,
urceolate carapace, from the anterior extre-
mity of which are emitted variable, numerous
or multifid tentacular expansions. Aquatic.

The carapace is membranous, often en-
crusted with minute grains of sand (and
carbonate of lime ?) ; in some it is covered
with depressions or tubercles ; these form
the genus Eugfypha, D. The mode of repro-
duction has been observed in D. Enchelys,
which forms gemmae and also resolves itself
into four " spores."

Species very numerous.

D. proteiformis, E. (PI. 23. fig. 39). Cara-
pace oval or almost spherical, covered with
minute grains of sand; length 1-240".

D.oblonga,~Ei. (D.globulosa (?),D.) Cara-
pace oval, oblong, or rounded, smooth,
brownish; length 1-200".

BIBL. Ehr. In/us, p. 130 ; Ber. d. Berl.
Akad. 1840, &c. ; Dujardin, In/us, p. 248 ;
Schlumberger, Ann. des Sc. nat. 1 845. iii. 254 ;
Schneider, Ann. Nat. Hist. 2nd ser. xiv. p. 332.

DIGLENA, Ehr.— A genus of Rotatoria,
of the family Hydatinsea.

Char. Eyes two, frontal ; foot forked.

There are no other appendages than the
foot and the rotatory organ.

Nine species.

D. lacustris (PI. 34. figs. 21 , 22). Body oval,

transparent, truncate in front ; foot suddenly
attenuate, somewhat more than l-4th of the
body in length ; toes l-3rd part of the foot in
length; aquatic; length 1-70".

BIBL. Ehr. Infus. p. 441 ; Gosse, Ann.
Nat. Hist. 1851. viii. p. 200.

DILEPTUS, Duj.— A genus of Infusoria,
of the family Trichodinsea.

Char. Body fusiform, prolonged anteriorly
in the form of a swan's neck, with a lateral
mouth at the base of the prolongation ; en-
tire surface covered with vibratile cilia, which
are more distinct in front and near the mouth.

D. folium, D. (PI. 23. fig. 40). Body very
flexible, in the form of a lanceolate leaf, nar-
rowed in front ; with nodular, reticulated,
irregular ribs; aquatic; length l-160tol- 120".

D. anser (Amphileptus anser, E.).

D. margaritifer (Amphileptus marg., E.).

Dujardin separates these species from the
genus Amphileptus, on account of their not
possessing a reticulated integument like those
of the latter, and their consequently under-
going diffluence.

BIBL. Duj. Infus. p. 404.

DILOPHOSPHORA,Desm.— A genus of
Sphseronemei (Co-
niomycetous Fungi),
consisting of Sphce-
ria-like plants (with-
out asci), growing
upon the leaf-sheaths
and the glumes of
grasses; remarkable
for the curiously-
appendaged spores

(fig. 180). Dilophosphora graminis.

D.gramims,I)esm. sP°res magnified soo diams.
= Sphceria Alopecuri, Fries. Found in
France ; does not appear to have been met
with in Britain.

BIBL. Desmazieres,^ww. des Sc. nat. 2 ser.
xiv. p. 4. pi. 1. fig. 2.

DINEMOURA, Latr.— A genus of Crus-
tacea, belonging to the order Siphonostoma
and family Pandaridae.

Char. Lamellar elytriform appendages
covering the thorax, only one pair. Three
first pairs of feet setiferous; the posterior
foliaceous and membranous.

D. alata and D. Lamnce have both been
found upon the Beaumaris Shark (Lamna
monensis).

BIBL. Baird, Brit. Entomostr. p. 282.

DINEMASPORIUM, Lev.— A genus of
Phragmotrichacei (Coniomycetous Fungi),
consisting of minute plants forming spots
upon the leaves of grasses. D. gramineum,

DINOBRYINA.

[ 211 ]

DIPHYSCIACE^E.

Dinemasporium

gramineum.

Spores magn.

600 diams.

Lev., the only British species, Fig. 181.

= Excipula graminis, Berk.

Br. Fungi, No. 328, and Exc.

graminum, Corda. It has a

scattered conceptacle, closed at

first, and subsequently widely

opened, forming a disk covered

with white spores of a peculiar

form, abruptly produced into

filaments at each end (fig.

181).

BIBL. Berk, and Broome,
Ann. Nat. Hist. 2 ser. v. p.
456; Le'veille, Ann. des. Sc.
nat. 3 ser. v. p. 274 ; Corda,
Icon. Fung. iii. pi. 5. fig. 79.

DINOBRYINA, Ehr.— A family of Infu-
soria.

Char. Bodies variable in form, contained
in urceolate carapaces, which are either sin-
gle, or aggregated into a branched polypidom,
from the new carapaces remaining adherent
by their bases to the summits or the internal
bases of the preceding ; the result of multi-
plication by gemmation. (Astasisea with a
carapace.)

Two genera, Dinobryon and Epipyxis.
In Dinobryon an anterior red eye-spot is
present, but not in Epipyxis. In the former
a flagelliform filament is present; this is
sometimes met with in the latter, but not
constantly.

BIBL. Ehr. Infus. p. 122; Duj. In/us.
p. 320.

DINOBRYON, Ehr.— A genus of Infu-
soria, of the family Dinobryina.

Char. Carapaces urceolate, united into
the form of a branched polypidom.

D. sertularia, E. (PL 23. fig. 41). Cara-
paces sessile or subsessile, slightly constricted
near the somewhat expanded and excised
end; aquatic; length of polypidom 1-144
to 1-120", of individuals 1-570".

Bodies yellow or green, with a red eye-
spot in front.

D. 5ocz«/e,E. "I probably different stages or
D. gradient, f mere varieties of the former.
D.petiolatum, D. (PL 23. fig. 42). Cara-
paces with long stalks, bodies green ; aqua-
tic; length of polypidom 1-100", of a cara-
pace 1-1420".

BIBL. Ehr. Infus. p. 124, and Ber. d.
Berl Akad. 1840. p. 199 ; Duj. Infus. p. 321.
DINOCHARIS, Ehr.— A genus of Rota-
toria, of the family Euchlanidota.

Char. A single cervical eye ; foot forked ;
carapace closed beneath, and without teeth
at the ends.

Jaws with one (or two?) teeth each.
Aquatic. Two horns at the base of the
foot.

D. tetractis (PL 34. fig. 23 ; fig. 24, teeth).
Carapace acutely triangular, two horns at
the base of the foot, and two toes ; length
1-120".

Two other species.
BIBL. Ehr. Infus. p. 471.
DINOPHYSIS, Ehr.— A genus of Infu-
soria, of the family Peridinaea.

Char. Free, single ; carapace membranous,
urceolate, with a transverse ciliated furrow,
and a median plicate crest ; no eye-spot.

Form, that of Vaginicola ; nature that of
Peridinium. The transverse furrow is close
to the truncated anterior end, and from this
furrow there extends down the body a folded
crest or fringe, like that of Stentor, except
that it is a part of the carapace. A crown of
cilia exists around the neck, and a longer
flagelliform filament. Carapace punctate.

D. acuta. Posterior end of carapace sub-
acute; marine; diameter 1-570".

D. Michaelis. Posterior end rounded;
marine ; diameter 1-570".

Found in sea- water with luminous animals;
probably themselves luminous.

BIBL. Ehr. Abh. d. Berl. Akad. 1839.
pp. 125. 151.

DION, Lindl. — A genus of Cycadacese
(Gymnospermous Flowering Plants). The
stem of Dion edule, a Mexican plant, con-
tains abundance of starch, which is extracted
and used as an arrow-root. See CYCADACESE
and STARCH.

DIOPHRYS, Duj.— A genus of Infusoria,
of the family Plaesconiaea.

Char. Body of irregular discoidal form,
thick, concave above and convex beneath,
with five large vibratile cilia at the anterior,
and four or five very long geniculate setae
near the posterior end. Marine.

D. marina (PL 23. fig. 43 ; a, under view ;
b, side view). Body oval, with a longitudinal
excavation; length 1-580".
BIBL. Duj. Infus. p. 445.
DIPHYSCIACE^E.— A family of opercu-
lated Acrocarpous Mosses, having a capsule
of very curious structure. The leaves are of
two kinds, the cauline tongue-shaped, com-
posed of perfectly Pottioid, densely hexago-
nal parenchymatous cells filled with chloro-
phyll; the perichaetial leaves much protruded,
exceeding the cauline, composed of cells ul-
timately destitute of chlorophyll, therefore
of looser texture. Capsule very large,
oblique, gibbose, somewhat like that of Bux~

p2

DIPHYSCIUM.

[ 212 ]

DIPLOZOON.

baumia. Inflorescence monoecious. British
genus.

DIPHYSCIUM, Mohr.— Calyptra conical,
covering the operculum. Peristorae simple,
internal, resembling that of Buxbaumia, sur-
rounded at the base by a large, multiplex,
soluble annulus.

D.foliorum, Mohr . = Buxbaumia foil osa,L .

DIPLASIEJ3.— A subtribe of Polypodae-
ous Ferns, with indusiate sori.

I. Didymochl&na. Sori elliptical, sub-
immersed. Indusium elliptical, affixed in
the middle longitudinally, free on both sides
(figs. 178 & 179). Vein's pinnate.

II. Diplasium. Sori linear, more or less
elongated, not immersed. Indusium linear,
bilateral on bilateral sori. Veins pinnate.

III. Oxygonium. Sori linear, elongated.
Indusium linear, bilateral on bilateral sori.
Veins anastomosing in hexagonal spots.

DIPLASIUM, Presl.— A genus of Dipla-
sieae (Polypodseous Ferns). Exotic.

DIPLAX, Gosse.— A genus of Rotatoria,
of the family Euchlanidota.

Char. Those of Salpina, except that the
eye is wanting, and the carapace (which, as
in that genus, is cleft down the back) is
destitute of spines both in front and behind ;
foot and toes long and slender.

Forms a connecting link between Salpina
and Dinocharis.

D. compressa. Carapace in side view
forming nearly a parallelogram, greatly com-
pressed; length 1-176". Aquatic.

D. trigona. Carapace trilateral ; surface
delicately punctured; length 1-160". Aquatic.
BIBL. Gosse, Ann. Nat. Hist. 1851. viii.
p. 201.

DIPLODIA, Fr.— A genus of Sphserone-
mei (Coniomycetous Fungi), usually growing
upon dead twigs, &c., bursting through the
epidermis. Numerous species have been
described as British by Mr. Berkeley, but
the resemblance of many to various Sphtsrice
is remarked by him, and it seems probable
that they are only stylosporous forms of spe-
cies belonging to that genus or its allies, as
species of Tympanis have been found by him
and by Tulasne witli the spores like &Diplodia
at the same time with asci.

BIBL. Berk. Ann. Nat. Hist. vi. p. 365.
pi. 11, 2 ser. v. p. 371, xiii. p. 459; Hook
Journal of Botany, iii. 320, v. p. 40 ; Le-
veille', Ann. des Sc. nat. 3 ser. v. p. 290
Tulasne, idem. xx. p. 136.

DIPLODONTUS, Duges.— A genus o
Arachnida, of the order Acarina, and family
Hvdrachnea.

Char. Mandibles terminated by a straight,
cute, and immoveable tooth, to which is
ipposed a moveable hook or claw; palpi
hortish, with the fourth joint longest and
erminated by a point as long as the fifth
oint ; coxae not very broad, in four separate
groups, the posterior of which are semi-
divergent; a bivalve, granulated, heart-shaped
genital plate, the apex directed forwards.

D. scapularis (PI. 2. fig. 30 ; fig. a, labium
with a palp, under view ; b, a separate man-
dible more magnified than a) . Eyes very smal 1
)ut projecting, wide apart, placed at the an-
terior rounded angles of the body, blackish
and reniform, arising from the fusion of two
stemmata. Anterior half of the body black,
speckled with a few red spots ; posterior half
scarlet, but divided by a median longitudinal
black band. Length of female 1-10" ; male
l-3rd or l-4th the size of the female.

D. filipes. Palpi much curved down-
wards, but little visible from above. Body
elliptical, depressed, bright red, sometimes
marbled with dark brown spots, from the
digestive organs being visible through the
integument. Eyes four, at the very anterior
margin, so as to be best seen from beneath.
Integument finely granular, without hairs.
Legs red. Length 1-25".
D. mendax. Duges, ut infra.
BIBL. Duges, Ann. des Sc. nat. 2 ser.
1834. i. p. 148.

DIPLONEIS, Ehr.— A genus of Diato-
macese, not now retained.

DIPLOZOON, Nordm.— A supposed ge-
nus of Entozoa, of the family Trematoda.
The members have since been shown to
consist of two individuals in a state of con-
jugation.

Char. Body of individuals soft, elongated
and flattened, united in pairs by their fusion
near the middle, thus resembling an X ;
each body terminated posteriorly by a trans-
verse, oval, or almost quadrilateral expan-
sion, furnished with four suctorial acetabula
or disks.

Mouth terminal, anterior, accompanied by
two oblong suctorial disks.

D. paradoxum, the double animal. Found
upon the gills of freshwater fishes, as the
carp, the roach, the bream, &c. Length
1-6 to 1-5", or twice this length.

The separate individuals, for which Dujar-
din has proposed the generic name Diporpa,
are smaller than those in a state of conjuga-
tion. Length 1-100 to 1-45"; and contain
no trace of reproductive organs. The ova
are formed in each individual after the con-

DIPPING-TUBES.

[ 213 ]

DISSODON.

jugation has taken place ; they are yellow,
with the shell narrowed and prolonged into
a spiral or coil.

BIBL. Nordmann, Mikrogr. Beitr'dg. 1832.
i. p. 56, Ann. d. Sc. nat. 1833. xxx.; Ehren-
berg, Wiegmann's Archiv, 1835, ii. p. 128 ;
Mayer, Beitr'dg. z. Anat. d. Entoz. p. 23 ;
Siebold, Sieb. and Kolliker's Zeits. /. Wis-
sensch. Zool. iii. p. 62 ; Vogt, Mutter's Ar-
chiv, 1841. p. 33.

DIPPING-TUBES. INTR. p. xxi.

DISCELIACE m.— A family of operculate
Acrocarpous Mosses, of gregarious habit,
very dwarf and stemless, arising from a green
prothallium spreading on the ground. The
sheathing leaves are appressed, oblong, acu-
minate and nerveless, composed of cells lax
at the base and apex, rhomboidally paren-
chymatous, destitute of chlorophyll, rusces-
cent and empty. The capsule is subglobose
and inclined, with a short collum, annulate
and long-stalked. The antheridial and ar-
chegonial flowers are upon the same runner
of the prothallium. British genus :

DISCELIUM, Brid.— Calyptra longish,
very narrow, split almost to the summit,
wider in the middle, with the margin involute
on each side at the base. Peristome simple,
of sixteen lanceolate teeth, fissile in the
middle, trabeculate, striate, cartilaginous,
reddish or orange.

Discelium nudum, Brid. = Weissia nuda,
Hook.

DISCELLA, Berk, and Br.— A genus of
Melanconiei(Coniomycetous Fungi), forming
scattered, disk-like, dark spots upon twigs;
at first covered by the epidermis, which after-
wards splits and separates. Five species are
described, occurring on the willow, lime,
plane, and elder.

BIBL. Berk. andBroome, Ann. Nat. Hist.
2 ser. v. 376. pi. 12. fig. 8.

DISCOCEPHALUS, E.— A genus of In-
fusoria, of the family Euplota.

Char. Head distinct from the body; hooks
present, but neither styles nor teeth.

D. rotatorius (PI. 23. fig. 44). Hyaline,
flat, rounded at each end; head narrower
than the body; length 1-380". Found in
the Red Sea. Imperfectly examined.

BIBL. Ehr. Infus. p. 375.

DISCOMYCETES.— The name of one of
the families of Fungi under Fries's classifi-
cation, including the HELVELLACEI and
PHACIDIACEI of the ASCOMYCETES.

DISCOPLEA, Ehr.— A genus of Diato-
macese, not now retained.

DISCOSIA, Libert.— A genus of Sphsero-

nemei (Coniomycetous Fungi), probably re-
lated to some of the Sphcerice, as stylosporous
forms. The species have been described
under various names, and the genus Pnlycti-
dium of Notaris is synonymous with it. The
British species recorded seems to have
been greatly confused by different writers,
for the Discosia alnea, Libert, found on the
leaves of alder and beech=S'jwfoma artocreas,
Tode, Xyloma fagineum, Pers., Phlyctidium
nitidum, Wallr., Ph. clypeatum, Notaris ; and
from its name we conclude also the Dothidea
alnea, Pers. of Hook. Brit. Flor., with its
synonymes. Fries, in his Summa Veg., gives
D. artocreas, alnea, and clypeata as three
distinct species.

BIBL. Leveille, Ann. des Sc. nat. 3 ser. v.
286; Fries, Summa Veget. 423; Fresenius,
Beitr. z. Mycol. Heft i. p. 66. pi. 8; De
Notaris, Mem. Acad. di Torino, ser. 2. x.
(1849); Berk., Hook. Brit. Flor. p. 278. 288.

DISELMIS, Duj. = CHLAMIDOMONAS,
Ehr. ( Chlamidomonas pulvisculus, E. = Di-
selmis viridis, D.; PI. 3. fig. 2. b, c.; PI. 23.
group 30). See PROTOCOCCUS.

Dujardin describes a marine species, D.
marina. Body almost globular, obtuse, and
rounded in front, granular within (and from
generic characters), with a non-contractile
tegument, and two similar cilia.

He adds to this genus, D. Dunalii—Mo-
nas Dunalii, Joly, giving rise to the red
colour of the reservoirs of the salt-works of
the Mediterranean; oval or oblong, often
constricted in the middle ; colourless when
young, greenish when older, red when
adult ; no eye-spot. Probably some marine
Algaj.

BIBL. Dujardin, Infus. p. 340; Joly, Hist,
d'un Petit Crustace, fyc. 1840.

DISOMA, Ehr. — A genus of Infusoria, of
the family Enchelia.

Char. Body double, not ciliated ; mouth
without teeth, ciliated and truncated. (=.En-
chelys with a double body.)

D. vacillans (PI. 23. fig. 45). Segments
clavate, filiform; hyaline and narrowed at
the anterior end; length 1-380 to 1-288".
In the Red Sea.

BIBL. Ehr. Inf. p. 302.

DISSODON, Grev. and Arnott.— A genus
of Splachnaceae (Acrocarpous operculate
Mosses), including some Splanchna of
authors and a Cystodon.

D. Frb'hlichianus, Grev. and Arnott =
Splanchnum Frohlichianum, Hedw.

D.splanchnoides,Grev. and Arn.= Cystodon
splanchnoides, Br.

DISTEMMA.

[ 214 ]

DOLICHOSPERMUM.

DISTEMMA, Ehr.— A genus of Rotatoria,
of the family Hydatinsea.

Char. Eyes two, cervical ; foot forked.
D.forficula (PI. 34. fig. 25; fig. 26, teeth).
Body cylindrico - conical ; eyes red; toes
strong, recurved, toothed at the base ; aqua-
tic; length 1-120".

Three other species, two of which are
aquatic, and one marine. In the latter, D.
marina, the cervical eye-spots are colourless;
if these do not really represent eyes, this
species must be referred to the genus Pleuro-
trocha.

BIBL. Ehr. Infus. p. 449.
DISTICHIACEjE.— A family of opercu-
late Acrocarpous (terminal-fruited) Mosses,
of csespitose habit ; the stem increasing to-
wards the point, simple or branched; the
leaves with a dorsal keel-like nerve, equitant-
concave, densely imbricatively overlapping,
parenchymatously areolated. Cells minute,
with thick walls, somewhat papillose, very
densely packed, squarish. Capsules oval,
equal. British genus :

DISTICHIUM, Br.and Schimper.— Calyp-
tra dimidiate. Capsule annulate. Peristome
simple, with sixteen equidistant teeth, free
at the base, once or several times slit from
the base to the apex, trabeculate, deep pur-
ple, homogeneous, smooth or rough. Inflo-
rescence monoecious. British species :

Distichium capillaceum, Br. and Sch. =
Didymodon capillaceus, Schrad.

D. inclinatum, Br. and Sch.=Didymodon
inclanatus, Sw.

DISTIGMA, Ehr.— A genus of Infusoria,
of the family Astasiaea.

Char. Unattached, eye-spots two, blackish.

There are no cilia, flagelliform filaments,

nor other locomotive appendages; motion

similar to that of a leech. Body variable in

form.

D. proteus (PI. 23. fig. 46 a). Body hya-
line, obtuse at the ends, alternately contracted
or expanded from side to side; eye-spots
distinct; aquatic; length 1-570 to 1-430".

D. viride (PI. 23. fig. 46 b}. Body filled
with green granules, alternately contracted
and expanded ; eye-spots distinct ; aquatic ;
length 1-570".

Two other aquatic species; one yellow,
the other colourless.

BIBL. Ehr. Infos, p. 116.
DISTOMA, Zeder.— A genus of Entozoa,
of the order Sterelmintha, and family Tre-
matoda.

Char. Body soft, depressed or cylindrical,
more or less elongated, not jointed; fur-

nished with two distinct and isolated suckers;
one anterior, terminal, and containing the
mouth, the other situated on the ventral
surface between the middle and the anterior
sixth of the body.

The species are very numerous ; Dujardin
describes 164. They are most common in
birds and fishes, generally inhabiting the
alimentary canal.

D. hepaticum, the fluke. Occurs in the
gall-bladder and hepatic ducts of sheep when
aifected with the 'rot.' It has also been
found in the horse, the ox, the goat, the
hare, and the stag. Length 4-5 to 1^".

Some of the other species are micro-
scopic.

BIBL. Dujardin, Hist. nat. d. Helminth.
p. 381 ; Mehlis, Obs. de Distom. hepat. fyc.
1825 ; Beneden, Ann. des Sc. nat. 3 ser.
Zool. xvii.

DOCIDIUM^relnsson.— A genus of Des-
midiacese.

Char. Cells single, straight, much elon-
gated, linear, sometimes attenuated towards
the ends; constricted at the middle, ends
truncate; segments usually inflated at the
base.

Docidium, like Closterium, has the termi-
nal spaces with moving molecules ; and its
vesicles are either scattered or arranged in a
single longitudinal row.

D. truncatum (PI. 10. fig. 38). Segments
three or four times as long as broad, with a
single inflation at the base ; suture project-
ing on each side ; length 1-80 to 1-72".

D. baculum (PI. 10. fig. 39). Segments
very slender, with a single conspicuous infla-
tion at the base, otherwise linear ; vesicles in
a single series; length 1-111".

D. nodulosum. Segments four to six times
as long as broad, constricted at regular in-
tervals so as to produce an undulated margin ;
suture projecting; length 1-50".

Three or four other species.

BIBL. Ralfs, Brit. Desmid. p. 155.

DOLICHOSPERMUM, Thwaites (PI. 4,
fig. 2). — A genus of Nostochacese, allied to
Trichormus, Sphcerozyga, &c., established
by Thwaites for five British species, from
which Hassall has separated one under the
name of Coniophytum. Thwaites noticed in
this genus that the contents escaped in an
undivided mass from the elongated and
mostly cylindrical spermatic cells, which are
invariably truncated at the ends.

1. D. inaquale, Ralfs. Filaments monili-
form ; ordinary cells at first quadrate, finally
orbicular ; vesicular cells large, spherical ;

DOODIA.

[ 215 ]

DRAPARNALDIA.

spermatic cells linear, catenate (Ralfs, Ann.
Nat. Hist. ser. 2. v. pi. 9. fig. 1). Form-
ing extensive strata, composed of thick gela-
tinous masses of a deep green colour, on
boggy pools ; filaments consisting of 100 to
200 cells.

2. D. Ralfsii (Kutring). Filaments moni-
liform ; ordinary cells spherical ; vesicular
cells elliptic ; spermatic cells elliptic or cy-
lindrical, one or two in each series. Ralfs, I. c.
pi. 9. fig. 2; Sphcerozyga Ralfsii, Thwaites,
Harvey's 'Man. Brit. Alga, 2 ed. p. 233.
Cylindrospermum Ralfsii, Kiitzing, Tabula
Phycologicce, i. pi. 98. fig. 7- Forming
extensive strata of a velvety rich dark green
colour, sometimes verging towards aeruginous
green ; on rivulets and in bogs.

3. D.Smithii, Thwaites. Filaments straight,
each included in a definite gelatinous sheath;
ordinary cells subspherical, compressed, about
as long as wide ; vesicular cells subspherical,
somewhat barrel-shaped, half as wide again
as the ordinary cells, puncta very distinct ;
spermatic cells cylindrical, very unequal in
length, and with the ends rounded and some-
what truncated. Ralfs, /. c. pi. 9. fig. 4.
Freshwater boggy pools.

4. D. Thwaitesii,JMfs. Filaments straight,
or nearly so ; ordinary cells quadrate ; vesi-
cular cells oblong, subquadrate, puncta very
distinct ; spermatic cells numerous, cylindri-
cal, with truncated ends, very variable in
length. Ralfs, 1. c. pi. 9. fig. 5. Sphcerozyga
Thwaitesii, Harvey, Man. Br. Alga, 2 ed.
232. In freshwater or brackish pools. (D.
Thompsoni, Ralfs, see CONIOPHYTUM.)

For further details, see Ralfs on Nostocha-
cea, Annals of Nat. History, ser. 2. v. 321.

DOODIA, R. Brown. — A genus of Asple-
nieae (Polypodaeous Ferns). Exotic.

DORYPHORA, Kiitz.— A genus of Dia-
tomaeeae.

Char. Frustules single, stalked; valves
orbicular, lanceolate or broadly elliptical,
with a median longitudinal line, but no no-
dules. Marine.

The valves are furnished with transverse
or slightly radiating lines, resolvable into
dots.

D. amphiceros, K. (PI. 12. fig. 29 ; a, side
view of frustule ; b, front view ; c, prepared
valve). Valves orbicular, lanceolate, or
broadly elliptical, ends produced; length
1-500 to 1-800".

D. Boeckii, S.(Cocconema B., K.). Valves
elongato-lanceolate, ends somewhat obtuse ;
length 1-144". (This species appears to
have a median and terminal nodules.)

BIBL. Kiitzing, Bacill. p. 74 ; Sp. Ala.
p. 50 ; Smith, Brit. Diatom, i. p. 77-

DOTIIIDEA, Fries.— A. genus of Sphae-
riacei ( Ascomycetous Fungi), mostly gi owing
upon leaves. Numerous species are de-
scribed as British by Mr. Berkeley, some of
which are now placed under other genera by
Fries ; thus D. Geranii, Robertiani, Ranun-
culi, Potentillce and Alchemillce of the Brit.
Flora, and D. Chcetomium, Kze., are species
of STIGMATEA in the Summa Veg.\ D. alnea
is removed to DISCOSIA, and D.pyrenophora
and sphceroides are placed under DOTHIORA,
Fries, a stylosporous form. The whole of
these plants require further study, since it is
probable that they are really connected with
the Sphaeronemei or Melanconiei, for the ob-
servations of Mr. Berkeley go to show that
Asteroma Ulmi is a form of Dothidea Ulmi,
while Tulasne has found upon Dothidea Ri-
besii spores or spermatia like those of Xyla-
rice, others in excavated cavities having the
character of the spores of Septoria, while in
ordinary cases the surface is covered with
conceptacles filled with eight-spored asci.
See CONIOMYCETES.

BIBL. Berk. Br. Fl. ii. pt. 2. p. 285; Ann.
Nat. Hist. vi. 364 ; Berk, and Br. Ann. Nat.
Hist. 2 ser. ix. 385 ; Fries, Summa Veget.
pp. 386. 418 & 421 ; Corda, Ic. Fung. iv.
p. 119. Also the Bibl. under CONIOMY-
CETES.

DOTHIORA, Fries. See DOTHIDEA.

DOXOCOCCUS, Ehr.— A genus of Infu-
soria, of the family Monadina.

Char. No tail ; no eye-spot ; motion nei-
ther that of simple progression nor rotation,
but an irregular kind of rolling-over.

Organ of locomotion unknown, Ehr.

D. ruber (PI. 23. fig. 47 a, after Ehr.).
Body globose, brick-red, more or less opake;
breadth 1-1728". Aquatic.

This organism is almost beyond doubt the
same as that represented in PI. 23. fig. 24,
d &ndf(nobis),i. e. a form of Trachelomonas
volvocina (TRACHELOMONAS). This was
suspected by Ehrenberg.

D. pulvisculus, E. (PI. 23. fig. 47 b) is
probably an early stage of the same.

The other two species — D. globulus (sub-
globose or ovate, hyaline ; marine ; breadth
1-864"), and D. incequalis (subglobose, un-
equal, hyaline, speckled with green; aquatic;
breadth 1-2400") — are probably Algae, or
their spores.

BIBL. Ehr. Infus. p. 28.

DRAPARNALDIA, Bory.— A genus of
Chaetophoraceae(Confervoid Algae), especially

DRAPARNALDIA. [

distinguished (as limited here in accordance
with Kiitziug) by the filaments being com-
posed of an axis of cells of much greater
diameter than that of the cells forming the
branches (fig. 182). The species placed here
Fig. 182. Fig. 183.

216

DUMONTIA.

Draparnaldia glomerata.

Fig. 182. Portion of a filament. Magnified 200 diams.
Fig. 183. Portion of a branch discharging zoospores
from its cells. Magn. 400 diams.

by Hassall and others, devoid of this charac-
ter, will be found under STIGEOCLONIUM.
The green contents of the cells form a broad
band in the middle of the cell ; the mem-
brane of the Draparnaldia, like that of the
Chcetophorce, is very fugacious, and the fer-
tile cells soon dissolve after discharging the
zoospores; the latter have four cilia (the
cilia have been omitted in our cut, fig. 183).
The assemblages of filaments are gelatinous.
Three British species are described :

1. D. glomerata, Ag. (fig. 182). Principal
filament about 1-800" in diameter, irregularly
branched; ramelli 1-2400 to 1-3000", in
ovate tufts, generally alternate, and patent.
Hassall, Br. Fr. Alg. pi. 13. 1 ; Engl. Bot.
p. 1746; Vauch. Conserves, pi. 12. fig. 1.
Common in streams and wells.

2. D. plumosa, Ag. Principal filaments
somewhat pinnately branched, size about the
same as the preceding; ramelli in linear-
lanceolate tufts, mostly approximated to the
axis. Vauch. pi. 11. fig. 2 (Kiitzing refers
HassalPs plumosa (I. c. pi. 12. fig. 1) to D.
opposita, Ag. as doubtful). Common in
streams and wells.

3. D. repetita, Hass. Principal filaments
composed of repeated series of cells, each
series consisting of five or six cells, diminish-

ing in size from the lowest to the highest,
the series adjoining each other obliquely;
tufts of ramelli dense, alternate. Hass. L c.
pi. 12. fig. 2. Rare.

See STIGEOCLONIUM.

BIBL. Bory, Annales du Museum, xii. ;
Vaucher (as Batrachospermum), Conferves
d'Eau douce ; Link (as Charospermum), Hor.
phys.iii.', Hassall, L c. p. 118; Decaisne,
Ann. des Sc. nat. 2 ser. xvii. p. 314; Thuret,
ibid. 3 ser. xiv. p. 1 5.

DREPANOPHYLLE.E.— A family of
operculate Acrocarpous (terminal-fruited)
Mosses; containing only one East Indian
genus, Drepanophyllum, Rich., imperfectly
known in its details.

DRIMYS, Forst.— A genus of Magno-
liaceae (Dicotyledonous Plants), remarkable
for the microscopic structure of the wood.
See WINTERED.

DRYOSTACHIUM, J. Sm.— A genus of
Polypodiese (Ferns) with very much branched
anastomosing veins, with free branches in the
meshes.

DUCK-WEED. See LEMNA.

DUCTS. — A term used in structural bo-
tany, applied to those forms
of the so-called vascular tissue
which consist of long tubes
constructed out of perpendi-
cular rows of cells, which are
thrown into one by the ab-
sorption of their adjoining
ends. Ducts are thus easily
distinguished from vessels
(which taper off to closed ends)
by the constrictions upon the
walls of the tubes, indicating
the junctions of the compo- ^^
nent cells (fig. 184). See Dotted duct from

TISSUES, VEGETABLE, and the Melon.

VESSELS. Maen- 25° diams-

DUDRESNAIA, Bonnem. — A genus of
Cryptonemiacese (Florideous Algae), contain-
ing two minute British species, with delicate,
branched, filiform fronds, a few inches high,
of rose-red or reddish-brown colour. Both
D. coccinea, which is a very rare plant, and
seldom found except on the south coasts of
England and Ireland, and D. Hudsoni, a not
uncommon sea-weed, present very elegant
microscopic structure, the fronds being com-
posed of a central cellular axis, clothed with
tufts of delicate, dichotomous, moniliform
filaments, standing perpendicularly upon it.
BIBL. Harvey, Brit. Alg. p. 154. pi. 21 C.
Pkyc. Brit. pi. 110. 244.

DUMONTIA, Lamx.— A genus of Cryp-

DURA MATER.

[ 217 ]

DYTISCUS.

tonemiaceae (Florideous Algae), containing
one British species, D. filiformis, having a
delicate tubular frond, of yellowish, greenish,
or purple colour, of variable length and dia-
meter, with numerous filiform branches,
which are long on short fronds, and short on
long fronds ; growing commonly on rocks,&c.
between tide-marks. The wall'of the tube is
composed of a double layer of tissue, the
outer of roundish cells, the inner of longish
cells forming filamentous rows. The spores
are attached in clusters upon the internal
wall of the tube (which is filled up with ge-
latinous substance), while the tetraspores
are found among the surface-cells.

BIBL. Harvey, Brit. Alg. p. 147. pi. 20 a ;
Phyc. Brit. pi. 59; Greville, Alg. Brit. pi. 17.

DURA MATER. — This strong, somewhat
elastic membrane, of a tendinous aspect,
consists of white fibrous tissue, with a few
nuclear fibres. The former is composed of
bundles, interlacing in various directions.
The dura mater is lined internally by a layer
of flat, polygonal, nucleated, epithelial cells,
representing the reflected layer of the arach-
noid membrane.

BIBL. Treatises on Anatomy, Kolliker,
Handbuch d. Gewebelehre, and Mikrosko-
pische Anatomie.

DYTISCID.E.— A family, and

DYTISCUS, Linn., or Dyticus.—K genus
of Coleopterous Insects, belonging to the
family Dytiscidae.

The characters of the family are, — antennas
long and slender ; external lobe of maxillae
articulated; anterior pah- of legs shorter
than the posterior pairs, which are flattened
and fringed with hairs. Aquatic.

The genus Dytiscus is characterized by the
three first joints of the anterior tarsi in the
male being very large, and expanded into a
patella or shield ; the didactyle claws, and the
maxillary palpi having the second and third
joints of equal length.

The species of Dytiscus are of large size ;
one of them, D. marginalis, is common in
ponds and pools.

The head is well adapted for the display of
the trophi, or organs of the mouth. The
labrum is transverse; the mandibles short
and robust, with a strong internal tooth ;
the maxillse are short, flat, and ciliated in-
ternally, with the tip acute ; the outer lobe
palpiform ; the true maxillary palpi are about
twice as long as the maxillse ; the mentum is
transverse, with the sides produced into two
lobes ; the labium is short and square, the
palpi about twice its length, and three-

jointed. The structure of the anterior tarsi
in the male (PL 27. fig. 6 a) is very curious ;
the three basal joints being expanded late-
rally so as to form a broad and rounded patella
or shield, convex above, and covered beneath
with a number of variously-sized suckers
or discs, some of which are stalked (fig. 6 b,
one of the smaller ones). This structure
enables the male to retain his situation upon
the back of the female, the elytra of the lat-
ter being furrowed longitudinally, to aid in
this effect. The three basal joints of the tarsi
of the middle pan* of legs are also flattened
beneath, and covered with the stalked disks.

Fig. 185.

Dytiscus latus. Natural size.

The full-grown larvae are about two inches
in length. They are of a dark ochre or dirty
brown colour ; the body long, subcylindrical,
and eleven-jointed ; the two terminal joints
are long and conical, the sides of the apex
being fringed with hairs. The terminal seg-
ment is fiirnished with a pair of long and
slender pilose appendages, by means of
which the insect can suspend itself at the
surface of the water ; these are tubular, and
communicate with the tracheae of the body.
The head (PI. 28. fig. 14) is large, oval, or
rounded, depressed, and with five or six
small elevated tubercles near the anterior
angles representing the eyes (fig. 14 a). Two
rudimentary, slender, seven-jointed antennae
(b) are inserted in front of the eyes. The
mouth has no aperture; the food, consisting
of the juices of the prey, passes through a
canal traversing the long, sickle-shaped,
acute mandibles (c). The maxillae (d) are
slender, cylindrical, and terminated by a
short lateral spine ; the maxillary palpi (e)
are of the same thickness, arising from the

EBONY.

[ 218 ]

ECHINOCOCCUS.

tip of the maxillae, and seven-jointed. The
labial palpi (/) are slender and four-jointed,
the first and third joints being very short.

The head of the larva, and the three pairs
of legs of the perfect insect, are commonly
mounted as microscopic objects, as are those
of other genera belonging to this family, —
Acilius, &c.

BIBL. Westwood, Introduction, &c. i. p.
95 ; Stephens, British Beetles.

E.

EBONY.— The heart-wood of species of
Diospyros (Ebenaceae, Dicotyledons), re-
markable for its solidity and black colour.
See WOOD.

ECCRINA, Leidy. — See ENTEROBBYUS.

ECHINELLA, Acharius. — A term applied
first to a group of ova of some aquatic
animal, next to a genus of Infusoria, more
recently to a genus of Diatomaceae, but now
no longer used.

ECHINOBOTRYUM, Corda.— A genus
of Torulacei (Coniomycetous Fungi). E.
atrum has been found in Britain parasitic
upon a species of Pachnocybe.

BIBL. Berk, and Broome, Ann. Nat. Hist.
2 ser. v. p. 466; Corda, Icon. Fung.\\. fig. 6.

ECHINOCOCCUS, Hud.— A supposed
genus of Entozoa, of the order Sterelmintha
and family Cystica ; recently shown to con-
sist of the larvae of Tcenia.

Char. Consisting of a vesicle of very
variable size, sometimes surrounded by a coat
of condensed areolar tissue, and containing
within, one or more secondary cysts ;
attached to the inner wall of these cysts, or
suspended in their liquid contents, are
numerous oblong, rounded, or oval bodies,
each with four suckers, and a double crown
of hooks.

E. veterinorum, the only species (PI. 16.

s. 1 & 2). Occurs in the liver, the cavity
the abdomen, the heart, the voluntary
muscles, and the ventricles of the brain of
man; in the liver, lungs, &c. of the ox, sheep,
goat, ape, pig, &c. Commonly called hyda-
tids. The walls of the true cysts consist of
numerous concentric layers or plates, resem-
bling those of colloid cells or cysts. The
liquid existing within the cysts is yellowish
or reddish, albuminous, and frequently con-
tains plates of cholesterine, and crystals of
bilifulvine (PI. 9. fig. 15) (see BILE) ; some
of the latter resemble in form and colour
those of H^EMATOIDINE. The larvae appear
to the naked eye as minute white, opake
specks; varying in size from about the

1-300 to 1-100" in length. They also vary
greatly in form ; when the head is retracted
(fig. 1 a)they appear more rounded than when
this is protruded (fig. 1 c, 1 d, If). The hooks
surrounding the anterior end of the body
(fig. 1 b) consist of a broadish basal portion,
an internal transverse blunt tooth, and a
curved terminal portion or claw ; they are
about the 1-1500 to 1-1000" in length. In
some of the larvae a kind of pedicle exists at
the base, by which they are attached to the
wall of the cyst (figs. 1 a and 1 c); sometimes
two or more lines may be perceived, running
from the head towards the pedicle, and con-
nected in front by a transverse line ; pro-
bably representing vessels (fig. 1 c). Inter-
spersed through the substance of the body,
are minute, highly refractive corpuscles con-
taining carbonate of lime.

In the quite recent state, the larvae have
been seen swimming actively in the liquid of
the cyst; this motion is produced by cilia
existing upon the surface of the body.
Mingled with the perfect larvae are generally
found some in which neither hooks nor
suckers are visible, and in which the form is
very irregular; some of these assume the
natural form, when treated with acetic acid.

The larvae appear usually to be developed
by gemmation from the interior of the cysts;
but as Kuhn long since showed, they are
sometimes produced by external gemmation
(fig. 2) : the contents produce a slight pro-
trusion of a part of the wall of a cyst ; the
protruded portion enlarges, afterwards be-
coming constricted at its base, at last pro-
bably separating from the parent, to become
itself a parent in the same manner. The
contents of the new cysts in the above
instance were at first simply granular, in the
larger and more developed cysts, the hooks
were also present. Hence it appears that
the larvae cannot be regarded as the parasites
of a cyst, but must be viewed as arising from
a partial segmentation of the contents of the
parent. The example figured in PI. 16. fig. 2
was not isolated; there were many, contained
with numerous other larger cysts, of the most
varied size, all in one very large parent-cyst.

The Echinococci do not attain their full
development into T&nice, unless they reach
the alimentary canal. The cysts and their
contents, including the Echinococci, undergo
a kind of degeneration, becoming partially
converted into fatty or calcareous matter;
or the entire contents become amorphous
and granular, the hooks remaining longest
unaltered, but finally disappearing also.

ECHINODERMATA.

[ 219 ]

ECHINUS.

See ACEPHALOCYST.
BIBL. Kuhn, Ann. des Sc. nat. 1 ser.xxix.
p. 273 ; Siebold, Wiegmann's Arcliiv, 1845.
ii. p. 241, and Siebold and Kolliker's Zeitschr.
iv. ; Gluge, Ann. des Sc.nat. 2 ser. viii. p. 314 ;
O\\en,Hunterian Lectures,!, p. 46; Dujardin,
Helminthes, p. 635; Huxley, Ann. Nat. Hist.
2 ser. xiv. p. 3/9.

ECHINODERMATA.— A class in the
Animal Kingdom, including the species of
star-fishes (Jsterzas), of sea-hedgehogs or sea-
eggs (Echinus), of sea-slugs (Holothuria),
&c.

The Echinodermata are marine animals,
with a coriaceous or calcareous integument ;
alimentary canal distinct, suspended in the
cavity of the abdomen, and with either one
or two orifices ; distinct organs of circulation
and respiration ; sexes not always distinct,
and external generative organs never present;
disposition of organs generally quinary; body
generally radiate or globose, sometimes cy-
lindrical; nervous system forming a ring
generally surrounding the mouth and giving
oif radiate branches.

A cutaneous skeleton usually exists as a
network of calcareous corpuscles (PL 37.
fig. 1), or numerous calcareous plates,
pretty regularly perforated so as to form a
solid continuous network (PI. 37. fig. 2).
The plates are sometimes moveable, at others
connected by sutures ; some are perforated
with larger apertures — the ambulacral pores ;
they are often furnished with calcareous
appendages,tubercles, prickles, spines, hooks,
&c. ; some being imbedded in the leathery
integument itself. Many of these appendages
form beautiful microscopic objects, and pos-
sess very remarkable analytic power (see
ECHINUS, SYNAPTA and SHELL).

The muscular system consists of distinct
flattened primitive fibrils and bundles, not
transversely striated. The organs of loco-
motion exist in the form of little tentacle-
like organs, the so-called feet or ambulacra.
These are very contractile, hollow prolonga-
tions of the cutaneous surface, expanded at
the end, and connected by the ambulacral
pores with contractile sacs — the ambulacral
vesicles — placed on the inner surface of the
leathery or calcareous covering of the body,
and acting as organs of adhesion and as feelers.
In the Echinidea (Echinus-family) and
Asteridea (Asterias-fsimily), other curious
appendages occur, called PedicellaritB(Pl.37.
fig. 3) ; they are met with all over the cuta-
neous surface, and consist of a forcipate or
valvular apparatus, acting as organs of pre-

hension. The Pedicellarice of the Asteridea
usually consist of two long forceps-like or
two broad valvular arms, and have hence
been divided into forcipate and valvate Pedi-
cellarifB. They are mostly without a stalk.
In the Echinidea (Echinus) they are most
numerous around the mouth, and have been
subdivided, according to their form, into
1. Gemmifonn, having three short lentil-
shaped arms; 2. Tridactyle, having three
long and laterally toothed arms; and 3. Ophi-
ocephalous,with three spoon-shaped laterally
toothed arms. These Pedicettaria contain a
reticular calcareous mass as a basis, and in
Echinus are placed upon a stalk, the lower
portion of which encloses a calcareous
nucleus, whilst the other portions are soft,
extensile and spirally retractile. The Pedi-
cellarice of Echinus, which are partially
covered with ciliated epithelium, can seize
larger or smaller bodies, and pass them from
one to the other ; so that an object grasped
by one of them situated on the posterior
half of the body, or near the anal region, can
gradually pass it on towards the mouth.

The abdominal cavity of the Echinoder-
mata is always filled with sea-water, kept in
motion by cilia covering the intestinal canal.

A true blood-vessel system, as well as the
water-vessel system, is also present, into the
structure of which and other particulars we
have no space to enter.

BIBL. Siebold, Vergleich. Anat. p. 74;
Cycl. Anat. and Phys. (Sharpey) ii. p. 30 ;
Agassiz, Monograph d'Echinod.viv. etfoss.;
Valentin, Monogr. d'Echinoderm. livr. iv. ;
Fprbes, Hist, of Brit. Starfishes, fyc.; Muller
and Troschel, System d. Asteriden ; Muller,
Abh. d. Berl. Akad. 1846-1851 (Huxley,
Ann. Nat. Hist. 1851 (viii. p. 1).

ECHINORHYNCHUS, Muller. — A
genus of Entozoa, of the order Sterelmintha,
and family Acanthocephala.

Char. Body cylindrical or sacciform, some-
what elastic, transversely rugose, obtuse at
both ends ; furnished with a retractile pro-
boscis, which is armed with from one to sixty
regular transverse rows of recurved spines ;
sexes distinct ; no mouth.

The species, which are very numerous,
many microscopic, reside in the alimentary
canal, most commonly of fishes, less so in
that of mammals, and still more rarely in
that of birds.

BIBL. Dujardin, Hist. nat. d. Helminth.
p. 483 ; Cloquet, Anat. d. vers Intestin.

ECHINUS, Lam.— A genus of Echino-
dermata, of the family Echinidea.

ECTOCARPACE.E.

[ 220 ]

EGGS.

The species are popularly known as * sea-
urchins,' or * sea-eggs.'

The beautifully symmetrical structure of
their spines, and their curious Pedicellarice,
afford favourite objects to the admirers of
nature's minute wonders. These organs are
not confined to this single genus of the
family.

See ECHINODERMATA and SHELL.

BIBL. Forbes, Brit. Starfishes, fyc., p. 167;
Agassiz, Monogr. d'Echinoderm.

ECTOCARPACE^.— A family of Fu-
coidese. Olive-coloured, articulated, fili-
form sea-weeds, with sporanges producing
ciliated zoospores either external, attached
to the jointed ramuli, or formed out of some
of the interstitial cells.

Synopsis of the British Genera.

* Frond rigid j each articulation composed
of numerous cells (Sphacelarieae).

I. Cladostephus. Ramuli whorled.

II. Sphacelaria. Ramuli distichous,
pinnated.

** Frond flaccid ; each articulation com-
posed of a single cell.

III. Ectocarpus. Frond branching, ra-
muli scattered.

IV. Myriotrichia. Frond unbranched,
ramuli whorled, tipped with pellucid fibres.

BIBL. See the genera.

ECTOCARPUS, Lyngb— A genus of EC-
tocarpaceae (Fucoid Algae), consisting of
olive or brown sea-weeds, with fronds com-
posed of flaccid capillary filaments, growing
between tide-marks, or upon other Algae.
The filaments are of very simple structure,
the main axes or branches being composed
of single rows of cells(fig. 186) -pig. 186.
as in Cladophora. The repro-
ductive bodies at present
known, ciliated zoospores, are
formed in the cells of the
branches; sometimes in the
terminal cells, producing the
siliquose or elliptical (fig. 186)
sporanges, and sometimes in
interstitial cells, beyond which
the branch is prolonged into
a fine filament. In E. si-
liculosus the extremities of
the branches are converted
into sporanges ; the cell-con-
tents first divide into a number Portion of a fila.
of layers, while the part of ment bearing la-
the filament containing these teraieUipticaispo-
s wells up and acquires the Ma^! 50 diams.

pod-like form; the layers of contents are
then resolved into lines of zoospores
piled regularly one above another. The
summit of the pod finally bursts, and the
zoospores escape. The empty sporange
exhibits fine transverse striae, as if delicate
septa existed between the layers of zoospores.
In E. litoralis, Harv. (E. firmus, Ag.) the
fertile cells are not terminal, but interstitial,
and form beaded rows surmounted by a hair-
like prolongation of the branch; the zoo-
spores escape by a lateral pore. The germi-
nation of these zoospores has been observed
by Thuret. Sixteen British species are de-
scribed by Harvey, some of which are com-
mon, particularly the two above mentioned.

BIBL. Harvey, Brit. Mar. Ala. 68. pi. 9c;
Phyc. Brit. pi. 162. 197, &c. ; English Bo-
tany, pi. 2290. 2319, &c.; Thuret, Ann. des
Sc. nat. 3 ser. xiv. p. 234. pi. 24. figs. 1-7;
Agardh, Ann. des Sc. nat. 2 ser. vi. p. 197 ;
Crouan, ibid. xii. p. 248. pi. 5.

EEL (Anguilla}. — It is popularly believed
that the eel has no scales. They are, how-
ever, present, but immersed in the skin; and
their structure is curious (SCALES of FISH).
The dried skin of the Eel, mounted in Ca-
nada balsam, exhibits well the scales, covered
by the epidermis, and the beautiful layer of
stellate pigment-cells.

BIBL. Yarrell, Brit. Fishes, ii.

EELS, in paste (ANGUILLULA GLUTI-

NIS).

EELS, in vinegar (ANGUILLULA ACETI).

EGGS. — Theminute ova of certain animals
have always been favourite microscopic objects
on account of their curious forms, the beau-
tiful structure of their outer chitinous enve-
lope, their varied colours, and the singular
lids with which some of them are furnished.
The most interesting are those of insects;
among them we may mention the brown
eggs of the puss-moth, Cerura vinula (PL 31.
fig. 19); of the large cabbage-butterfly, Pon-
tiabrassicce (PI. 31. fig. 32), or the small
cabbage-butterfly, Pontia rapas (PI. 31. fig.
21); of the small tortoise-shell butterfly, Va-
nessa urticfB ; the angle-shades moth, Noctua
or Phlogophora meticulosa ; the common
meadow brown butterfly, Hipparchia Janira-,
the brimstone-moth, Rumia Cratccgata ; the
water-scorpion, Nepa ranatra ; the common
cow-dung-fly, Scatophaga stercoraria ; the
bug, Cimex 'lectularius (PI. 31. fig. 20), &c.

Their surfaces exhibit markings of the
most varied forms; spines, tubercles, pits or
processes, sometimes of considerable length
(PI. 16. figs. 22, 23), often arranged with

ELACHISTEA.

[ 221 ]

ELAPHOMYCES.

great symmetry, and frequently closely re-
sembling the cellular structure of plants in
appearance. Sometimes very delicate angular
spaces are mapped out upon them, the inter-
spaces being most minutely dotted, as in the
eggs of the common blow-fly, Musca vomi-
toria (PI. 27. fig. 35).

It is a general fact, exemplified in both
the animal and vegetable kingdom, that
unicellular, or the corresponding stages or
phases of the higher organisms, exhibit some
kind of markings upon their external mem-
brane or wall ; as is seen in the cells of the
Desmidiacese, the Diatomacere, the eggs of
animals,, the seeds of plants (PL 31. figs. 14
to 19).

At certain seasons of the year, the eggs of
aquatic animals are provided with a very
thick horny coat, as in the Entomostraca,
Hydra, &c. These have been called winter-
ova, from the notion that here was a defence
against a low temperature ; they correspond
to the resting-spores or resting-stages of the
Infusoria and Algae, some of which were
formerly included in the animal kingdom.
The formation of this coat can scarcely have
any relation to temperature, either from its
structure, or from its requirement in an or-
ganism which has no heat to retain. Its
presence would be perfectly intelligible,
however, as a means of protection from eva-
poration, when the pools become dry; and
for this purpose its structure is well adapted.
It might also afford a protection against the
attacks of predatory animals, many of which
could easily devour an ovarian ovum, while
they could not break through the horny
cases of the winter ova ; and these winter
ova are only formed when the ova are not
to be hatched soon after extrusion from the
parent. The ova of those animals, which
are never hatched immediately after leaving
the parent, have always a coat corresponding
to that of the winter ova.

The structure and development of eggs
are considered under OVA; see also SHELL.
BIBL. See OVA.

ELACHISTEA, Fries.— A genus of My-
rionemacea3 (Fucoid Alga). Minute epi-
phytic sea-weeds, consisting of a dense tuft
of simple, articulated, olivaceous filaments,
from a common tubercular base composed
of a closely combined mass of dichotomously
branched filaments, growing upon larger
Fucoids, such as Fucus, Himanthalia, Cysto-
seira, &c. The fructification is borne in two
forms : oosporanges (spores, Harvey), and
trichosporanges (paranemata, Harvey). The

oosporanges are formed of metamorphosed
terminal cells at the ends of the dichotomous
filaments ; they are long ovoid sacs, the con-
tents of which are ultimately converted into
a vast number of zoospores. The tricho-
sporanges arise in exactly the same place
and way, but take the form pf long, slender,
articulated filaments, in the joints of which
similar but smaller zoospores are developed.
Both forms of fructification nestle on the
surface of the tubercle of the frond, at the
base of the long simple filaments. The zoo-
spores of both kinds of fruit germinate, and
these occur together in some cases (E. at-
tenuata), in others at different seasons of the
year. Harvey describes seven British spe-
cies ; the tufts of some are half an inch long,
of others less than a line.

BIBL. Harvey, Brit. Mar. Alg. p. 49. pi.
10 F; Phyc. Brit. pi. 240. 260, 261, &c. ;
Dillw. Conferva, pi. 66, &c. ; Thuret, Ann.
des Sc. nat. 3 ser. xiv. p. 236. pi. 25. figs.
1-4.

EL^EAGNACE^E.— A family of Dicoty-
ledons, the leaves of which are usually co-
vered with a kind of scurf formed of very
elegant microscopic scales. See HAIRS and
HIPPOPHAE.

ELAPHOMYCES, Nees.— A genus of
Tuberacei (Ascomycetous Fungi), consisting
of subterraneous truffle-like plants, with a

Fig. 187.

Fig. 188.

Fig. 187. Elaphomyces hirtus. Section, nat. size.

Fig. 188. E.variegatus. Filaments of capillitium, with
asci containing spores; and also loose spores which have
escaped. Magnified 300 diameters.

ELASTIC LIGAMENTS. [ 222 ]

ELASTIC TISSUE.

warty or hairy rind, not bursting sponta-
neously, but divided into little chambers
internally by intersecting plates of sporife-
rous tissue. The spores are formed in sacs
(asci) (fig. 188), from four to eight in each,
arising from branched, anastomosing fila-
ments (capillitium). Two species are de-
scribed in the British Flora, — E. granulatus,
growing in heathy ground, and E. muricatus,
Fr. (E. variegatus, Vitt., Tulasne), attached
to the rootlets of beeches. L. and C. Tulasne
have carefully analysed this genus.

BIBL. Berk, in Brit. Flora, ii. pt. 2. p.
306 ; Ann. Nat. Hist. vi. p. 430. pi. 1 1. fig. 10;
L. R. and C. Tulasne, Ann. des Sc, nat.
2 ser. xvi. p. 5. pi. 1-4 ; Mon. Hypog. Fungi,
Paris, 1850; Vittadini, Monog. Tuber. App.
p. 66, &c. pi. 3 & 4.

ELASTIC LIGAMENTS. — These are
Fig. 189.

Transverse section of the ligamentum nuchse of an ox,
after treatment with solution of caustic soda : a, areolar
tissue, appearing transparent ; b, section of elastic fibres.
Magnified 350 diameters.

Fig. 190.

Elastic fibres : a, from a human ligamentum subflavum,
with intervening areolar tissue, b. Magnified 450 diams.

yellowish, strong bands, consisting of elastic
or yellow fibrous tissue, with a small quan-
tity of areolar tissue. They are met with as
conuecting the arches of the vertebrae (liga-
menta subflava) in the stylo-hyoid and in-
ternal lateral ligaments of the jaw, and the
ligamentum nuchae, or ' paxy-waxy of ani-
mals.' They contain but few vessels, and
no nerves. The elastic fibres (fig. 190) are
from 1-7500 to 1-3500" in breadth, slightly
flattened (fig. 189), mixed with still finer and
some coarser elastic fibres, forming a dense
network, taking a general direction parallel
to the long axis of the spine. Between these
fibres are loose undulating bundles of areolar
tissue, running parallel to the elastic fibres.

BIBL. Kolliker, Mikrosk. Anat. ii. 306,
and Gewebel. d. Mensch. p. 215.

ELASTIC TISSUE, of animals, or yellow
fibrous tissue, occurs in the ligamenta sub-
flava of the vertebrae ; the thyro-hyoid and
cricoid membranes ; the vocal chords ; the
trachea, forming the longitudinal elastic
bands of that tube and its branches; the
internal lateral ligament of the jaw; the
stylo-hyoid ligament; the transversalis fascia
of the abdomen ; the blood-vessels, and
almost everywhere mixed with the fibres of
areolar tissue.

It differs from white fibrous tissue in its
elasticity and its yellow colour.

Its elementary form is that of round or
flattened fibres, varying in size from an

Fig. 191.

Fig. 192.

Fig. 191. Network of elastic tissue, from the middle
coat of the pulmonary artery of the horse. Magnified
350 diameters.

Fig. 192. Network of fine elastic fibres from the perito-
neum of a child. Magnified 350 diameters ,

almost immeasurable breadth to that of

ELASTIC TISSUE.

[ 223 ]

ELATERS.

1-2200" or even more ; the lines have been
termed nuclear-fibres by the Germans ; they
are either isolated, arranged in bundles, or
branching and anastomosing (fig. 192) ;
sometimes undulating or spiral, at others
nearly straight. When broken, they curl
up, the ends appearing abrupt or truncated.
They are highly refractive, their edges
appearing dark, well-defined, and mostly
smooth, but sometimes toothed or serrated.
Sometimes . they exhibit transverse cracks
upon the surface.

They are easily distinguishable from fibres
of areolar tissue by the use of acetic acid,
which has little or no effect upon them, and
this is also the case with solution of potash.
Sometimes by their anastomoses they form
fibrous networks (fig. 192), or plates perfo-
rated irregularly by holes — fenestrated
membranes (fig. 191). The fibres are also
themselves sometimes transversely perforated
by irregular rounded apertures.

Fig. 193.

Fig. 194.

'

Fig. 193. Formative cells of elastic tissue, from the
tendo-Achilles ; a, of a four months' embryo ; b, of a
seven months' foetus ; some of the cells are free, with one
or two processes, others fused in twos and threes. Magni-
fied 350 diameters.

Fig. 194. Stellate formative cells of nuclear fibres, from
the tendo-Achilles of a newly-born infant. Magnified
350 diameters.

The chemical composition of elastic tissue

has not been accurately determined; it
appears rather referable to the proteine than
the gelatine group of compounds. It is
coloured red by Millon's test, but not by
that of Pettenkofer; it does not yield
gelatine by boiling.

Elastic tissue is developed from cells. In
all parts of embryos where elastic tissue
occurs, peculiar fusiform or stellate cells
(fig. 193 a) with acute ends or processes are
met with, by the fusion of which (figs. 193 b
& 194), long fibres or networks are formed, in
which the spots corresponding to the cells at
first form dilatations with elongated nuclei.
The fibres frequently remain in this condi-
tion, forming a modification of the so-called
nuclear-fibres ; or all traces of the original
composition vanish, uniform fibres or net-
works alone remaining. There is, however,
still some difference of opinion among phy-
siologists as to the development of elastic, as
well as of areolar tissue.

Elastic tissue occurs in the same situations
in all classes of the Vertebrata as in man,
also in some special localities, as in the
ligaments of the claws of the cat, the folds
of the wing-membrane, and the pulmonary
sacs of birds. In the Invertebrata, this
tissue appears to occur but rarely, and it is
uncertain whether the elastic ligaments
existing in them, e.g. those of the mollusca,
agree anatomically and chemically with the
elastic tissue of the higher animals or not.

BIBL. Kolliker, Gewebelehre d. Mensch.
p. 45 (and the BIBL. of that article); see also
CHEMISTRY.

ELATERS.— This name is applied to two
forms of structure occurring in the higher
Cryptogamous Plants. The elliptical spores
of the Equisetaceae are furnished with what
are called elaters, viz. four elastic filaments,
attached about the middle of one side, which
are coiled once or twice round the spore before
it is discharged from the capsule, in the po-
sition where they were originally developed;
but when the spore is discharged, they un-
coil with elasticity, causing the spore to be
jerked away. They appear to be produced
by the outer coat of the spore splitting in
spiral fissures, and separating in ribands from
the inner coat. See EQUISETACEAE.

The elaters of the Liverworts orHepaticacea3
are of different nature ; they consist of more
or less elongated delicate membranous tubes,
which are closed cells, inside which one or
more elastic spiral fibres are coiled up. They
occur mixed with the spores in the capsules
of the Jungermanniese, sometimes attached

ELDER.

[ 224 ]

to the valves ; they here mostly present the
appearance of cylindrical cellulose tubes,
closed at the ends, with a flat spiral band
coiled in an open spiral, adherent to the cell-
membrane forming the wall (PI. 32. fig. 38).
The elaters found among the spores of Mar-
chantia polymorpha (PI. 32. figs. 36,37) are
very long, and contain a double coil, the
ends of the two fibres coalescing into a loop
at each extremity (PL 32. fig. 37 b) ; so that
the entire fibre may be compared to a piece
of string with its ends united, and laid out
so as to represent two cords, side by side,
which are then twisted spirally round one
another. In TARGIONIA the tubes are
sometimes branched. The spiral fibres have
been stated by some authors to originate
from the gradual accumulation of granules
in a spiral line upon the primary cell-wall ;
but this is erroneous ; their development is
similar to that of the spiral fibres of vessels.
See HEPATICACE^E,

Structures apparently analogous to these
elaters of the Hepaticaceae occur in some of
the Myxogastrous Fungi, as in TRICHIA
(PL 32. fig. 39 a), while in other genera of
this family filamentous bodies, either plain or
obscurely marked, occur. In Batarrea, also,
one of the Puff-balls, a kind of elater, exists
accompanying the spores (see TRICHOGAS-
TRES). It has been stated by Schleiden
and Schacht that the elaters of these
Fungi are solid filaments with spiral ridges
upon them, or else flat solid ribands twisted
on their longitudinal axis. This statement
is at variance with our observations, and is
not borne out by the drawings given by these
authors themselves. Mr. Currie, while also
contesting Schleiden' s view, states that the
spiral line is a ridge outside a tube, a condi-
tion of things unlike anything else we are
acquainted with in vegetables.

The elaters of Trichia require a very high
power for their elucidation, an eighth or
twelfth, with a high eye-piece, and a good
light ; they may then be seen to consist of
tubes with spiral fibrous secondary deposits
upon the inside of their walls (PL 32. fig. 40).
See SPIRAL STRUCTURES.

BIBL. See under EQUISETACE^, MAR-
CHANTIA, TRICHIA, SPIRAL STRUCTURES.
ELDER. — Sambucus niger, the common
Elder-tree (Caprifoliaceae, Dicotyledons), is
remarkable for the great development of its
pith ; sections of this furnish very accessible
and convenient illustrations of vegetable
parenchyma. This pith is also used by
microscopists for cleaning their object-

ELYTRA.

it is extracted from the branches in
suitable lengths, dried and carefullypreserved
from dust. The face of the objective is
polished with the end of one of these cylin-
ders of pith, and a fresh surface is obtained
every time it is used, by cutting off a thin
slice with a clean razor. By this means all
danger of scratching the lenses is avoided.

ELYTRA.— The horny anterior pair of
wiugs of the Coleoptera ; sometimes called
wing-covers or wing-cases, because they
cover and protect the subjacent pair of wings
of these insects, when not in use.

The elytra may be regarded as consisting
of an elongated, depressed fold of the inte-
gument, comparable to the web between the
fingers, or that of the bat's wing. Four
structures are distinguishable in them : — 1, an
outer, firmly adherent, epidermic layer, com-
posed of minute cells, frequently undistin-
guishable, or at least only to be detected in
parts; this layer is continued around the
margins of the elytra, so as to cover their
inferior surface also, forming, 2, the inner epi-
dermic layer, in which the cells are statedtobe
less distinct, more rounded, and more closely
placed than those in the upper layer, hence
presenting a more distinctly angular form;
this layer is easily detached from the elytra,
and its surface next the body of the insect
is frequently furnished with a number of
very minute hairs, or spiniform papillae
directed backwards (PL 2?. fig. 2). Beneath
the outer epidermic layer is 3, a layer of
dark resinous pigment, whether contained in
cells or not has not been determined. 4. an
intermediate portion, composing the prin-
cipal thickness of the elytrum, representing
the two fused strata of the cutis, and consist-
ing of a number of fibres, running in different
directions, variously interlacing, anastomo-
sing and crossing, so as to form numerous
plates or secondary layers, many of which
present a fenestrated appearance ; as many
as sixteen of these plates have been sepa-
rated.

The veins or nerves of the elytra either
traverse the intermediate thick layer of the
elytra, or run between its under surface and
the inner epidermic layer, to which they
sometimes remain adherent. See INSECTS.
The structure of the elytra can only be
made out by macerating them for a very long
time in solution of caustic potash, or water.
BIBL. Schmidt, Taylor's Scientific Me-
moirs, v. p. 16; Meyer, Muller's Archiv,
1842, p. 12; Nicolet, Ann. des So. nat. 3rd
ser. vii.; and the BIBL. of INSECTS.

EMBRYO.

[ 225 ]

EMBRYO.

EMBRYO, OF PLANTS. — This is the
name applied to the rudimentary plant con-
tained in all true seeds, which are especially
distinguished from spores by this character;
since in all plants reproduced by spores, the
rudiment of the new individual is developed
after the separation of the reproductive
body from the parent plant. Seeds con-
taining embryos are borne exclusively by
Flowering plants ; and while the external con-
ditions under which the seeds are produced
afford the character for the first subdivision
of this province of the Vegetable Kingdom
(ANGIOSPERMS and GYMNOSPERMS), the
structure of the embryo is taken as the most
striking character in further subdividing the
Angiospermous Flowering Plants into their
two great natural groups, viz. Monocotyledons
and Dicotyledons, in which, respectively, the
embryo bears one or two cotyledons or seed-
leaves. In a perfectly developed embryo we
distinguish three parts, the cotyledons, the
plumule or bud, and iheradicleor rudimentary
root : the part at the base of the plumule from
whence the cotyledons and radicle start in
opposite directions is sometimes called the
cauliculus; in a Dicotyledonous embryo
there exist a pair of opposite cotyledons
enclosing the plumule between them, the
whole being seated upon the upper end of
the radicle ; in the Monocotyledons a single
cotyledon is rolled round the plumule (like
the leaf-sheath of a grass round the stem),
and continuous below with the radicle, which
is usually less distinct than in the Dicotyle-
dons. Cases occur both among the Dicoty-
ledons and the Monocotyledons where the
typical structure is departed from. Thus in
Orobanchacese (Dicotyledons) the embryo is
a mere globular mass of cellular tissue, the
result of an arrest of development, the coty-
ledons and radicle never becoming distinct ;
the same is the case in the Orchidaceze
among the Monocotyledons, the embryo not
advancing beyond the state of a globular

Fig. 195.

mass of parenchyma. The relation of such

embryos to the perfect forms is well illustrated
by comparing the stages of growth of
embryos which acquire fully-developed coty-
ledons and radicle (fig. 195). The apparent
anomaly of such cases occurring in the
natural classes characterized by the presence
of one or two cotyledons, is of a kind familiar
to all botanists and zoologists ; no one cha-
racter of a natural group can be regarded as
universal and arbitraiy ; it is the presence of
a majority that decides, and thus the above
plants fall under those classes, from the cha-
racters of their wood, foliage, flowers, &c.,
although their embryos are devoid of coty-
ledons. In Cuscuta, a leafless plant, the
embryo has no distinct cotyledons. Other
anomalies of another kind also occur. Some
Monocotyledons, such as those of Grasses,
have the rudiment of a second cotyledon,
but this is above and not opposite the other
larger one. In Dicotyledons the cotyledons
are not unfrequently unequal, and sometimes
soldered together. In the Coniferse the
embryos appear to have four, eight, or more
cotyledons in different cases, but it is stated
that there exist only two, divided or com-
pound cotyledons (see SEEDS).

Occasionally more than one embryo occurs
in a seed (see POLYEMBRYONY), and in the
Coniferae a number of embryos are at first
produced, of which one only becomes per-
fectly developed (see GYMNOSPERMIA).

The embryo sometimes constitutes the
whole mass of the seed, merely enclosed in
the coats ; in other cases it is imbedded in a
mass of albumen. In the former case the
tissue of the cotyledons often assumes cha-
racters similar to those of the ALBUMEN,
serving as a receptacle for stored nutriment
for the germinating plant, in the form of
fleshy secondary deposits, starch, oil, &c.
The position of the embryo in the albumen,
or the modes in which the embryo is folded
up within the seed-coats, are of great im-
portance in systematic botany, for the charac-
terization of families. Particulars regarding
these points, and the manner of examining
them, are given under the head of SEED.
The development of embryos is described un-
der OVULE. The GERMINATION of embryos
is placed under its separate head. See also OR-
CHIDACE^E, OROBANCHACE.E, CUSCUTA.

BIBL. General works on Structural
Botany ; Brongniart, Ann. des Sc. nat. xii.
p. 14, &c. ; Jussieu, Ann. des Sc. nat. 2 ser.
xi. p. 341; St. Hilaire, Lecons de Botanique,
Ann. des Sc. nat. 2 ser. v. p. 193; Duchartre,
Ann. des Sc. nat. 3 ser. x. p. 207, and the

Q

EMBRYO-SAC.

[ 226 ]

ENCALYPTA.

Bibl. of the articles OVULE, SEED, &c.,
above referred to.

EMBRYO-SAC, OF PLANTS.— A cell
which becomes enlarged into a sac in the
substance of the upper part of the nucleus
of the ovule or rudiment of the seed. In
the cavity of this are developed the germinal
vesicles (PI. 38. figs. 3, 4, 5), one of which
(occasionally more), after fertilization, gives
origin to the EMBRYO. The most common
condition of the embryo -sac is that of a large
cavity excavated in the nucleus, bounded by
its own cell-membrane, and containing abun-
dant protoplasm, and subsequently germinal
vesicles and endosperm-cells (see OVULE).
Not unfrequently, however, it becomes de-
veloped into diverse saccate processes, either
pushing their way through the substance of
the nucleus in variable directions (Scrophu-
lariaceae, &c.), or emerging from the micro-
pyle, coming to meet the pollen- tube (Vis-
cum), or even so much developed externally
that the embryo is formed and perfected
altogether outside the nucleus (S ant alum).
These and other conditions are further de-
scribed under OVULE. When the germinal
vesicle is fertilized, and is undergoing deve-
lopment to produce the embryo, the embryo-
sac often becomes completely filled with
endosperm-cells, at first free, but afterwards
adhering together through their crowded
condition. These may persist and form an
endosperm to the seed, as in Nuphar, where
there is an additional episperm formed out-
side the embryo-sac from the substance of
the nucleus. More frequently, both in albu-
minous and exalbuminous seeds, the endo-
sperm originally existing inside the embryo-
sac becomes absorbed through the pressure
of the growing embryo, and altogether obli-
terated, the embryo gradually filling up the
cavity, and by further expansion obliterating
all trace of the embryo-sac itself. (See AL-
BUMEN, of Seeds.)

In the Coniferse, the embryo-sac, origi-
nally formed by the excessive expansion of
one of the cells near the apex of the nucleus,
becomes subsequently filled up by cellular
tissue, in the upper part of which become
developed the bodies called corpuscula, each
of which possesses a kind of secondary em-
bryo-sac of its own, in which the germinal
vesicles aredeveloped(seeGYMNospERMiA).

The term embryo-sac might also be applied
to the large cell at the base of the archegonia
of the FERNS, LYCOPODIACE.E, MOSSES.
(See under these heads.)

BIBL. See OVULE and GYMNOSPERMIA.

EMYDIUM, Doy ere (Echiniscus, Schultze) .
— A genus of Arachnida, of the order Colo-
poda, and family Tardigrada.

Char. Head furnished with appendages ;
mouth conical, without appendages or ter-
minal sucker ; epidermis semisolid, present-
ing, especially on the upper surface of the
body, an evident annular division.

E. fe*f«cfo(PL4Lfig.7). Reddish-brown;
body ovoid, opake ; snout couica], presenting
traces of division into three rings ; head
indistinctly divided into three segments,
the first and third presenting short setiform
filaments supported upon very short tuber-
cles, the second with a palpiform, blunt, and
flattened appendage ; pharyngeal tube very
slender; styles straight; bulb without an
internal jointed frame- work; eye-spots small,
oval, simple, most visible at the under aspect
of the body ; trunk divided into four simple
rings, with spines and long filaments ; legs
three-jointed, each with large and strong
claws, the posterior pair with a kind of spur
also at the back part of the lower margin of
the second joint; movement excessively
slow; length, from the end of the extended
snout to the posterior border of the fourth
ring, 1-80". Found on the moss covering
tiled roofs ; common.

E. spinulosum \

E.granulatumj ™

BIBL. Doyere, Ann. des Sc. nat. 1840.
xiv. p. 279.

ENCALYPTA, Schreb.— A genus of Ca-

Fig. 196.

Fig. 197.

Encalypta commutata.

Fig. 196. A single plant. Magnified 5 diameters.
Fig. 197. The mouth of the capsule, showing the rudi-
mentary peristome. Magnified 10 diameters.

ENCEPHALARTOS.

[ 227 ]

ENCYONEMA.

lymperaceae (Pottioid Mosses), containing
several British species.

Fig. 198.

Fig. 199.

Encalypta commutata.

Fig. 198. A capsule on its stalk, with vaginule at base,
and calyptra above. Magnified 10 diameters.

Fig. 1QQ. The capsule enclosed in its calyptra. Mag-
nified 20 diameters.

1 . Encalypta vulgaris, Hedw.

2. E. ciliata, Hedw.

3. E. rhabdocarpa, Schwagr.

4. E. streptocarpa, Hedw.

E. commutata (figs. 196-9), Nees and
Hsch., grows on the highest Alps of Europe,
in fissures of rocks bordering the eternal
snow.

ENCEPHALARTOS, Lehm.— A genus
of Cycadaceae (Gymnospermous Flowering
Plants). The Cape species are called Caffre
bread-trees, on account of the quantity of
starch in their trunks. (See CYCADA-
CMM.)

ENCEPHALOID, or ENCEPHALOID
CANCER. — That form of cancer in which the
morbid substance has the appearance and
consistence of the medullary part of the
brain; hence sometimes called medullary
cancer.

See TUMOURS, CANCEROUS.

ENCHELIA, Ehr. — A family of Infu-
soria.

Char. No carapace ; oral and anal orifices
at the opposite ends of the body.

Locomotive organs consisting of cilia; not
detected, however, in two species.

Ehrenberg distinguishes the genera thus :

r Sur-
face
with

Mouth -» fBody i

directly | oral I single / ' '

( cilia i

t ^j no lip J L double . . Dis

ia Mouth obliquely r no neck Trl
L truncate, with lip I a neck Lac

Disoma.

Trichoda.

Lacrymaria.

Mouth
tooth- «
less

Mouth with teeth. ....................... Prorodon.

Dujardin's family Enchelia, founded upon
different characters, bears no relation to that
of Ehrenberg. He defines it as consisting
of animals partly or entirely covered with
cilia, scattered without order ; no mouth :
and subdivides it thus : —

C?ia at one end .............. Acomia.

all over Cilia in a longitudinal furrow . . Gastrochceta.
Cilia all alike ................ Enchelys.

One long straight;
Icilium posteriorly /

.,
Uronem

BIBL. Ehrenb. Infus. p. 298 ; Dujardin,
Infus. p. 380.

ENCHELYS, Hill.— A genus of Infusoria,
of the family Enchelia, Ehr.

Char. Body single, free, without vibratile
cilia on the surface ; mouth without teeth,
ciliated, directly truncated. Aquatic.

E. pupa, E. (PL 23. fig. 48). Body ovate,
turgid, attenuated in front, containing yel-
lowish-green granules ; length 1-144".

E. farcimen. Smaller than the last
(1-432"); internally whitish.

Two other species.

Dujardin's genus Enchelys does not agree
with that of Ehrenberg. The characters
are : body cylindrical, oblong, or ovoid, sur-
rounded with straight, uniform, vibratile
cilia, scattered without order. He admits
five species :— E. nodulosa (PL 23. fig. 49)
= Cyclidium glaucoma, E. (according to
Stein), or Pantotrichum enchelys, E. (accord-
ing to Dujardin) ; E. triquetra (not different
from the last, Stein); and three other im-
perfectly examined species.

BIBL. Ehrenb. Infus. p. 298 ; Dujardin,
Infus. p. 385; Stein, Infus. p. 137.

ENCHONDROMA. See TUMOURS.

ENCYONEMA, Kiitz.— A genus of Dia-
tomaceae.

Char. Frustules resembling those of Cym-
bella, arranged mostly in longitudinal series,
in a simple, delicate, gelatinous tube.

Valves very variable in form, even in the
same tube, showing how little dependence is
to be placed upon this feature as a character.

Q2

ENDICTYA.

[ 228 ]

ENDOSMOSE.

E. paradoxum (PI. 14. fig. 10). Aquatic;
length of frustules 1-1560 to 1-600".

Kiitzing describes two other species, —
E. caspitosum and E. prostratum, — which
are probably varieties only of the above.

The Rev. Mr. Berkeley directs attention to
the rows of eggs of an insect, immersed in
a gelatinous filiform sheath, closely resem-
bling in appearance the filaments of Encyo-
nema, and formerly placed among Diatomacese
by Agardh and Kiitzing, under the name of
Gloionema paradoxum. The action of a red
heat or nitric acid upon the supposed frus-
tules would have detected this error, which
was, however, effected by tracing their de-
velopment into the larva of the insect.

BIBL. Kiitzing, BacilL p. 82, and Sp.Alg.
p. 61; Ralfs, Ann. Nat. Hist. 1845. xvi.
p. Ill; Berkeley, ibid. 1841. vii. p. 449.

ENDICTYA, Ehr. = COSCINODISCUS in
part. E. oceanica = C. oceanicus, K.

ENDOCARPEJE.— A family of Angio-
carpous or closed-fruited Lichens, charac-
terized by closed apothecia imbedded in the
thallus, bursting by a distinct, regular, pro-
minent pore (ostiole).

Synopsis of British Genera.

I. Endocarpon. Thallus crustaceous or
cartilaginous, often lobed or foliaceous, hori-
zontal. Apothecia enclosed in the thallus,
globose; nucleus gelatinous, deliquescing;
thallodal perithecium membranous, pale and
thin ; pore prominent.

II. Sagedia. Thallus somewhat crusta-
ceous, horizontal. Apothecia enclosed within
the thallus, globose; nucleus gelatinous,
deliquescent ; perithecium membranous,
thin, at length becoming black ; pore distinct,
attenuated into a slender neck, dilated at
the apex, perforated.

III. Chiodecton. Thallus crustaceous.
Apothecia wart-shaped, formed of the erum-
pent medullary layer, pulverulent; nuclei
numerous, aggregated and immersed in the
thallodal warts, waxy-gelatinous, supported
on vertical processes or divisions of an opake
blackish-brown torus ; pores somewhat disk-
shaped, distinct, prominent, not perforated.

IV. Pertusaria. Thallus cartilaginous,
membranous, spreading, adnate, uniform.
Apothecia wart-shaped, normally covered by
the cortical layer of the thallus, enclosing
one or many waxy, gelatinous nuclei, enve-
loped by the thin, pale, membranous, thallo-
dal perithecium ; pore depressed, perforated.

V. Thelotrema. Thallus crustaceo-carti-
laginous, spreading, adnate, reniform. Apo-

thecia wart-shaped, formed of the thallus,
at first closed, afterwards margined, with
an open apex, enclosing a deeply sunken
nucleus, ultimately collapsed into a de-
pressed rigid disk, enveloped in a distinct
membranous perithecium, lacero-dehiscent
at the apex.

BIBL. See the genera.

ENDOCARPON, Hedw.— A genus of
Endocarpeae (Angiocarpous Lichens), with a
crustaceous, often lobed or foliaceous thallus,
some of which grow upon bark, others upon
damp rocks. The perithecia or conceptacles
are imbedded, and distinguished externally
merely by a slightly prominent apex, while
spermagonia are likewise produced in the sub-
stance of the thallus, opening by a minute
pore in the surface. The perithecia are lined
with thecae containing spores which readily
germinate when sown. The spermagonia
are lined with jointed sterigmata, bearing at
their summits minute stick-shaped spermatia
(see LICHENS).

Endocarpon is interesting as offering the
most perfect type of the Angiocarpous Li-
chens. Leighton enumerates seventeen
British species, besides numerous varieties.

BIBL. Leighton, Angiocarpous Lichens,
Ray Society, 1851. p. 10. pi. 1-6; Tulasne,
Ann. des Sc. nat. 3 ser. xvii. p. 90. 213.
pi. 10 & 12; Hook. Er. Fl. ii. pt. 1. p. 159;
Schrerer, Enumeratio, p. 230. pi. 9. fig. 2.

ENDOCHROME.— This word is in ge-
neral use among Algologists in this country
and in France, whence it was derived ; and
it is synonymous with the German inhalt or
cell-contents, being applied to the miscella-
neous collection of substances and structures
enclosed in the cavity of a cell, that is to say,
within the cellulose wall. In an Alga, therefore,
like Zygnema for instance, it comprehends
the primordial utricle or layer of protoplasm
lining the cell-wall, together with the chloro-
phyll-globules or vesicles, starch-granules,
nucleus and liquid and granular protoplasm
contained in the cavity of the cell. It is
perhaps a useful word in roughly describing a
species, but is too indefinite to be admissible
in any accurate description of cellular struc-
tures ; moreover, as it is not a definite col-
lection of substances, nor always coloured,
the use of the term cell-contents is to be
preferred in all cases, as not indicating any
positive characters.

ENDOGEN. See MONOCOTYLEDON.

ENDOSMOSE.— This name is applied to
a phsenomenon which takes place when two
different liquids, having an attraction for each

ENDOSPERM.

[ 229 ]

ENTOMOSTRACA.

other, are separated merely by a porous dia-
phragm or an organic membrane. A diffusion
takes place, by which the liquids become
mixed, but one of them flows more rapidly
into the other. Thus when alcohol and water
are so placed, the water flows into the alcohol
(endosmose} much more strongly than the al-
cohol into the water (exosmose). The same
attraction occurs when syrup or a solution of
gum is substituted for the spirit, and also al-
kaline salts. When acids or acid salts are
placed in the same relation to water, the
current is strongest towards the water. Acids
and alkaline solutions exert the strongest
action, neutral substances the weakest. Di-
lute solutions act more efficiently (propor-
tionately) than strong ones. The phenomena
have been attributed to diffusion and to ca-
pillarity, but these are insufficient to explain
them. Graham thinks the osmotic movements
attributable to chemical action. The import-
ance of the effects of endosmose on micro-
scopic objects viewed in liquids, has been
mentioned in the INTRODUCTION (xxxv).
Delicate structures are often advantageously
wetted with dilute solutions of sugar, or bet-
ter, common salt, to prevent the changes
from endosmosis, which result from the use
of pure water.

BIBL. Fischer, Poggend. Annal. Bd. xi.
p. 126 ; Dutrochet, Cycl Anat. and Phys.
ii. p. 98; General Works on Physics, as Buff,
Experimental-Physik ; Pouillet, Siemens de
Physique; PescheVs Physics, &c.; Graham,
Proc. Royal Soc. vii. p. 83.

ENDOSPERM. See ALBUMEN, of Plants.

ENDOSPORE.— The name applied by
some authors to the inner coat of spores.
See SPORE.

ENERTHENEMA, Bowm.— A genus of
Myxogastres (Gasteromycetous Fungi), in-
teresting from the fact that the spores have
been observed in situ; they are produced,
five or six together, in globular sacs (asci)
attached to the free apices of the filaments
of the capillitium, which arise from a disk at
the top of the percurrent stem. E. elegans
was found by Mr. Bowman near Wrexham,
and it has since been found in South Carolina.

BIBL. Bowman, Linn. Trans, xvi, p. 151.
pi. 16; Berk, and Broome, Ann. Nat. Hist.
2 ser. v. p. 366. pi. 11. fig. 7-

ENTEROBRYUS, Leidy.— A supposed
genus of Kiitzing's Leptomiteae, probably
the mycelium of some fungus, found in the
intestines of insects.

ECCRINA, Leidy, is another of these forms.

BIBL. Leidy, Proc. Nat. Hist. Soc. Phi-

ladelphia, 1849. p. 225, Ann. Nat. Hist.
2 ser. v. p. 72 ; Robin, Vegetaux Parasites,
ed. 2. 1853. p. 395. pi. 4. figs. 5, 6.

ENTEROMORPHA, Link.— A genus of
Ulvacese (Confervoid Algae), consisting of
aquatic and marine plants, with branched,
tubular, green fronds, the walls of the tubes
being composed of a single flat layer of poly-
gonal cells. These plants are reproduced by
ciliated zoospores, formed in considerable
numbers from the transformed contents of
the cells (PL 5. fig. 4). In this genus Thu-
ret states that two forms of zoospores occur;
one large and four- ciliated, the other in
fronds with a yellower tint, smaller, and
with two cilia ; both kinds germinate. The
zoospores escape from the cells by a pore on
the outer surface (PI. 5. fig. 4 a), near the
centre of the cells, and the latter persist for
some time in an empty condition. The
marine forms, of which nine species are
described by Harvey, are mostly from 1-2'"
to several lines in diameter, but many inches
long. E. Grevillei, Thuret ( Ulva Lactuca,
Grev., Harv.), however, is thicker and sac-
cate, finally bursting. E. intestinalis, which
grows both in the sea and in brackish and
freshwater ditches, often attains a length of
2 feet and more, and varies in thickness from
1"' to 2-3''.

BIBL. Harvey, Brit. Mar. Ala. p. 213.
pi. 25 D, Phyc. Brit. pi. 63. 262. 282, &c. ;
Greville, Alg. Brit. p. 179-82, Sc. Crypt. Fl.
t. 313, Eng.Bot. 2137 & 2328 ; Thuret, Ann.
des Sc. nat. 3 ser. xiv. 224. pi. 20. fig. 8-12;
Mem. Soc. desSc. nat. de Cherbourg ,ii. (1854).

ENTEROPLEA, Ehr. — A genus of Rota-
toria, of the family Hydatinaea.

Char. Eye-spots none; teeth absent; foot
forked.

E. hydatina (PL 34. fig. 27). Body conical,
hyaline; foot small; aquatic; length 1-120".

Resembles Hydatina senta, but is smaller.

BIBL. Ehrenb. Infus. p. 411.

ENTOMONEIS, Ehr. = Amphiprora, in
part. E. alata = A. alata.

ENTOMOSTRACA.— A division of the
class Crustacea.

Char. Free; aquatic or marine; body
more or less distinctly jointed, mostly con-
tained in a horny, leathery or brittle shell or
carapace, formed of one or more pieces,
sometimes bivalve; branchiae attached either
to the jaws or legs ; legs jointed, and more
or less ciliated ; development accompanied
by a regular moulting or change of shell,
sometimes amounting to metamorphosis.

Many of the Entomostraca are very com-

ENTOMOSTRACA.

[ 230 ]

ENTOMOSTRAOA.

mon in ponds, pools, and other collections
of water; when examined with the naked
eye, in a bottle or glass containing the water,
they appear as minute specks, generally in
active and often jerking motion.

The shell is often beautifully transparent,
sometimes spotted with pigment ; it consists
of chitine impregnated with a variable amount
of carbonate of lime, which is sometimes so
great as to render it brittle, and to cause
copious effervescence on the addition of a
dilute acid ; and when boiled it turns red,
just like the shell of a lobster. It varies in
structure, sometimes consisting of two valves,
united at the back, resembling the bivalve
shell of a mussel; at others it is simply
folded at the back so as to appear bivalve,
without really being so ; or it consists of a
number of rings or segments. It often pre-
sents a reticular appearance resembling that
of a cell-structure.

The body itself, which is more or less
intimately connected with the shell, is mostly
divided into numerous segments. The head
is furnished with one or two pairs of antennae ;
the superior, — sometimes called also the
anterior, the antenna simply, or the anten-
nules, — are usually smallest, and in some
genera easily overlooked (PI. 15. fig. 28 a) ;
sometimes one or both of them are furnished
in the male with a hinge-joint, allowing con-
siderable flexure, so as to permit of its
grasping the female (PI. 15. fig. 8 a, of male ;
9 a, of female); sometimes they are long,
and provided with a tuft of filaments
(PL 15. figs. 17, 18); at others, they are
simply long, and filiform or setaceous (fig.
38). The inferior pair, — called also anten-
nules, posterior antennae, antennae simply,
rami, or second pair of antennas, — vary in size
and structure like the former ; being some-
times large and branched (fig. 28 b], and
serving to row the animals through the
water, at others resembling legs (fig. 5, \7,
&c.). In some genera they are furnished
with curious appendages, effecting the pur-
pose of the hinge-jointed superior antennae.

The eyes are usually large, the pigment
black or red, and the muscles and the nervous
branches distributed to them from the
cephalic ganglion very distinct.

A labrum or upper lip is often present,
compressed and terminated by a hairy lobe
(fig. 35). Behind this are situated two
mandibles, furnished with either blunt or
pointed teeth, often having a palpus or palp-
like organ (figs. 1 1, 20, 34). Next to these,
come a pair of maxillae, jaws, or foot-jaws

(figs. 12, 36), furnished with spines, hooks
or claws, and sometimes branchiae (fig. 21).
Behind these are a second pair of foot-jaws
(figs. 13, 22). The legs are variable in
number and structure ; they are often fur-
nished with flattened processes, fringed with
beautifully ciliated or plumose filaments
(figs. 30, 31, 32), thus exposing a large
extent of surface to the water, by which
respiration is effected, hence they represent
gills, and are called branchiae or branchial feet;
similar branchiae are often appended to the
foot-jaws ; and they are in constant motion,
even when the animal is at rest.

As the structure and arrangement of these
parts afford characters for distinguishing the
genera, &c., the details are given under their
respective names.

The abdomen is of variable length, jointed,
and often resembles a tail in appearance
(figs. 3,8); sometimes it is bilobed; sometimes
furnished with a kind of spur near the end, for
supporting the ova within the shell. In some
gen era, the external ovaries containing the ova
pass out between two of the abdominal joints,
yet remaining attached, and giving a remark-
able appearance to the animals (figs. 9, 38).
The intestinal canal is usually straight or but
slightly curved, sometimes, however, it is
coiled (fig. 7) ; the Entomostraca are mostly
herbivorous, although some are carnivorous.
The sexes have not been distinguished in all
the Entomostraca, although in some they are
perfectly distinct. It appears also that in
certain of them, reproduction takes place
according to the law of alternation of gene-
rations— females only being producedthrough
several generations, and the males appearing
only at certain seasons.

The spermatozoa are often of most remark-
able structure (see SPERMATOZOA). The
ova are mostly rounded; sometimes they are
covered with spines, and often brilliantly
coloured. They are either hatched in the
external ovaries mentioned above, or in a
space between the body of the parent and
the posterior part of the shell, or they are
deposited in masses upon and glued to water-
plants, and hatched independently of the
parents.

At particular seasons of the year, the ova
in certain species are furnished with thick
capsules, and imbedded in a dark opake sub-
stance, presenting a minutely cellular appear-
ance, and occupying the above-mentioned
interspace between the body of the animaland
the back of the shell (fig. 37 a). This is called
the ephippium, and the ova — ephippial or

ENTOMOSTRACA.

[ 231 ]

ENTOMOSTRACA.

winter-ova; and the envelopes are supposed
to act as a defence from the cold of winter
(EGGS).

When first hatched, the young (fig. 16)
differ very strikingly in form and structure
from the adults (figs. 8, 9).

The larval forms of the higher Crustacea
often bear considerable resemblance to the
perfect Entomostraca.

The minute structure of the Entomostraca
is very difficult to determine ; for although
the body and shell are frequently compara-
tively transparent, the parts are exceedingly
delicate and soft, so that they are easily
crushed and mutilated, and their appearance
distorted.

The Entomostraca are best preserved in
solution of chloride of calcium (see PRESER-
VATION).

Some of the Entomostraca are found fossil.

Systematic arrangement.

Legion 1. Lophyropoda. Branchiae at-
tached to the organs of the mouth; legs
few, not exceeding five pairs, serving for
locomotion, articulations mostly more or less
cylindrical ; antennae two pairs, one pair
used as organs of motion.
Order 1. Ostracoda. Shell consisting of two
valves, entirely enclosing the body; legs
two or three pairs, adapted for progres-
sion ; no external ovary.

Fam. 1. CYPRID^. Superior antennas long,

with numerous joints, and a pencil or

tuft of long filaments; inferior stout

and pediform; eye single; legs two pairs.

Candona, Cypris.

Fam. 2. CYTHERID.E. Superior antenna?
without the pencil of long filaments ;
eye single ; legs three pairs.
Cythere, Cythereis.

Fam. 3. CYPRIDINAD^I. Both pairs of
antenna3 pediform ; eyes two, peduncu-
lated; legs two pairs, one pair always
enclosed within the shell, and of remark-
able structure ; abdomen terminated by
a broad lamellar plate, with strong hooks
and spines.
Cypridina.

Order 2. Copepoda. Shell jointed, forming
a buckler, enclosing the head and thorax ;
legs five pairs, mostly adapted for swim-
ming; ovary external.

Fam. 1. CYCLOPID^E. Head consolidated
with the thorax; foot -jaws two pairs,
generally small; legs five pairs, the

fifth pair rudimentary ; eye single ; both
superior (larger) antennae in the male
furnished with a swollen hinge-joint.

Cyclops, Cant hoc amptus, Arpacticus,
Alteutha.

Fam. 2. DIAPTOMID^E. Head consolidated
with the first joint of thorax; foot-jaws
three pairs, well developed; legs five
pairs, the last pair differing in structure
from the others, and differing from each
other in the two sexes; eye single,
sometimes pedunculated in the male;
right antenna only with the swollen
hinge-joint in the male.

Diaptomus, Anomalocera, Temora.

Fam. 3. CETOCHILID^E. Head consolidated
with first joint of thorax; foot-jaws
three pairs, strongly developed; legs
five pairs ; eyes two ; right antenna
only with the hinge-joint in the male.
Cetochilus.
Provisionally Notodelphys.

Legion 2. BrancMopoda. Branchiae at-
tached to the legs ; legs from four to sixty
pairs.

Order 1. Phyllopoda. Legs from eleven to
sixty pairs in number, joints foliaceous
and branchiform, chiefly adapted for re-
spiration and not motion; eyes two or
three, sometimes pedunculated ; antennae
one or two pairs, neither adapted for
swimming.

Fam. 1. BRANCHIPODIDA. Body not en-
closed in a carapace or shell ; antennae
two pairs, the inferior with prehensile
appendages in the male; legs eleven
pairs.

Artemia, Branchipus.

Fam. 2. ASPIDEPHORA. Body enclosed in
a shell ; antennae one or two pairs ;
legs more than eleven pairs.
Apus, Nebalia.

Order 2. Cladocera. Legs four to six pairs,
chiefly branchial ; eye single and very
large; antennae two pairs, inferior large,
branched and adapted for swimming.
Fam. 1. DAPHNIAD^E. Superior antennae
very small, inferior large, two-branched;
legs five or six pairs, all enclosed within
the carapace ; eye single, large.

Daphnia, Daphnella, Macrothrix,
Moina, Bosmina, Sida.
Fam. 2. POLYPHEMID.E. Inferior antennae
two branched, one branch four-, the
other three-jointed ; lower part of shell
forming a large vacant space for con-

ENTOPHYTES.

[ 232 ]

ENTOSTHODON.

taining the ova and young; eye very
large; legs four pairs, not contained
within the shell.

Fam. 3. LYNCEID^E. Superior antennae
very short ; inferior of moderate size,
branched, each branch three-jointed;
legs five pairs ; eye single, with a black
spot in front; intestine convoluted,
having one complete turn and a half.

Acroperus, Alona, Camptocercus,
Chydorus, Eurycercus, Peracantha,
Pleuroxus.

See CRUSTACEA and SIPHONOSTOMA.
BIBL. Baird, Brit. Entomostr.; M.-Ed-
wards, Hist. nat. d. Crustac. iii. ; Straus,
Mem. d. Mus. d. Hist. nat. 1819. v. p. 380,
and 1821,vii.p.33; Koch, Deutschl. Crustac.;
Desmarest, Cons. Gen. s. I. Crustac. ; Jones,
Entom. of the Cretaceous form. (Palceontogr.
Soc.); Zenker, Miiller's Archiv, 1851,
(Micr. Trans, i. p. 2/3), and the Bibl. of the
genera.

ENTOPHYTES.— A general term applied
to parasitic plants (chiefly Fungi), growing
in the interior of animal or vegetable struc-
tures. See PARASITES, VEGETABLE.

ENTOPLYA, Ehr — A genus of Diato-
maceae.

Char. Frustules prismatic, compressed,
multivalve (?); valves contiguous, in a simple
straight series like the leaves of a book, the
inner ones with a very large median aperture,
the two end valves transversely striated, not
alike, one of them being convex outwards and
entire (not perforated), the other concave,
and with a large pore (?) at each end.

It is stated to approach Achnanihes in the
curved form; in its tabellar form, Tessella,
and that it most nearly agrees with Biblarium.
E. australis (Surirellal austr. K.). Valves
linear, rounded at each end, with more than
forty transverse costa3, traversed by a longi-
tudinal flexuous line; inner plates in the
adult state sixteen, in the young state only
three ; marine, and found in guano ; length
1-240", in the young state 1-720", and with
only six costae between the pores.

(The pores are probably only inflated pro-
ductions of the valves, like those of Biddul-
phia; and the plates are perhaps only hoops;
they are not valves, because the holes in
them are continuous, so that there is but a
single cavity in the frustule.)

BIBL. Ehr. Ber. d. Berl. Akad, 1848. p. 6.
ENTOSELENIA, Ehr.— A genus of La-
gen as.

Char. Shell calcareous, globose or ovate,
sometimes compressed, with a tube arising

rom the orifice and projecting downwards
nto the cavity of the shell.

These elegant organisms are found living,
adherent to marine algae, fuci, &c., and fossil
n sea-sand and mud.

E.globosa(P\. 19; fig. 19 b, longitudinal
section). Shell ovato-globose, smooth, not
compressed ; mouth slightly projecting, ob-
tuse; internal tube patulous at the extre-
mity, and sometimes reaching nearly the
Bottom of the cavity.

Very rare. Shell densely perforated with
very minute foramina; length 1-144".

E. marginata. Shell nearly orbicular,
smooth, compressed, surrounded by a thin
marginal layer; mouth slightly and gradually
produced ; internal tube usually curved ;
length 1-150".

a. lucida. Elongate, pyriform, marginal
lamina thickened, tube mostly straight ;
length 1-80".

E. lineata. Shell ovate, truncate, some-
times with a minute neck ; surface with fine
longitudinal striae; tube straight, nearly
reaching the bottom; dull leaden colour;
length 1-120".

E. squamosa. Shell ovato-globose, neck
minute; surface pitted, pits irregular in
form and arrangement ; tube patulous ;
length 1-127".

a. catenulata (PI. 19. fig. 20). Pits very
small, square or hexagonal, arranged in lon-
gitudinal rows ; length 1-100".

$. scalariformis. Pits as in the last, but
few and large; length 1-115".

y. hexagona (PI. 19. fig. 23). Pits large,
hexagonal, not in distinct longitudinal rows;
length 1-130".

BIBL. Williamson, Ann. Nat. Hist. 1848.
i.p. 1.

ENTOSTHODON, Schwagr.— A genus

Fig. 200.

Entosthodon Templetoni.
Fragment of the peristome. Magnified 100 diameters.

of Funariaceae (Acrocarpous Mosses), inclu-
ding some of the Gymnostoma and Weissice
of authors.

ENTOZOA.

[ 233 ]

ENTOZOA.

1. E. ericetorum, C. Miill. = Gymnosto-
mumfasciculare, Hook, and Tayl.

2. E. Templetoni, Schwagr. = Weissia
Templet oni, Hook, and Tayl.

ENTOZOA.— A class of Animals.
The Entozoa are animals residing para-
sitically, during either the whole, or a part of
then* lives, in the cavities or in the substance
of the organs of other animals; they are
very generally met with throughout the
Animal Kingdom; and they derive their
nourishment from the liquids of those ani-
mals of which they constitute the parasites.
Their form is mostly elongate, and the body
more or less distinctly jointed.

The integument consists of a delicate ho-
mogeneous epidermis, often thrown into
numerous transverse folds ; sometimes also
into longitudinal folds, giving the body a
winged appearance. In some species, it is
furnished with papillae, spines, or horny
reflexed prickles, either scattered over the
greater part of the surface, or confined to the
anterior extremity of the body ; in the latter
case serving as organs of adhesion. Beneath
the epidermis is the cutis, intimately fused
with, or almost entirely consisting of layers
of transverse, longitudinal and oblique flat-
tened fusiform muscular fibres, resembling
the organic or un striped muscular fibres
of the Vertebrata.

Beneath, or in the substance of the skin,
in the Cestoid Entozoa, are numerous
minute oval or rounded bodies, containing
carbonate and phosphate of lime ; these are
regarded as forming the rudiments of a cuta-
neous skeleton, and they possess a concentric
laminated structure.

The form and structure of the head and its
appendages, in the shape of hooks, suckers,
&c., are described with the genera and
species, as their form and arrangement are
used as generic characters.

The nervous system of the Entozoa is not
well known. In the cystic or larval forms,
none has been detected. In the Cestoids
and Acanthocephala, it appears to consist of
a single cephalic ganglion, sending off
branches to the proboscis. In the Trema-
toda, of two cesophageal ganglia, connected
by a transverse chord, and sending off two
lateral branches, which traverse the body
longitudinally. In the Nematoidea, it is
composed of a single longitudinal cord, fur-
nished at its origin and termination with a
ganglion.

Organs of special sense appear to be
absent in the Entozoa, excluding that of

touch, which resides in the various cephalic
appendages. In some, especially in the
ciliated embryonic form, there are red or
black cervical spots,which have been regarded
as eyes ; but they do not appear to contain
any refracting body comparable to a lens.
Helminthologists are not agreed as to the
presence of a digestive, circulating, and
water-vessel system in the Cestoidea and
Acanthocephala ; for certain tubes found in
them are regarded as belonging to each of
these systems by different authors. In most
of the remaining Entozoa, the digestive
apparatus is well developed, the mouth
distinct, the posterior portion of the alimen-
tary tube much ramified, and terminating
either in a caecal extremity or in a distinct
anus. Remarks upon these systems will be
found under the genera.

Propagation. — The Entozoa are propa-
gated by spontaneous division, by gemma-
tion or the formation of gemmae, and by
sexual organs, and they illustrate the law of
alternation of generation.

The spontaneous division, which is always
transverse, differs from that of the Infusoria
and Polypi, in the new individuals produced
not being perfect; a certain number of organs
only being reproduced, as the joints of the
body in the Cestoidea.

The formation of gemmae occurs in the larval
forms of Ttsnia, Ccenurus and Echinococcus.
In those Entozoa which are propagated
by sexes, the individuals are either herma-
phrodite or unisexual. In the Cestoidea the
sexual organs are usually repeated in each
joint, except those near the head. And it
appears that there are two kinds of ovaries,
one for the production of the germ (the
germinal vesicle and spot), and the other for
the yolk. In addition to which, there is
mostly a uterus, vagina, testis, penis (or
spiculum), and vesicula seminalis. The ova
are round or oval, often furnished with a
shell, which sometimes has a lid.

The development of the ova of the Entozoa
takes place according to two methods; either
the yolk-mass undergoes the ordinary process
of segmentation, ultimately forming the em-
bryo ; or, large transparent embryonal cells
form in the yolk, the latter not becoming
segmented, but undergoing subdivision and
diminution in size, the growth of the em-
bryonal cells continuing at the expense of
the yolk-mass until it is entirely consumed ;
the entire mass then becomes covered with
a delicate epithelium, which is sometimes
ciliated, and forms the embryo.

ENTOZOA.

[ 234 ]

EPENDYMA.

In numerous instances, after this primary
stage of development — the emhryonal cell
condition — has been attained, the embryo
does not become directly developed into a
form of being resembling the parent, but the
intermediate larval or nurse forms, described
under ALTERNATION OF GENERATION, are
produced from it by a non-sexual process,
and ultimately, forming the last stage of the
metamorphosis, beings resembling the parent
and furnished with sexual organs are pro-
duced. The discovery of the alternation of
generation has brought to light the fact that
many of the supposed species of Entozoa
are only the larval or nurse forms of the
true species ; and that many of these forms
only complete their stages of metamorphosis
when placed under particular circumstances.

The following arrangement may serve as
an index to the articles upon the Entozoa,
contained in this work : —

Order 1. Sterelmintha. Alimentary canal
often absent, or not distinct; when present,
with a single orifice only, and branched.

Fam. 1. CESTOIDEA (tape-worms). Body
strap-shaped, distinctly or indistinctly
divided into transverse joints; male and
female organs in each joint; alimentary
canal doubtful or indistinct.
Bothriocephalus, Tcenia.
(Cystica) Nurse or larval forms of
Cestoidea.

Fam. 2. TREMATODA. Body mostly flat-
tened ; alimentary canal distinct,
branched ; male and female organs in
each individual.

Amphistoma, Diplozoon (Diporpa),
Distoma.

Fam. 3. ACANTHOCEPHALA. Body flatten-
ed, transversely wrinkled, becoming
cylindrically distended by the imbibition
of water; sexual organs in separate
individuals.

(Echinorhynchus.}

Fam. 4. GORDIACEA (hair-worms). Body
filamentous,cylindrical, alimentary canal
present ; sexes separate.

Gordius, Mermis.

Fam. 5. PROTOZOIDEA or GREGARINIDA.
Probably larval states of some other
organisms.
Gregarina.

Order 2. Ccelelmintha. Alimentary canal
present, distinct, simple, with two orifices.

Fam. 1. NEMATOIDEA (round worms).

Body cylindrical, hollow; sexes sepa-
rate.

Anguillula, Tricocephalus, Filaria,
Ascaris (Oxyurus), ? Trichina.

See ACEPHALOCYSTS.

BIBL. Siebold, Vergleich Anat. Ill, and
Ann. d. Sc. nat. 3rd ser. Zool. xxvi. p. 376 ;
Rudolphi, Entozoor. Hist, nat., and Entoz.
Synops. ; Dujardin, Hist. nat. d. Helminth. ;
Cloquet, Anat. d. vers Intest. ; Wedl, Grundz.
d. Path. Anat.; Bremser, Icones Helminth.;
Owen, Todd's Cycl ii. Ill; Blanchard, Ann.
d. Sc. nat. 3rd ser. Zool. vii. viii. x. xi. xii.;
Vogt, Ann. Nat. Hist. 2nd ser. ix. 437 ;
Beneden, Les vers Cestoides, 1850 ; id.
Ann. d. Sc. nat. 1851. 3rd ser. xvii. 23
(Trematoda) ; id. Prize Essay (not yet
published), abstract in Cosmos, iv. 267 and
382 ; ibid. Kuchenmeister ; Siebold and
Bilharz, Sieb. and Kollik.'s Zeits. iv.; Crep-
lin and Gurlt, Wiegmann's Archiv, 1845-
1851; V.d. Hoeven, Handb. d. Zool.i. 154.

EOSPHORA, Ehr.— A genus of Rotatoria,
of the family Hydatmgea.

Char. Eyes three, sessile, two frontal, one
cervical ; foot forked. Aquatic.

There are three species.

E. digitata (PL 34. figs. 28 ; 29, teeth).
Body conical, hyaline, not auricled, toes
one-third of the foot in length. Length 1 -96".

BIBL. Ehr. In/us, p. 451.

EPEIRA, Walck.— A genus of Arachnida,
of the order Araneidea.

E. diadema (the common autumnal
garden- spider) forms a favourable object
for the examination of the various structural
peculiarities of spiders ; as the integument
(PI. 2. fig. 4) ; the legs, with their hairs and
claws (figs. 8, a, b,) ; the toothed hairs at
the end of the feet (fig. 8) show very clearly
the transition from the hairs to the claws ;
in fact, that the latter are mere modifications
of the former ; also the lung-plates (figs. 9,
9 b) ; the spinnerets, the web (fig. 11), &c.

BIBL. Walckenaer, Hist. nat. d. Apteres;
Cuvier, new dateless edition; Brandt,
Medizin. Zool.; V. d. Hoeven, Handb. d.
Zool. i. 573.

EPENDYMA VENTRICULORUM —
Is the name given to a layer which coats
those portions of the ventricles of the brain
which are not connected with the prolonga-
tions of the pia mater ; as the floor of the
fourth ventricle, the aqueduct of Sylvius,
the floor and the sides of the third ventricle,
the ventricle of the septum lucidum, with the
roof, the anterior and posterior cornua and a

EPHEBE.

[ 235 ]

EPHEMERID.E.

considerable part of the inferior cornua, and
of the lateral ventricles. It consists of a
layer of delicate ciliated epithelium, situated
either immediately upon the cerebral sub-
stance, or upon an intermediate layer of
areolar tissue, or of a soft, homogeneous or
granular mass. The cells are nucleated, and
vary in diameter from 1-960 to 1-490";
they sometimes contain pigment.

The ependyma is considered by many
anatomists as a portion of the arachnoid

Fig. 201.

Magnified 350 diameters.
Corpora amylacea, from the human ependyma.

membrane. Corpora amylacea are often met
with beneath it, as is sometimes also brain-
sand.

BIBL. Kolliker, Mikr. Anat. ii.

EPHEBE, Fr. — A genus of Lichineae
(Gymnocarpous Lichens), usually described
in an imperfect state as species of Stigonema,
a supposed genus of Algae. E. pubescens
has a hairy branched cartilaginous frond,
covering the surface of damp rocks with a
blackish green felt ; the branches are sub-
ulate and the plant is dioecious ; some speci-
mens have the branches swollen into spindle-
shaped receptacles, in which are imbedded
numerous conceptacles, opening by a pore,
lined with clavate thecce, each containing
eight uniseptate spores-, other specimens
bear spherical or subovoid,subapical|?ycrcicfo'a,
in which are immersed spermagonia, dehis-
cing by a pore, containing numerous linear
basidia (sterigmata), supporting very slender
oblong spermatia. The substance of the
branches consists of three layers; the outer-
most, which gives the Lichen its cartilaginous
consistence, is formed of thick and resisting
tissue ; the intermediate layer is formed of
large cells (gonidiat), which are at first
rounded, then angular by compression, red-
dish brown or green, at first in fours, finally
subdividing into groups of cells, which
render the surface of the branches tubercular.
These groups in perfect examples form
transverse bands, separated from each other
by tissue of a lighter colour, in the substance
of the larger branches; in the young branches
they are piled one above another, without

any separating tissue. The third layer is
the medullary, which fills up the centre of
the branches ; it is in this that the concep-
tacles and spermagonia are developed. Two
supposed species of Stigonema, Ag. (atro-
virens and mammillosum), have been found
in fruit as perfect Ephebes, by Mr. Thwaites ;
it is not stated whether they are distinct
species. Fries speaks of E. pubescens and
E. mammillosum. According to Flotow,
forms of this Lichen have been described
under many names by Kiitzing and others.
It is the Collema pubescens of Schserer's
Enumer., Cornicularia pubescens of Acharius.

See STIGONEMA.

BIBL. Bornet, Ann. des Sc. nat. 3 ser.
xviii. p. 155. pi. 7; Berk, and Br. Ann. Nat.
Hist. 2 ser. vii. p. 188 ; Von Flotow, Bot.
Zeit. viii. p. 73 (1850) ; Fries, Summa Veg.
122. A long enumeration of authors is given
by Bornet.

EPHEDRA, L— A genus of Gnetaceae
(Gymnospermous Flowering Plants), remark-
able for the jointed character of the stems,
the peculiar character of the wood, and
other points of structure.

See GNETACE.E and WOOD.

EPHEMERA, Linn. — A genus of Neu-
ropterous Insects, of the family Ephemeridae.

Char. Wings four; posterior filaments
three ; head of larva with cornua.

The larva and pupa are favourite micro-
scopic objects, for showing the dorsal vessel,
the circulation, branchial plates, &c. See
EPHEMERID.E.

EPHEMERE^E.— A family of inopercu-
late Acrocarpous (terminal-fruited) Mosses,
usually dwarf, caespitose or gregarious. Stem
almost simple. Leaves more or less oval or
lanceolate, slightly concave, pellucid, with or
without nerves. Cells of the leaves paren-
chymatous, lax in all parts, elongate, not
papillose. Capsule mostly obliquely apicu-
lated.

British Genus.

I. EPHEMERUM. Calyptra campanulate.
Inflorescence monoecious or direcious (anthe-
ridia on a very short special branch situated
near the base of the stem).

EPHEMERID.E (Mayflies),— A family
of Neuropterous Insects.

Characterized by the minute size of the
antennae ; the unequal size of the anterior
and posterior pairs of wings ; the membra-
nous and almost obsolete mouth ; and the
elongated jointed setae at the posterior end
of the bodv.

EPHEMERID.E.

[ 236 ]

EPIDERMIS.

Body long, slender, and soft ; head small,
transverse-trigonate, eyes large, nearly oval,

Fig. 202.

Ephemera Swammerdamii. Nat. size.

lateral; ocelli three, forming a triangle
between the eyes; antennae three-jointed,
the two basal joints thick, the third forming
a long slender seta. Abdomen consisting of
nine joints ; the terminal the longest, and
gradually narrowed and furnished at the apex
in both sexes with two or three long, slender,
many -jointed filaments. Legs slender; an-
terior pair in the males porrected, much
elongated, with the tibia3 and tarsi appearing
soldered together; basal tarsal joint very
minute, tarsi five-jointed, terminated in the
forelegs of the male by two oval pulvilli ; in
the four posterior legs tarsi short, five-jointed,
and terminated by a large oval pulvillus, and
a single broad notched claw.

These insects must have been seen by
every one, rising and falling on the wing,
near the banks of rivers and pools ; in the
perfect state, their life lasts but a few hours,
whence the name. The ova are deposited
in the water. The larva bears a considerable
resemblance to the pupa, from which it
differs in the absence of rudimentary wing
covers; they are frequently mistaken for
each other.

The pupa of the common Ephemera (vul-
gata] (PL 28. fig. 15) has the prothorax as
broad as the head, transverse-quadrate ; the
mesothorax gibbous ; the head rather small,
with two short horns in front, and two horny
toothed mandibles, furnished at their upper
angles with a long curved horn; labrum
flat, membranous, ciliated, and with the
angles rounded; maxillae small, membra-
nous, curved, pointed at the tip, and inter-
nally setose; maxillary palpi four-jointed,
and not extending beyond the front of the
head; labium large, membranous, four-lobed,
and furnished with a broad tongue ; labial
palpi broad and three-jointed; antenna
about twice the length of the head, many-
jointed and ciliated ; legs short, broad, and
much compressed ; tarsi two-jointed, with a
terminal hook; abdomen nine-jointed, the

six basal segments being furnished on each
side with a pair of elongated, rather narrow
gills or branchial plates (a),
with long, narrow filaments at
their edges, through each of
which a trachea extends to the
tip ; the tracheae from each con-
tiguous pair of filaments uniting
near the base, and then running
to the large tube which traverses
the centre of each plate ; there
are in all twenty-four branchial
plates. At the end of the abdo-
men are three elegantly feathery setae.

The larvae and pupae of the Ephemeridae
may be most easily caught in the ring-net ;
they are perhaps best preserved in glycerine,
or solution of chloride of calcium.

BIBL. Westwood, Introduction, fyc. ;
Pictet, Hist. nat. d. Ins. Neuropt., 2nd
monogr.fam. d. Ephem. 1843 ; Curtis, Brit.
Entom. 708.

EPHEMERUM, Harape.— A genus of
Ephemerese (Acrocarpous Mosses), including
part of Phascum of authors.

1. Ephemerum serratum, Hmp. = Phas-
cum serratum, Schreb.

2. Eph< crassinervium, C. Miill. = Ph.
crassinervium, Schwagr.

3. Eph. patens, limp. =.Ph. patens, IcLe&w.
EPHIPPIA.— The winter-ova of the En-

tomostraca. See EGGS and ENTOMOS-

TRACA.

BIBL. Baird, Brit. Entomostr. p. 84.

EPIBLEMA. See the EPIDERMIS, of
Plants.

EPICOCCUM, Lk.— A genus of Stilbacei
(Hyphomycetous Fungi), parasitic upon dead
leaves, &c., consisting of very minute, grega-
rious tubercles, somewhat linearly arranged,
reddish or purplish, containing numerous
spherical, smooth or roughish, reticulate
spores. E. negkctum is adnate to a short
pedicel. When mature the stroma is quite
covered with spores about 1-2000" in dia-
meter. Uredo Equiseti, Br. Flora, is au
Epicoccum with smooth spores.

BIBL. Desmaz. Ann. des Sc. nat. 2 ser.
xvii. p. 95 ; Berk, and Broome, Ann. Nat.
Hist. 2 ser. v. p. 466 ; Fries, Summa Veg.
p. 476.

EPIDERMIS, OF ANIMALS. See SKIN.

EPIDERMIS, OF PLANTS.— There are
few parts of the structure of vegetables that
have given rise to more discussion than the
epidermal cells and the tissue they constitute.
Even the term epidermis has become to a
certain extent equivocal, since it is used by

EPIDERMIS.

[ 237 ]

EPIDERMIS.

some authors in the sense in which cuticle is
used by others, and vice versa. Our limits
prevent us from entering far upon the dis-
cussions, and our object here, therefore, will
be to state as briefly as possible the most
remarkable facts, and the explanations which
are received by the best authorities.

If we gently scrape up the surface of the
leaf of a hyacinth, or other soft-leaved
bulbous plant, and seize a little piece of the
ragged edge with a pair of fine forceps, we
may strip off large pieces of what appears to
the naked eye to be a thin homogeneous
pellicle. When this is placed under the micro-
scope, it is found to be composed of a layer
of cells united firmly together by their sides,
like stones in a pavement, but loosely con-
nected with the subjacent tissue, which
adheres here and there to the detached strip
in ragged patches. The firm continuous
layer of cells is what botanists call the epi-
dermis of plants. Such a layer of cells
clothes the entire surface of the higher
plants., from the Flowering plants down to
those in which the organs, such as the leaves,
are reduced to mere layers of cells like the
epidermis itself, as in the Mosses. In a very
young and delicate state, such as we find it
clothing the surface of organs still concealed
in buds, or of young ovules in the ovary, it
has been called epiblema (Schleiden). A
rather more solid form, but still soft and
devoid of thickening layers, such as exists
on the surface of the growing parts of root-
lets, &c., is called epithelium (Schleiden) ;
both these terms appear useless, and only
calculated to confuse the student still more
than the use of the words epidermis and
cuticle, which already endanger misconcep-
tion from the very different characters of the
structures called by those names in animal
organs.

When a layer of epidermis is macerated in
nitric acid, a thin pellicle, destitute of
cellular structure, becomes detached in sheets

Fig. 203.

Cuticle of a cabbage-leaf, removed by the action of nitric acid

p, hairs ; f, orifices corresponding to stomates.

Magnified 250 diameters.

from the outer surface of the plate of epi-
dermal cells ; this is the cuticle (fig. 203), of
botanical anatomists, concerning which much
misconception has prevailed. As epidermis
advances in age it becomes considerably soli-
dified, especially on evergreen leaves, and on
shoots of shrubs, &c. which remain green
for a lengthened period, such as Aucuba and
Viscum. In most cases, however, the epider-
mis of structures belonging to the stem dis-
appears about the same time as the leaves
fall off, and is replaced by the suberous
layer of the bark structure, which change is
evident externally by the surface assuming a
brown colour, the subjacent tissue containing
chlorophyll being hidden. The green colour
of parts clothed with epidermis depends
upon the subjacent tissue showing through
the transparent epidermis, the cells of which
are always colourless, and filled with watery
contents.

When sections are made perpendicularly to
the surface of any fully developed leaf, but
above all of those of leathery texture, the
walls of the cells next the external surface
are found much thicker than the rest, this
thickening extending more or less down over
the contiguous side-walls. When such sections
are treated with sulphuric acid and iodine, the
greater part of the thickness, from without
inward, of this outer wall, is stained yellow,
while the rest of the walls assume the blue
colour ordinarily taken by cellulose with
these reagents. Some authors suppose that
the whole of this yellow part corresponds to
the cuticle above mentioned, but such is not
the case; if such a section is boiled or
macerated for a long time in solution of
caustic potash, then washed well with water
and treated with tincture of iodine, the thick
upper wall also assumes the blue tint, and,
moreover, a laminated structure becomes
evident in it, showing that it is produced by
the deposition of secondary layers inside the
cell. The true layer of cuticle (which is
dissolved off by the continued action of
potash) is really extremely thin in
almost all cases. The true nature of
this thickening of the outer walls is
well illustrated by the epidermis of
Viscum (Mistletoe), which remains
upon the shoots for many years ; here
several layers of cells subjacent to the
original superficial stratum become
involved in the process of solidifica-
tion, and their cavities completely filled
up by the secondary deposits. The
true structure of the enormously thick

EPIDERMIS.

[ 238 ]

EPIDERMIS.

epidermal layer of old shoots, as brought out
by the action of potash^ is seen in the
example, fig. 26 of PI. 38. The true cuticle
is sometimes of considerable thickness, as in
the leaves of Cycas (PL 38. fig. 28). The
thickening layers of the epidermal cells are
true SECONDARY DEPOSITS ; the nature of
the cuticle is yet uncertain ; some regard it
as a kind of excretion hardened over the
surface, others as the persistent original
outer wall of the parent cells of the epi-
dermal cells, metamorphosed chemically
when exposed directly to the action of the
air (in a manner analogous to that in which
the parent-cell membranes become converted
into a gelatinous investment of the filaments
of Confervae, the cells of Palmellaceae, &c.).
This seems borne out to some extent by the
change of condition of the consolidated part
of the outer walls, coloured yellow by sul-
phuric acid and iodine ; but it is unknown
whether there is here a real chemical change,
or merely an infiltration capable of being
removed by the action of potash (see SECON-
DARY DEPOSITS).

Although the cellular plants possess no
true epidermal layer, the superficial cells
form a kind of cortical structure in the
Lichens and larger Algae, and in the lower
Algae the cells of the filaments, &c. compo-
sing the fronds, bear some resemblance to
epidermal cells in structure, insomuch that
they have a laminated wall (partly produced
by the persistence of those of the parent-cell
after cell- division), with the outer layer pos-
sessing much of the physical characters of
the cuticle of the higher plants. As just
mentioned, the gelatinous sheaths of the
lower Algae must be regarded as a kind of
cuticle, and as produced by gradual disor-
ganization of the outer layers of membrane
while cell-development and the formation of
new layers is going on within. For further
discussion of the nature of the thickening
layers of epidermis, see INTERCELLULAR
SUBSTANCE.

The epidermis and its appendages offer a
great variety of points of interest to the
microscopist. The epidermis of those
growing parts of the higher plants which are
exposed to the air is not absolutely continu-
ous and without orifices like the epidermis of
roots, but is perforated with myriads of
breathing pores or STOMATES (fig. 204 S) as
they are called. These consist of gaps left
by the separation of the superficial epidermal
cells at their meeting angles, the interspace
between them being guarded and more or

less filled up by a pair of cells, situated just
beneath the outer orifice, and having a slit-
like passage between them.

Hairs, scales, thorns, stings, and the
various forms of glands of plants, are appen-
dages of the epidermal structure, being pro-
duced by the peculiar development of parti-
cular cells or groups of cells of this superfi-
cial layer.

We have already alluded to the different
conditions of the epidermis in different parts
of plants. The delicate layer covering young
organs in buds becomes very variously deve-
loped as these attain the complete conditions.
On the leaves and shoots the epidermis be-
comes consolidated by secondary deposits,
and this in greatest proportion on leathery
or woody leaves, &c., such as those of ever-
greens, shrubs, and trees. Remarkable ex-
amples of this may be found in the leaves of
the Proteaceae, Cycadaceae, the Holly, Box,
&c. (woody), and in the Aloes, Cactaceae,
Oleander, Hakea, Ficus, &c. (leathery). In
all cases the solid character of foliage de-
pends almost exclusively upon the character
of the epidermis by which the leaves are
clothed. The epidermis of the outer scales
of winter-buds of trees is remarkably thick.
The thickening layers are sometimes found
on the walls of the stomatal cells and adja-
cent cells bounding the intercellular cavity,
forming the pseudo-structure called a cistome
(see STOMATES).

The epidermis of petals and similar deli-
cate organs never acquires much solidity,
but the outer walls often become elevated
more or less above the surface, producing a mi-
nute papillosity of the epidermis, which gives
the peculiar glistening appearance. When
this elevation goes still further, villi or short
hairs are produced, rendering the surface
velvety (see HAIRS).

The side walls of epidermal cells are
sometimes flat faces of tolerably regular
geometrical figures, such as cubes, parallele-
pipeds, hexagonal prisms, &c.; butnotunfre-
quently they are very sinuous, and then,
when the epidermis is seen from above, it
does not look like ordinary parenchyma,
with square, rectangular, or hexagonal tes-
selae, but the component cells are fitted to-
gether so as to present lines, which, when
regular, might be described by the heraldic
terms, scalloped, wavy, indented, &c. (PL 28.
fig. 15) ; and when less regular, resemble
roughly the lines of joint in the old-fashioned
puzzle-maps of children (fig. 204). Such
forms of the epidermis are found on petals

EPIDERMIS.

[ 239 ]

EPIPYXIS.

frequently, on the leaves of Ferns, on those
of Hellebore, &c., and appear very pleasing
microscopic objects, especially as, in addition
to the lines, the storaates at the angles add
to the elegance of the pattern.

Fig. 204.

%
f\

Epidermis from petal of the balsam, with stomates, S .

The epidermal cells here have elegantly sinuous side-walls.

Magnified 200 diameters.

The cuticle not unfrequently undergoes a
change, which at present is not at all under-
stood. This is seen on many petals, as those
of the Daffodil, and on leaves, as those of the
genus Helleborus, Dianthus, &c., when the
epidermis is viewed from above, in the form
of elevated striae running in various ways
over the surface, sometimes converging in
the centre of each cell, in other cases running
in tortuous lines over the surface, continuous
beyond the boundaries of the individual cells.
A similar condition of the cuticle occurs upon
the HAIRS of many plants, especially of Cru-
ciferae, Ranunculaceae, Boragineas, &c. This
condition is evidently analogous to the equally
mysterious states of the outer membrane of
POLLEN-GRAINS and SPORES, where points,
ridges, reticulations, &c. of the same kind
. constantly occur.

The stomates are found on both surfaces
of many leaves of delicate structure, but
most abundantly on the lower surface; in
other plants they occur exclusively on the
lower face ; in floating leaves they exist only
on the upper face ; while on submerged
leaves none at all occur, and the epidermis
here has no very distinct difference from
that of young roots. The characters of
STOMATES are spoken of more at length

under that head, as also those of HAIRS,
SCALES, STINGS, THORNS, GLANDS.

The epidermis of the Equisetacese and the
Grasses is remarkable for the deposition of
silica, apparently in the walls of the cells of
the epidermis, to such an extent and so
equably, that the whole of the organic mat-
ter may be removed by heat or acids, and
a perfect skeleton of the structure be ob-
tained, composed exclusively of silex, exhi-
biting the boundary lines of the epidermal
cells and the stomates (the dentate side-
walls, with the stomates arranged in linear
series, are described in most microscopic
books in a very curious manner, from an old
paper by Sir D. Brewster). Preparations of
this structure are obtained by treating little
pieces of the wall of the fistular stem with
strong nitric acid, to remove alkalies, and
then burning them until quite white on a
slip of platinum or very thin glass. These
should be mounted in Canada balsam.

The seeds of many plants are clothed with
an epidermis of remarkable character, the
cells containing spiral fibres ; this occurs in
the ACANTHACE^, in COLLOMIA, SALVIA,
&c., and is further treated under those heads
and under HAIRS and SPIRAL STRUC-
TURES.

BIBL. H. von Mohl, The Vegetable Cell
(transl. 1852), Linncea, xvi. p. 401 (1842),
Verm. Schrift. p. 260, Ann. des Sc. nat. 2 ser.
xix. p. 201, ibid. 3 ser. iii. p. 158, Bot. Zeit.
v. p. 497 (1847) (transl. Scientific Memoirs,
new series), ibid. vii. p. 593 (1849); Schlei-
den, Grundzuge der Wiss. Bot. 3 ed. p. 335
(Principles, p. 70) ; Brongniart, Ann. des Sc.
nat. xviii. p. 427, 2 ser. i. p. 65 ; Link, Elem.
Phil. Bot. i. p. 83 ; Wigand, Intercellular-
substanz u. Cuticula, Brunswick, 1850;
Karsten, Bot. Zeit. vi. p. 729 (1848) ; Cohn,
Linntea, xxiii. p. 337 (1850) ; Hartig, En-
twickl. der Pflanze, 1843, Ann. des Sc. nat.
3 ser. i. p. 352 ; Unger, Bot. Zeit. v. p. 289
(1847); Garreau, Ann. des Sc. nat. 3 ser.
xiii. 304; Mulder and Harting, Mulder's
Phys. Chem. (Edinb. transl. p. 470. 1849) ;
Goldmann, Bot. Zeit. vi. p. 857 (1848);
Schacht, Die Pflanzenzelle, p. 89. Berlin,

EPIPYXIS, Ehr.— A genus of Infusoria,
of the family Dinobryina.

Char. Fixed by a pedicle ; eye-spot ab-
sent.

No cilia, nor appendages.

E. utriculus (PI. 23. fig. 50). Carapace
urceolate; body filled with yellowish gra-
nules; aquatic; length 1-650".

EPISTYLIS.

[ 240 ]

EPITHELIUM.

Probably the young state of Dinobryon
sertularia, like which it contains a disk-
shaped nucleus.

BIBL. Ehrenb. In/us, p. 123; Stein,
In/us, p. 205.

EPISTYLIS, Ehr.— A genus of Infusoria,
of the family Vorticellina.

Char. Pedicle rigid (not contractile), sim-
ple or branched; all the bodies of the ani-
mals of the same form. Aquatic;= Vorticella
or Carchesium with a rigid pedicle.

Stein has pointed out the occurrence of
the encysting process in the species of this
genus. The same author also indicates the
presence of a lid-like discoidal process, pro-
trusihle from the orifice, and, like the latter,
furnished with vibratile cilia ; but this does
not occur in all the species admitted by
Ehrenberg. The species are numerous, and
mostly attached to aquatic animals or

E. anastatica (PI. 23. fig. 51 a, c). Body
small, conical, not plicate, anterior margin
large and projecting; pedicle dichotomous,
smooth, or covered with minute foreign bo-
dies; entire length 1-144 to 1-14"; of single
body, 1-288".

E. grandis (PI. 23. fig. 51 b, single body).
Body large, broadly campanulate; pedicle
decumbent, slender, smooth, laxly branched,
not jointed, forming large tufts ; length of
body 1-140 to 1-120".

E. vegetans (AnthopTiysa Mulleri, Duj.)

BIBL. Ehrenb. In/us, p. 279 ; Stein, In-
fus. passim.

EPITEA, Fr. See UREDINEI, PHRAG-
MIDIUM, and MELAMPSORA.

EPITHELIUM.— The membranous layer
lining the various internal cavities, and co-
vering the internal free surfaces of animal
bodies, as the mucous canals and cavities,
and their involutions forming the glands and
ducts, the serous cavities, the vessels, &c.

It serves to form a protection to the sur-
faces, to secrete a lubricating liquid, by
which the effects of friction of one against
the other are prevented, and to separate
from the blood the special secretions of the
various glandular organs.

It consists of one or more layers of nu-
cleated cells, the form and arrangement of
which are very variable. They are either
round, polygonal, spindle-shaped, cylindrical
or conical.

Three kinds of epithelium are usually dis-
tinguished, but intermediate forms are also
met with.

1. Pavement-, or tesselated, epithelium.

This consists of one or more layers of
roundish, oval, or polygonal, flattened
cells, about 1-2000 to 1-500" in diameter,
and containing nuclei with nucleoli. It
occurs upon the surface of the serous and
synovial membranes ; the membrane of the
aqueous humour, the choroid, the capsule
of the lens, the retina, and the conjunctiva
of the bulb of the eye ; the cavity of the
tympanum ; the lower half of the pharynx,
the oesophagus, the endocardium; some
veins ; many glands and ducts, as the race-
mose, the sudoriparous and ceruminous
glands; the hepatic ducts; the vagina and
female urethra ; the bladder, uterus, pelvis,
and tubules of the kidneys ; and the lungs.
In the arteries and many veins the cells are
spindle-shaped.

2. Cylindrical epithelium. In this form,
the cells are either cylindrical, conical, or
pyramidal, about 1-1000" in length, and so
situated that the axis of the epithelial scales
or cells is at right angles to the surface upon
which they are placed. Sometimes the sub-
jacent cells are of a rounded form.

Cylinder-epithelium is met with in Lieber-
kuhn's follicles, and the ducts of the gastric
as well as those of all other glands opening
into the intestine ; in the lachrymal and the
mammary glands; the male urethra; the
vas deferens; the vesiculse seminales, the
prostatic ducts, with Cowper's and the ute-
rine glands.

3. Ciliated epithelium. In this the form
and arrangement of the cells is much the
same as in the last ; but their free ends are
furnished with numerous vibratile cilia (PI.
40. fig. 12).

Ciliated epithelium occurs in the larynx,
trachea, and bronchi; the nares and pha-
rynx above the level of the base of the nasal
bones, and the cavities opening into them ;
the inner surface of the membrana tympani,
the Eustachian tube ; the uterus, the Fallo-
pian tubes; the lachrymal sac and nasal
duct; the palpebral conjunctiva; and the
ependyma.

The epithelium covering the outer surface
of the body forms the epidermis or cuticle.

Further particulars are given under the
heads of the organs or tissues in connexion
with which the epithelia are found.

BIBL. Kolliker, Mikrosk. Anat. and
Handb. d. Gewebel. ; Valentin, Wagner's
Handw. d. Phys., art. Flimmerbewegung and
Epithel. ; Henle, Allgemein. Anat. ; Paget,
Forbes 's Medical Review, xiv. ; Todd and
Bowman, Physiology.

EPITHELIUM.

[ 241 ]

EQUISETACEJE.

EPITHELIUM, OF PLANTS. See EPI-
DERMIS, of Plants.

EPITHEMIA, Brebisson.— A genus of
Diatomaceae.

Char. Frustules single, attached by a part
of the surface to other bodies ; valves with
transverse or slightly radiant striae, some of
them not resolvable into dots.

Frustules prismatic, quadrangular, mostly
curved, sometimes slightly undulating in the
side view; one face of front view (that by which
they are attached) flat or concave, the other
convex and broader than the former, so that
the transverse section forms a trapezoid.
Between, or corresponding with the trans-
verse striae (canaliculi, Smith), not resolvable
into dots, are often transverse rows of dots
or depressions.

The species are numerous. Aquatic and
marine. Conjugation has been observed in
three of them.

E. turgida (Eunotia turgida, Ehr.) (PI. 12.
fig. 32: a, side view; b, front view). Front
view oblong, slightly dilated towards the
middle ; side view somewhat convex, gradu-
ally attenuated towards the very obtuse ends.
Aquatic; length 1-240". In conjugation,
PI. 6. fig. 6, a, b, c, d, e.

E. gibba. Straight ; inflated in the mid-
dle on each side in front view; side view
gibbous in the middle on one side, ends
rounded, very obtuse, striae transverse ; aqua-
tic; length 1-140".

BIBL. Kiitzing, Bacillar. p. 33, and Sp.
Alg. p. 1 ; Smith, Brit. Diatom, i. p. 13.

EPOCHNIUM, Lk.— A genus of Sepe-
doniei (Hyphomycetous Fungi), forming a
stratum over larger fungi or dead twigs,
consisting of a mycelium of irregularly
branched and anastomosing filaments, which
bear on short lateral branchlets oblong or
globular, septate spores, which soon fall off
and lie among the mycelium-threads.

E. fungorum is very common, forming
a dark green stratum over Thelephorce ;
E. macrosporoideum was found by Mr.
Berkeley on a dead twig, apparently of red
currant.

BIBL. Berk, in Brit. Flora, vol. ii. pt. 2.
p. 352, Ann. Nat. Hist. i. p. 263. pi. 8. fig.

EQUISETACE.E and EQUISETUM.—
This is a very distinctly characterized family
of Flowerless Plants, consisting of a single
genus, iheEquiseta, or Horse-tails, which are
immediately recognized, when one species is
known, by the peculiar aspect aud habit of
growth. The Equiseta are found in damp

Fig. 205.

or wet places under the form of erect, simple
or branched, green or dull brown stems, ap-
parently devoid of leaves, jointed at short
intervals, and furnished with a short mem-
branous sheath, toothed at its free margin,
at each joint; where branches exist, they
are sent off in circles at the joints ; and the
branches themselves, also jointed, sometimes
send off similar circles of secondary branches.
The stems and branches are alike tubular,
and present in almost all cases a rather
coarsely (perpendicularly) streaked surface.
The stems appearing above ground are shoots
from a creeping underground stem (fig. 205),
which differs from the erect
stems inbeing of a deep brown
colour and solid, in givingoff
root-fibrils, and sometimes
in being covered with hairs.
The erect stems are either
barren or fertile; in the
barren stems the joints be-
come gradually thinner up-
wards from a certain point,
at last tapering off to an ob-
tuse apex; the fertile stems
bear a kind of club-shaped
head, resembling in some
degree the male cones of
Coniferous trees, or more
particularly those of some
Cycads (fig. 205). These
club-shaped bodies are the
fruits or heads of sporanges.
The creeping underground
stem or rhizome branches
on any or all sides, but the
branches do not all rise as
erect stems or shafts ; some grow out under-
ground, and their joints become swollen
into globular or spindle-shaped tubers, some-
times in a long row of successive joints, so as
to form a necklace-shaped body, and these
tubers ordinarily break away from each other
and from the parent-stem, each to form a
new plant.

The anatomical structure of the rhizome
and shafts presents some interesting points.
In the solid rhizome the centre is occupied
by cellular tissue of tolerably strong texture ;
outside this, as seen in a cross section, stands
a circle of air-canals, each surrounded by a
ring of vascular bundles ; next comes a com-
plete circle of vascular bundles composed
almost wholly of annular ducts; between
this vascular ring and the outside lies pa-
renchyma like that in the centre, traversed
by another concentric circle of air-canals,

EQUISETACE^.

[ 242 ]

EQUISETACE.E.

and immediately beneath the epidermal cells
there exists a layer of compact blackish-
brown parenchymatous cells. When the
rhizome is coated with hairs, these are formed
by development of the epidermal cells
into slender, tubular processes. Tracing
the solid rhizome up towards the points
where the erect stems arise, the central cel-
lular substance is gradually lost, and the
outer portions are modified in their arrange-
ment. The distribution of the air-canals
and the vascular bundles varies; in some
cases, the peculiarities are even regular
enough to afford specific characters. The
surface is clothed by an epidermis composed
of elongated cells often elevated into papillae,
and especially remarkable for the quantity
of silica deposited in their walls. This epi-
dermis is studded with variously formed sto-
mates ordinarily arranged in double lines;
and the forms of the epidermal cells and
stomates are perfectly preserved in the sili-
ceous ash which remains after burning off
the organic substance from a portion of this
EPIDERMIS, offering a curious microscopic
object. Between the epidermis and the
central cavity, in a cross-section, lie, first, a
layer of thick-walled elongated cells, within
which, in the angular-stemmed species, come
a circle of masses, usually crescentic, of cel-
lular tissue containing chlorophyll. Next
come usually two concentric rings of air-
canals, those of the inner circle being indi-
vidually surrounded by annular ducts, and,
moreover, in some species a circle of 6-10
vascular bundles separates the inner from
the outer circle of air-canals ; the structure
of the bundles is variable, exhibiting annular,
spiral, and reticulated ducts. The inner
circle of air-canals lies in the parenchyma
which bounds the central cavity. At each
joint this cavity is cut off by a diaphragm
composed of three layers, in the intermediate
of which, of brownish cellular tissue, lies an
anastomosing ring, where all the vascular
bundles coalesce and give off branches to the
sheath (and branches when present).

The club-shaped fruit-spikes consist of a
central axis forming the last joint of the
stem, on which are attached numerous
mushroom-shaped sporanges, the stalk of
each adhering to the central axis, so that we
only see the upper side of the cap externally
(figs. 206, 207). This has an angular bor-
der, and the adjacent sporanges being very
close, the outer ends of these bodies cause a
tesselated appearance of the whole in the
earlier stages of development. As the spo-

ranges ripen, they separate more from each
other ; and when one is removed (fig. 208)

Fig. 206.

Fig. 207.

Fig. 208.

Fig. 209.

Equisetum arvense.

Fig. 206. Fruit spike. Magnified 3 diams.

Fig 207. A spike halved vertically. Magn. 3 diams.

Fig. 208. A sporange removed from the preceding.

Magn. 25 diams.
Fig. 209. A spore with elaters uncoiling. Magn. 200

diams.

it is seen to possess a number of little pouch -
like cases under the overhanging outer por-
tion and round the stalk; these pouches
burst by a perpendicular slit inwards, and
discharge the spores.

The spores of the Equiseta are very re-
markable, and unlike any other known ve-
getable structure. They are roundish cells,
with apparently only one coat, for the outer
coat splits up into four thread-like processes
(elaters), thickest and rather clubbed at their
free ends. While the spore remains on the
sporange, these fibres are rolled round the
spore ; but when the spores are discharged,
the coiled fibres uncurl (fig. 209), and assist in
scattering the spores, their elasticity causing
them to spring about.

The Equiseta possess only this one kind
of spore, and the germination is analogous
to that of the Ferns, in which likewise only
one kind of spore exists. The membrane of
the spore pushes out a pouch-like process,
which after a time becomes cut off by a sep-

EQUISETACE^.

243 ]

ERVILIA.

turn ; the end-cell grows on and multiplies in
both directions, until a tabulated prothallium
is produced; on this arise archegonia and
antheridia (on distinct individuals), resem-
bling in all essential respects those produced
on the corresponding structure in the FERNS.
After the fertilization of an archegonium,
the germ-cell contained in it becomes deve-
loped as an embryo, and a new Equisetum
stem of the ordinary structure springs up
(fig. 210), forming a creeping rhizome with

Fig. 210.

Equisetum arvense.

Young stem arising from a prothallium.
Magnified 15 diameters.

upright fistular shafts, resembling the parent
plant from which the spores were derived.
The family Equisetaceae is represented only
by a single genus in existing vegetation,
containing only herbaceous plants. The
Equisetaceae of former ages were far more
important as regards size. The follow-
ing may be given as the character of the
genus : —

Equisetum, Linn. Stems erect, cylin-
drical, smooth, striate, fistular, articulated,
simple or with whorled branches (occasion-
ally with whorled branchlets), bearing mem-
branous tooth-like leaves, connate and form-
ing a short erect sheath encircling each
articulation. Thecae unilocular, six or seven
together, adnate all round the under sur-
face of a peltate sporange; the sporanges
arranged in terminal spikes or cones. Spores
numerous, with four filaments arising at one
point, coiled elastically a few times round
the spore, and terminating in spathulate
ends, — springing loose from the spore when
the latter is discharged.

BIBL. Francis's British Ferns, 5th ed.

1855 ; Thuret, Ann. des Sc. nat. 3 ser. xi.
p. 5; Milde, Bot. Zeit. viii. p. 448 (1850),
and x. p. 537 (1852), Linncea, xxiii. p. 545
(1850); Hofmeister, Vergleich. Unters. 1851,
Verh. k. Sachs. Akad. d. Wiss. iv. p. 123 ;
Bischoff, G. W., Kryptogam. Gewachse,

1 heft. p. 27. pi. 3, 4, 5 (1838), Botan.Zeit. xi.
p. 97 (1853), transl. in Ann. des Sc. nat.
3 ser. xix. p. 232 ; Pringsheim, Bot. Zeit.
xi. p. 241 (1853).

EREBONEMA, Rom.— A supposed genus
of Kiitzing's family Leptomiteae. Some im-
perfect filamentous organism, probably be-
longing to a Fungus.

BIBL. Romer, Deutschl. Ala. p. 70; Kiit-
zing, Sp. Alg. p. 157.

ERETES, Wemeck.— A genus of Infuso-
ria, of the family Cryptomonadina.

Char. Those of Phacelomonas with a ca-
rapace.

One species : the spores of an Alga (?).

BIBL. Werneck, Eer. d. Berl. Akad. 1844.
p. 377-

ERGOT and ERGOT^ETIA. See CLA-

VICEPS.

ERINEUM, Pers.— A supposed genus of
Fungi, really consisting of abnormal deve-
lopments of the cells of the epidermis of the
trees upon which they are supposed to be
parasitic. They occur chiefly upon the Amen-
taceae, Aceraceae, and Rosaceae (Apple-trees,
Plum-trees, &c.).

BIBL. Fries, Syst. My col. iii. p. 521 ;
Berkeley in Lindley's Veg. Kingdom, art.
Funaales.

ERIOSPORA, Berk. & Br.— A genus of
Melanconiei (Coniomycetous Fungi), de-
scribed (E. leucostoma] as forming minute
brown spots upon dead leaves of the bulrush.
The conceptacles are globose, and collected
in numbers on the stroma, bursting by a
single common (white-bordered) pore to dis-
charge the spores (stylospores), which are
filiform and very slender, and arise in fours
from a sporophore. Probably corresponds
to the genus Robergea among the Ascospo-
rous Fungi. (See CONIOMYCETES.)

BIBL. Berk, and Br. Ann. Nat. Hist.

2 ser. v. p. 455. pi. 11. fig. 1.
ERVILIA, Duj.— A genus of Infusoria, of

the family Ervilina.

Char. Oval, compressed; carapace open
on one side and in front ; vibratile cilia issu-
ing from the fissure ; a lateral pedicle at the
posterior end of the body. Marine.

E. legumen = Euplotes monostylus, E.
(PI. 23. fig. 52; b, side view). Body very
transparent, exhibiting vacuoles ; length

R2

ERVILINA.

[ 244 ]

ERYSIPHE.

1-650 to 1-420". The pedicle becomes ag-
glutinated to foreign bodies.

BIBL. Duj. Infus. p. 455.

ERVILINA, Duj.— A family of Infusoria.

Char. Body oval, more or less depressed,
partly covered by a membranous persistent
carapace, furnished with cilia upon the ex-
posed parts, and having a short pedicle re-
sembling a tail.

Reproduction by transverse division.

Two genera : Ervilia, carapace open in
front and on one side ; and Trochilia, cara-
pace open in front only.

Dujardin questions whether Urocentrum,
E. does not belong to this family.

BIBL. Duj. Infus. p. 454.

ERUPTIONS/cuTANEOus.— The scales,
crusts, scabs, contents of vesicles, pus-
tules, &c., formed in various diseases of
the skin, usually consist of epidermic cells
alone, more or less flattened or otherwise
altered ; or of these with the ordinary pro-
ducts of inflammation. Granules of soot are
frequently found, in London at least, mixed
with the above elements. Fungi exist in the
crusts of some skin diseases, as FAVUS, &c.
The fungi discovered (?) in the pustules of
small-pox have become extinct. The itch-
insect (SARCOPTES) must not be forgotten,
nor DEMODEX.

ERYNGIUM.— A genus of Umbellifera
(Dicotyledons), a species of which, E. mari-
timum, known as Sea- holly, found on sandy
sea-shores, has a long, fleshy, underground
stem and branches, the wood of which is of
peculiar character, consisting chiefly of very
large pitted ducts, forming an elegant micro-
scopic object. (See WOOD.)

ERYSIPHE, Hedw.fil.— A genus of Peri-
sporacei (Ascomycetous Fungi), consisting of
little mildews overgrowing the leaves of
living plants. The mycelium is formed of
slender ramified filaments, which spread and
form an entangled web over the epidermis of
the infected plant, but do not appear to pe-
netrate into the substance, so that these
Fungi are not seemingly true parasites.
From the creeping mycelium arise numerous
upright, shortly-jointed filaments, the last
one or more of the succeeding joints of
which swells so as to render the erect fila-
ment clavate or moniliform. These expanded
cells become detached with the greatest
readiness, and when they fall upon the sup-
porting leaf, germinate and produce new
mycelium threads. In this state the Ery-
siphes cannot be distinguished from the genus
Oidium; and as this state is succeeded in

most cases by the true conceptacle of the
genus Erysiphe, the Oidia (such as 0. Tuckeri,
the Vine-Fungus), which grow under the
same circumstances, but do not produce
conceptacles, are regarded by most authors
as imperfect Erysiphes. (See OIDIUM.)
When the mycelium of an Erysiphe is deve-
loped late in the year, it seldom produces
anything but the ovate cells (conidia), but
if developed early in the summer, the myce-
lium grows at certain points into denser
white patches (receptacles, Lev.), from which
arise the conceptacles. These are small glo •
bular sacs, composed of a double layer of
cells ; from the base of the outside of the
sac arise a number of radiating filaments, sim-
ple or branched (appendicles, Lev.), while in
its interior are developed one or many sacs
(asci, sporanges, Lev.), in each of which are
produced eight spores. In addition to the
above, a third form of fruit occurs, in which
the conidium becomes transformed into a sac
(pycnidiuni) filled with minute spores.

Leveille, in an elaborate essay on this ge-
nus, has subdivided it into five genera, which
may perhaps be better taken as subgenera,
and may be distinguished in the following
manner : —

Conceptacles with one ascus.

Appendicles dichotomously branched . . 1. Podosphaeria.
„ floccose 2. Sphcerotheca.

Conceptacles with many asci.

„ aciculate 3. Phyllactinia.

,, uncinate 4. Uncinula.

„ dichotomously branched . . 5. Calocladia.

„ floccose 6. Erysiphe.

Podosphceria does not seem to be repre-
sented in Britain.

Sphcerotheca. The Rose-mildew, E. pan-
nosa, Auct., belongs to this group, and is
distinguished from E. macularis, Wallr. (S.
Castagnei, J. Lev.), the Hop-mildew, by
the appendicles of the former being white,
while those of the latter are coloured. The
mycelium of the rose-mildew seems to be
the same thing as Oidium leucoconium,Desm.
The similar structure of the hop-mildew has
been described and figured (from Dr. Plom-
ley's drawings) in the Trans, of the Horti-
cultural Society.

Phyllactinia. E. guttata, Schlecht, com-
mon on the hazel and other trees and large
shrubs, is distinguished from the other forms
of Phyllactinia by having a bulbous base to
its asci, which contain only two spores.

Uncinula. E. adunca, Schlecht, is referred
here ; its distinctive character is the exist-
ence of four spores in each ascus. Found on

ERYTHRJEUS.

[ 245 ]

EUASTRUM.

willows. E. bicornis, Lk., occurring upon
maples, &c., has eight spores.

Calocladia. E. penicillata, occurring onFz-
burnum Opulus, &c. The ultimate branches
of the appendicles are turned up, and the
four asci contain each eight spores; the
appendicles are thick upward from the base.
Perhaps part of the E. penicillata of the
Brit. FL belongs to C. berberidis and gros-
sularice, Lev., which have the terminal
branches of the appendicles straight and
cylindrical. Both have many-spored asci,
but in the latter the appendicles are rectan-
gularly dichotomous and bidentate, while in
the former they are twice or thrice dichoto-
mous and obtuse.

Erysiphe. E. Pisi, Grev. is E. Martii of
Leveille, distinguished by its globose, many-
spored asci and the hyaline appendicles. E.
tortilis, Lk. has coloured appendicles ten or
more times the length of the conceptacle. It
grows on Cornus sanguinea, the Dogwood
tree. E. communis, Lev., is not very well
characterized ; it has coloured appendicles,
which are only twice or thrice as long as the
conceptacle ; the asci vary from four to eight,
as do also the spores contained in each.
This species grows on a great variety of her-
baceous plants, Ranunculacese, Composite,
Leguminosa3, Cruciferee, Polygonacese, &c.

Perhaps a doubt might be admitted whe-
ther the above subdivisions really represent
more than six species of this genus.

BIBL. Leveille, Ann. d. Sc. not. 3 ser. xv.
p. 109. pi. 6-11; Berk, in Hook, Brit. Flora,
11. pt. 2. p. 325, Trans. Hort. Soc. London,
ix. p. 61 ; Greville, Sc. Crypt. FL pi. 134,
164. figs. 2. 296; Tulasne, Comptes Rendus,
Oct. 17, 1853. See also OIDIUM.

ERYTHRJ2US, Duges.— See ANYSTIS.
Under that head we omitted the characters
of A. ruricola, }Heyd..,Eryth. ruricola, Duges
(PL 41. fig. 4 ; PI. 2. fig. 3 ; a, palp ; b, man-
dible), which is probably not uncommon.
They are : — Body depressed, nearly oval, but
slightly emarginate at the sides, and some-
what broader behind than before; a few
hairs scattered over the surface ; eyes two,
black, placed at the anterior obtuse angles of
the body ; colour bright carmine, sometimes
blackish in the middle, paler along the back
and in front ; legs and palpi colourless, ex-
cept a bright red spot on each of the joints
at a little distance from the body.

EUACTIS, Kiitz.— A genus of Oscillato-
riacese (Confervoid Alg«), of the tribe Rivu-
larieae, consisting of little, hard, solid, elastic,
mostly hemispherical bodies, from 1-2 to 2'"

in diameter, growing upon stones in the sea
or rivers, &c. ; concentrically zoned, com-
posed of radiating, flagelliform, repeatedly
sheathed filaments, the sheaths of which are
open and slit above (PI. 4. fig. 16), but con-
nected together side by side, so as to form a
tough gelatinous mass, not becoming en-
crusted with carbonate of lime. To this
genus Kiitzing refers Rivularia plicata, atra,
and perhaps applanata of Harvey. These
plants are interesting on account of the
fibrous decomposition of the gelatinous
sheaths.

BIBL. Harvey, Brit. Mar. Alg. p. 222.
pi. 26 A. (Rivularia) ; Kiitzing, Sp. Alg.
p. 339, Tab. Phyc. cent. ii. pi. 74-82.

EUASTRUM, Ehr.— A genus of Desmi-
diacese.

Char. Cells single, compressed, deeply
divided into two segments, which are gene-
rally pyramidal and furnished with circular
protuberances, lobed or sinuated at the mar-
gins, and emarginate at the ends.

Mr. Ralfs describes twenty-one British
species, of which the following are the most
common.

* Segments deeply lobed; end lobe distinct,
cuneate, partly included in a notch be-
tween the lateral lobes.

E. verrucosum (PI. 10. fig. 14). Rough ;
segments three-lobed, lobes broadly cuneate,
with a shallow notch; length 1-267".

E. oblongum (PI. 1 0.fig. 15). Smooth, ob-
long; segments five-lobed; lobes cuneate,
emarginate ; length 1-156".

E. crassum. Smooth; segments three-
lobed, subquadrilateral ; end lobe cuneate;
length 1-190 to 1-130".
** Segments sinuated ; end lobe exserted
and united with the basal portion by a
distinct neck.

E. didelta (PI. 10. fig. 16 ; 17, empty cell).
Segments with inflated base, intermediate
tubercles, and notched and scarcely dilated
ends ; side view, four shallow lateral lobes,
and one at each end; length 1-185".

*** End lobe indistinct; frequently a process
or acute angle at the corners of the ter-
minal portion.

E. elegans. Oblong; ends emarginate*
pouting, and rounded; length 1-890 to

Conjugation has been observed in several
species; the sporangia are spherical, with
conical tubercles, or acute or obtuse spines.

BIBL. Ralfs, Brit. Desmid. p. 78.

EUCAMPIA.

[ 246 ]

EUGLENA.

EUCAMPIA, Ehr. — A marine organism,
allied to the Desmidiaceae, among which it
is placed by Kiitzing. It forms articulated,
arcuate, fasciseform, microscopic fronds, com-
posed of hyaline, wedge-shaped joints, exca-
vated in the. middle at both ends, with yel-
lowish granular contents. The joints shrink
in drying, and are destroyed by heat. The
bundles of E. zodiacus, the only species, are
1-96'" broad, the length of the joints being
H or 2 times the breadth (PI. 41. fig. 10).

BIBL. Ehrenb. Leb. Kreidethierch. Abh,
Berl. Akad. 1839. p. 125; Kutzing, Sp.
Algarum, p. 191, Kieselsch. Bacillar. pi. 21.
fig. 21.

EUCERTYDIUM, Ehr.— A genus of Po-
lycistina.

E. ampulla (PI. 31. fig. 25, front view;
fig. 26, under view).

See POLYCISTINA.

EUCHLANIDOTA, Ehr.— A family of
Rotatoria.

Char. Rotatory organ multiple, or divided
into more than two lobes; a carapace pre-
sent.

The carapace forms either a testa or a
scutellum ; various appendages are present,
representing either straight bristles, curved
bristles, or hooks, minute horns, — so-called
respiratory tubes or antennae, — and in one
genus a frontal hood.

The eleven genera are thus distinguished :

Eyes absent ; foot forked .............. { £g£? °'

Eyes present.
Eye single (cervical).
Foot styliform.
Carapace depressed .............. Monostyla.

„ prismatic .............. Mastigocerca,

Foot forked.
Carapace open beneath .......... Etichlanis.

„ closed beneath
Carapace with horns .......... Salpina.

,, without horns ........ Dinocharis.

Eyes two (frontal).
Foot styliform .................... Monocerca.

„ forked.

Carapace compressed or prismatic Colurus.
Carapace depressed or cylindrical.

Head without a hood ........ Metopidia.

„ with a hood ............ Stephanops.

Eyes four ; foot forked .............. Kquamella.

* Diplax, Gosse, does not differ from Lepadella, E.

BIBL. Ehrenb. In/us, p. 455.

EUCHLANIS, Ehr.— A genus of Rota-
toria, of the family Euchlanidota.

Char. Eye single, cervical ; foot forked ;
carapace cleft or open on the ventral surface.
Aquatic.

Ehrenberg describes six species, to which
Gosse adds three.

E. triquetra (PI. 34. fig. 30 ; fig. 31, teeth).

Carapace very large, with a dorsal crest;
foot without setae; length 1-48".

BIBL. Ehrenb. In/us, p. 461 ; Gosse, Ann.
Nat. Hist. 1851. viii. p. 200.

EUDORINA, Ehr.— A supposed genus of
Volvocinese (Confervoid Algae). Eudorina
elegans is described as a cluster of globular
green corpuscles, containing from fifteen to
thirty or fifty of them, enclosed in a hyaline
common envelope, about 1-180" in diameter,
from which each protrudes a single cilium.
What we have found answering nearest to
this (PI. 3. fig. 14) has the zoospore-like
corpuscles provided with a pair of cilia. It
is said that Eudorina has the power of throw-
ing oif its outer envelope or mantle, and
forming a new one. This strengthens our
suspicion that it is only a young form of
Volvox, in course of development from the
resting-spore, which must throw oif its outer
firm coat in this way. Eudorina elegans is
most abundant in spring, in ponds with Vol-
vox, (f Chlamidomonas'' &c. See VOLVOX.

BIBL. Ehr. Infusionsth. p. 62; Dujardin,
In/us, p. 317; Pritchard, Infusoria.

EUGLENA, Ehr.— A genus of Infusoria,
of the family Astasiaea.

Char. Unattached; a red eye-speck; a
tail-like process, and a single flagelliform
filament.

Many species, or rather forms, are distin-
guished by Ehrenberg and Dujardin. They
are often present in vast numbers in pools,
&c., rendering them green or red, and form-
ing a brilliant pellicle upon the surface.

In the free condition, the Euglence swim
about in the water, not apparently by the
help of the flagelliform filament, which seems
to be often deficient, but by the contractile
action of the whole body, the changes of
form and movements of which may be
roughly compared to that of the common
leech when crawling sluggishly over the sur-
face of a glass. The Euglence present many
points of resemblance to the lower Algae,
especially Protococcus, like them varying in
colour from green to red, and, moreover,
passing through a resting stage, encysted in
a kind of cell- membrane, which is sometimes
gelatinous, transparent, and spherical, some-
times rather horny, and polygonal in form.
The encysted forms occur commonly aggre-
gated together into indefinite frond -like
masses, and the individuals multiply by divi-
sion into two, four, &c., in this quiescent
stage. The frond-like groups may be found
in autumn, and even under the ice in winter,
while the active forms abound most in spring

EUGLENIA.

[ 247 ]

EUPLOTA.

in fine weather. These creatures require
further investigation, for the settlement of
the specific characters and the relations to
their congeners. (See ASTASIE^E.) We can
only notice two or three of the forms.

E. pyrum (PI. 24. fig. 1). Body, when ex-
tended, oval, turgid, pyriform, obliquely
furrowed, green ; tail nearly as long as the
body, acute. Aquatic; length 1-1150 to
1-860".

E. viridis (PI. 24. fig. 2 a, b). Fusiform
when extended ; head narrowed, short ; tail
conical, short (not cleft) ; green, hyaline at
the ends. Aquatic; length 1-1150 to
1-240".

E. longicauda, PTiacus longic., D. (PI. 24.
figs. 3 & 63). Depressed, elliptical or oval,
frequently twisted on its long axis, green,
with longitudinal striae; tail as long as the
body, hyaline, subulate. Aquatic; length
1-280 to 1-120".

E. acus (PI. 24. fig. 4). Fusiform, slender,
subulate, straight, green in the middle ; head
attenuate, somewhat truncate, hyaline ; tail
very acute, hyaline. Aquatic; length 1-570
to 1-216".

BIBL. Ehrenb. Infus. p. 104 ; Dujardin,
Infus. p. 358; Morren, Rube} action des
Eaux. Brux. 1841.

EUGLENIA, Duj. (Infusoria). See As-

TASI^EA.

The essential character of this family is
the presence of a contractile integument;
this is probably of little importance, as in
many cases the nature of the integument has
been shown to depend upon season, locality,
and stage of development.

EUGLYPHA, Duj,— A genus of Infusoria,
of the family Rhizopoda.

Char. Free ; single ; carapace membra-
nous, transparent, resisting, elongato-ovoid,
urceolate, covered with rows of tubercles or
depressions; orifice toothed; expansions
numerous, simple.

This genus appears unnecessarily separated
from Difflugia, E.

E. tuberculata (PI. 23. fig. 53). Carapace
covered with oblique or longitudinal rows of
rounded tubercles. Aquatic ; length 1-280".
Sometimes posterior spines are present.

E. alveolata (PI. 23. fig. 54). Carapace
covered with polygonal depressions, in re-
gular oblique rows. Aquatic; length 1-280".
Posterior spines also present.

See DIFFLUGIA.

BIBL. Dujard. Infus. p. 251.

EUMERIDION, Kiitz. — Consolidated
with MERIDION.

EUNOTIA, Ehr. — A genus of Diato-
maceae.

Char. Frustules free, single or binate,
quadrilateral ; linear or linear-oblong in front
view, curved or concavo-convex in side view ;
valves with terminal puncta (nodules ?) and
transverse or slightly radiating striae, but no
canaliculi. Aquatic and fossil. Allied to
Epit hernia.

Many of the species have undulations or
ridges upon the convex surfaces ; striae re-
solvable into dots, but in some species diffi-
cult to detect; transverse section of frus-
tule trapezoidal.

Kiitzing describes forty -four species;
Smith admits seven as British.

E. tetraodon (Himantidium tetr., K.) (PI.
18. fig. 30; «, side view; b, front view).
Frustules with four ridges ; striae distinct ;
length 1-570".

E. monodon (Himant. monodon, K.). Side
view lunate, no ridges, slightly constricted
near the obtuse ends ; striae obscure ; length
1-800".

E. triodon. Ridges three ; ends attenuate,
rounded; striae obscure; length 1-500".

BIBL. Kiitzing, Eacill. p. 36, and Sp.Alg.
p. 4 ; Smith, Brit. Diatom, i. p. 15 ; Ralfs,
Ann. Nat. Hist. 1844. xiii. p. 459.

EUPHORBIA.— AgenusofEuphorbiacese
(Dicotyledons) including the British spurges,
or devil's-milk plants, characterized by the
white milky juice which exudes from them
when bruised or broken. The milk-sap is
contained in special structures, called milk-
vessels, which abound most in the bark, and
in the peripheral part of the pith. For then-
characters and that of the milky juice, see
LATEX-VESSELS, and LATEX.

EUPLOTA, Ehr.— A family of Infusoria.

Char. Body surrounded by a carapace;
two distinct alimentary orifices, neither of
which is terminal (= Oxytrichina with a ca-
rapace).

Locomotive organs consisting of cilia,
hooks, claws, or styles. Dujardin states
that the carapace undergoes diffluence like
the substance of the body.

The genera are thus distinguished : —

Cilia, fivrftl,fT, ->

claws, or * .1 Head distinct .... Discocephalus.

hooks < JJJJb J No ^ti^rt head ' ' Himantophorus.

nortyta LMouth with teeth Chlamidodon.

Cilia, claws, and styles present Euplotes.

Dujardin includes this family in his Plces-
conina.

BIBL. Ehrenb. Infus. p. 374; Dujard.
Infus. p. 429.

EUPLOTES.

[ 248 ]

EUROTIUM.

EUPLOTES, Ehr. (Plasconia, Duj. for
the most part). — A genus of Infusoria, of
the family Euplota, E.

Char. Furnished with cilia, styles, and
hooks ; teeth absent.

The species are very numerous.

E. patella, E. (Plcesconiapat., D.) (PI. 24.
fig. 5; a, under view; b, side view). Cara-
pace a testa, oval or suhorhicular, slightly
truncated in front, margins extending be-
yond the depressed body ; dorsum raised or
bossed with fine radiating striae ; cilia form-
ing a curvilinear series. Aquatic; length
1-288 to 1-216".

E. cimex, E. (Coccudina cimex, D.).

E. charon, E. (Plcesconia charon, D.).

E. vannus, E. (PL vannus, D.) (PI. 24.
fig. 6).

E. monostyla, E. (Ervilia legumen, D.)
(PI. 23. fig. 52).

BIBL. Ehrenb. Infus. p. 377; Duj. In/us.
p. 435 ; Stein, Infus. p. 158.

EUPODISCUS, Ehr.— A genus of Diato-
maceae.

Char. Frustules single, disk-shaped, cir-
cular, without internal septa; valves fur-
nished with tubular or spiniform processes.
Marine and fossil.

The processes are so easily broken off,
that the apertures corresponding to the
points of attachment are generally alone
seen. The valves appear either distinctly
areolar, the depressions being large ; granu-
lar, from their being minute ; or striated.

Two groups are recognizable :

a. Eupodiscus proper. Valves areolar.
E. argus (PL 12. fig. 30; a, side view;

b, front view). Valves slightly convex ;
processes three; diameter 1-156".

E. sculptus, Sm. (PI. 12. fig. 31). Valves
striated, central striae forming a quatrefoil ;
processes two; diameter 1-770 to 1-400".

b. Aulacodiscus, E. Valves granular ;
processes very short, their bases connected
with the centre of the valve by a furrow.

BIBL. Ehrenb. Abh. d. Berl. Akad. 1839,
id. Bericht. 1844. p. 73, 1845. p. 361; Smith,
Brit. Diat. i. p. 24 ; Kiitzing, Sp. Alg, p.
134.

EUPOTIUM. — A genus of Marattiaceous
Ferns. Exotic.

EUROTIUM, Lk.— A genus of Mucorini
(Hyphomycetous Fungi), on the distinct
nature of which great doubt is thrown by
the recent observations of De Bary. E. her-
bariorum of authors is a mildew, common

upon preserved fruits, forming a whitish or
yellow crust, composed of interwoven myce-
lium filaments, which are delicate when
young, but become thickened and often co-
loured with age. Upon these are produced
globular conceptacles or peridia, from 1-15
to 1-20"' in diameter, composed of a dis-
tinctly cellular membrane, enclosing little
sacs or asci containing several minute spores.
According to De Bary, these conceptacles
are produced upon the mycelium of Asper-
gillus, under certain unknown conditions,
and the ordinary fructification of Aspergillus
is only a basidiosporous form of the same
plant which produces an ascophorous form
in the Eurotium fruit. He states that he
not only found them growing upon the con-
tinuations of the same branched mycelium
filament, but that he has raised Aspergillus,
which fruited, from the spores both of As-
pergillus fruits and of Eurotium. He was
unable to obtain Eurotium from Aspergillus
spores. The connexion between these forms
is regarded by him as analogous to that be-
tween Oidium and Erysiphe, but the con-
ceptacles of Eurotium do not originate in
the same way as those of Erysiphe from the
mycelium filaments. According to his ela-
borate account, the production of the fruit
of Eurotium takes place in a most remark-
able manner. The ends of the branches of
the mycelium coil up like a cork-screw, be-
coming more closely approximated, until at
length they come into contact, and form a
cylindrical or conical mass, marked exter-
nally by the spiral lines of conjunction of
the turns of the filament. The mode of
transformation into the cellular conceptacle
could not be traced in its minute details,
but all possible stages were found upon the
same mycelium, between the loose spiral
coil and the globular sac, composed of a
distinctly cellular membrane, in the cavity of
which became developed the asci or parent-
cells of the spores. The ripe spores often
exhibit a curious form, like little cylinders
with a concavo-convex cap applied over each
end ; these appear to be the two halves of
the dehiscent outer membrane (exospore),
for in the germination of perfectly globular
forms the mycelium filaments break through
the outer tough coat, like a pollen-tube from
the inner coat of a pollen-grain. The spores
are about 1-350"' in diameter, and of a light
yellow colour in mass. The dimensions, &c.
of Eurotium, like those of Aspergillus, seem
to vary with the external conditions.

The above curious phsenomena deserve

EURYCERCUS.

[ 249 ]

EXPECTORATION.

more investigation, which may readily be
made by a practised microscopist, since the
materials are everywhere at hand, on decay-
ing fruits, mildewed preserves, or plants
imperfectly dried for herbaria, &c.

Eurotium Rosarum, Greville (Sc. Crypt.
Fl.)=Erysiphe pannosa.

BIBL. Berk, in Hook. Brit. Fl. ii. pt. 2.
p. 333; Greville, Scot. Crypt. Fl. pi. 164.
fig. 1 ; Sowerby (Farinaria), pi. 379. fig. 3 ;
De Bary, Eot. Zeit. xii. p. 425 (1854) ; Riess,
ibid. xi. p. 134, and Fresenius, p. 474 (1853).

EURYCERCUS, Baird (Lynceus, in part,
Mull.). — A genus of Entomostraca, of the
order Cladocera, and family Lynceidse.

Char. Subquadrangular (in side view) ;
abdomen very broad, flattened, densely ser-
rated; beak blunt, slightly curved down-
wards. Aquatic.

E. lamellatus (PI. 15. fig. 39). Shell olive,
ciliated on the anterior ventricose margin,
arched behind ; beak rather blunt and short;
superior antennae terminated in six short
spines, each with a fine seta or bristle ; an-
terior branch of inferior antennae with five
long filaments, one from the end of the first
and second joints, three from the third, as
also a small spine; posterior branch with
three long filaments at the end of the last
joint, the first and second each with a short
spine only.

It generally lives at the bottom of the
vessel in which it is kept.

BIBL. Baird, Brit. Entom. p. 123.

EVADNE, Loven.— A genus of Entomo-
straca, of the order Cladocera, and family
Polyphemidae.

Char. Abdomen short, scarcely projecting
from the shell ; head not distinct from the
body; marine.

E.Nordmanni (PL 14. fig. 30). Colourless,
excepting the eye.

Forms part of the food of the herring.

BIBL. Loven, Wiegmann's Archiv, 1838.
Bd. i. p. 143; M.-Edwards, Hist. Nat. d.
Crustac. iii. 390; Baird, Brit. Entom. p.
114.

EVERNIA, Ach. (Physcia, Schserer).—
A genus of Parmeliaceae (Gymnocarpous
Lichens), containing one species (E.prunas-
tri), common on trees, but not often found
in fruit.

BIBL. Hooker, Brit. Flor. ii. pt. 2. p. 228;
Schserer, Enumeratio Crit. p. 11.

EXCIPULA, Fr.— A genus of Phragmo-
trichacei (Coniomycetous Fungi), forming
horny tubercles on dead stems and leaves,
finally opening by an entire orbicular aperture.

The stylospores are elongated, lanceolate
or fusiform, and long hair-like processes are
sometimes mixed with the sporophores which
line the disk. Four British species are re-
corded : E. Rubi and E. striaosa of Fries,
and E. macrotricha and E. ch&tostroma of
Berk, and Br. Perhaps related to some
Ascomycetous form. (See CONIOMYCETES.)

BIBL. Berk, in Hook. Br. Flor. ii. pt. 2.
p. 296 ; Berk, and Broome, Ann. Nat. Hist.
2 ser. v. 456. pi. 11. fig. 2.

EXIDIA, Fr.—A genus of Tremellini
(Hymenomycetous Fungi), forming gelati-
nous, flat, or sometimes undulated and ear-
like coloured expansions on the trunks and
branches of trees. Common in autumn and
winter. Tulasne has lately published some
interesting observations on the structure of
the hymenium which clothes the upper face.
This is composed of a densish layer of very
slender filaments, which bear at their free

Fig. 211.

Fig. 212.

Exidia recisa.

Fig. 211. Upper surface. Fig. 212. Lower surface.
Natural size.

surface globular cells (basidia) divided verti-
cally into two or four chambers ; from each
of these arises a slender process (sterigma),
at the end of which is developed a stylospore.
In E.spiculosa, spermatia were also observed
in young specimens, at the ends of very
slender filaments passing through the muci-
laginous layer overlying the layer of basidia.
(See DACRYMYCES and other genera of
TREMELLINI.)

BIBL. Berk, in Hook. Brit. FL ii. pt. 2.
p. 217; Tulasne, Ann. des Sc. nat. 3 ser.
xix. p. 202. pi. 11 &12.

EXOCOCCUS, Nageli.— Probably a Pro-
tococcus or Palmella.

BIBL. Nageli, Neuer Algensyst. p. 169.

EXOGEN. See DICOTYLEDON.

EXOSMOSE. See ENDOSMOSE.

EXPECTORATION. — The various ob-
jects which may be found in the expectora-
tion are noticed under their respective heads,
or those of the tissues from which they are
derived ; a list only need be given here.

Mucous corpuscles, i. e. young epithelial

EXUDATION.

[ 250 ]

EYE.

cells; mature epithelial cells, of the pave-
ment, cylinder, or ciliated forms ; exudation
globules, or granule - cells ; pus and pyoid
corpuscles ; coloured corpuscles of the blood;
pseudo-membranous flakes of fibrine ; tuber-
cule ; fatty matter in the form of globules,
rarely of crystals; earthy matters, amorphous
or crystalline; various substances derived
from the food, as muscular fibre, starch-
granules, cellular tissue, &c. ; entozoa, or
fragments of them, as portions of the cysts
or hooks of Echinococcus ; infusoria and
algae, as Monads, Bacteria, Sarcina, &c.;
carbon and true pigment, either in the free

Fig. 213.

Section of the membranes of the eye, near the ciliary processes.

ScL, sclerotica; C, cornea; Pr. oil,, ciliary process ; Ca, anterior chamber ;
Cp, posterior chamber; Cv, vitreous humour; C.P., canal of Petit; L, lens ;
7, iris ; a, conjunctiva of the cornea, — epithelial layer ; b, subjacent elastic layer ;
c, fibrous layer of the cornea ; d, membrane of the aqueous humour ; e, its epi-
thelium ; /, end of the membrane and its fusion with the fibres g, which pass to
the iris at i, forming the pectinate ligament ; h, venous canal ; k, ciliary liga-
ment or muscle arising from the inner wall I of the venous canal ; m, pigment-
layer of ciliary processes ; n, that of iris ; o, fibrous layer of iris ; p, its epithe-
lium ; q, anterior wall of capsule of lens; s, epithelium of capsule ; t, anterior
thickened portion of hyaloid membrane; u, zonule of Zinn, or anterior lamina
of hyaloid membrane ; v, posterior lamina of the same ; w, colourless epithelium
of the ciliary processes ; w', anterior end of this epithelium ; x, conjunctiva of
sclerotica ; x, posterior wall of the capsule of the lens.
Magnified 12 diameters.

state or contained within epithelial cells ;
and fragments of pulmonary tissue.

The aid of the microscope in the examina-
tion of the expectoration will occasionally
throw an unexpected light upon the dia-
gnosis of disease.

EXUDATION, and EXUDATION COR-
PUSCLES. See INFLAMMATION.

EXUVIUM (exuvia ; or exuviae, plur.). —
The cast or shed skin of animals. The exu-
vium of many minute animals exhibits the
form and structure of the skin, and the parts
upon which it is moulded, better than these
can be discerned in the living animals, on
account of its transparence.
The exuvium of the TRI-
TON (PI. 40. fig. 11) exhi-
bits the cellular structure
of the epidermis very beau-
tifully.

EYE. — From want of
space, we are compelled to
assume that the reader pos-
sesses a knowledge of the
component parts of the eye
and their relative position,
as far as can be obtained
without the use of magni-
fying glasses. These parts
are described in all works
upon anatomy, and in most
of those upon optics.

The outer fibrous coat of
the eye is commonlyregarded
as consisting of two parts :
one anterior, smaller and
transparent, — the cornea ;
the other, posterior, larger
and opaque, — the sclero-
tica. The history of the
development and the mi-
nute structure of these,
proves that they must be
considered as forming a sin-
gle continuous membrane.
The sclerotica (fig. 213.
Scl.}, or tunica albuginea,
covers the posterior four-
fifths of the ball of the
eye; it is a milk-white,
very firm, fibrous mem-
brane, continuous poste-
riorly with the sheath of
the optic nerve, becoming
gradually thinner in front,
except at its termination,
where the tendons of the
recti muscles become fused

EYE.

I 251 ]

EYE.

with it. It consists of areolar tissue, the
bundles of which are mostly straight, in-
timately united as in the tendons, forming
alternating, longitudinal and transverse
layers of various breadth and thickness.
Mingled with the areolar tissue are nume-
rous fine elastic fibres, in the form of a
network, with thickenings which indicate
the remains of the nuclei of the formative
cells; these, in the inner portions, contain
pigment. During life, the elements of this
network, in parts, appear to involve canals
with liquid contents; so that when dried,
they contain air.

The cornea may be regarded as consisting
of three-layers : — 1, the corneal conjunctiva ;
2, the true cornea ; and 3, the membrane of
the aqueous humour.

The true cornea (fig. 213 c), which forms
the principal part of the membrane, consists
of a substance nearly allied to areolar tissue.
Its elements are pale bundles, from 1-6000 to
1-3000" in diameter, with still finer fibrillse,
united to form larger flat bundles, the sur-
faces of which are parallel to that of the
cornea ; these are connected with the bun-
dles before and behind, so as to form a coarse
reticular tissue. Between the bundles are a
large number of anastomosing, fusiform, and
stellate nucleated cells of imperfectly-deve-
loped elastic tissue. The cells undergo fatty
degeneration, partly forming the arcus seni-
lis ; and they sometimes contain pigment.

The corneal conjunctiva (fig. 213 a b] con-
sists of laminated soft epithelium ; the under
layer of cells elongated and placed perpen-
dicularly to the surface, the middle cells
rounded, those in the upper layer forming
softer nucleated plates. Many of the latter
are furnished with larger or smaller depres-
sions, arising from mutual pressure, so as to
appear stellate in the side view. Beneath
the epithelium is a structureless layer, — the
anterior elastic membrane, consisting of the
remains of the formerly vascular layer of the
corneal conjunctiva.

The membrane of the aqueous humour (fig.
213 d) consists of an elastic, perfectly struc-
tureless membrane, somewhat loosely con-
nected with the cornea, and an inner epithe-
lial lining. Towards the circumference of
the cornea, the membrane of the aqueous
humour merges into a peculiar system of
fibres, which commence near the margin of
the cornea, at the anterior surface of the
aqueous membrane (fig. 213 g) as an extended
network of fine fibres, resembling elastic
fibrillse; this increases in thickness, and at

the very margin of the cornea the aqueous
membrane becomes lost in a tolerably dense
network of these coarse fibres, which curve
around the margin of the iris (fig. 213 «),
some passing through the anterior chamber,
and become fused with the anterior surface
of this membrane and the ciliary ligament
(or muscle). These fibres form foe. pectinate
ligament of the iris, which is much more
distinct in some animals (as the dog) than in
man.

The epithelium of the aqueous membrane
consists of a single layer of polygonal cells.
These become smaller near the margin of
the cornea, where the membrane terminates
as a continuous layer ; but isolated portions
of elongated or spindle-shaped cells are con-
tinued over the pectinate ligament to the
anterior surface of the iris.

The cornea yields chondrine on boiling,
and not gelatine.

The choroid membrane contains a large
number of blood-vessels, and abounds in
pigment. Its anterior, smaller, and trans-
verse portion forms the iris.

The posterior portion, or proper choroid
membrane, is from 1-360 to 1-180" in thick-
ness, and extends from the entrance of the
optic nerve to near the anterior margin of
the sclerotica, where it becomes thicker,
forming the ciliary body, whence it is con-
tinued into the iris. It is connected with
the sclerotica by vessels and nerves, and by
some of the pigment-cells of its outer layer
being continued into the areolar tissue of the
sclerotica. The lamina fusca of authors is
constituted by a portion of the membrane
thus left adherent, when attempts are made
to separate it from the sclerotica.

The choroid consists essentially of two
parts, an outer vascular and thicker layer, —
the proper choroid; and an inner deeply
coloured layer, — the pigmentum nigrum*
The former may again be separated into
three parts, although these are not really
distinct : — 1, an outer, brown, soft layer,
which supports the ciliary nerves and long
ciliary vessels, and contains anteriorly the
ciliary ligament, — the outer pigment layer ;

2, a less highly coloured proper vascular
layer, with the larger arteries and veins ; and

3, a colourless delicate inner layer, contain-
ing an extremely copious capillary network,
— the choro- capillary membrane, which does
not extend anteriorly beyond the margin of
the retina. The stroma of the choroid pro-
per consists of elastic tissue, in the form of
very irregular spindle-shaped or stellate

EYE.

[ 252 ]

EYE.

1-600(T in length,
Fig. 214.

cells, from 1-1500 to
either paler,or contain-
ing a large quantity of
pigment, and anasto-
mosing by numerous
long and very slen-
der processes (fig.2 14).
These cells are most
distinct in the outer
layer ; whilst more
internally, and espe-
cially in the choro-
capillary membrane,
they gradually pass
into a homogeneous
Or slightly striated Cells from the stroma of the

nucleated tissue, either ^oroid-. a, containing ?ig-

i -j.A j went ; o, fusiform cells with-

COntammg little and Out pigment ;c, anastomosis
ultimately no pig- of the former,
ment. Magn. 350 diams.

In some animals the choroid membrane
contains muscular fibres. Between the stro-
ma and the pigmentum nigrum, is a very
thin elastic layer ; this is either structure-
less, granular or finely reticulated, and is
comparable to a basement membrane.

The ciliary ligament, or, properly, ciliary
muscle, — tensor choroida (fig. 213 &), —
is composed of a tolerably thick layer of
radiating unstriated muscular fibres : these,
intermixed with pigment-cells of the choroid,
pass from the anterior margin of the sclero-
tica to the ciliary body, and lose themselves
in its anterior half, opposite the base of the
ciliary processes. The fibre-cells are 1-600"
in length, broader than most fibre-cells, and
not easily isolated in man.

The ciliary processes consist of the same
stroma as the choroid, but the stellate cells
are more delicate and fewer ; and with
the exception of those at their base, do not
contain pigment; nor are they furnished with
the elastic lamina.

The pigmentum nigrum (fig. 213, m) lines

Fig. 215.

Cells of the human pigmentum nigrum: a, surface
view; b, side view; c, pigment- granules.

Magnified 350 diameters.

the inner surface of the choroid, and as far

as the termination of the retina consists of a
single layer of beautiful, regularly six-sided
cells (fig. 215, a, 6), from 1-2000 to 1-1500"
in diameter ; they contain abundance of pig-
ment. Beyond the margin of the retina, the
cells form mostly two layers, and become
rounded and more loaded with pigment. The
granules of pigment are very minute, rounded,
from 1-20,000 to 1-30,000" in diameter,
and exhibit molecular motion. In the
eyes of albinos, and in the region of the
tapetum of animals, the cells contain no pig-
ment.

The iris (fig. 213, I) consists of three
layers: an anterior epithelial layer, a pos-
terior layer of pigment, called the uvea, and
continued from the inner pigment layer of
the choroid, and a middle, the thickest or
fibrous layer.

The fibrous layer differs from the choroid,
in containing areolar tissue, forming delicate
loose bundles, some of which pursue a radia-
ting, others a circular course, and interlacing
variously; in this tissue are a number of
spindle-shaped or stellate cells, containing
pigments, corresponding to those of the
choroid; and in addition to numerous blood-
vessels and nerves, two sets of muscular
fibres ; the latter in some animals are trans-
versely striated, but in man they resemble
the ordinary unstriped fibre-cells, and are
1-600 to 1-400" in length. One set forms
a sphincter for closing the pupil, its fibres
taking a circular direction; the other set
consists of bundles of radiating fibre-cells,
traversing the stroma of the iris. The pig-
ment layer or uvea consists of the same
elements as those of the corresponding layer
of the choroid.

The anterior coat consists of a single layer
of rounded, flattened, epithelial cells.

The blood-vessels of the choroid membrane
and ciliary processes are easily injected (e. g.
in the sheep or ox) from the ciliary arteries,
and form a magnificent object.

Retina. — The structure of the retina is so
extremely complicated, that we have not
space to give more than a sketch of its com-
ponent elements.

Eight layers are apparently present in a
transverse section of the retina (fig. 216),
excluding the hyaloid membrane, a ; viz. 1,
the layer of bacilli and cones (fig. 216, k, i) ;
2, an outer (A) ; 3, an intermediate (g}, and
4, an inner (/) granular layer ; 5, a layer of
nerve-cells (e); 6, the expansion of the optic
nerve (d) ; 7, the inner ends of the radial
fibres (c) ; and 8, the limiting membrane (&).

EYE.

[ 253 ]

EYE.

The limiting membrane (5) is an extremely
Fig. 216.

Perpendicular section of a piece of the posterior part of
the human retina.

a, hyaloid membrane with nuclei ; b, limiting mem-
brane ; c, ends of the radiating fibres, so altered as to
present a cellular appearance ; d, expansion of the optic
nerve ; e, layer of nerve-cells ; /, inner granular layer ; g,
intermediate or finely granular layer, in which the radia-
ting fibres are more distinct than elsewhere ; h, outer
granular layer ; i, inner division of the layer of bacilli with
the cones ; k, outer division, with the processes of the cones
and the true bacilli.

Magnified 250 diameters.

delicate structureless film, covering the inner
surface of the retina, including the entrance
of the optic nerve, and the punctum aureum.

The expansion of the optic nerves forms a
membranous layer of extremely delicate
transversely radiating fibrils (fig. 217, 3),
from 1-24,000 to 1-12,000" in diameter, and
mostly exhibiting varicosities. They contain
no nuclei in their course, nor do they appear
to contain axial fibres. They are aggregated
into flattened bundles, which either run
parallel or anastomose with each other. They
appear to terminate in, or rather to arise
from the nerve-cells of the retina ; and are
absent, or at least as a coherent layer, oppo-
site the punctum aureum.

The layer of nerve-cells (e) consists of
ordinary nerve-cells, pyriform, roundish or
angular, with pale processes ; they vary in
diameter from 1-3000 to 1-750".

The remainder of the retina is com-
posed of a very large number of parallel,
very slender (1-60,000 to 1-20,000" dia-
meter), highly refractive, radiating fibres or
tubes, with their axes at right angles to
the surface of the choroid upon which
their outer end rests, whilst their inner
triangular or branched extremities are in
contact with the limiting membrane. They
produce the striated appearance presented
by a section of the retina (fig. 216). They
are furnished at certain parts of their course
with expansions containing each a nucleus ;

and the fibres are very numerous. These
Fig. 217.

z.

Elements of the human retina. 1 . Radial fibres with
bacilli; k, bacillus connected with the fibre (r) by its
inner acute end ; h, nucleated expansion (cell), appearing
in the outer granular layer ; /, expanded end of the fibre
resting upon the limiting membrane m ; k1, a bacillus
connected with a cone i ; r1, fibre running from the cone
to the cell /of the inner granular layer ; », branched ter-
mination of a radial fibre often present. 2. Bacilli sepa-
rated from the fibres, broken and curved, &c. 3. Fibrils
from the expansion of the human optic nerve ; a a, larger,
b, smaller fibrils with varicosities ; c, undulating pale fibres
belonging probably to the proper radiating system. 4.
Two cones connected with bacilli, and fragments of the
fibres remaining : a, bacillus ; b, cone ; c, nucleus of
cone.

Magnified 350 diameters.

nucleated expansions being opposite each
other, or in the same planes, give rise to the
appearance of distinct granular layers men-
tioned above. The more internal nucleated
expansions are connected with the nerve-
cells of the retina by minute nerve-tubes.

Their outer portions have been distin-
guished as the bacilli and cones, but the
whole probably forms one continuous system
of nerve-cells and tubes.

The bacilli, regarded (fig. 217, 1 &, &', 2) as
distinct bodies, are cylindrical, narrow and
elongated; of the same breadth throughout;
truncated externally, and terminating inter-
nally in a more slender portion of the fibre;
they are from 1-430 to 1-330" in length and
1-15,000" in breadth; near the point of
attachment to the fibre is a transverse line.
They are extremely delicate, and easily

EYE.

[ 254 ]

EYE.

broken or deformed. The cones(fig.217,l«,4i)
are bacilli with a conical or pyriform body ;
and are also very easily injured. A slight
constriction divides each cone into two parts,
the innermost of which (fig. 217, 4 c) contains
a nucleus. .The cones are from 1-6000 to
1-4000" in diameter. In most parts of the
retina the cones are surrounded by several
bacilli ; opposite the punctum aureum, they
alone form a continuous layer ; whilst at its
margins, single bacilli intervene between the

Fig. 218.

End view of the rows of bacilli and cones from the out-
side. 1, opposite the punctum aureum (cones only) : 2,
at its margins ; 3, at the middle of the retina, a, cones
or spaces corresponding to them ; b, bacilli of the cones,
the ends of which are often situated somewhat beneath
the level of those of the true bacilli, c.

Magnified 350 diameters.

cones (fig. 21 8). Opposite the entrance of the
optic nerve, both bacilli and cones are absent.
These curious bodies are more distinctly seen
in many animals than in man (PL 41. fig. 5).

The radial system of fibres pass between
the nerve-cells of the retina and the meshes
of the optic nerve to reach the limiting
membrane. The inner ends of the fibres
next the latter membrane, when overlapping
each other, and especially when swollen by
the action of water, present the appearance
of a number of rounded or angular cells
(fig. 216, c); for which they were once mis-
taken.

It is thus evident, that, excepting the layer
of nerve-cells and that of the fibres of the
optic nerves, the retina cannot truly be con-
sidered as composed of layers. The series
of bacilli and cones when torn from their
connexion with the radial fibres, form the
so-called Jacob's membrane.

We cannot enter into the physiology of
these radial fibres, which have been shown
to be the percipients of light.

Crystalline lens, or, simply, crystalline. The
crystalline lens is contained in a capsule (fig.
213, q. 3), consisting of a perfectly structure-
less, very elastic membrane, the anterior half
of which is lined with a single layer of very

transparent, polygonal, epithelial cells (fig.

213, s), from 1-2000 to 1-1200" in diameter.

The lens itself consists of long, transparent,

six-sided, flattened fibres (fig. 219), from

Fibres or tubes of the lens of the ox.
Magnified 350 diameters.

1-4800 to 1-2400" in breadth and 1-8500 to
1-1300" in thickness ; these are tubular, at
least in the outer portions of the lens, and
contain a tenacious sarcodic substance, which
escapes from the ends of the broken fibres
in irregular globules, The form of the fibres
is best seen in a transverse section (fig. 220).

Fig. 220.

Transverse section of the fibres or tubes of the human
lens.

Magnified 350 diameters.

The fibres are firmer, narrower, and more
highly refractive towards the centre of the
lens. Their general arrangement is such,

EYE.

[ 255 ]

EYE.

that their broad surfaces are parallel with
the surface of the lens ; and that they follow
a direction from the middle of the anterior to
that of the posterior surface, curving laterally
in their course ; not, however, exactly from
the middle, but from the arms of a star-shaped
kind of centre : at which parts (figs. 221, 222)
the fibres are replaced by a homogeneous

Fig. 221.

Anterior view of human crystalline lens (adult) ; show-
ing the stars and the direction of the fibres.

Magnified 5 diameters.

or finely granular matter. The arms of the
star present upon the surfaces, are the extre-
mities of planes extending through the
substance of the lens, from which the
inner fibres take their origin. The arms

Fig. 222.

Posterior view of lens.
Magnified 5 diameters.

of the anterior and posterior stars are
not parallel with each other, nor are the
fibres arising from any part of the arm
of one cross, inserted into the correspon-
ding part of the arm of the opposite cross.
Great variety exists in different animals in
the structure and arrangement of these stars

and planes. Thus, in the human foetus, the
star has three arms or planes ; whilst in the
adult, there are from nine to sixteen, of
which three are frequently more distinct
than the others. In some animals they are
replaced by a pole, from which the fibres
radiate like meridians ; as in the cod, the
Triton, and Salamandra ; in others, there is
a single plane, as in some fishes, the frog,
the hare, the rabbit, and the dolphin; whilst
in most of the mammalia there are three,
and in the whale, the bear, and the elephant
there are four.

The edges and marginal surfaces of the
fibres of the lens are uneven or toothed, so that
their lateral connexion becomes more inti-
mate ; hence the lens separates more readily
into parallel laminae in the direction of the
surface, than in the opposite direction.

In many animals, especially fishes, as the
cod, the roach, &c., the irregularities of the
fibres of the lens are replaced by beautiful
teeth (PI. 41, fig. 6).

Vitreous humour, or body, is enclosed in
a membrane, the hyaloid membrane, which
behind the dentate margin of the retina is
extremely thin and delicate ; anterior to this
it becomes firmer (fig. 213, t) and passes,
forming the zonule of Zinn to fuse with the
capsule of the lens. In thus doing, it sepa-
rates into two layers, a posterior (v), which
becomes consolidated with the capsule of
the lens, somewhat behind its margin; and
an anterior (u), connected with the ciliary
processes, which becomes attached to the
capsule of the lens a little in front of its cir-
cumference ; between these two is the canal
of Petit ( C.P.). The structure of the vitreous
body is still obscure.

The structure of the eye is very difficult
of examination, the parts being so delicate
and easily injured. Many of them can be
made out by dissecting the eye under water,
but the more delicate structures should be
immersed in the liquid of the anterior
chamber ; solution of chromic acid is useful
for hardening the parts to allow of sections
being made with a Valentin's knife. The lens
should be hardened by maceration, either in
solution of chromic acid, or by drying. The
fibres may be well preserved in the dry state.

The structure of the eyes of the lower
animals is briefly noticed under the classes,
&c. In the mammalia generally, it is essen-
tially the same as in man, and the eye of the
ox or sheep may be selected for examination.

BIBL. Kolliker, Mikroskop. Anat. bd. ii;
Todd and Bowman's Physiol. of Man.

EYLAIS.

[ 256 ]

FAVELLIDIUM.

EYLAIS, Latr. — A genus of Arachnida,
of the order Acarina, and family Hydrach-
nea.

Char. Palpi longish, fourth joint longest,
the fifth obtuse, somewhat tumid, spinous ;
mandibles imguiculate ; rostrum very short,
mouth round ; body depressed ; two approxi-
mate pairs of eyes ; coxae comparatively nar-
row, the fourth only in contact with the third
at its base.

E. extendens (PI. 2. fig. 28). Skin soft,
furrowed, with the ramified alimentary canal
visible through its substance. Between the
two anterior coxae (d) is seen the bilobed
labium (a), the posterior portion containing
the round and ciliated mouth, the anterior
portion forming a kind of hood; palpi (b)
with the three first joints very short; mandible
consisting of a long thick joint, with a thick
mobile claw (c). Fig. 28 d, under surface of
body, exhibiting from before backwards:
the mouth, with the hood, and the palpi;
next two groups of anterior coxae ; the vulva
and two stigmata ; the four posterior coxae ;
and lastly, the anus in the middle, with a
stigma on each side.

The larvae are hexapod, reddish, pellucid,
with the eyes four, wide apart.

BIBL. Duges, Ann. des Sc. not. 2 ser. i.
p. 156; Gervais, Walcken. Arachnid, iii.
p. 207 ; Koch, Deutschl. Crustac.

F.

FADYENIA, Hook.— A genus of Nephro-
dieae (Polypodaeous Ferns). Exotic.

FAECES.— We shall not dwell upon the
nature of the objects contained in the foeces;
suffice it to say, that they may consist of, —
the elements of the various secretions poured
into the intestinal canal; the products of
inflammation; undigested remains of arti-
cles of food, or bodies taken with the food
or drink ; and entozoa. Some of these re-
semble others very closely to the naked eye.
The use of chemical reagents should never
be omitted in their examination.

BIBL. See CHEMISTRY, Animal.

FASCIAE.— The fasciae consist of the same
elements as AREOLAR TISSUE, and present
all the varieties of arrangement intermediate
between it and TENDON.

FATTY DEGENERATION. See DE-
GENERATION, FATTY.

FATTY TISSUE, or ADIPOSE TISSUE.—
This is formed of colourless cells, with a
very delicate, transparent, structureless cell-

wall, enclosing, in the normal state, globules
of yellowish fat (PL 40. fig. 41). The cells
generally occur in groups, surrounded by or
imbedded in areolar tissue. They are rounded
when isolated, or polygonal when aggregated,
and from 1-800 to 1-300" in diameter; and
the fat so fills them, that neither the nucleus
which they contain, nor the cell-wall, is visi-
ble. The fat may be removed by drying
them, and digesting with aether, when the
cells appear contracted and wrinkled. In
emaciated and dropsical subjects, each cell
contains a number of small globules of fat,
frequently of a reddish colour (PI. 30. fig. 3),
together with serum, and the nucleus is very
distinct. Sometimes in these cases the cells
are somewhat spindle-shaped or stellate.
The fat contained in the cells is ordinarily in
a liquid state, but sometimes the margarine
separates in the crystalline form (PI. /. fig.
16 a).

In the mammalia generally the fatty tissue
occurs in the same localities, and has the
same structure as in man. In fishes, the fatty
matter is deposited principally in the liver.
In reptiles, it occurs chiefly in the abdomen;
thus in the frog and toad it forms long ap-
pendages occupying the sides of the spine.
In birds, it exists chiefly between the peri-
toneum and the abdominal muscles, and in
some of the bones. In many of the lower
animals it appears to exist in the state of
solution only.

Fatty matter maybe deposited in cells of all
kinds, as in FATTY DEGENERATION. During
the development of cells, it exists in solu-
tion. The action of solution of potash is
often of service in distinguishing globules of
sarcode, which have a high refractive power,
and much resemble those of fat from this
substance, as it dissolves the former, but not
the latter.

BIBL. Todd and Bowman, Phys. of Man',
Kolliker, Mikroskop. Anat. 1.

FAVELLA. — A form of the conceptacular
fruit of the Florideous Algae, where the
spores are collected in spherical masses, si-
tuated wholly upon the external surface of
the frond, as in Ceramium and Callitham-
nion.

FAVELLIDIUM.— A form of the concep-
tacular fruit of the Florideous Algae, when
the spores are collected in spherical masses,
attached to the wall of the frond or imbedded
in its substance, as in Halymenia and Du-
montia. The term is usually extended to
similar fruits not perfectly immersed, e. g.
those of Gigartina, Gelidium, &c., where

FAVUS.

[ 257 ]

FEGATELLA.

they form tubercles upon the branches.
Sometimes these tubercles open by a pore
on the surface, when mature, to emit the
spores.

FAVUS (Porrigo in part, Willan and
Bateman). — A disease of the skin, charac-
terized by the presence of cup-shaped iso-
lated or aggregated crusts, consisting of a
Fungus. (See ACHORION and PUCCINIA.)
FEATHERS, OF BIRDS.— Feathers agree
in all essential points of structure with the
hairs of other animals.

Each feather is composed of a quill, con-
taining the pith, a shaft, and a vane or beard,
with its barbs. The whole consists of a
number of epidermic cells, often containing
pigment, but in most parts so consolidated
or fused together as to be imperceptible.

In the quill, the cells are flattened, elon-
gated, and arranged with their long axis in
the direction of that of the feather, and their
nuclei have the same form as those of the
corresponding part (cortex) of the human
hair. The cells of the pith are often undis-
tinguishable in old feathers, whilst in the
younger ones they are very distinct, rounded
or polygonal, and contain air. The shaft
and the barbs exhibit the same cortical and
medullary structure ; the latter is often beau-
tifully distinct (PI. 17. figs. 14 & 15 c), and
causes them to resemble closely the hairs of
some Rodents. The barbs are sometimes
furnished with secondary barbs, or processes,
resembling them in form, but differing mostly
in the absence of the pith.

Feathers are developed in a capsule, and
from a pulp or matrix, as in the case of hairs .
Hence a feather may be regarded simply as
a large, doubly or triply pinnate hair.

During development, the cell structure is
very distinct; but in the mature feathers,
digestion with solution of caustic potash is
requisite to render this visible, and frequently
even under these circumstances, the nuclei
alone can be detected.

The barbs of some feathers resemble the
shafts, being rounded or angular, and free or
unattached (figs. 17 & 18); but in others
they are flattened, and linked together in a re-
markable manner, much resembling that met
with in the wings of Hymenopterous and other
Insects (PL 27. figs. 1 1 & 13), and which has
been so often adduced as one of the many
wonderful instances of design in the creation.
Thus, the upper or outer margin of each
barb is fringed on both sides with hair-like
elongated processes or pinnae (PI. 17. fig. 15
a, b), which differ in structure on the two

sides. On one, and this always the same
side of each barb (fig. 15 b}, the pinna3 are
toothed on one edge (fig. 16 b*), whilst the
pinnae arising from the other side (fig. 15 c)
exhibit, beyond the middle, a number of
curved hooks (fig. 16 «), which clasp around
the first kind existing upon the adjacent
barb, so as to retain a firm hold upon them,
this being aided by the teeth, which prevent
them from slipping. If the relative position
of the two sets of pinnae which spring from
two adjacent barbs be examined, it will be
seen that they cross each other at a consider-
able angle, so that any pinna from one barb
crosses several of those belonging to the
next barb. Hence each pinna is connected
by its hooks with several of those which it
crosses ; for the pinnae with hooks are situ-
ated outside or above those not furnished
with these appendages. The under or inner
margin of each barb is simply membranous,
and curved so as to overlap that of the next.

The free barbs of feathers are often met
with in the examination of liquids, &c., left
exposed to the air (figs. 17 & 18).

BIBL. Schwann, Mikrosk. Untersuch. ;
Reclam, De Plumar. Evolut. fyc.

FEET.— In descriptions, &c. of the Arti-
culata, especially of Insects, the word/<?e£ is
mostly used to designate the legs; hence
when met with in the works of systematic
and other writers on these classes, it must
be understood to mean the legs.

FEET, OF INSECTS. See INSECTS, Legs.

FEGATELLA,IUddi(Ca»*ocep&a/M*,Hill).
— A genus of Marchantiaceous Hepaticaceae.
F. conica (Marchantia conica, Br. Flora), the
only British species, is not uncommon, and

Fig. 223.

Fig. 224.

Fegatella conica.

Fig. 223. Vertical section of the upper part of a fertile
receptacle, showing four of the sporanges surrounded by
their perigones and epigones almost enclosed in the coni-
cal receptacle. Magnified 10 diams.

Fig. 224. A sporange just before bursting, enclosed in
ts epigone ; its pedicel detached at the base. Magn. 20
diams.

s one of the largest of the tribe. It is dis-
tinguished from Marchantia by its nearly

FERMENTATION.

[ 258 ]

FERMENTATION.

entire conical fertile receptacle. The dicho-
tomously divided frond is of a yellowish
green colour. This genus is remarkable for
the mode in which the pedicel of the spo-
range becomes detached from the base of the
epigone before the former bursts (fig. 224) ;
the perigone holds the sporange firmly be-
tween its valves until empty, and then lets
it fall out, together with its pedicel. Hence
fully-dev eloped sporanges are seldomfound in
dried specimens. (See MARCHANTIE^E.)

BIBL. Hooker, Brit. Flora, v. pt. 1. p. 107;
Bischoff, Nova Acta Acad. N. C. xvii. 970.
pi. 68, English Botany, pi. 504.

FERMENTATION.— Thedefinition given
by Mulder is, — a chemical action effected by
certain substances and transferred to others;
the primary substances being at the same
time decomposed, though they do not com-
municate any of their elements to the new
products. Under this name are understood
various processes of decomposition of organic
compounds, although it would be desirable
to restrict it to those taking place with the
cooperation of living organisms. The most
familiar examples of the fermentation pro-
duced by the growth of living organisms, are
those which convert saccharine infusions into
spirit, vegetable juices into beer, wine, &c.,
or vinegar, and occurring generally in watery
solutions of vegetable substances containing
saccharine matters or other ternary com-
pounds with a certain amount of nitrogen ;
with these is included also the putrefactive
fermentation of moist animal or other highly
nitrogenous substances.

The vinous fermentation appears to de-
pend entirely upon the growth of Yeast, a
microscopic fungus, in the liquid (seeYE AST);
and the same plant is not only capable of pro-
ducing the conversion of spirit into vinegar,
but will also give rise to the peculiar fer-
mentations of milk, tannic acid, &c. Much
obscurity yet prevails upon this subject, but
all investigations appear to tend in the direc-
tion of proving that these changes are abso-
lutely dependent upon the agency of Fungi.
The nature and characters of the fungoid
productions are themselves but imperfectly
understood, for the same species seems to
present very different forms under different
conditions of temperature and in different
liquids, while it is very possible that the
same changes may be produced in any given
liquid by the growth of the mycelium of dif-
ferent kinds of Fungi. The Yeast-plant, as
ordinarily known, appears so often associated
with Penicillium, that it is impossible not to

suspect some relation between them. We
find that beer, exposed to the air at ordinary
summer temperatures, soon becomes coated
with the minuter globules (spores) of Yeast,
forming a dry-looking whitish powder over
the surface, and very soon after Penicillium
glaucum makes its appearance in fruit.
Turpin found the same thing in milk. Again,
the * vinegar-plant,' as it is called, which
converts solutions of sugar into vinegar,
seems to be undoubtedly the mycelium of
Penicillium glaucum, as it fruits with the
characters of this when the liquid is ex-
hausted; but the gelatinous mass of myce-
lium contains, intermixed with the ordinary
filaments of this genus, spherical and ellip-
tical cells and chains of cells of all sizes,
many of which are undistinguishable from
the Yeast-plant, and the mycelium oWidium.
It must be recollected also, that the growth
of true Yeast is favoured by a certain amount
of heat, while the Penicillium-mycelmm.
grows luxuriantly at ordinary temperatures.
The ' mother' of vinegar, which finally
decomposes the acid, appears to be the same
plant, and no satisfactory distinction can be
drawn between this and those mycelia form-
ing cloudy flocks in and decomposing various
saline solutions, &c., described as species of
Hygrocrocis, Leptomitus, &c. The decay
of wood, again, is often greatly accelerated
by the growth of the mycelium of Fungi,
which seems to decompose the organic com-
pounds in the wood in the same way that
the Yeast does those in organic liquids. A
general law indeed appears to prevail through-
out the Fungi, that their nutrition differs
from that of all other plants in depending
exclusively on the absorption and decompo-
sition (with the evolution of carbonic acid)
of organic compounds, therefore consisting
of the performance of the operation of fer-
mentation on the organic matters upon which
they feed. Details upon the microscopic
phenomena attending fermentation produced
by Fungi will be found under YEAST, VINE-
GAR-PLANT, TORULA and PENICILLIUM,
and PARASITIC FUNGI.

The fermentation of animal substances,
and of vegetable substances containing abun-
dance of nitrogen, in which ammonia is libe-
rated, is generally called putrefaction, or the
putrefractive fermentation. This process
appears to be accompanied or produced by
the growth of living organisms differing from
those causing the fermentations alluded to in
the foregoing paragraphs. These are the
extremely minute creatures called Vibriones,

FERNS.

[ 259 ]

FERNS.

5 laced by most authors in the Animal King-
om, among the Infusoria, but with no satis-
factory character by which they can be dis-
tinguished from many vegetable organisms,
and differing from animals in their behaviour
with potash. (See VIBRIO.) These creatures
appear in myriads during the decomposition
which takes place when a piece of meat, &c.,
slices of potato, fleshy Fungi, &c., are kept
moist and exposed to the air for some days
in warm weather; and they continue to multi-
ply until the putrefaction is complete, when
they die away. It is a question perhaps
whether these organisms liberate the ammo-
nia and carbonic acid by a kind of respiration
while living, or as an excrement, or whether
these gases result from the decay of the dead
individuals. These points require much fur-
ther investigation.

One point of interest connected with the
fermentation-plants must not be passed over,
viz. that the supposed distinction between
the chemical processes of nutrition in ani-
mals and plants, falls to the ground when
these Fungi are taken into consideration, as
they do not live by converting inorganic
substances into organic compounds, but, like
animals, decompose ready-formed organic
compounds into others and into their inor-
ganic elements.

The cause of the presence of these living
creatures in decomposing substances was
formerly referred to an autonomous produc-
tion of them, but this idea is not entertained
now. (See GENERATION, SPONTANEOUS.)
The whole question of fermentation is in
an unsatisfactory state, which must be the
excuse for this imperfect notice, especially
as it would be to go beyond our sphere to
enter upon the chemical theories of contact,
&c., and the analogous decompositions oc-
curring either evidently or apparently with-
out the production of independent micro-
scopic organisms.

BIBL. Mulder, Chemistry of Veg. and
Anim. Phys. Fromberg's transl. 1849. p. 42;
Gmelin, Handbook of Organic Chemistry,
Lowig, Chemie der Organ. Verb. i. p. 223 ;
Turpin, Mcmoires; Mitscherlich, Poggend.
Annal. Iv. p. 224, Lehrbuch, 4 ed. p. 371,
Bericht. Berlin Akad. ; Cagniard Latour,
Poggen. Annal. xli. p. 193; Schwann, ibid.
p.184; \Jre,Biblioth. Univers. Genev. 1839;
Helmholtz, Mutter's Archiv, 1843. p. 453 ;
Boutron and Fremy, Erdm. and Marchand
Journ. xxiv. p. 364. See also under TORULA
and PENICILLIUM.

FERNS.— This class of Flowerless Plants

offers very many points of interest to the mi-
croscopist, and indeed the use of magnifying
instruments is indispensable in their exami-
nation for botanical purposes. The Ferns
are characterized by the position of their
spore-cases or fruits, which are collected into
what to the naked eye look like streaks, spots,
or patches of a brown colour (sori) at the
back or lower surface of the leaves (fig. 225),

Fig. 225.

Scolopendrum vulgare.

Nat. size.

or at their margins ; these fertile leaves
either resembling the rest, or being modified
in a manner which more or less disguises
their nature, as in what are miscalled ' flow-
ering Ferns' (Osmunda (figs. 226 & 227),
Botrychium, &c.).

The Ferns possess a stem which is more
or less developed in different cases ; in our
native kinds it is either a slender, horizontal,
subterraneous rhizome or rootstock, or a
thick, short, erect one, rising little above the
ground ; but in foreign kinds this erect stem
attains the form and dimensions of a tree,
growing up into a tall unbranched columnar
stem, sometimes more than fifty feet high.
The anatomical structure of the stem of the
Ferns is peculiar and special, depending on

s2

FERNS.

[ 260 ]

FERNS,

the character and arrangement of the fibro-
Fig. 226. Fig. 227.

Osmunda regalis.

Fig. 226. Upper part of a frond l-6th the nat. size.
Fig, 227. A fertile pinnule bearing thecae without pa-
renchyma. Magnified 10 diams.

vascular bundles (see TISSUES, VEGETA-
BLE), which afford the best examples of that
form of elementary tissue called the SCALA-
RIFORM DUCTS. The creeping rhizomes
are often clothed more or less thickly (as are
also the leaf-stalks) with brown membranous
scales, called RAMENTA, and these often
afford elegant microscopic objects, from the
peculiar arrangements of the cells. The
leaves are generally very greatly developed,
and the green blade is of more or less com-
plex structure in different genera. In the
Hymenophylla, or Filmy Ferns, the leaf is a
mere membrane of a single layer of cells,
through which ramify scalariform ducts, to
form the veins, consequently there are no
stomates there ; but in the larger forms, as
in the leaf of Pteris for example, the leaf has
an upper and lower epidermis with stomates,
with loose cellular tissue (mesophyllum), be-
tween and through which ramify the fibro-
vascular veins ; the epidermal cells often have
elegantly zigzaged or waving side-walls,
which produce a pleasing appearance in the
sections of the structure obtained in slices
shaved off horizontally from the surface of
the leaf.

The mode of ramification of the veins or
nerves of the leaves is important in system-
atic Filicology, and may be observed for
such purposes by immersing the dried leaflets
in turpentine or oil, or mounting them in
Canada balsam. The collections of sporanges

or capsules on the back of the leaves some-
times occur on all of these ; in other cases
there are barren leaves and fertile leaves, the
latter of which are generally somewhat mo-
dified in form, deprived of a certain portion
of the green expanded structure, and reduced
occasionally to a mere ramification of veins
or ribs supporting the sporanges (fig. 227).

The groups of sporanges are called sori ;
they diifer much in form and arrangement,
and are either naked (Poly podium), or co-
vered by a special membranous structure,
more or less continuous with the epidermis
of the lower surface of the leaf, called an
indusium (fig. 228); sometimes this indusium

Fig. 228.

Nephrodium.

Pinnule with indusiate sori.
Magnified 10 diameters.

is so constructed as to form a kind of cup
(figs. 131 & 154), which again exhibits a
great variety of modifications. (See SORI
and INDUSIUM.)

The sporanges or thecte are usually
collected in great numbers in the sori, and
consist of minute stalked sacs or cases, com-
posed of simple cellular membrane, the
cells of which are either all alike (Opmo-
GLOSSUM), or a row of them running almost
round the sac are modified by the thickening
of their walls, so as to form an elastic band

FERNS.

[ 261 ]

FERNS.

(annulus or connecticule), which causes the
bursting of the sac when ripe. In the Poly
podiaceae the annulus starts from the stalk
of the capsule (fig. 229) ; in Hymenophyllum

Fig. 229.

Marginaria verrucosa.
Thecae. Magnified 25 diameters.

and Trichomanes it runs round in an oblique
line (like the ecliptic line on the globe) ; in
Gleichenia it is also oblique (fig. 235),
and in Schiz&a and Aneimia (fig. 12. p. 34),

Fig. 230.

Fig. 231,

Fig. 232. Fig. 233. Fig. 234.

Ceratopteris thalictroides.

Fig. 230. Theca. Magn. 50 diams.

Fig. 231. Do., bursting. Do.

Fig. 232-4. Spores. Magn. 150 diams.

Fig. 235.

Gleichenia.
A theca. Magnified 40 diams.

&c. it forms a kind of cap on the summit of
the case.

These membranous sporanges a"re filled
with spores having a double coat, like pol-
len-grains, and as in these, the outer coat is
ordinarily coloured, and either smoothish or
marked with points, streaks, ridges, or reti-
culations (figs.232-4,236-9). (See SPORES.)

Fig. 236.

Fig. 237.

Fig. 239.

O O

Spores of Ferns.

Fig. 236. Aneimia asplenifolia.

Fig. 237. Polypodium aureum.

Fig. 238. Cystopteris fragilis.

Fig. 239. Pteris longifolia.

Magnified 100 diameters.

The reproduction of the Ferns by their
spores exhibits some very remarkable phae-
nomena. When the spores are sown, they
germinate after a time by a protrusion of
the inner coat as a delicate membranous
pouch (fig. 240), which elongates and be-
comes divided by septa into an articulated
cellular filament ; some of the cells emit
slender tubular filaments (which are not cut
off by septa), apparently radical hairs, and
while these remain uncoloured, the larger
cells from which they arise acquire chloro-
phyll-granules. The young prothallium,
as it is called, increases in size by cell-
division, and at length acquires a somewhat
heart-shaped form (figs. 241-3), and soon
some of its cells produce, upon the under
surface, the structures called antheridia,
which consist of stalked cellular bodies, of
simple but peculiar structure, in the interior
of which are developed minute cellules con-
taining ciliated spiral filaments (spermato-
zoids), which, on the bursting of the anthe-
ridial sac, escape not only from this, but
from their own parent-cells, and swim about
actively in the water by the aid of their
vibratile cilia (PI. 32. fig. 34).

These antherids are often formed in large
numbers, and the prothallium goes on pro-
ducing them as long as it exists ; but at a
period somewhat later than the earlier an-
therids, there appear near the middle, at the
front of the under surface of the prothallium,

FERNS.

[ 262 J

FIBRINE.

other cellular bodies of more complex struc-
ture, which are the archegonia or ovule-like
bodies. The archegone consists of a cellular

papilla, composed of a few colourless cells,
with a canal running down its centre (an
intercellular passage) leading to a cell (em-

Fig. 240.

Fig. 241.

Fig. 242.

Fig. 243.

Germination of Pteris longifolia. Magn. 100 diams.

Fie. 244.

bryo-cell) at the bottom, contained in a cavity
(embryo-sac] in the substance of the prothal-
lium. It is supposed that the ciliated spiral fi-
laments make their way down this canal, like
the pollen-tubes through the micropyles of
Phanerogamous ovules(Hofmeister states that
he has actually seen this), and then the em-
bryo-cell becomes developed into an embryo,
which soon exhibits rudimentary leaves and
rootlets, bursts out from the cavity of the
prothallium (which decays away), and grows
up into the ordinary leaf-bearing stem of the
Ferns (fig. 244). The pro-
thallia bear a variable number
of archegones, but not nearly
so many as of antherids, and
they exhibit, in most fully-
developedspecimens,anumber
of effete organs of both kinds,
which are readily distinguished
by the deep brown colour as-
sumed by the membranes
lining their cavities.

The Ferns likewise produce gemmce on the
leaves of full-grown plants, and even the
prothallia are capable of vegetative multipli-
cation ; for if their archegones are all abor-
tive, they go on vegetating for a long time,
and produce new prothallia by some of their
marginal cells budding out and repeating
the original mode of growth of the spore
itself. These innovations usually bear an-
therids alone, and not archegones.

The Ferns are divided into four families
by microscopic characters.

1. POLYPODIACE^E. The sporanges on
the lower surface of the leaves, in groups
of very varied form, but never blended to-

Pteris, seedling.

gether. The annulus always exists, is vari-
able, and serves to distinguish the tribes.

2. MARATTIACE^E. Sporanges on the
lower surface of the leaves ; usually blended
together, sometimes only very closely ap-
proximated ; without an annulus.

3. OPHIOGLOSSE^E. Sporanges on the
lower surface of the leaf (reduced to mere
ribs); never blended together; without an
annulus.

4. HYMENOPHYLLE.E. Sporanges at-
tached to a common stalk prolonged from
the end of a vein of the leaf, and contained
in a kind of cup formed by a lobe of the leaf
above and an indusial lobe of similar charac-
ter prolonged from the lower surface of the
leaf. Sporanges with an obliquely trans-
verse annulus.

BIBL. Hooker, Genera Filicum ; Presl,
Tentamen Pteridographice, Prag, 1836;
Pa.yer\.,BotaniqueCryptogamique, Paris, 1850;
Bischoff, Kryptogamische Gewachse, Nuremb.
1828 ; Mohl (Structure), in Martins' s Plant.
Kryptog. Brazil ; Moore, Handbook of Bri-
tish Ferns ; Newman, British Ferns. For
minute particulars of the reproduction, see
Henfrey, On the Development of Ferns from
their Spores, Linnean Transactions, vol. xxi.
p. 117. 1853, On the Reproduction of Crypto-
gamia, Annals of Nat. History, 1852, and
the papers of Suminski, Hofmeister, Mette-
nius, De Mercklin, Thuret, and others there
quoted; Hofmeister, Ann. Nat. Hist. xiv.
p. 272.

FIBRINE.— Fibrine is soluble in, or ren-
dered so transparent by acetic acid, as to be
invisible. Its chemical relation to the other
proteine-compounds has not been satisfacto-

FIBROINE.

[ 263 ] FILAMENTOUS STRUCTURES.

rily determined. A substance resembling
fibrine in many of its characters, if not iden-
tical with it, occurs upon the surfaces of in-
flamed membrane, &c. ; in these cases it
generally includes the other elements of in-
flammation, and almost always a number of
minute granules of fat.

Fibrine is coloured by the test-liquids of
Millon ami Pettenkofer.

The fibnnous plasma of the lower animals
resembles fibrine in many respects, but does
not separate in fibres.

See BLOOD, p. 83.

BIBL. That of CHEMISTRY, ANIMAL.

FIBROINE. — The principal constituent
of silk, cobwebs, and the horny skeleton of
sponges. In the pure state, it is white, in-
soluble in water, alcohol, aether, acetic acid,
and ammonia. It is amorphous.

BIBL. That of CHEMISTRY, ANIMAL.

FIBRO-PLASTIC TISSUE. See TIS-
SUE, FIBRO-PLASTIC.

FIBROUS and FIBRO - VASCULAR
BUNDLES. See TISSUES, VEGETABLE.
FIBROUS STRUCTURES, OF PLANTS.

— This term is somewhat equivocal, and re-
quires a little explanation here. In common
language all vegetable substances are termed
fibrous which can be separated into more or
less fine threads possessing a certain degree
of tenacity ; special examples are furnished
by those forming the materials for textile
fabrics. But the anatomical or microscopical
structures comprehended here are exceedingly
varied, including not only liber-fibres, but
spiral vessels, and even hairs. Thus while
Flax (PI. 21. fig. 2) is the liber of Linum
usitatissimum, Hemp (PI. 21. fig. 6) of Can-
nabis, Jute (PI. 21. fig. 3) of Corchorus
capsularis, &c., Puya (PI. 21. fig. 26) of
Boshmeria Puya, and the material of Chinese
grass cloth (PI. 21 . fig. 25) of Boehmeria
nivea, Coir (PI. 21. fig. 4), the liber-like
fibre of the husk of the cocoa-nut, — the
Manilla hemp (PI. 21. fig. 7) is composed of
the fibro-vascular bundles of Musa textilis,
and Cotton (PI. 21. fig. 1) consists of the
hairs covering the seeds of species of Gossy-
pium. These and similar substances may be
conveniently referred to the article TEXTILE
SUBSTANCES, but they are also spoken of
under LIBER, HAIRS, and under their re-
spective heads.

In botanical language, the word fibre has
come into use in two very different senses.
First, any long cell attenuated to a point at
both ends, and with its walls thickened with
ligneous secondary deposits, is called a, fibre

fibrt

some authors. Thus the term woody
•e is applied to the shorter cells of this
kind which make up the substance of most
solid woods, while the term liber-fibre is ap-
plied (with more justice) to the often ex-
tremely elongated wood-tubes which form
the elements of the liber of Dicotyledons
and the woody part of the fibro-vascular
bundles of the Monocotyledons. (See TIS-
SUES, VEGETABLE.) The characters of
structures of this kind will be given under
LIBER and WOOD. Secondly, the term
fibre is applied to the secondary deposits
upon the walls of cells, vessels, ducts, &c.,
which, instead of forming continuous pitted
layers, take the pattern of spiral or analogous
lines, and, by increasing in consistence, sub-
sequently form real fibres, often elastically
unreliable, of firmer substance than the
cell-wall upon which they were originally
deposited. The numerous modifications of
these fibrous deposits upon the walls of cells
are spoken of under the heads of SPIRAL
STRUCTURES, VESSELS, and SECONDARY
DEPOSITS.

It must not be omitted here that the walls
of many cells and liber-fibres, which appear
at first sight to be composed of homogeneous
laminse, may often be made to exhibit spiral
streaks, by the use of reagents and macera-
tion ; indeed, they present themselves during
the natural dissolution of the membranes of
some oftheOscillatoriacese (AINACTIS, SCHI-
ZOSIPHON (PI. 4. figs. 13, 15). Hence some
authors have recently recurred to the old
notion that all vegetable membranes are
formed of fibres cemented or blended toge-
ther. This is again strongly combated by
others, as regards the primary membrane of
cells. We enter more particularly into the
details under the article SPIRAL STRUC-
TURES of Plants.

FICUS, Linn. (Figs).— A large genus of
Urticaceae (Dicotyledons), some of which
possess remarkably thick epidermis and cu-
rious pseudo-glandular structures connected
with it. Ficus elastica, one of the plants
yielding india-rubber, now commonly grown
in pots in rooms, is a good example. The
clavate bodies (PI. 39. fig. 27) of Meyen, de-
veloped in cavities in the leaf, beneath the
epidermis, contain crystalline deposits. (See
GLANDS and RAPHIDES.)

FILAMENTOUS STRUCTURES, OF
PLANTS. — This name would be more appli-
cable than fibrous structures to such sub-
stances as COTTON, which consists of elon-
gated hairs (PI. 21. fig. 1), and indeed to all

FILARIA.

[ 264 ]

FISSIDENTE^E.

elongated cellular filaments with thin and
collapsing walls. It would include all long
vegetable hairs, like those formingthe comaon
many seeds (Poplars, Asclepias, Gossypium,
&c.), also those forming felty coatings on
the epidermis, as in many Composit8e,&c. It is
also applicable to the cells of most of the
Confervoid Algse, to the mycelium (flocci) of
Fungi, and to the medullary layer of the
Lichens. Many other instances will suggest
themselves to the microscopist.

FILARIA, Miill.— A genus of Entozoa, of
the order Ccelelmintha, and family Nema-
toidea.

Char. Body filiform, very long, nearly
uniform ; head not distinct from the body ;
mouth round or triangular, naked or with
papillae; white, yellowish, or red, from 48
to 100 times as long as broad ; oesopha-
gus short, tubular, narrower than the in-
testine; anus terminal, or nearly so; spi-
cula two, of unequal size, more or less twisted;
vulva situated very near the anterior extremity.

Several species, many of which have been
but imperfectly examined. They are most
commonly found in the abdominal cavity,
and between the peritoneal folds of mam-
malia and birds, in the air-cells of the latter,
sometimes in the subcutaneous cellular tis-
sue. Species are also met with in reptiles,
fishes, and insects.

F. medinensis. The hair- or Guinea- worm.
Common in the intertropical regions of the
old world. Length 6" to 10'; breadth 1-20
to 1-10".

F. bronchialis. Occurs in the human
bronchi.

F. lachrymaUs. In the lachrymal gland.

F. oculi. In the globe of the eye, or be-
beneath the conjunctiva.

Two species occur in fresh water, under
the leaves of aquatic plants.

F. aquatilis. Fern, white, constricted be-
hind the spherical head ; tegument not stri-
ated ; oesophagus capillary, very long, sinu-
ous; tail gradually narrowed to a curved
point; vulva anterior to the middle of the
body ; length 3-10 to 4-10" ; breadth 1-250".

F. lacustris. Fern, reddish- white, slightly
narrowed in front, but without a constriction;
mouth very small, lateral, and oblique ; oeso-
phagus filiform, very long, nodose at its
origin; tail conical, obtuse, terminating
obliquely in a very small point; tegument
not striated ; vulva behind the middle ;
length 1-2"; breadth 1-140".

BIBL. Dujardin, Helminthes, p. 42; V.
d. Hoeven, Handb. d. Zool p. 179.

FILICACE.E. See FERNS.

FIR. See PINUS, CONIFERS, and WOOD.

FISSIDENTE^E.— A family of opercu-
late Acrocarpous (sometimes cladocarpous)
Mosses, of gregarious or crespitose habit,
with simple or much-branched stems. The
leaves are amplexicaul (fig. 247), composed
of minute parenchymatous cells, closely are-

Fin-. 245.

Fig. 251.

Fig. 246.

Fig. 248.

Fig. 247.

Fissidens bryoides.

Fig. 245. A plant of F. bryoides. Magn. 7 diams.

Figs. 246 & 247. Leaves detached. More magnified to
show the appendage.

Figs. 248, 24Q, 250. Sections of 246, at various heights
from the base.

Fig. 251. Fragment of peristome. Magn. 100 diams.

olated, often very papillose, produced at the
back and point into a lamina beyond the
leaf (figs. 246 - 250), whence three parts
are distinguished in the latter: — 1, the
true horizontal blade ; 2, the dorsal lamina,

FISSIDENS.

[ 265 ]

FLORIDE.E.

arising vertically from the back of the nerve ;
3, the apical lamina, the preceding lamina
produced beyond the true horizontal blade
of the leaf in a two-edged form, on each side
of the nerve. Capsule equal, rarely annu-
late. British genus :

FISSIDENS, Hedw.— A genus of Fissi-
deiitese. Character that of the family. In-
florescence monoecious or dioecious, terminal
on the main stem or on short secondary
branches. Montague has separated the spe-
cies with an entire calyptra under the generic
name of Conomitrium.

Fruit lateral.

1. Fissidens taxifolium, Hedw. = Dicra-
num taxifolium, Sw.

2. F. adiantoides, Hedw.=D. adiantoides,
Sw.

Fruit terminal.

3. F bryoides, Hedw. (fig. 245)=D.6ry-
oides, Sw.

4. F. incurvus, Schwagr. = D. bryoides y,
Hook. Brit. VI.

5. F.osmundioides,Hed\v.=D. bryoides ft,
Hook. Br. Fl. (Conomitrium, C. Mull.)

6. F. Bloxami, Wilson, Lond. Jour. Bot.
iv. 195.

FLANNEL, NATURAL.— This term has
been applied to sheets or layers, of a harsh,
fibrous texture,sometimes found coveringmea-
dows, rocks, &c. after an inundation. It con-
sists of the interwoven filaments of Confervas,
with adherent or entangled Diatomaceae, In-
fusoria, crystals of carbonate of lime, &c. To
the naked eye it closely resembles a piece of
coarse or loosely woven cloth. Similar layers
are frequently found upon the margins of
pools during the summer. As the water
evaporates, the Confervae and other organisms
remain supported upon the stems of rushes,
or blades of grass, and when dry, form the
yellowish, greenish, or greyish layers of the
so-called natural flannel.
See PAPER, METEORIC.
FLAX.— The liber-fibres from the stems
of the Flax-plant, Linum usitatissimum (nat.
ord. Linaceae, Dicotyledons). Under the
microscope, the fibres (PL 21 . fig. 2) are
readily distinguished from Cotton by the
form and consistence, being round and at-
tenuated to a point at each end, and of a
firm woody consistence which prevents them
from collapsing, and having pits in the wall.
New Zealand Flax is a totally different sub-
stance. (See PHORMIUM.) See FIBROUS
STRUCTURES, of Plants, and LIBER.
FLEA. See PULEX.

FLINT. — The organisms contained in
flint are the same as those met with in agate
and chalk ; and the remarks made upon their
relation to the formation of agate apply
equally to the case of flint. They consist
principally of the fibres, spicula, and gem-
mules of sponges ; the valves of the Diato-
maceae ; fragments of the shells of Mollusca
and Echinodermata ; the scales of fishes ;
and the sporangia of the Desmidiaceae, which
were formerly regarded as distinct organisms
(XANTHIDIA).

In the examination of flint, thin sections
should be made by grinding and polishing ;
some kinds exhibit the organisms containedin
them best by reflected, others by transmitted
light. Some specimens, in which they are
abundant, will exhibit them well in chips
removed by a hammer.
See AGATE and CHALK.
BIBL. That of AGATE and CHALK;
Ehrenb. Ann. Nat. Hist. 1838. ii. 162; An-
sted, ibid. 1844. xiii. 248 ; Bowerbank, ibid.
1847. xix. 240.

FLORIDE^orRHODOSPORE^.— An
order of Algae. Red sea-weeds, some of the
common species of which must be familiar
to every one, as the delicate, feathery or leaf-
like plants brought away by most visitors to
the sea-coast; and the red colour, more or
less permanent or fleeting, is a pretty general
characteristic of this order, varying however
to purple, brown, and mixed tints of red,
green, and yellow, into dirty white. They
chiefly grow in deeper water than the other
sea-weeds, and are met with in finest and
darkest colour in deep tide-pools of sea-
water, especially on the side facing the north,
where they are overhung by the larger dark-
coloured Algae, and thus shaded from the
sun's rays. The greater number do not grow
more than six inches high, few more than
two feet. The simplest forms are filaments
composed of cylindrical cells attached end to
end ; they next rise to a gelatinous or car-
tilaginous expansion, composed of such fila-
mentous structures adherent in layers, and
forming a compact frond of definite shape.
These are said to be of filamentous structure.
Others have the frond composed of a num-
ber of polygonal cells, evenly arranged, and
with thick walls, or, as some state, an inter-
cellular substance binding them altogether
into a mass ; these are technically said to be
of cellular structure. Sometimes all the
cells of the frond contain colouring matter,
sometimes only those of the surface, or of a
shallow superficial stratum.

FLORIDE^E.

[ 266 ]

FLORIDE.E.

The general external appearance of the
Red Sea-weeds is very varied. Sometimes
the fronds are like little leafless bushes;
at others they form broad laminae ; some-
times the lower part is stalk-like, and the
upper parts spread into leaf-like lobes. In
Delesseria we have a close imitation of a
regularly formed leaf of one of the higher
plants. The leaf-like forms are either sim-
ple, lobed, or exquisitely pinnate or fea-
thered, and the Rhodosperms of warmer
climates exhibit most elegantly reticulated
fronds. Some of these plants deposit car-
bonate of lime in their tissues in such quan-
tity that they become quite stony, so that the
vegetable form alone remaining, they are com-
monly mistaken for true corals (see CORAL).
By placing these corallines and nullipores in
vinegar or dilute hydrochloric acid, the lime
is removed, and the cellular vegetable orga-
nization may be recognized. The tropical
forms of the corallines are far more varied
and beautiful than our own.

The fructification of these plants, like that
of the other Algae, is as yet but imperfectly
known. We find on them three distinct
forms of what appear certainly to be. repro-
ductive structures, but their relative and
special physiological values have still to be
ascertained. The three kinds of structure
known are called, — 1, tetraspores ; 2, spores ;
3, anther ozoids, or by some, spermatozoids.

1. The tetraspores. The structures known
under this name are of similar organization
throughout this order ; they consist of an
oblong or globular external cell or sac (peri-
spore), at first filled with granular contents,
which contents subsequently separate into
four portions, called sporules, either by three
transverse fissures (fig. 262) ; by two fis-

Fig. 252.

Rhynchococcus coronopifolius.

Section of the frond with tetraspores.

Magn. 200 diams.

sures at right angles, cutting them into
quarters like an orange; or by tri-radiate

fissures which part them into the 'tetra-
hedraP group (fig. 253) so often found in the
division of spore- and pollen-cells ; the last
two occur in the spherical tetraspores. The

Fig. 253.

Fig. 254.

Hildenbrandtia san-

Ptilota plumosa.

Section of frond with tetraspores.
Magn. 200 diams.

tetraspores are rarely found collected in any
capsular structure, but in the Corallines (fig.
141), and in some few foreign genera, they
are grouped in hollow
cases (conceptacles, fig.
254). In many instances,
however, they are found
in pod-like bodies (stichi-
dia, fig. 1 60), either formed
by metamorphosis of por-
tions of the lobes or lobules
of the frond (Plocamium),
or arising independently
on it. In others the tetra-
spores are naked (Calli-
thammon), scattered over section ofTclcepta-

the Sides Or fixed at the cle containing tetra-

tips of the branches. In 8P°res-
the majority of cases, how- Ma&n' 50 diams-
ever, these bodies are immersed in the sub-
stance of the lobes or lobules, not evident
externally except by the darker colour of the
frond at the point where they are collected;
a lens is then required for their detection ;
they here appear to be formed either of the
cells of the surface or of others immediately
subjacent. Harvey and Thwaites regard
these bodies as gemmules or gonidia. De-
caisne, J. Agardh, and most of the other
leading Algologists regard them as true
spores.

2. The spores are simpler structures than
the tetraspores, but mostly occupy a more
important position. They are never scattered

FLORIDE^E.

[ 267 ]

FLORIDE.E.

through the frond, but always grouped in
definite masses, generally enclosed in a spe-
cial capsule or conceptacle (which by the
naked eye may readily be mistaken for a sti-
chidium or tetraspore-case). The simplest
form of the spore-fruit consists of spherical
masses of spores attached to the wall of the
frond or imbedded in its substance, without
a proper conceptacle, in which latter case
the cells surrounding the mass of spores are
devoid of colouring matter ; such a fruit is
called afavellidium, and occurs in Halymenia,
and the same name is ordinarily applied to
fruits of similar structure not perfectly im-
mersed, such as those of Gigartina, Gelidium,
&c., where they form tubercular swellings
on the lobes. In some cases the tubercles
present a pore at the summit, when mature,
through which the spores find exit. When
such a fruit is wholly external, as in Cera-
mium and Callithamnion, it is called afavella.
The coccidium, characteristic of Delesseria,
Nitophyllum, &c., which is nearly related to
this, either occurs on lateral branches, or is
sessile on the face of the frond, and consists
of a hollow case with thick cellular walls,
containing a dense tuft of angular spores
attached to a central column. It is generally
imperforate, but occasionally exhibits a pore
through which the spores escape. The cera-
midium is the most complete form of the
conceptacular fruit, and is an ovate or urn-
shaped case, furnished with an apical pore,
and containing a tuft of pear-shaped spores
arising from the base of the cavity. The
walls are usually thin and membranous, and
the hollow space considerable, as in Poly-
siphonia, Laurencia, Dasya, &c.

Peculiar bodies, forming external warts,
and composed entirely of vertical fibres, but
without spores, called nemathecia, are some-
times confounded with the conceptacular
fruit, and are probably immature forms of it.

3. The spermatozoids are found in peculiar
structures, to which the name of antheridia
has been applied, from the supposed analogy
to the organs so called in the other Crypto-
gamous plants. The antheridia are produced
pretty much in the same situations as the
other organs of fructification, and are always
developed on different individuals. They are
collections of very small colourless cells,
sometimes collected into a bunch, as in
Griffithsia, sometimes enclosed in a transpa-
rent tube, as in Potysiphonia, or clothing a
kind of irregularly-shaped flat plate, as in
Laurencia, &c. Each of the minute cells is
said by Nageli and Derbes to contain a sper-

matozoid; according to the former, a spiral
filament, which he did not see move ; ac-
cording to the latter, a transparent globule,
with a tail-like appendage moving actively
for a few moments. Thuret could not see
either the spiral filament or the whip- or tail-
like appendage, but believes that the cell of
the antheridium contains a transparent cor-
puscle, spherical in Polysiphonia, more or
less elongated in other genera, presenting no
trace of a spiral thread, but with slightly
granular contents. These corpuscles were ex-
pelled from the antheridia by a slow move-
ment which appeared purely mechanical, and
when outside, they remained at perfect rest.

Synopsis of the Families.

1. RHODOMELACE.E. Frond cellular,
areolated or articulated. Ceramidia external.
Tetraspores in rows, immersed in ramuli, or
contained in proper receptacles (stichidia).

2. LAURENCIACE.E. Frond cellular, con-
tinuous. Ceramidia external. Tetraspores
scattered, immersed in the branches and
ramuli.

3. CORALLINACE.E. Frond calcareous or
crustaceous, rigid. Ceramidia external, con-
taining the tetraspores.

4. DELESSERIACE^E. Frond cellular,
continuous, areolated. Coccidia external.
Tetraspores collected into definite clusters
(son).

5. RHODYMENIACE^E. Frond cellular,
continuous, the superficial cells minute.
Coccidia external. Tetraspores scattered
through the frond, or forming undefined,
cloud-like patches.

6. CRYPTONEMIACE.E. Frond fibroso-
cellular, composed of articulated fibres, con-
nected together by gelatine. Favellidia
immersed in the frond or sub-external. Te-
traspores immersed in the frond.

7. CERAMIACE^E. Frond filiform, con-
sisting of an articulated filament, simple, or
coated with a stratum of small cells. Fa-
vellee naked berry-like masses. Tetraspores
external, or partially immersed.

8. PORPHYRACE^B. Frond plane and
exceedingly thin, or tubular and filiform, of
a purplish colour, with oval spores in sori,
and tetraspores scattered over the frond.

(See under the heads of the Tribes for
further information.)

BIBL. Harvey, Brit. Marine Algce, 2 ed.
1849, Phycologia Britannica ; Kiitzing,
Phycologia generalis. See also under the
families.

FLOSCULARIA.

[ 268 ]

FORAMINIFERA.

FLOSCULARIA, Oken, Ehr.— A genus
of Rotatoria, of the family Flosculariaea.

Char. Attached ; eyes two, red ; carapaces
single; rotatory organ divided into more
than four lobes, with elongated cilia radia-
ting from their extremities.

Eyes sometimes absent in the adult ani-
mals. Sheath or carapace frequently so
transparent as to be scarcely distinguishable.
Rotatory organ with five or six lobes. The
number, however, appears variable, for
Ehrenberg, in regard to the genus, states in
one place that the lobes are five or six, in
another, that they are always six. The so-
called proboscis is probably only one of the
lobes of the rotatory organs.

F. ornata, E. (PL 34. fig. 32). Carapace
hyaline ; rotatory lobes six (Ehr.), five (Duj.),
with long cilia, but no central proboscis;
aquatic; length 1-108".

Lobes of rotatory organ thickened at the
ends.

F. proboscidea, E. Carapace hyaline;
rotatory organ six-lobed, with short cilia
surrounding a central proboscis ; aquatic ;
length, when extended, 1-18". Teeth (fig.
33).

F. campanulata, Dob. Differs from F.
ornata, Ehr. in having five lobes, and these
flattened; aquatic; length 1-50" when ex-
tended.

F. cornuta, Dob. Rotatory organ five-
lobed, one of the lobes with a narrowed, not
ciliated cornu attached, arising from its out-
side ; cilia long ; aquatic ; length, when ex-
tended, 1-40".

The last two species must be regarded as
very doubtfully distinct.

These exquisitely beautiful animals are
found adhering to aquatic plants, as Con-
ferva, Ceratophyllum, fyc.

BIBL. Ehr. Infus. 407 ; Duj. Infus. 609;
Dobie, Ann. Nat. Hist. 1849. iv. p. 233.

FLOSCULARLEA.— A family of Infu-
soria.

Char. Furnished with a carapace or sheath;
rotatory organ single, with a flexuous, lobed
or divided margin.

The cilia are often long, and only vibrate
occasionally, mostly remaining rigidly ex-
tended.

Genera.

Eyes absent 1. Tubicolaria.

Eye single 2. Stephanoceros.

r 9 lohed / sin?le ' ' ' ' 3' Limnias-
Eyes f Rotatory! I aggregate. . 4. Lacinularia.
two I organ 1 4-lobed 5. Melicerta.

*• 5- or 6-lobed 6. Floscularia.

The eyes in some of the genera (Stepha-

noceros and Floscularia) disappear in the
adult state, so that they must be looked for
in the young, or even in the partly hatched
ova, in which they may often be distinctly
seen.

BIBL. Ehrenberg, Infus. p. 398.

FLUSTRA, Linn. (Sea-mat). A genus of
Polypi, of the order Bryozoa, and family
Escharidse.

Char. Polypidom plant-like, membranous,
foliaceous or crustaceous; cells in contact,
alternate, in several rows, and on one or
both sides of the polypidom; aperture trans-
verse, semicircular or lunate, valvular and
subterminal. Marine.

Ten British species.

* Foliaceous, attached by the base; with
cells on both sides.

F. foliacea. Cells narrow at the base,
rounded at the end, with scattered marginal
spines. Common.

Polypidom lobed, and about 4" high.

F. chartacea. Cells oblong, slightly
broader in the middle ; lateral margins with
a single minute spine.

About 1" in height.

F. truncata. Cells linear-oblong, truncate
at the end, margins without spines.

Four or five inches high.

** Foliaceous, with cells on one side only.

F. carbasea (PI. 33. figs. 19, 20). Cells
oblong, narrowed and truncate at the base,
margin without spines.

About 2" in height.

F. avicularis. Cells in four or five rows,
oblong, their margins with two spines on
each side near the aperture.

About 1'' in height.

*** Crustaceous.

F. membranacea. Cells oblong, with a
tubercle on each side at the end. Common,
forming an incrustation upon Fuci, &c.

Some species of Flustra form good ex-
amples for the examination of the bird's-head
processes (PI. 33. fig. 26), which occur upon
the margins of the lobes of the polypidom.

BIBL. Johnston, Brit. Zoophyt. 342 ;
Reid, Ann. Nat. Hist. 1845, xvi. 385.

FLY. See MUSCA.

FONTINALIS, L.— A genus of Mosses.
See NECKERA.

FORAMINIFERA or POLYTHA-
LAMIA. — The organisms comprised under
this title are so imperfectly known, that

FORAMINIFERA.

[ 269 ]

FORAMINIFERA.

little can with certainty be laid down re-
garding their structural and systematic rela-
tions. They are contained within calcareous
shells, which are polythalamous or divided
transversely by partitions or septa into a
number of chambers. The chambers in some
are perfectly distinct from each other,
although aggregated to form a compound
shell (PI. 18. figs. 17, 18) ; in others, the
septa are perforated with one or more aper-
tures (figs. 10, 19), the margins of which are
sometimes tubular or prolonged to form a
sipho or funnel-like tube (fig. 10). The
shell is variable in shape ; but it is usually
either cylindrical, consisting of a number of
cells or chambers arranged end to end in
one or more rows, or spiral, when the
rows of chambers are coiled. As the more
recently-formed chambers are often larger
than the others, the shells are generally more
or less pyramidal. In a few genera and
species, the shell consists of a single cell
only, without septa.

The outer surface of the shells presents a
punctate or dotted appearance, arising from
the presence of very numerous foramina,
whence the name Foraminifera. The fora-
mina are the outer orifices of tubes passing
through the walls of the shell. The arrange-
ment of these tubes and that of another set,
traversing the walls and the septa of the
shells, as well as, in fact, the general struc-
ture of the shell, may perhaps be well
illustrated by a description of the shell of
Operculina arabica (PI. 18. fig. 22), in which
they have been carefully traced by Mr. Carter.
In the shell of Operculina arabica, the outer
surface, after the removal of a greenish epi-
dermic layer, is seen to be covered with large
and small papillae (fig. 23) ; the former (b)
1-2150", the latter (a) 1-8600" in diameter,
neither of which are present over the septa
or at the margin of the shell. Each of the
septa encloses within its walls two calcareous
tubes, spaces or vessels, one on each side —
the intraseptal vessels (figs. 26 a, 27 c); these
are about 1-1900" in diameter, and in their
course give off two sets of lateral branches,
terminating upon the two surfaces of the
septum in which they run. The tubes
communicate at each end with a network of
smaller ones; one set of which ramifies in
the upper, the other in the under wall or
margin of each chamber ; these are the mar-
ginal plexuses (fig. 27 / /), and the former
terminate upon the outer margin of the shell
(9 9}- The inner wall of the chambers is
pierced by innumerable tubes about 1-9000"

in diameter, which pass directly downwards
from the small papillae on the outer surface
(fig. 25 d). In a vertical section of the shell,
in addition to these tubes, seven, eight or
more parallel horizontal lines are seen (fig.
25 c) ; these are the lines of contact of the
layers composing the shell, or the lines of
growth. The margin of the shell is composed
of hollow calcareous spicula (fig. 24), 1 -23/"
long and 1-900" broad. In a transverse sec-
tion of the margin, more than 100 of these
are seen, forming a triangular bundle or
cord (fig. 28 a), the apex being directed
towards the chamber, the base outwards
forming the free rounded margin of the
shell, and parallel to its sides run the papil-
lary tubes of the chamber (fig. 28 b).

The tubes passing through the walls of
the chambers are common to all the Forami-
nifera, but the papillae are not ; whether the
spicula, the intraseptal vessels and the mar-
ginal plexuses are of general occurrence, has
not been ascertained; but the two latter
have been detected by Mr. Williamson in the
shell of Faujasina, who denies, however,
their communication with the chambers,
admitting merely that with the common
tubes of the shell.

In addition to the common foramina and
the orifices of the marginal plexus, the
chambers, especially those which terminate
the series, are furnished with other larger aper-
tures opening externally; these are of various
forms and differently situated; sometimes
they are round, numerous and comparatively
small (PI. 18. fig. 13); at others they are
single and large (fig. 18), circular, semicir-
cular or lunate (fig. 3). According toEhren-
berg, these are often closed by a valve,
so as to be invisible when the animal is con-
tracted or dead. This author also compares
them with the apertures of the polype-cells
of Pennatula, Alcyonium and Lobularia, in
which calcareous particles contained in the
integument so completely close the cells,
as to render the opening no longer percep-
tible. The reader will not fail to perceive
the analogy between the closure of the cells
in the latter instances by calcareous particles,
and in Operculina by the cord (?) of calca-
reous spicula. But how much of the evidence
upon which Ehrenberg's views upon the
Foraminifera are based, rests upon analogical
reasoning, and how much upon observation,
is known only to himself, as is unfortunately
too often the case in regard to his results.

The nature of the animal body contained
within the shell has been very differently

FORAMINIFERA.

[ 270 ]

FORAMINIFERA.

viewed. The Foraminifera were formerly con-
sidered as microscopic Cephalopods. Ehren-
berg regards them as belonging to the Bry-
ozoa among Polypes; viewing the several
chambers as either inhabited in common by
a single individual after the manner of the
Mollusca, or each chamber by a distinct
animal, as in Flustra, &c. ; and the siphonal
apertures as corresponding to so many distinct
individuals in each chamber. This author
also states that the first and largest cell, some-
times also the second, and occasionally those
as far back as the fourth, frequently contain
the transparent part of the animal only;
whilst beyond this, the cells are filled with
two differently-coloured organs; one and
the principal, gray or greenish, representing
the alimentary canal and frequently contain-
ing Diatomaceae ; the other being yellowish
and forming the ovarium; some of the
smaller cells being empty.

On the other hand, Dujardin, with whom, on
the whole, later authors agree, views the Fora-
minifera as allied to the Arcellina ; regarding
the body as single, and composed of a simple
sarcodic substance, without the distinct sepa-
ration of organs ; and the filiform processes
(pseudopodia) which issue from the various
external apertures of the shell, as comparable
to those of Amceba, Arcella and other mem-
bers of the family. Certain it is, at least,
that delicate filiform processes issue from the
common foramina in the shell (PI. 18. fig. 19),
by the aid of which locomotion and perhaps
nutrition are performed. The same functions
are probably to be attributed to the tentacle-
like processes which are protrusile through
the larger orifices (fig. 18 a). The nature of
the contents of the intraseptal and marginal
vessels is doubtful ; Mr. Carter regards them
as performing a water-vessel function com-
parable to that of the circulating system of
the sponges (Grantia) ; whilst Mr. William-
son considers them to be filled with the
organic substance of the body.

There is an evident analogy between the
structure of the shell in the Foraminifera,
and that of some Cephalopoda (Nautilus) ;
in the general form, the occurrence of the
septa and of the sipho. But there is a curious
difference between the arrangement of these
parts in the two instances ; for in the Fora-
minifera the septa are convex outwards or
towards the last chamber, towards which also
the sipho is prolonged, whilst in the Cepha-
lopods those relations are inverted.

The shells of the Foraminifera are com-
posed principally of carbonate of lime, and

therefore effervesce copiously when a dilute
acid is added to them. By carefully acting
upon the recent organisms with muriatic
acid, in the proportion of a drop of the strong
acid to a watch-glass full of water containing
them, the animal is left (PI. 18. figs. 5, 8,
20), retaining the general form of the shell,
which it has moulded upon itself.

Recent Foraminifera can be procured by
dredging, or sometimes from the sand of the
sea-shore. In the latter case, the sand
should be spread upon a piece of black paper,
or the black disc (!NTROD. p. xxiii), and
examined as an opake object; when the shells
may be easily distinguished by their forms
and separated.

In the fossil state, the Foraminifera abound
in chalk; from which they may be obtained
in the manner directed under CHALK ; in
fact, this substance constitutes the best
source of them for examination. In certain
calcareous rocks or limestones, they are also
extremely numerous. Thus, in the stone of
which the buildings in Paris are constructed,
the shells of Miliola, Lam., are so abundant,
that this city may be said to be built of
them.

The shells of the nummulites or coin-
stones which form mountains in the Medi-
terranean regions, and of which the pyramids
of Egypt are principally composed, agree in
essential structure with those of the Forami-
nifera (PL 18. fig. 29).

The following arrangement of a few of the
most common or interesting forms of the
Foraminifera may serve as an index to the
genera and species selected for illustration ;
but it is far from certain that the interpreta-
tion given to the structural appearances is
correct.

Monosomatia. A single animal in each cell.

Fam. 1. MILIOLINA. Shell simple, body not

jointed. Two genera: Miliola, Ehr. (not

Lam.), in which the shell is calcareous;

and Gromia, in which it is membranous.

In this group, certain of the Liagenee

should also probably be placed (LAGEN.E).

Fam. 2. NODOSARINA, Chambers nume-
rous, arranged in a single straight or
curved series ; body jointed.

Marginulina. Aperture lateral (excentric),
beaked ; cells turgid.

M. raphanus (PL 18. figs. 7, 9, 10 ; 8, body
freed from shell by acid).
Fam. 3. TEXTULARINA. Cells numerous,

FORAMINIFERA.

[ 271 ]

FOSSIL WOOD.

arranged in a simple alternate series;
body jointed.

Textularia or Textilaria. Aperture lateral,
not beaked, situated beneath the apex
(sublunate).

T. aciculata. Shell smooth, longer than
broad ; joints oblong, oblique.

T. aspera (PL 18. fig. 39, fragment of).
Shell rough on the surface, longer than
broad ; joints globose.

T. globulosa(P\. 18. fig. 35). Shell smooth,
longer than broad ; joints globose.

T. striata (PI. 18. fig. 34). Shell longi-
tudinally striated on the surface, longer than
broad ; joints globose.

Fam. 4. UVELLTNA. Cells aggregated into
a spiral, which is conical, longer than
broad, and rarely diffonned or subglo-
bose; body jointed.

Rosalina. Series of cells regularly spiral,
continuous; aperture simple (not closed
by a lid).

R. IfBvigata (PL 18. fig. 37; 36, basal
view). Shell subglobose, surface very deli-
cately punctate ; joints globose, nodose.

R. globularis. Differs from the last in the
lenticular and not subglobose form of the
shell.

Fam. 5. ROTALINA. Cells aggregated into
a simple, depressed, discoidal or lenti-
cular spiral ; body jointed.

Rotalia. Spiral visible on both sides,
somewhat oblique ; orifice slightly de-
current, not toothed.

R. Beccarii (PL 18. figs. 1-6). Shell
large, shining, surface very delicately punc-
tate ; joints slightly prominent.

R. globulosa (PL 18. figs. 40 a; 41, cell-
chambers containing air). Shell smooth,
surface entire ; joints globose, prominent.

R. turgida (PL 18. fig. 38). Shell smooth,
margin obsoletely keeled ; joints not promi-
nent.

R. perforata (PL 18. fig. 21, recent ; fig.
33, from chalk). Surface punctured; joints
globose, prominent.

Operculina. Spiral flat, evident on both
sides; aperture transverse, cells com-

Op. arabica, Carter (PL 18. fig. 22). Spi-
ral closed, forming three to four turns ;
siphonal apertures numerous, the largest
long, narrow, crescentic and arching over
the preceding whorl.

Planulina. Spiral flattened, lenticular,
evident on one side only, margin not
spinous, orifice naked.

Polysomatia. Numerous animals in each

shell.

a. Bodies single, and unjointed in each
chamber.

Fam. 6. ASTERODISCINA.
Asterodiscus.

Fam. 7. SORITINA. Orifices situated in one
plane, closed with a lid; shells flat,
discoidal.

Sorites. Cells concentric, alternate.

S. orliculus (PL 18. figs. 16-18). Shell
large, orbicular, membranaceo-plane, smooth,
cells bidentate at the base.

/3. Bodies jointed and aggregated.

Fam. 8. HELICOTROCHINA. Orifices mostly
situated on the inner side of the first
pair of cells ; spiral lenticular, closed or
embracing.

Geoponus. Umbilical disk none.

G. stella-borealis (PL 18. figs. 19; 20,
body freed from shell). Shells (compound)
not striated on the surface, smooth, deli-
cately punctate.

See CHALK, LAGENA and RHIZOPODA.

BIBL. D'Orbigny, Diet, universel d'Hist.
nat. 1845. v. and Foraminiferesfossiles, 1846;
Ehrenberg, Abhandl. d. Berl. Akad. 1838
and 1839, or Weaver's abstr., Ann. Nat.
Hist. 1841. vii. pp.296, 374; Dujardin, Ann.
d. Sc. nat. 1835. iv. and v.; Clark, Ann. Nat.
Hist. 1849. iii. 380, 1850. v. 161 ; William-
son, Trans. Micr. Soc. ii. and Micr. Journ.
i. ; Carpenter, Trans. Geol. Soc. 1849 ;
Carter, Ann. Nat. Hist. 1852. x.

FORMIC ACID, or acid of ants.— This
acid occurs in ants, especially the red ant,
Formica rufa ; in the stinging hairs of some
insects, as of the procession-caterpillar (Bom-
byx processionaria) ; and the poisonous
secretion of the stings ; perhaps also in the
stinging organs of the Acalephae and Polypes.
In the higher animals it is a frequent pro-
duct of the oxidation of organic substances ;
it is also found in the juice of flesh, in
the urine, in vomited liquids, and in the
blood.

See CHEMISTRY.

FOSSIL INFUSORIA.— The fossil valves
of the Diatomacea3 were formerly so called.
See DIATOMACE.E.

FOSSIL WOOD.— This occurs in very

FOSSOMBRONIA.

[ 272 ]

FROG.

different conditions, as for example converted
into lignite, and the modifications of coal, or
with the vegetable substance almost entirely
removed and replaced by silex, preserving all
the organic forms of the tissues. The mode
of examining and mounting COAL, &c., is
given under that article. Silicified woods
which have been completely infiltrated and
solidified require to be cut into thin sections
and polished by the lapidary ; the friable
kinds, where the infiltration has merely filled
the cavities of the cells and vessels, may be
split with a knife and mounted in balsam.
Examples are given in PL 19. figs. 29-33.
Fig. 32. PI. 39 exhibits concretions of silica
imitating structure. The stems of Palms and
Dicotyledonous trees are met with completely
converted into siliceous blocks, sections of
which exhibit all the minutia3 of the struc-
ture.

FOSSOMBRONIA, Raddi.— A genus of
Pelliea3 (Hepaticaceae), nearly allied in the
character of its vegetative structure to the
Jungermanniea3, having large, squarish, irre-
gularly waved leaves; the stout stems are
procumbent and set with purple radicles all
along the under side. The fruit-stalk arises
from the under side of the stem and turns
back, the perichsete is very large, and the
capsule bursts irregularly into four slender
erose valves. F. pusilla is the Jungermannia
pusilla of the British Flora; found chiefly on
clay banks.

BIBL. Hook. Brit. Jungerm. pi. 69, Brit.
Flor. ii. pt. 2. p. 117; Endlicher, Gen. Plant.
suppl. i. no. 472-7.

FOVILLA. — The name applied to the
minute granules contained in the liquid filling
the pollen-cell and passing into the pollen-
tube of Flowering Plants. These minute
granules, which are of various, but altogether
indefinite sizes, exhibit an active quivering
motion, the ' molecular motion ' as it is
called, which is displayed in the same way
by all finely-divided solid substances, living
or dead, and is apparently dependent on
purely physical causes. They appear to
consist of starch-grains, minute globules of
oil, and granules of protoplasm probably
composed of proteine compounds. These
granules are exceedingly transparent in many
kinds of pollen when fresh, apparently from
their refracting power being partly equal to
that of the fluid surrounding them. The
granules may then be made visible by adding
water.

FRAGILARIA, Lyngb.— A genus of Dia-
tomacese.

Char. Frustules (in front view) linear,
symmetrical, united into straight or curved
flat filaments; valves lanceolate, oblong or
linear; markings as in Diatoma, no no-
dules.

Differs from Diatoma in the filaments not
becoming separated into zigzag chains.

Kiitzing enumerates sixteen species, of
which ten are doubtful.

F. capucina, K. (F. rhabdosoma, E.) (PI.
12. fig. 33). Filaments more or less elon-
gate; frustules linear and rectangular in front
view; valves narrowly and acutely lanceo-
late; breadth of filament 1-700". Aquatic.
No stria3 perceptible under ordinary illumi-
nation. Common in pools, &c.

F. virescens, Ralfs (F. pectinalis, Ehr.).
Filaments more or less elongate ; frustules
in front view linear, rectangular or cuneate ;
valves contracted and obtuse at the ends.
Aquatic. Endochrome green.

One of the recognized species is marine ;
and several of the doubtful species are marine
or fossil.

BIBL. Kiitzing, Bacill. p. 45; ibid. Sp.
Alg. p. 14; Ralfs, Ann. Nat. Hist. 1843, xii.
106.

FREDERICELLA, Gervais.— A genus of
Polypi, of the order Bryozoa, and family
Plumatellidse.

Char. Polypidom fixed, coriaceous, tubular,
branched ; polypes protruding from the ends
of the branches; tentacular disk orbicular;
tentacles about twenty-four, arranged on the
margin of the disk in a single series, and
invested at their origin by a membrane.
Aquatic.

F. sultana. Polype-cells erect, cvlindrical.

Height of polypidom about 2*'; tufted,
shrubby ; stem dichotomously branched.

F. dilatata. Polype-cells dilated towards
the orifice.

BIBL. Allman, Ann. Nat. Hist. 1844. xiii.
331 ; Johnston, Brit. Zoophytes, p. 405.

FROG. — The common frog (Rana tempo-
raria) affords a means of studying several
interesting points of structure . Thus, by gently
scrapingthebackof the roof of the mouth with
the handle of a scalpel, ciliated epithelium
(PI. 40. fig. 12) may be obtained, and the
ciliary movement studied. The circulation
in the web of the foot, and the phenomena
of inflammation may be observed, by enclo-
sing a frog in a wet bag, leaving one leg
projecting. The bag containing the frog
may then be placed upon a plate of wood,
with a circular aperture at one end, over
which the foot is to be extended by tying

FRULLANIA. [ 5

the toes with silk or cotton threads to little
tacks or nails driven into the wooden plate.
Metal " frog- plates" are sold for the pur-
pose. Section of the kidney of the frog,
made with a Valentin's knife, will show the
ciliated epithelium of the necks of the uri-
nary tubules. The circulation of the blood
in the lungs and the mesentery may be ex-
amined, but the animal should be rendered
insensible by chloroform before the experi-
ment.

The ova of the frog (frogs' spawn) have
formed the subject of some of our most in-
teresting experiments on impregnation and
development. The larvae (tadpoles) exhibit
well the circulation in the gills, tail, and
more transparent parts, and afford easily ob-
tained materials for the study of the develop-
ment of the tissues. The chorda dorsalis is
well seen in a young tadpole. The frog and
tadpole are however inferior in most respects
to the Triton and its larva for exhibiting
these phaenomena.

The injected organs of the frog afford
most interesting and beautiful preparations ;
especially the lungs, kidneys, skin, tongue,
and web of the foot. The injection should
be thrown in at the heart, and the slightest
possible force used.

The simplest method of killing a frog
without injury, is to immerse and retain it in
warm water. The primary effect of this pro-
cess is, however, only that of producing
asphyxia ; so that if it be removed from the
water and exposed to the air too soon after
immersion, even, as in injection, after the
pipe has been fixed in the heart, it will re-
vive ; and probably when the operator has
returned from stirring the injection, the frog
will have vanished, and may perhaps be
found jumping on the floor. Such unneces-
sary cruelty may easily be avoided by attend-
ing to the above remark.

FRULLANIA, Raddi.— A genus of Jun-
germannieae (Hepaticaceae), containing three
British species, the Jungermannia Hutchin-
sice, dilatata, and Tamarisci of Hooker's
British Flora. F. dilatata is very common,
creeping on the bark of trees, its dark brown,
dry foliage appearing like minute spreading
blotches; the almost sessile capsules are
somewhat inconspicuous, but are distin-
guished by their whitish colour. The valves
of the capsule and the elaters afford beautiful
microscopic objects, illustrative of the spiral
structures in cells. F. Tamarisci (fig. 255)
has longer and more regularly pinnate stems,
forming large lax tufts on the ground and

3 ] FRUSTULIA.

low bushes, chiefly in sub-Alpine coun-
tries.

Fig. 255.

Frullania Tamarisci.

Portion of a stem with branches bearing the perichsetes
from which the sporanges emerge.

Magn. 5 diams.

BIBL. Hook. Brit. Jungermannice^ pis. 1,
5, 6, Brit. Flora, ii. pt. 1. p. 128 ; Endlicher,
Gen. Plant. Suppl. i. No. 472-10.

FRUSTULIA, Ag.— A genus of Diato-
maceae.

Char. Frustules resembling those of Navi-
cula, irregularly scattered through an amor-
phous gelatinous mass. Aquatic.

F. salina, Ehr. Frustules in front view
very narrowly linear, rounded at the ends ;
valves suddenly acute at the ends, transverse
striae evident; gelatinous envelope continu-
ous; length of frustules 1-2200 to 1-864".
Found in a saline spring.

This organism is of particular interest,
as having formed the subject of Schmidt's
ultimate analysis, in which he determined
the presence of cellulose. (DIATOMACE^,
p. 200.)

F. saxonica, Rab.(P1.13. fig.17). Frustules
in front view linear, rounded at the ends ;
valves elliptical, somewhat acute.

Forms dirty olive-brown, gelatinous, tre-
mulous masses, contained in small pits in
rocks.

F. membranacea, nobis (PI. 41. fig. 6).
Frustules in front view linear, very slightly
narrowed towards the ends ; valves lanceo-
late, constricted near the obtuse ends; length
of frustules 1-1250".

This was found abundantly forming a thin
stratum or film upon the sides of a glass jar
containing water-plants.

Rabenhorst describes four other aquatic
species.

BIBL. Ehrenb. Infus. p. 232; Kiitzing,

T

FUCACE^.

[ 274 ]

FUCOIDE^.

p. 109, id. Sp. Alg. p. 96 ; Rabenhorst, Die
Siissw. Diat. p. 50.

FUCACEJ3. — A family of Fucoidese.
Olive-coloured inarticulate sea-weeds, whose
reproductive organs are borne in stalked sacs
upon the walls of spherical cavities excavated
in the substance of the frond. Fructification
sporanges or spore-sacs and antheridia. The
spores of Fucus divide into two, four or eight
within the sac ; those of the other genera
remain undivided. The antheridia are filled
with spermatozoids (or antherozoids), which
in Fucus have been seen to fertilize the
spores. See Fucus.

Synopsis of British Genera.
* Air-vessels stalked.

I. SARGASSUM. Branches bearing ribbed
leaves; air-vessels simple.

II. HALIDRYS. Frond linear, pinnate,
leafless ; air-vessels divided into several cells
by transverse partitions.

** Air-vessels immersed in the substance of
the frond, or absent.

III. CYSTOSEIRA. Root scutate. Frond
much branched, bushy. Receptacles cel-
lular.

IV. PYCNOPHYCUS. Root branching.
Frond cylindrical. Receptacles cellular.

V. Fucus. Root scutate. Frond dicho-
tomous. Receptacles filled with mucus, tra-
versed by jointed threads.

VI. HIMANTHALIA. Root scutate. Frond
cup- shaped. Receptacles (frond-like) very
long, strap-shaped, dichotomously branched.

FUCOIDESE, or MELANOSPORE^.—
An order of Algae, derivingtheir ordinary name
from the Fucus or Wrack, one of the most
frequent genera of the family. They present
many remarkable points of difference from
the red sea-weeds in their higher forms,
while the lowest forms approach the simpler
genera of that order and the higher forms of
the Chlorosperms. The Fucoids are exclu-
sively marine, and are at once distinguished
by their olive or dark-brown colour, and al-
though some of the larger kinds grow in deep
water, the majority are met with on rocks
between high and low water mark, where
they are exposed to the atmosphere at each
efflux of the sea ; those which are drawn up
from deep water occasionally prove that this
exposure is necessary for healthy growth, by
their weak structure and the absence of fruc-
tification. Some of them are also provided
with air-bladders, which maintain them float-
ing or erect, and with at least their upper

lobes little beneath the surface of the water.
These air-bladders are very well seen in our
common Bladder- wrack (Fucus vesiculosus,
fig. 256), and still more so in the celebrated
Gulf- weed (Sargassum bacciferum), where
the stalked berry-like bladders are the most
striking feature of the plant.

All the larger kinds grow on rocks, to
which they are attached by a root-like struc-
ture, of somewhat conical form, cleaving
like the ' sucker' with which school-boys lift
stones, to the rock; in many this cone is
solid, and composed of tough cellular tissue;
in others, especially the Laminariacese, it is
composed of a number of stout, super jacent,
branched cords, growing out of the frond
one above another, and attaching themselves
to the rock, like the roots of a Tree-fern or
a Palm. Some (Pycnophycus) spring from
a creeping stem-like portion, spreading in a
netted mass over the rocks ; while many of
the smaller are parasitical, or more properly,
epiphytic, growing on the fronds of the
larger kinds, to which they attach themselves
by minute 'sucker'-hke disks. Some appear
to be true parasites (Elachistets and Myrio-
nemata). Several are of minute size, but
very few strictly microscopic. Almost all
present three regions, resembling respect-
ively the root, stem, and leaf or leaves of
the higher plants, although they are not or-
dinarily regarded as the morphological ana-
logues of them. In a few cases the frond is
a shapeless mass or crust, lying close to the
surface of the rocks. None become calcified
like the Corallines.

The fructification of these plants is still in
a somewhat obscure condition as regards the
order in general, for great apparent diversi-
ties occur in the physiological phenomena
presented by what at first appear like iden-
tical structures. We have here, as in the
Floridece, three distinct forms of reproductive
structure, known respectively as — 1, zoo-
spores ; 2, spores ; and 3, spermatozoids.

1. The zoospores are the reproductive bo-
dies most frequently met with, and in the
lower forms the arrangements are not very
different from those in the filamentous Con-
fervoids. In ECTOCARPUS, where the frond
is composed of jointed cellular filaments, the
cells at the ends of the branches, or other
articulations, become enlarged and filled with
granular matter which is ultimately converted
into zoospores. These organs are called by
Thuret oosporanges, and are commonly de-
scribed as spores in algological works ; but
they burst and discharge the numerous mi-

FUCOIDE.E.

[ 275 ]

FUCOIDE.E.

croscopic zoospores, which are pear-shaped,
with a clear, beak-like, narrow end, of olive
colour, and have two cilia, not arising from
the beak, but from a reddish point on the
coloured portion ; one cilium is longer than
the other, and directed forwards; the other
is short, and trails behind like a kind of rud-
der. Their movements are very active, and
they seek the light. When they germinate,
they become immoveable and spherical, ac-
quire a membranous coat, and emit a tubular
prolongation, which soon becomes divided
by cross septa, and is developed into a new
frond. These plants present, in addition to
the oosporanges, another structure called by
Thuret trichosporanges, consisting of very
slender and usually rather short, jointed fila-
ments, in each joint (cell) of which a single
zoospore is produced. The trichosporanges
occur in considerable number, occupying the
same place as the oosporanges, which they
sometimes accompany, but ordinarily only
one kind of organ is found on the same plant
at the same time. The zoospores are per-
fectly similar, except that those produced
singly in the filaments are not so large as
those developed in large numbers in the
large ovate oosporanges.

The two kinds of sporange producing zoo-
spores have been found in theMyrioneinaceae,
Chordariacese, Sporochnacese, Punctariaceae,
and Dictyosiphonaceae ; in Chorda lomentaria
only the trichosporanges, and in the other
Laminariaceae only the oosporanges have been
seen at present.

The Cutleriacese present the remarkable
phenomenon of the occurrence of sporanges
containing zoospores together with anthe-
ridia analogous to those of the Fucaceae.
(See CUTLERIA.)

2. The spores occur in the Dictyotaceae
and the Fucaceae, as large granular bodies of
ovate form, enclosed in a sac or sporange
(perispore), and clothed besides by a gelatinous
coat, called the epispore ; these large spores
are always devoid of power of motion. In
some cases they are simple reproductive
spores, in others they subdivide, after esca-
ping from the perispore, into two, four, or
eight sporules, each capable of germination.
(See Fucus, and figs. 257, 260.) In the Dic-
tyotaceae these spores are collected into defi-
nite groups (son) on the surface of the frond.
It is not stated by algologists whether an-
theridia have been found here. In the Fu-
caceae the spores are found in spherical cavi-
ties immersed in the substance of the frond,
sometimes occurring in all parts, sometimes

collected in special regions. These cavities
communicate with the external surface by
pores, and are usually perceptible from the
swollen, slimy appearance where they exist.
Where no general receptacles exist, the
little spherical chambers are excavated in
the frond ; where these do occur, as in Fucus,
the spherical chambers are attached to the
inside of their walls, one beneath each ex-
ternal pore. These chambers, called by some
scaphidia, by others conceptacles, contain
spores or antheridia, or both. The spores
occur in sacs consisting of a cell (perispore)
springing from the wall of the chamber.
(See Fucus.)

3. The spermatozoids have been met with,
as well as zoospores, in the Cutleriaceae.
The spermatozoids (or antherozoids, as Thu-
ret terms them) exactly resemble those of
Halidrys and Pycnophycus, described in the

In the Fucaceae the spermatozoids or an-
therozoids occur with the spores above de-
scribed. In Fucus canaliculatus (Pelvetia,
Dene, and Thuret) and F. platy carpus, Thu-
ret, the antheridia are found, in company
with the spores, in the conceptacles ; in the
other species of Fucus the two kinds of or-
gans are never met with together in the same
conceptacle ; in Himanthalia lorea they are
on distinct plants ; in Halidrys siliquosa in-
termingled, and in Pycnophycus tuberculatus
in the same chamber, but not mixed. The
antheridia of these plants consist of transpa-
rent ovoid sacs, inserted in great number on
the branched hairs (paranematd), clothing
the inside of the fruit-chambers or scaphidia
(fig. 258). In some genera they have a
double coat, in others only one ; when two
exist, the inner is expelled as a sac on the
rupture of the antheridium ; when only one
exists, the spermatozoids are expelled indi-
vidually and freely from the single coat, which
always remains attached upon its support.
The spermatozoids or antherozoids found in
these sacs are little hyaline globules, each
enclosing a granule of grey colour in Fucus
canaliculatus, red-orange in all other species
of Fucus and other genera. They bear two
locomotive cilia, very slender, and of unequal
length. The form of the corpuscles and the
arrangement of the cilia differ in different
genera. In all the species of Fucus the
spermatozoids are of the shape of little
bottles, the neck of which, always foremost
in the movement, bears the shortest cilium ;
the longer arises from the coloured granule,
and trails behind. In Halidrys, Pycnophycus,

T2

FUCOIDE^E.

[ 276 ]

FUCUS.

and Cystoseira, the corpuscle is oval or sphe-
rical in one dimension, and compressed,
sometimes a little convex, in the other;
both the cilia are inserted on the red granule,
and during the locomotion the corpuscle
turns upon its own axis, with the longer
cilium in advance, vibrating with rapidity,
while the shorter is motionless. In Himan-
thalia the antheridia have a double coat; the
form of the antherozoids is not well under-
stood. The antherozoids of the Fucaceae
have been shown by Thuret, their discoverer,
to be analogous to the spermatozoids of the
higher Cryptogamia, and to perform a ferti-
lizing function, not to reproduce the plant,
like the zoospores of the other tribes ; in
these plants this appears to be effected solely
by the large olive-coloured spores. (See Fu-

CACEvE.)

Synopsis of the Tribes.

1. FUCACE^B. Frond leathery or membra-
nous, cellular. Fructification: spores and
antheridia contained together or separately
in spherical cavities imbedded in the frond.

2. DICTYOTACE^E. Frond cellular, flat,
compact. Fructification : spores arranged in
definite spots or lines (sori) on the sur-
face.

3. CUTLERIACE.E. Frond cellular, com-
pact, ribless. Fructification : dot-like, scat-
tered collections of oosporanges divided
in eight compartments ; and antheridia,
consisting of chambered filaments in groups
of curved jointed hairs.

4. LAMINARIACE^E. Frond leathery or
gelatinous, cellular. Fructification : oospo-
ranges in indefinite cloud-like patches, or
covering the whole surface of the frond ; or
trichosporanges clothing the whole surface
of the frond like an epidermis.

5. DICTYOSIPHONACE^E. Frond cylin-
drical, branched, of filamentous structure.
Fructification : ovoid oosporanges imbedded
lengthways in the substance of the frond,
opening by a pore on the surface.

6. PUNCTARIACE^J. Frond cylindrical or
flat, unbranched, cellular. Fructification :
ovate oosporanges in groups on the surface,
intermixed with clavate filaments (para-
physes).

7. SPOROCHNACE^E. Frond leathery or
membranous, cellular, branched. Fructifi-
cation : oosporanges or trichosporanges at-
tached to external jointed filaments, free or
collected in knob-like masses.

8. CHORDARIACE^E. Frond cartilaginous
or gelatinous, composed of horizontal and

vertical jointed filaments interlaced. Fruc-
tication : oosporanges springing from the
base of the vertical filaments forming the
epidermis of the frond; and trichospo-
ranges developed later from the filaments
surrounding the oosporanges.

9. MYRIONEMACE^E. Frond tuber-shaped,
crustaceous, or spreading as a crust, of
filamentous structure. Fructification :
oosporanges, and trichosporanges attached
to the superficial filaments, and concealed
among them.

10. ECTOCARPACE^E. Frond filiform,
jointed. Fructification : oosporanges, ovate
sacs developed at the ends or interme-
diate joints of the filaments; and tricho-
sporanges, consisting of minute jointed fila-
ments found in similar situations.

BIBL. See under the Families.

FUCUS, Linn.— A genus of Fucacea; (Fu-
coid Algae), including some of the commonest
and most abundant of our olive-coloured sea-
weeds, growing upon rocks and stones be-
tween tide-marks, their large fronds waving
in the water at high-water, and lying matted
together over the rocks when the tide is out ;
continually cast ashore in quantities after
rough weather. F. vesiculosus, the common
bladder-wrack, is familiar to every one who
has visited a sea-coast. Decaisne and Thu-
ret divide the genus into three: Pelvetia
(F. canaliculata], Ozothallia (F. nodosus),
and Fucus proper, including F. serratus,
vesiculosus and ceranoides.

In F. nodosus and F. Mackaii the recep-
tacles are lateral and stalked, but in all
the rest they are terminal and continuous
with the frond (fig. 256), forming oval, thick-
Fig 256.

F. vesiculosus.

End of a branch of F. vesiculosus, bearing two terminal
receptacles.

Half the nat, size.

FUCUS.

[ 277 ]

FUCUS.

ened clubs, on which, by the naked eye, may
be distinguished a number of spots or pores.
These are the orifices of the conceptacles,
which are globular cases immersed in the
substance of the receptacle, and communi-
cating with the outer surface by a pore (fig.
257). The central portion of the receptacle

Fig. 257.

Fucus canaliculatus.

Section of a conceptacle of F. canaliculatus, containing
sporanges, antheridia, and paraphyses.

Magnified 40 diameters.

is filled up with a delicate network of jointed
filaments surrounded by a gelatinous sub-
stance, this medullary structure forming a
bond of union between the numerous concep-
tacles. The internal wall of the conceptacles
is lined with a dense mass of delicate jointed
filaments (fig. 257) standing vertically (para-
physes}, among which appear the stalked
spore-sacs alone in the dioecious and monoe-
cious forms, mixed with antheridia in the
hermaphrodite. The anlheridia occur alone in
similar conceptacles in the monoecious and di-
oecious forms. F. canaliculatus is hermaphro-
dite (like Pycnophycus tuberculatus, which
however has antheridia only at the upper
part of the conceptacle, near the pore, spore-
sacs at the lower part) ; in F. serratus, cera-
noides, vesiculosus, and nodosus, the male
and female conceptacles occur, usually on
distinct plants, but both kinds sometimes
occur on F. nodosus. The male and female
individuals of the dioecious species may often
be distinguished, when mature, by the yel-
lowish colour the antheridia give to the re-
ceptacles ; and if these are exposed for a
short time to the air, the antheridia are ex-
pelled in masses through the pores of the
conceptacles, and form little orange-coloured
papillae. The female plants under similar
circumstances exhibit olive-coloured papillae
at the mouths of the pores, consisting of
masses of spores.

The sporanges or spore-sacs consist of
ovate sacs, stalked on the walls of the con-

ceptacle (fig. 257) ; they have a double mem-
brane, an outer, the sporange or perispore,
and an inner, the epispore; these are un-
distinguishable until the spores escape, but
then the epispore becomes evident as an
inner sac. The epispore encloses at first a
mass of olive-coloured cell-contents ; in F.
canaliculatus (Pelvetia) this divides into two
spores, in F. nodosus (Ozothallia) into four,
and in F. serratus, vesiculosus, and the other
Fuci proper, into eight, by segmentation.
When mature, the sporange bursts at the
apex, the epispore enclosing the spores is
expelled, and makes its way towards the
pore of the conceptacle, and falls into the
water, where it undergoes the following
modifications. Taking F. vesiculosus as an
example, the expelled epispore encloses eight
spores, forming what Thuret calls an octo-
spore. This swells, and the spores become
rounded, separating from each other, and
the upper part of the epispore begins to dis-
solve. The spores become removed from
the lower part of the epispore (marked by
the impression of the stalk of the sporange),
and it then becomes evident that they are
enclosed in a third membrane, which is at-
tached to the epispore in the centre of its
base, so that as the spores emerge from the
dissolving summit of the epispore, the inter-
nal membrane becomes stretched upward,
until it finally bursts and sets the spores
free. These changes of the octospore are
generally passed through in about an hour,
sometimes much more rapidly.

The antheridia consist of minute ovate
sacs, attached in great numbers to hair-like
filaments growing from the internal surface
of the conceptacle (fig. 258). When young,

Fig. 258.

Fig. 259.

F. nodosus.

F. serratus.

Fig. 258. A branched cell bearing a perfect and imper-
fect antheridium. Magn. 200 diams.

Fig. 259. Sac of an antheridium nearly empty, with
a free spermatozoid. Magn. 400 diams.

they are filled with colourless granular mat-
ter, but subsequently this becomes condensed
into little corpuscles (spermatozoids or an-
therozoids), forming a greyish mass dotted
with orange points. The sac is double, and

FUCUS.

[ 278 ]

FUNARIA.

the internal one is expelled from the outer
like the epispore from the sporange, and
finds its way out from the pore of the con-
ceptacle. The spermatozoids which fill up
the central part begin to move actively, and
the sac soon bursts at one or both ends to
discharge them. The spermatozoids (fig.
259) are excessively minute, transparent bo-
dies, scarcely 1-5000" long, enclosing a gra-
nule of an orange-colour in most spores, but
greyish in F. canaliculatus. The spermato-
zoids have two cilia, of unequal length, one
directed forwards, the other backwards ; the
form of the spermatozoids and the direction
of the cilia vary in different species ; the one
directed forward usually moving with great
rapidity, and producing locomotion, while
the other trails behind like a rudder.

The most interesting and important point
connected with the genus Fucus is the pro-
cess of fecundation, which has been distinctly
made out by Thuret, showing the existence
of sexes in the Algae, at least in one fa-
mily.

When a drop of (sea-) water containing
active spermatozoids is added upon a slide,
upon which the free spores above described
have been previously placed, the whole ope-
ration of the fertilization may be traced
under the microscope. The spermatozoids
attach themselves in great numbers to the
spores, and by the motion of the cilia com-
municate to them a rotatory movement, often
very rapid. The field of the microscope
becomes covered with these large brownish
spheres bristling with spermatozoids, and
rolling in all directions among the crowd
of those still unattached. After about half
an hour, the movement of the spores ceases;
the spermatozoids move for some time longer.
On the next day such fertilized spores will
be found coated with a membrane, the pre-
sence of which is readily made out by placing
the spore in syrup, which causes the granular
contents to contract and shrink away from
the envelope, which, moreover, may be co-
loured blue by sulphuric acid and iodine.
The spore then begins to enlarge and grow
by cell-division, one end becoming elongated
into a transparent filament like a radicle
(fig. 260) ; several more of these are after-
wards formed as the upper part grows, and
they become organs of attachment by which
the young frond is fixed to a stone or other
support. The above description corresponds
in all essentials to the process as it occurs in
the other species. The spores of F. vesicu-
losus have been fertilized with spermatozoids

of F. serratus by Thuret, but no other ex-
periments of hybridation succeeded.

Fig. 260.

F. serratus.

Fig. 260. Spores of F. serratus in various stages of
germination. Magnified 100 diameters.

One or two other points deserve notice.
The orange spot of the spermatozoids is co-
loured blue by sulphuric acid (like CHLORO-
PHYLL). Sugar and sulphuric acid colour
the spermatozoids red (PROTEINE). The
membrane of the sporange (perispore] is co •
loured blue by sulphuric acid and iodine
(CELLULOSE), but this is not the case with
the epispore nor the internal membrane, even
after treatment with caustic potash. In F.
canaliculatus, however, there is a laminated
coat immediately surrounding the spores,
which, when placed in sea-water, separate,
while the coat swells and forms a kind of ge-
latinous envelope, which appears as if covered
with cilia; these pseudo-cilia appear to be
analogous to the similar appearances in the
gelatinous sheaths of DESMIDIACE^E and
other CONFERVOIDS.

The months from December to March are
the most favourable for observing the above
phenomena. No covering glass must be
used on the slide, unless prevented by a thin
glass support from pressing on the spores
and deforming them. A power of 150 to 200
diameters suffices for most of the observa-
tions ; for the spermatozoids and the actual
fecundation, a power of 300. Sea-water must
always be used. The germination of the
spores may be observed by placing them on
glass slides moistened with sea-water, and
keeping them under a bell-glass standing in
a dish containing sand moistened with sea-
water.

BIBL. Harvey, Br. Marine Alg. p. 18. pi.
1 D', Phyc. Brit. pi. 47. 52. 158. 214 ; Gre-
ville, Alg. Brit. pi. 181; Decaisne and Thu-
ret, Ann. des Sc. nat. 3 ser. iii. p. 5 ; Thuret,
ibid. xvi. p. 6, 4 se'r. ii. 197.

FUNARIA, Schreb.— A genus of Funa-
riaceas (Acrocarpous Mosses), the common

FUNARIACE.E.

[ 279 ]

species of which (F. hygrometricd) is well-
known on account of the hygroscopic cha-
racter of its fruit-stalk, which twists in dry-
ing, and untwists again when wetted.

1. Funaria hyyrometrica, Hedw.

2. F. Muhlenberyii, Schwagr.

3. F. hibemica, Hook.
FUNARIACE.E.— A family of Funarioi-

deae (Acrocarpous Mosses), of loosely-tufted
or gregarious habit, growing on the ground ;
the stem loosely leaved, very simple. Inflo-
rescence monoecious; antheridial flowers
disk-shaped, mostly terminal on a special
branch. Antheridia small, oval. Archegones
small, narrowly apiculate. Paraphyses fili-
form at base, club-shaped and articulate at
the apex. Peristome, if present, cartilagi-
nous, red, streaked, with solitary, oblique,
trabeculate teeth.

British Genera.

I. FUNARIA. Capsule asymmetrically
arched (fig. 261) ; orifice oblique, very small;

Fig. 261. Fig. 262.

F. hibemica.

Fig. 261 . A ripe capsule with its twisted seta.
Fig. 262. An immature capsule, covered by its calyptra.
Magnified 25 diameters.

stalk much curved, elongated, very hygro-
scopic and twisting. Calyptra ventricose-
dimidiate, rounded at the base, obtuse,
shorter than the capsule, or larger and trun-
cate at the base (fig. 262). Peristome dou-
ble, erect ; outer of sixteen, oblique, broadly
lanceolate-subulate, trabeculate teeth, with
appendices near the point (fig. 263), chained
together at the apex by a reticular disk ; the
inner as many as the outer, opposite and
adnate at the base, lanceolate, granular, with
a longitudinal line. Cells of the operculum
circinately -reticulate at the apex.

FUNARIACE.E.

Fig. 263.

^£y

F. hibemica.

Teeth of the peristome, with appendices.
Magnified 150 diameters.

II. PYRAMIDIUM. Calyptra squarely-py-
ramidal, apiculate, entire at the base, far ex-
ceeding the capsule, totally covering it, in-
flated and persistent, bursting at the middle
of the side, longer. Capsule symmetrical,
erect, pyriform, without a peristome. Oper-
culum regularly areolate. J?is. 264.

III. PHYSCOMITRI-
UM. Calyptra mitre-
shaped, split at the
base into several laci-
niae, entire below, much
shorter than the cap-
sule, with a long api-
culus. Capsule sym-
metrical, straight, pyri-
form, without a peri-
stome. Operculum re-
gularly areolate.

FV. ENTOSTHODON. Physcomitrium pyriforme.
Calyptra bladder-like, Capsule, mag. 25 diams.
dimidiate, with a long apiculus, entire,
rounded or truncate, readily splitting. Cap-
sule symmetrical, pear-shaped, straight, or
declined on an arched stalk, with or without
a peristome. Peristome, if present, horizon-
tal, erect when dry, simple, internal wanting
or scarcely perceptible, composed of very
short lacinioe. Teeth lanceolate, without
appendages, simple or twin, flat outside,
trabeculate within, mostly oblique at the
summit, connivent but not connate. Oper-
culum regularly areolate.

V. AMBLYODON. Calyptra hood-like, nar-
row, very fugacious, longish, very slender, com-
posed at the apex of very small, thickened,
square cells. Capsule asymmetrical, pear-
shaped, straight, with a peristome and an
annulus. Peristome double, external : teeth
sixteen, short, lanceolate, obtuse, erect, tra-
beculate with a slender longitudinal line;

internal : teeth equal in number, lanceolate,
subulate, fissile longitudinally in the middle,
smooth, much exceeding the external in
length, yellowish, placed on a shortly-grooved
membrane. Operculum regularly areolate.
FUNARIOIDEJ4 ,— A suborder of opercu-
lated Acrocarpous (terminal-fruited) Mosses,
with broadly-oval, spathulate leaves, fur-
nished with a lax cylindrical nerve, composed
entirely of large parenchymatous cells, lax
and parallelogrammic at the base, lax, hexa-
gonal, or polygonal towards the apex, often
very densely filled with chlorophyll-granules,
more or less pellucid. Capsule pyriform,
apophysate, the neck (collum} mostly bearing
stomates on its epidermis (fig. 266).

Fig. 265. Fig, 266.

FUNARIOIDE^E [ 280 ] FUNGI.

some have supposed. They are allied by
certain forms with the Algae and with the
Lichens, but they are distinguished from all
outwardly similar forms of the first by the
spore- bearing fruits always being elevated
into the air, when mature, although the
thallus or mycelium may be aquatic. The
higher forms of Fungi can scarcely be con-
founded with the higher Algae. The separa-
tion from the Lichens is more difficult, and
promises to be still less practicable the more
we know of the plants ; indeed, some authors
have already come to the conclusion that the
Lichens must be reduced to forms of Fungi.
Yet the presence of green gonidial cells in
the thallus will generally sufficiently distin-
guish the Lichens. We shall here follow
the old plan ; and the distinction ordinarily
laid down is, that the Lichens are entirely
aerial encrusting plants, while the Fungi
have their vegetative structure immersed in
the medium in which they grow.

The structures of all Fungi exhibit a well-
defined separation into two parts, namely,
1, a mycelium (thallus), or vegetative struc-
ture, consisting of a mass of exceedingly
delicate, jointed and branched, colourless,
interlacing filaments, forming a kind of cot-
tony or felty mass when growing in the earth,
in vegetable structures, &c., or cloudy flocks
when growing in decomposing liquids ; 2, of
the reproductive structure or fruit, which,
unlike the mycelium, differs extremely in
appearance in the various tribes.

The mycelium may be well examined in
the "spawn" used for planting mushroom-
beds, since this cottony substance consists
of the mycelium of that plant ; the forma-
tion and growth of the mycelium of the mi-
croscopic species, such as moulds, mildews,
&c., may be traced under the microscope by
scattering some of the dust-like fructifica-
tions (as the blue powder of common paste-
mould) upon slips of glass, and keeping them
in a warmish place under a bell-glass over
water, for several days. The filaments will
be seen spreading from the spores in all di-
rections, and often the formation of the fruc-
tification is exhibited.

The fructification of the simplest Fungi is
nothing more than a modification of one or
more cells at the ends of a filament which
rises up from the general body of the myce-
lium. In TORULA, one or more globular
cells are produced at the ends of filaments
composed of elongated, more or less cylin •
drical cells (PI. 20. fig. 7) ; these globules
drop off, and develope into new mycelia. In

F. hygrometrica.

Fig. 265. Portion of the annulus. Magn. 150 diams.
Fig. 266. Epidermis of the collum, with stomates.

Magn. 150 diams.

This suborder is divided into two families :

1. Funariacece. Stem very simple, ter-
restrial.

2. Splachnacece. Stem very much branched,
mostly occurring upon dung of animals.

FUNGI.— A class of Cellular, Flowerless
Plants, growing in or upon damp (vegetable)
mould, in or upon the wood and the herba-
ceous parts of living or dead plants, upon
living or decaying animal substances, in so-
lutions of organic mixtures, &c. A very
large portion of the plants belonging to this
strange class are microscopic bodies, only to
be made out clearly by means of a very high
magnifying power; as in the rest of the
Thallophytes, moreover, the reproductive
bodies are simple and exceedingly minute in
the most complex forms of Fungi ; and con-
sequently dissection under the microscope is
requisite when it is desired to obtain a satis-
factory insight into their natural history.

The Fungi do not appear to be capable of
assimilating inorganic food, and are distin-
guished from healthy specimens of almost
all other plants by the total absence of the
colour depending on the presence of chloro-
phyll or its red modifications; for it is scarcely
to be doubted that the various colourless
filamentous structures (Leptomitese, &c.)>
occurring in infusions, chemical solutions
and the like, are Fungi, and not Algae, as

FUNGI. [ 281 ]

Botrytis (figs. 79, 80, 267), the tips of the
Fig. 267.

Botrytis vulgaris.
Fertile filaments. Magnified 200 diams,

fertile filaments are branched and clothed
with heaps of spores arising from short pe-
dicels. In Penicillium (PL 20. fig. 15), the
filament which rises up forks at the end,
each branch forking again, and so on, until
a close, tufted pencil of branches is formed,
each branch bearing a bead-like row of spores,
which drop off separately. Innumerable
modifications of this mode of fructification
are met with in the microscopic Fungi, and
the same plan also forms the basis of the
fructification of some of the highest forms.
The way in which the greater complexity
arises is by an increased development of the
structures supporting the layer of tissue (hy-
menium) upon which the spores are borne.
Thus in the leathery Fungi growing over
damp trunks of trees and dead wood, such
as the Hydna, Thelephoree, Hexagonia (figs.
268, 269), the conspicuous fungous mass

Fig. 268.

Hexagonia glabra.
Upper surface. Nat. size.

(which is all that ordinary observers notice)
developed from a flocculent mycelium im-
bedded in the matrix on which the plant
grows, is a fruit, composed of dense cellular

FUNGI.

Fig. 269.

Hexagonia glabra. Nat. size.
Lower surface, with orifices of the hymenium.

tissue, and possessing pits, channels, cavi-
ties, or the like, the walls of which are clothed
with papillose cells, each bearing four free
sporules, which drop off singly to reproduce
the plant. The Mushroom, as gathered and
brought to table, is merely the 'fruit' of the
Fungus (Agaricus], and similar cells bearing
four sporules are found clothing the flat
sides of the paper-like plates or * gills' which
radiate on the under side of the flat ' cap' of
the Fungus. (See BASJDIOSPORES.)

Another mode of fructification is met with
in the Fungi, and by this they in some cases
come exceedingly close to the Lichens. The
simplest form of the second kind of fructifi-
cation is seen in the ' Mildews ' (Eurotium,
Mucor, &c.), where the upright filament
arising from the flocculent mycelium does
not bear free spores, as in Penicillium, Botry-
tis, &c., but a comparatively large sac, filled
with minute sporules; and these sporules
are scattered by the bursting of the sac. In
the Helvella, Pezizce, Spathulea (fig. 40),
Leotia (fig. 42), &c., structures of a fleshy
or leathery character, growing upon damp
wood, &c., we have counterparts to the
Hydna, Thelephoree, &c., since they have fruits
arising from a flocculent mycelium, but their
spore-bearing cells appear as definite groups
of vesicles or sacs of elongated form,producing
sporules (usually eight) in their cavities. In the
Truffles (Tuber, Elaphomyces, fig. 187), &c.
the spores are found in fours or eights, in sacs
in the internal convoluted substance (while
in the Puff-balls, where the internal mass
finally breaks up into powder, the spores are
developed free, as in the Agarics, &c.). More
minute accounts of these structures will be
found under THECASPORES and the various
genera.

It was long imagined that these two modes
of producing the spores afforded a firm basis
for the classification of the Fungi, but recent
discoveries seem to indicate that characters

FUNGI.

[ 282 ]

FURCULARIA.

derived from the fructification are as unsafe
here as in the Algae in the present state of
our knowledge. Thus the division of the
Fungi into Basidiosporous and Thecaspo-
rous, according as the spores grow upon free
points (basidia) or in the interior of sacs
(thecee or «sc«),must be given up, since Messrs.
Tulasne, Berkeley and Broome have shown
that both kinds of structure occur in the
same species of Fungi at different epochs of
their growth. Tulasne has also pointed out
a peculiar structure analogous to the so-
called spermatozoids of the Lichens, namely
very minute cylindrical bodies growing upon
free points from the fructifying surfaces of
the Fungi ; these bodies, quite distinct from
the basidiospores and thecaspores, are called
spermatia (PL 20. figs. 3, 4, 17, s). The
physiological relations of these various
structures are as yet quite obscure, and they
are dwelt upon but slightly here, from the
absence of definite generalizations on the
subject ; they present a field for most desi-
rable observations.

The minutiae of the structure of the Fungi
will be treated most satisfactorily under
the heads of the orders (ASCOMYCETES,
CONIOMYCETES), since the elements are
very similar in all, while the modes of com-
bination are very varied, and in most cases
peculiar to the families.

The Fungi are divided by Mr. Berkeley
into six orders, and as the facts which have
lately come to light, throwing doubt on the
validity of some of the divisions, are not yet
sufficiently numerous to allow of satisfactory
general conclusions, we adopt these orders as
practically convenient, reserving the remarks
on this subject to the description of certain fa-
milies. (See SPH^ERONEMEI, SPH^RIACEI.)

1. HYMENOMYCETES or AGARICOIDE^E
(Mushrooms, &c.). Mycelium floccose, in-
conspicuous, bearing conspicuous fleshy
fruits of various forms, which expand when
perfect so as to expose the hymenium or
sporiferous membrane to the air. Spores
generally borne in fours on short pedicels
arising from cells of the hymenium.

2. GASTEROMYCETES or LYCOPERDOI-
DE.E (Puff-balls, &c.). Mycelium floccose,
inconspicuous, bearing usually globular or
oval leathery fruits, which are at first solid,
with internal convolutions clothed by the
hymenium, bearing the spores in fours on
distinct pedicels, the internal convoluted
portions finally breaking up and constituting
a pulverulent or gelatinous mass enclosed in
a leathery membrane (peridium).

3. CONIOMYCETES or UREDOIDE.E
(Smuts, fyc.}. Mycelium filamentous, para-
sitical, bearing usually sessile masses of
(microscopic) fructification, consisting of
groups of sessile or stalked spores, some-
times septate.

4. HYPHOMYCETES or BOTRYTOIDE^S
(Mildews, fyc.) (Microscopic). Mycelium
filamentous, epiphytic, producing erect fila-
ments bearing terminal, free, single, simple
or septate spores.

5. ASCOMYCETES or HELVELLOIDE^B
(Truffles, Morells, &c.). Mycelium inconspi-
cuous, bearing fleshy, leathery, horny or
gelatinous, lobed or wart-like fructifications,
containing internally or on the surface groups
of elongated sacs (asci or thecce), in the in-
terior of which the spores (generally eight)
are developed.

6. PHYSOMYCETES or MUCOROIDEJE
(Moulds}. Mycelium (microscopic) filamen-
tous, bearing stalked sacs containing nume-
rous exceedingly minute sporules.

BIBL. Berkeley, Fungales, in Lindley's
Vegetable Kingdom; Fungi, in Hooker's
British Flora ; also numerous papers in the
Ann. Nat. Hist. ; Montague, Organographic
and Physiologic Sketch of the class Fungi,
translated by Berkeley in Ann. Nat. Hist.
vol. ix. ; Corda, Icones Fungorum, Prague,
1837-40; Greville, Scottish Cryptogamic
Flora. See also the references given under
the heads of the families.

FUNGUS-BED.— Mycologists find this
very useful for growing the microscopic
Fungi. It is best made of a small wooden
box half-filled with damp bog-earth, and
covered with a plate of glass. In winter it
should be kept in a warm room.

FURCELLARIA, Lamx. — A genus of
Cryptonemiaceae (Florideous Algae), con-
taining one common British species, growing
on rocks and stones between tide-marks,
consisting of a fastigiate, dichotomously-
divided frond, 6 to 12" high, of a brownish-
purple colour, and somewhat cartilaginous
texture. The tetraspores, which are linearlv
arranged, are imbedded in the periphery of the
swollen pod-like extremities of the branches.
Conceptacular fruit as yet unknown.

BIBL. Harvey, Br. Mar. Alg. p. 147.
pi. 18 C., Phyc. Brit. pi. 94 ; Greville, Alg.
Brit. pi. 11, Eng. Bot. pi. 894.

FURCULARIA, Lam.— A genus of Rota-
toria, of the family Hydatinaea.

Char. Eye single, frontal; tail-like foot
forked. Several species; all aquatic but
one, which is marine.

FUSARIUM.

[ 283 ]

GAMMARUS.

F. Reinhardtii, E. (PL 34. fig. 34 ; fig. 33,
teeth). Body fusiform, truncated in front ;
foot elongate, cylindrical ; toes two, short ;
length 1-120".

Found creeping upon Laomedea geniculata.

F. gibba. Body oblong, slightly com-
pressed, dorsally convex, ventrally flat;
toes styliform, half as long as the body;
length 1-96". Aquatic.

BIBL. Ehrenb. Infus. p. 41.9 ; Dujardin,
In/us, p. 648; Gosse, Ann. Nat. Hist. 1851.
viii. p. 199.

FUSARIUM, Lk.- A genus of Stilbacei
(Hyphomycetous Fungi), not very satis-
factorily distinguished from FUSISPORIUM,
but having a firm cellular, pulvinate, fleshy
stroma, upon which the spores are borne on
distinct sporophores, glued together into an
erumpent discoid stratum. F. tremelloides
is common, forming roundish orange-red
spots on decaying nettle-stems. F. roseum
forms little gregarious red dots on the stems
of beans, Jerusalem artichokes, and other
plants.

BIBL. Berk. Hook. Brit. Flora, ii. pt. 2.
p. 355 ; Fries, System. Myc. iii. 469, Summa
Veg. 472 ; Greville, Sc. Crypt. Flora, pi. 20;
Fresenius, Beitr. zur Mycologie, Heft 1.
p. 35.

FUSIDIUM, Lk. See FUSISPORIUM.

FUSISPORIUM, Lk.— A genus of Sepe-
doniei (Hyphomycetous Fungi), growing
upon vegetable substances, often when de-
caying, forming either a kind of mildew or
subsequently an extensive gelatinous stra-
tum, bearing spindle-shaped
spores (fig. 2/0). The myce-
lium is composed of very de-
licate filaments, which are
generally evanescent, and
partially dissolve so as to
glue the fallen spores into a
mass upon a tremelloid ma-
trix. Several species are of a
rose-colour. The genus Fu-
sidium, Lk., is separated by
some authors, and placed
among the Mucedines, on account of its
evanescent mycelium and the absence of a
stroma, from Fusisporium, Lk., in which
the mycelium is converted into an effused
gelatinous stratum; but the distinction ap-
pears unimportant. Numerous species are
recorded as British. F. atrovirens is a de-
structive mildew on onions. F. griseum is
common on dead leaves. F. fosni is remark-
able for forming large orange -red patches,
many feet in width. The genus FUSARIUM

Fig. 270.

Fusisporium.

Spores. Magn.

400 diams.

differs from this in the presence of a discoid
stroma.

BIBL. Berk. Hook. Brit. Flora, ii. pt. 2.

}. pi. 14.

fig. 28, z ser. vii. p. 1/8 ; rries, Syst. Myc.
iii. p. 442, Summa Veget. p. 473 ; Greville,
Sc. Crypt. Flora, pi. 102. figs. 1 & 2.

-i_j j. u j-i • jLrvsj.iv* .AAisi/rv* A*9 99t J. v\Ji u-j 11. I

p. 251, Ann. Nat. Hist. vi. p. 438. pi
fig. 28, 2 ser. vii. p. 178 ; Fries, Syst. J

G.

GALLIONELLA, Bory. = MELOSIRA,
Agardh . Gall. ferruginea= Didymohelixfer.

GALLS. — These are abnormal growths,
tumours as they might be called, produced
upon or in vegetables by the action of ani-
mals, especially insects of the family Hyme-
noptera. They are supposed to arise from the
irritation caused by a poisonous liquid dis-
charged into the orifice made by the insect
for the introduction of its egg. At all events
a convergence of the nutritive juices towards
the wound takes place, whence results a kind
of hypertrophy of the tissues, and frequentlv
the accumulation of such substances as starch
in the cells. The forms may be regular or
irregular; most of them are characteristic,
as for example, the well-known nut-gall, the
oak-apple, the bedeguar of the rose, &c.
Both cellular and vascular structures contri-
bute to form the substance of galls. We
cannot enter into their minute structure
here, but refer to an elaborate paper by Dr.
Lacaze-Duthiers.

BIBL. Lacaze-Duthiers, Ann. des Sc. nat.
3 ser. xix. 2/3, where also the earlier litera-
ture is given.

GALUMNA, Heyden, Gervais.— A genus
of Arachnida, of the order Acarina, and fa-
mily Oribatea.

Char. Abdomen subglobular, depressed ;
sides of the pseudo-thorax forming a salient
or wing-like angle; legs of moderate length.

This genus approximates to Belba.

The three species, the bodies of which are
of a blackish, blackish-chestnut, or ash-
colour, are found on mosses.

BIBL. Walckenaer, Arachnid. (Gervais);
Hermann, Mem. Apter. p. 91 ; Koch,
Deutschl. Crustac. &c.

GAMMARUS, Latr.— A genus of Crus-
tacea, of the order Amphipoda, and family
Gammarina.

The searcher for the freshwater Diatoma-
cese will surely meet with Gammarus pulex,
the freshwater shrimp, in muddy brooks and
streams. It attains a length of about 1-2",
and moves its curved body through the water
by means of its caudal appendages, fre-

GANGLION-GLOBULES. [ 284 ]

GASTEROMYCETES.

quently lying on its back or side during the
process. Gervais distinguishes G.fluviatilis
from G. pulex, by the former having a dorsal
spine at each abdominal joint, whilst in the
latter this is absent.

There are twenty-three species of Gam-
marus, many of them marine. Talitrus sal-
tator, the sand-hopper, found burrowing in
and hopping upon the sand of the sea-shore,
also belongs to the family Gammarina.

BIBL. Desmarest, Consid. general, s. I.
Crustac.', M. -Edwards, Crustac. iii. ; Ger-
vais, Ann. des Sc. nat. 1835. 2 ser. iv.; West-
wood, Phil. Trans. 1835.

GANGLION - GLOBULES, or NERVE-
CELLS. See NERVES.

GASTEROMYCETES. — An order of
Fungi, characterized by the production of
their free spores upon basidia seated on a
sporiferous structure forming convolutions
in the interior of an excavated fruit, which
ultimately bursts to allow the sporiferous
structure to expand and scatter its spores.
The fruit of the Gasteromycetes is ordinarily a
globular, elliptical, or shapeless mass, varying
in size from microscopic minuteness to the
dimensions of large leather balls, often
stalked, arising from an inconspicuous floc-
culent mycelium. This external body con-
sists of a leathery or membranous, simple or
double sac (peridium}, which bursts in va-
rious ways at maturity. When examined
young, these Fungi appear solid; but as they
advance, various structures become gradu-
ally marked out in their interior, and appear
more and more distinct until mature.

IntheNidulariacei little concept acles are de-
veloped in the interior of the sac-like peridium ;
and when the latter is mature, it opens like
a cup or vase at its summit, exhibiting the
conceptacles within, lying like eggs in a nest.
These conceptacles are hollow, and lined
with basidia bearing free spores. The Myxo-
gastres are minute Fungi growing upon
wood, leaves, &c., and looking at first to the
naked eye like patches of froth. They are
stated by authors to offer originally no trace
of organization, but to present, after a time,
floating spores, the mucilaginous mass finally
drying and dividing into a number of con-
ceptacles. This account is evidently crude
and imperfect, the mycelium threads being
overlooked. At certain stages, however, the
conceptacles do appear imbedded in mucila-
ginous matter, cementing them more or less
together, and they become free and isolated
after the mucilage has dried up. At matu-
rity, the conceptacles, which are sacs, and con-

sist of a double peridium, burst and emit the
sporiferous structure, which often rises from
the conceptacle and expands in various forms.
The sporiferous structure is called the capil-
litium, and consists of a collection of simple
or anastomosing filaments, either attached
to the peridium, and forming a kind of net-
work, from between the meshes of which
(probably the seat of their development) the
spores fall out ; or free and discharged with
the spores. The free filaments of several
genera are marked with striae, which in
TRICHIA may be clearly seen to arise from
a spiral fibrous structure like that of the
elaters of the Hepaticacese.

The Trichogastres exhibit in most cases
the appearance of a leather ball, arising from
an inconspicuous flocculent mycelium, but in
Broomeia the sporanges are imbedded in
large numbers in a common fleshy matrix.
The internal structure differs to a consider-
able extent in its earlier stages. The peri-
dium is either single or double, the inner
being often quite free, and becoming everted
at the time of dehiscence. The interior of
Polysaccum (fig. 271) and Scleroderma (fig.
274) consists in the early state of a mass of
structure formed by the production of the pe-
ridium, in the form of septa, in all directions
into the interior, so as to divide it into cham-
bers, each of which contains a nucleus of

Fig. 271.

Fig. 272.

Polysaccum crassipes.
Fig. 271. Natural size.
Fig. 272. Section from ditto, showing the loculi.

filamentous, cellular substance, or concepta-
cle, hollow in the centre, into which project
the ends of the filaments, bearing basidia
with two to six spores. At the epoch of
maturity all the internal structure has va-
nished, except the spores and detached par-
ticles of the filaments on which they were
developed, and these escape on the bursting

GASTEROMYCETES.
Fig. 273.

[ 285 ]

Polysaccum crassipes.

Cells of the hymenium, with basidia and spores.
Magn. 400 diams.

Fig. 274.

Fig. 275.

Scleroderma vulgare.

Fig. 274. Portion of the internal mass,
diams.

Magn. 200

Fig. 2/5. Cells of the hymenium, with basidia and
spores. Magn. 400 diams.

of the now bag-like peridium, as a fine pow-
der. In Lycoperdon, &c., it is not the peri-
dium which is continued inwards to form
chambers ; it forms a single or double sac,
containing a fleshy substance (gleba), hol-
lowed out into sinuous cavities clothed with
basidia. In course of ripening, the spongy
mass disappears, leaving only a collection of
minute spores and filamentous fragments,
which are emitted by the bursting of the pe-
ridium, a process exhibiting many curious
peculiarities in this group.

The Phalloidei are roundish or ovoid
fleshy balls in their earlier stages, but when
opened exhibit a distinct peridium and a
central lacimose, sporiferous structure. The

GASTEROMYCETES.
Fig. 276.

Lycoperdon cepaeforme.

Section of the gleba, showing the loculi, on the walls of
which the spores are produced.

Magn. 200 diams.

peridium consists of two layers, an inner

and an outer, united by firm gelatinous tis-

sue traversed by transverse membranous

septa, and exhibits a tendency to split, like

an orange, into quarters. When the peri-

dium bursts, which it usually does at the

apex, the central sporiferous structure

emerges, under various forms. In Phallus

it is a capitate or clavate co-

lumn ; in Clathrus (fig. 277),

an elegant, globular,, fleshy

trellis; in Aseroe, a column

with a stellate head, &c. In

all cases, the spores, which are

developed on convolutions of

the fleshy sporiferous mass

(gleba}, on basidia, are found

detached and confluent into a

wet, viscid mass adhering to the

sporiferous surface, at the time

this has emerged from the pe- The sporiferous

ridium and expanded to its full frame - work

size. This fluid condition of

Fig. 277.

the mature sporiferous layer is peridium.
distinctive between the Phal- i-6th nat. size.
loidei and the Hymenomycetes, to which they
bear many relations.

The Hypogaei receive their name from
their subterraneous habit of growth, in which
they resemble Truffles, a tribe of Ascomy-
cetes bearing much external similarity to
these plants (see TUBERACEI). The ge-
neral character is that of globular or de-
pressed balls, growing underground, sessile
on a flocculent mycelium. They exhibit a
peridium enclosing a fleshy gleba, excavated
into sinuous cavities lined by a membrane
bearing basidiospores. These fruits do not

GASTEROMYCETES.

[ 286

GELIDIUM.

burst, but set free their spores by decaying.
Lastly, the Podaxinei bear much resemblance
to the Trichogastres, but they always contain
a central fleshy column, called the hymeno-
phore. The young plants exhibit a peridium
passing internally into a fleshy mass hollowed
into labyrinthiform cavities (fig. 279), with a
solid column in the centre of all. The cavi-
ties are lined by a membrane bearing basi-
diospores (fig. 281). The gleba sometimes

Fig. 278.

Fig. 279.

Fig. 280.

Fig. 281,

Secotium erythrocephalum.

Fig. 278. Natural size.

Fig. 279. Vertical section.

Fig. 280. Vertical section through the head, showing
the labyrinthiform cavities.

Fig. 281. Portion of a septum dividing the loculi, bear-
ing basidia. Magnified 400 diameters.

breaks up into a pulverulent mass of spores
and filaments ; sometimes it is permanent.
The internal structure of this order presents
many points of great morphological interest,
but rather as regards the mode of arrange-
ment and composition of the tissues than
the character of the ultimate elements them-
selves, which consist of the ordinary filamen-
tous interwoven tissue of Fungi in the general
mass of the structure, and of globular loosely
packed cells in the sporiferous regions.

Synopsis of the Families.

1. PODAXINEI. Peridium dehiscent, en-
closing a sinuously excavated, fleshy, spori-
ferous mass, falling to powder or permanent
when mature, with a central solid column.

2. HYPOG^I. Peridium indehiscent,
coating a fleshy, sporiferous mass. Subter-
raneous, at first distended with jelly.

3. PHALLOIDEI. Peridium dehiscent,
enclosing a fleshy, sporiferous mass, which
emerges from the burst peridium as a club-
shaped or capitate column, or a globular
network of wrinkled fleshy processes, coated
on the sporiferous surfaces with a dark-
coloured foul-smelling slime (composed of
minute spores imbedded in mucus).

4. TRICHOGASTRES. Peridium double,
more or less distinct, dehiscent, enclosing a
multilocular, fleshy, sporiferous mass, which
finally breaks up into dust, without a central
column.

5. MYXOGASTRES. Peridium at first
developed from a mucilaginous matrix, sac-
like, dehiscent, emitting a reticulated fila-
mentous structure bearing the spores. (Mi-
nute, almost microscopic Fungi.)

6. NIDULARIACEI. Peridium dehiscent
and then forming a cup or nest, containing
either one or many globose oval or discoid
conceptacles, lined with filaments bearing
spores.

BIBL. See the Families.

GASTROCHJ3TA, Duj.— A genus of In-
fusoria, of the family Enchelia (Duj.).

Char. Body oval, with one side convex,
the other being traversed by a longitudinal
furrow, which is furnished with vibratile
cilia principally at the ends.

G.fissa (PI. 24. fig. 7). Body semitrans
parent, colourless, oval, truncated in front,
with a very minute, blunt point at the
middle of the posterior margin, convex and
smooth above. Aquatic; length 1-400".

BIBL. Dujardin, Infus. p. 385.

GELATINE.— This chemical proximate
principle constitutes the basis of the various
forms of white fibrous tissue, as existing in
the true skin, areolar tissue, tendon, ligaments,
the swimming-bladder of fishes (isinglass),&c.

It possesses no microscopic characters;
it forms a most valuable vehicle for the co-
louring matters of liquids for injection.

BIBL. See CHEMISTRY.

GELIDIUM, Lamx.— A genus of Cry-
ptonemiacese (Florideous Algae), of which one
species (G. corneum) is very common on our
shores. It has a red, pinnated, horny frond,
from two to six or eight inches high ; very

GEMM.E.

GENERATIONS.

variable in the appearance of its pinnate
subdivisions; both spores and tetraspores
are found on the ramules, the former in favel-
lidia immersed in swollen ramules.

BIBL. Harvey, Brit. Mar. Alg. p. 137.
pi. 17 B, Phyc. Brit. pi. 53.

GEMMAE.— This term is applied to those
cellular structures formed in Flowerless
Plants, which become detached, and repro-
duce the individual independently of the
spores. They correspond to the buds of the
Flowering Plants and the gonidia of the
Thallophytes. They present themselves in
various forms, generally either as minute
green bodies or as bulbils. The gemmae are
especially remarkable in MARCHANTIA.
They occur more commonly in the Mosses
and Hepaticae than in the Ferns and higher
Cryptogamia.

GENERATIONS, ALTERNATION OF.
— The general plan upon which the repro-
duction of animals is effected, viz. that of
sexes, involving the action of the spermatic
secretion upon the ova, and the subsequent
series of changes ultimately giving rise to
new individuals resembling the parents, is in
some instances departed from, and the em-
bryos of certain animals after their escape
from the ova, do not become directly deve-
loped into individuals resembling the parents,
but produce a new, larval kind of being,
which produces generations of the same
larval or other kinds, the last of which re-
semble the original parents.

While, therefore, in animals reproduced
by the ordinary sexual process, the new
individuals resemble each other, or differ
only in sex ; in those which produce these
alternate or intermediate generations, the
new individuals differ from the parents and
even from each other, until the last of the
series returns to the state of the first parents.
This mode of reproduction has received the
above name, from the alternation of the lar-
val generations with the ordinary sexual form.

Many instances of this process are men-
tioned under the heads of the Classes, &c.
in which they occur ; as under ACALEPH^E,
APHIS, ENTOZOA, T^ENIA, &c. Thus, for
instance, in the Acalephae, the ciliated embryo
(PI. 40. fig. 6) produced by the ordinary
sexual process, becomes fixed (fig. 7) and
passes into the state of an asexual polype
(fig. 8) ; it then reproduces new individuals
from gemmae and stolons (fig. 9), ultimately
becoming segmented (fig. 10), and produ-
cing new individuals which resemble the
sexual parents. The intermediate or nurse

forms are those represented in figs. 7-10.
Again, in Tcenia, the Cysticercus or Echino-
coccus forms the nurse, producing new indi-
viduals by gemmation ; these when reaching
the alimentary canal becoming transformed
into Tcenice with sexual organs.

But the alternation of generations, or a
modification of it, also occurs in animals in
which sexes are not known to exist, as in some
Infusoria. In these, the ordinary plan of
reproduction by division and gemmation is
departed from, and an animal differing from
the parent or a nurse form, resembling or
identical with Acineta and Actinophrys, is
produced, which give rise to embryos subse-
quently growing into the parent form. But
in these instances the nurse form is the
result of a kind of metamorphosis, rather
than of generation.

The phaenomena designated by the phrase
alternation of generations are also strikingly
exemplified in the vegetable kingdom ; but
the conditions are very complicated, and the
analogies with those occurring in animals
somewhat difficult to trace. The Mosses,
Hepaticacese and Ferns afford very clear
analogies to the Medusae, and others admit
of being made out; but it appears to us that
Steenstrup and others have confounded
various distinct points in the parallel drawn
between the alternation of generations of
animals and the metamorphoses (commonly
so-called) of plants. We will endeavour to
give a summary of the general facts con-
nected with the doctrine.

1. All animals and plants reproduced by
a sexual process (and there is reason to
believe that this will ultimately be found
universal), originate from a simple cell, and
undergo a series of changes, in the course of
their development to the complete form
endowed with sexual organs, in which they
assume forms analogous to animals (or
plants) belonging to classes of lower
(simpler) organization.

2. In the highest animals, the metamor-
phoses are intra-uterine, as in most of the Mam-
malia ; in the lower animals these metamor-
phoses are in part or wholly extra-uterine. In
thehigher plants the changes are partlyinfra-
uterine (i. e. the embryo has already become
a leafy axis within the ovary, but it becomes
perfected into the sexual form subsequently),
in the lower partly or wholly extra-uterine.

3. The lower animals and all plants are
capable of an asexual or vegetative repro-
duction, by the isolation and separation of a
portion of their substance.

GENERATION.

[ 288 J

GEORGIA.

4. Many animals and all plants are
capable of being multiplied by this vegetative
reproduction in their intermediate stages of
extra-uterine development, and in such cases
the reproduction, fissiparous, gemmiparous,
or other, assumes the character peculiar to
the class to which the intermediary form is
analogous (ex. gr. the polypiform reproduc-
tion of the Acalephae, the confervoid growth
and multiplication of the proembryo of the
Mosses). .The product of the vegetative
reproduction is either like or unlike the
body which produces it ; in the former case
the vegetative reproduction will be re-
peated, but in the latter case the product is
usually provided with sexual organs, and the
cycle of development is completed by the
reproduction of a fertilized ovum. In the
latter case we have what is called an alterna-
tion of generations.

It will be evident that we here exclude
from consideration the metamorphoses
within the sphere of the individual shoot on
plants, that is, the metamorphosis of the
leaf, the morphological element of the higher
plant. It appears to us that these are not to
be taken as parallels to the metamorphoses
of animals comprehended by Steenstrup
under the name of alternation of generations,
which would rather be found in the cases
where bulbs, bulbils, tubers, &c. appear in
the place of shoots, as the product of
branch-buds. The analogy would hold also
with the gemmce of the Mosses, &c., and with
the gonidia of the Thallophytes. Our space
does not admit of a more minute examina-
tion of the subject. Illustrations of the
phenomena in vegetables will be found
under FERNS, MOSSES, CONFERVOIDS,
LICHENS, certain Fungi, e. g. ERYSIPHE,
PENICILLIUM, &c.

BIBL. Steenstrup, Alternation of Gene-
rations, Trans, by Ray Soc. 1845; Owen,
Parthenogenesis and Ann. Nat. Hist. 1851.
ii. 59 ; Allen Thomson, Cycl. Anat. iv.
Supplem.; Huxley, Ann. Nat. Hist. 1851.
viii. p. 1, Brit, and For. Med. Rev. 1854. i.
204 ; A. Braun, Rejuvenescence in Nature,
Transl. by Ray Society, 1853.

GENERATION, SPONTANEOUS ; some-
times called equivocal generation, or epige-
nesis.

The doctrine of spontaneous generation
may now be said to have become a matter of
history. We have noticed under AIR (p. 20),
the experiment which negatived the idea
that microscopic plants and animals derive
their origin from the direct transformation

of decaying animal and vegetable remains.
We have also there stated the modes by
which the lower forms of organic life, most
commonly found in decomposing infusions,
propagate with extraordinary rapidity. The
other two principal instances which were
supposed to favour the doctrine of sponta-
neous generation, were the production of
the Spermatozoa and of the Entozoa.

It need scarcely be remarked that the Sper-
matozoa cannot be regarded as animals; they
are products of the metamorphosis of the con-
tents of cells (SPERMATOZOA, SPERM ATO-
ZOIDS); and the only ground for considering
them as animals was based upon their power
of motion, which we now know to be no ex-
clusive character of animality. The supposed
occurrence of particular species of Entozoa
within the bodies of other animals, not to be
found in any other situations, would natu-
rally appear to find a ready explanation in
the doctrine in question. Recent investiga-
tions have, however, proved that these sup-
posed species are larval or other forms of
true species of this Class, which do not
attain their perfect development on account
of their not existing in a suitable locality.

See GENERATIONS, ALTERNATION
OF.

BIBL. Schultz, Poggend. Annal. xli.
p. 184 ; Helmholtz, Journ. f. Prak. Chem.
xxxi. 429; Gross, Sieb. and Kollik. Zeitschr.
iii. p. 68 ; Reissek, JBer. d. Akad. z. Wien.
1851 ; Pineau, Ann. des Sc. nat., Zool. 1845.
1848.

GEOPONUS. See FORAMINIFERA.

GEORGIA, Ehrh.— A Fi 282.
genus of Mniaceous Moss-
es, called from the four
teeth of the peristome,
Tetraphis and Tetradon-
tium, but these names are
of later date than Ehrhart's
(1780). G. Mnemosyne
presents, besides its male
and female inflorescence,
a peculiar form of terminal
leafy bud (fig. 282), which
produces stalked gemmae
in the interior. In the
figure numerous arche-
gonia are also shown.

Georgia Browniana,
C. Mull. = Tetraphis
Browniana, Grev.

G. Mnemosyne, Ehrh. Georgia Mnemosyne.

rr, . -,. y ' jj .j A shoot with two

= TetraphlS pelludda, terminal leafy buds.

Hedw. Magn. 15 diameters.

GERANIUM.

[ 289 ]

GILLS.

GERANIUM. — In this genus, and appa-
rently in the rest of the Nat. Ord. Gera-
niaceae, the sepals are remarkable for the
cells containing numerous raphides regularly
arranged. They may be observed in the
common G. Robertianum and in the garden
Pelargonia. The sepals of the common wild
Gerania form pleasing objects when dried
and mounted in Canada balsam.

BIBL. Quekett, Ann. Nat. Hist, xviii.
p. 82.

GERMINAL VESICLE OF ANIMALS.
See OVUM.

GERMINAL VESICLE, OF PLANTS.
— This structure, the existence of which is
denied by Schleiden and Schaeht, but
affirmed by Amici, Mohl, Miiller, Henfrey,
Hofmeister, Tulasne, &c., is the germ of the
future plant, formed before impregnation
(Tulasne is doubtful whether before) in the
embryo-sac of Flowering Plants. In most
cases three are originally produced, as in
Orchis (PL 38. fig. 4), and in rare instances
two of these are fertilized, and two embryos
produced in one seed ; sometimes only
one exists, and ordinarily only one is ferti-
lized. This becomes at first elongated into
a cellular filament called the suspensor,
which is cut off by septa into several cells,
the last of which ordinarily becomes the
embryonal-vesicle or embryo-cell, which be-
comes developed into by the embryo (fig. 195.
page 225).

GERMINATION.— The act of develop-
ment of a seed or spore into a new plant.
The phsenomena attending the germination
of all the Cryptogamic plants require the aid
of the microscope for their investigation, and
are in most instances highly interesting and
important in a physiological point of view.
For particulars, see under the classes of Flow-
erless Plants.

GERRIS, Latr. — A genus of Hemipterous
(Heteropterous) Insects.

Gerris lacustris is everywhere seen skim-
ming the surface of water. It has the
basal joint of the antennae longest, the
four hind legs very long, and at a great di-
stance from the fore-legs. The legs do not
possess any special structure by which they
are enabled to repel the water, beyond a
number of short hairs.

Celia rivulorum, with the basal joint of
the antennas longest, the legs of moderate
length and equally apart, and Hydrometra
stagnorum, with the first and second joints
of the antennae short, the third being the
longest, are allied members of the same

family, and are commonly met with on the
surface of pools, &c.

In the anterior tarsi of Celia, minute mem-
branous retractile lobes have been described.

BIBL. Westwood, Introduction, 8fc.

GIGARTINA, Lamx.— A genus of Cry-
ptonemiaceae (Florideous Algae), with cartila-
ginous, irregularly-divided fronds, the internal
substance of which is composed of rather
lax tissue, the outer of dichotomous filaments
perpendicular to the surface, strongly united
by their moniliform terminations (fig. 283).

Fig. 283.

Gigartina pistillate.

Transverse section of the frond.

Magnified 50 diameters.

Four British species are known, growing
from 2 to 6 inches high, of a dull purple
colour. Reproduced by spores (in favellidia)
and tetraspores scattered among the peri-
pheral filaments.

BIBL. Harvey, British Marine Algee,
139. pi. 17 C; Greville, Alg. Brit. pp. 146,
147. pi. 16.

GILLETTS CONDENSER. See CON-
DENSER.

GILLS OF FISHES. — These organs form
beautiful and favourite injected objects. They
must be injected from the heart, or from the
branchial artery, which ascends from the
heart much in the same manner as the
pulmonary artery ascends from the heart of
the higher animals. It may be remarked
that the heart of fishes is situated much
nearer to the anterior end of the body than
in the Mammalia.

BIBL. Stannius, Lehrb. d. Vergl. Anat.',
Lereboullet, Anat. Compar. de VAppar.
Respir. ; Hyrtl, Med. Jahrbuch. d. (Ester.
St. bd. 24 ; Owen, Hunterian Lect. ii.

GILLS OF INSECTS, or branchiae. —

U

GINANNIA.

f 290 ]

GLANDS.

These are hair- or leaf-like processes (PI. 28.
figs. 2g, 15, 19, 31) projecting from the
surface of the body, and containing one or
more tracheae and their ramifications, which
communicate with those of the body gene-
rally. Insects furnished with gills or bran-
chiae have no occasion to rise to the surface
of the water in which they live, the diifusion
by which the respiratory process is effected
taking place between the gaseous contents
of the tracheae and those of the water.

GINANNIA, Montague. — A genus of
Cryptonemiaceae (Florideous Algae), contain-
ing one British species, G. furcellata, a rare,
pinky-red sea-weed about 2 to 6 inches
long, with a dichotomous, terete, membra-
naceo-gelatinous frond, the divisions of
which have a kind of fibrous axis. The
spores are produced in spherical concep-
tacles imbedded just beneath the surface of
the frond. .

BIBL. Harvey, Brit. Mar. Alg. p. 148.
pi. 19 C; E. Botany, y\. 1881.

GLANDS, OF ANIMALS. — Glands are
organs, the general function of which is to
separate from the blood certain compounds
destined to perform some special office in
the economy. They are divided into true
or secernent glands ; and vascular glands.

The secernent glands, the secretions from
which escape either by rupture, or through
ducts, are thus arranged :

1. Glands consisting of closed vesicles
which dehisce laterally : the Graafian vesicles
of the ovary, and the follicles (Nabothian) of
the cervix uteri.

2. Glands composed of cells reticularly
united : the liver.

3. Racemose or aggregated glands, in
which aggregations of roundish or elongated
glandular vesicles occur at the ends of the
excretory ducts. These are either : a, sim-
ple, with one or but few lobules, comprising
the mucous glands, the sebaceous and the
Meibomian follicles ; b, compound, with
many lobules, the, lacrymal and salivary
glands, the pancreas, the prostate, Cowper's
and the mammary glands ; in this category
must also be placed the lungs.

4. Tubular glands, in which the secreting
elements have a more or less tubular form.
These are either : a, simple, consisting of
one or but few caecal tubes ; including the
tubular gastric and intestinal (Lieberkuhn's),
the uterine, sudoriparous and ceruminous
glands ; b, compound, consisting of nume-
rous reticular or ramified glandular canals ;
comprising the testis and the kidney.

The vascular glands, which have no ducts
and the contents of which escape by trans-
udation, are subdivided into :

1 . Those composed of larger and smaller
cells imbedded in a stroma of areolar tissue ;
comprising the supra-renal capsules, and the
anterior lobules of the pineal gland.

2. The closed follicles which consist of
a basement-membrane, with an epithelial
lining and transparent contents, forming the
thyroid gland.

3. The closed follicles, with a capsule of
areolar tissue and contents consisting of
nuclei, cells and liquid, to which belong : a,
the solitary follicles of the stomach and
intestines ; b, the aggregated follicles of the
small intestines or Peyer's glands, in animals
also those of the stomach and large intes-
tines ; c, the glandular follicles of the root
of the tongue, and of the pharynx and the
tonsils ; d, the lymphatic glands.

4. Here belongs the spleen, consisting of
a cellular parenchyma containing numerous
closed follicles.

5. The thymus gland, in which aggre-
gated glandular vesicles open into a common
closed canal or wide space.

The glands are further noticed under their
respective heads.

BIBL. Kolliker, MikrosJc. Anat. and Ge-
webelehre, fyc. ; Henle, Ally em. Anat. ;
Wagner, Handwb'rterb. d. Phys. ; Todd and
Bowman, Phys. Anat. of Man ; Paget, Med.
Chir. Rev. 1842. xiv.

GLANDS, OF PLANTS.— The glands of
plants are special structures, formed of cel-
lular tissue, in which are produced secretions
of various kinds, such as oils, resins, &c.
They are ordinarily more or less closely con-
nected with the epidermal tissues, but not in
all cases, the latter instances forming a kind of
transition to the receptacles of special secre-
tions, turpentine-reservoirs, &c. found in the
interior of the stems of many plants. Glands
may be conveniently divided into external
and internal; the former are sessile, or
stalked (when they present the character of
glandular hairs, of various forms), while the
latter are generally visible externally as trans-
parent dots scattered over an organ, such
as a leaf, giving it the appearance of having
been pricked all over with a pin ; when of
more considerable dimensions, and with
thicker walls, they produce tuberculation of
the surface, as on the rind of the orange,
&c.

External glands. These maybe subdivided
into simple and compound.

GLANDS.

[ 291 ]

GLEICHENIE.E.

Simple external glands are either sessile
vesicles or hairs, composed of a single vesi-
cular or elongated epidermal cell filled with
secretion ; or they are hairs composed of a
simple row of cells, one or more of which
are filled with secretion. Examples of this
may be found in the epidermis of Primula
sinensis, Gilia tricolor, Erodium cicutarium,
Achimenes (PI. 21. fig. 32), Stachys, Marru-
bium, Digitalis purpurea (PL 21. fig. 33),
Antirrhinum majus (P1.21 . fig. 34), (Enothera,
Helleborus fcetidus, Scrophularia nodosa,
(PL 21. fig. 41), Sempervivum, Salvia, Thy-
mus, Melissa, Mesembryanthemum, Garden
Chrysanthemum (PL 21. fig. 30), &c.

The stings of the nettles are to be placed
here ; they consist of very long, tapering,
single hairs, with an obtuse point, and a bulb-
like expansion at the base imbedded in a
dense layer of epidermal tissue (PL 21. fig.
8). The hair is filled with the poisonous
secretion. When the point touches the skin,
it breaks off and allows the escape of the
fluid contents, which are squeezed out by
the pressure, and probably by the tension of
the tissue around the bulb.

Compound external glands differ from the
simple only in the fact that they are com-
posed of a greater or smaller number of cells
combined into a mass, usually of spherical
or allied form. They may be sessile, or
stalked upon a simple or compound hair.
Examples of sessile form occur in Dictamnus
albus (PL 21. figs. 38, 39), Robinia viscosa,
the leaf of the Mulberry and the HOP (PL 21 .
fig. 14), and the stipular glands of Cinchona,
Galium, &c. ; of the stalked, in the Rose
(PL 21. fig. 46), species of Rubus, Drosera,
and on many aromatic or viscid plants.

Internal glands. These consist of cavities
in the sub-epidermal tissue, of variable size,
bounded by a firm layer of cells, and filled
with oily or resinous "secretions. They ap-
pear to be formed either of one cell, when
small, or, when large, of a definite mass of
cells, which, after the production of the se-
cretion, have their walls obliterated so as to
form a large chamber; possibly, however,
they may be intercellular spaces into which
the secretion is poured out. Examples of
moderate dimensions are found in the leaves
of Dictamnus, Magnolia (PL 21. fig. 12),
Hypericum perforatum, and other species,
Myrtacece, Ruta graveolens (PL 21. fig. 11),
&c. Very large glands of this kind contain
the oil in the rind of the orange (fig. 284)
and other species of Citrus.

The nectaries of flowers have their tissue

metamorphosed into a condition resembling
that of the secreting part of glands, and the
hairs of the stigma of Flowering Plants pro-

Section of the rind of an orange, showing the internal
glands, R, KI

Magn. 50 diams.

duce a secretion at the period of impregna-
tion. Brongniart has lately pointed out the
existence of internal glands in the dissepi-
ments of the ovaries of the petaloid Mono-
cotyledons. These structures form a trans-
ition to the turpentine-canals, &c. of the
Coniferae. (See SECRETING ORGANS, of
Plants). The gummi-keulen of Meyen (cysto-
lithes of Weddell) are also related to glands.
(See RAPHIDES.)

BIBL. Meyen, Secretionsorgane der Pflan-
zen. Berlin, 1837; Manuals of Vegetable Ana-
tomy; Brongniart, Ann. des Sc. nat. 4 ser.
ii. p. 5 ; Lawson, Ann. Nat, Hist. 2 ser. xiv.
p. 161.

GLAUCOMA, Ehr.— A genus of Infuso-
ria, of the family Trachelina, E.

Char. Body ciliated all over ; mouth lon-
gitudinal, oval, without teeth, placed late-
rally near the anterior third or fourth of the
body, and furnished with one or two tremu-
lous laminae or lips.

Stein describes the encysting process as
occurring hi one species.

G. scintillans, E. (PL 24. fig. 8). Body
colourless, slightly depressed, elliptical or
ovate; sacculi large ; length 1-290''. Aqua-
tic, and in infusions (of hay, &c.).

G. viridis, D. Body green, oval ; mouth
large, nearer the middle than the anterior
end of the body; length 1-630". In putrid
rain-water collected in an empty wine-cask
coated with cream of tartar.

BIBL. Ehrenb. In/us, p. 334 ; Dujardin,
Infus. 475 ; Stein, In/us. 250.

GLEICHENIE.E.— A tribe of Polypodia-
ceous Ferns, distinguished by then* obliquely
annulated sporangia arranged in fours (fig.
286). Genera :

I. GLEICHENIA. Sporangia collected in
roundish sori. Indusium absent. Leaves
forking. Exotic (figs. 285 & 286).

GLENODINIUM.

Fig. 285.

[ 292 ]

GLCEOCAPSA.

Fig. 286.

Gleichenia.

Fig. 285. Fertile pinnules with sori. Magn. 5 diams.
Fig. 286. Sorus composed of four crucially arranged
capsules. Magn. 40 diams.

IL PLATYZOMA. Sporanges collected in
point-like sori. Indusium spurious, formed
by the revolute margin of the leaf. Leaves
undivided.

GLENODINIUM, Ehr.— A genus of In-
fusoria, of the family Peridinaea.

Char. Carapace membranous, rounded or
oblong, with one or more distinct furrows
furnished with vibratile cilia ; an elongated
or horse-shoe-shaped red (eye-) spot pre-
sent ; no horn-like processes.

These organisms are doubtful Infusoria.
They are common in pools and bog-water.

G. cinctum (PL 24. fig. 10, a, b). Ovate or
subglobose, ends obtuse, yellow; carapace
smooth; eye-spot large, transverse and semi-
lunar; length 1-576'°.

G. apiculatum (PL 24. fig. 10 c). Oval,
ends obtuse, greenish - yellow ; carapace
smooth; eye-spot oblong; length 1-480".

G. tabulatum. Oval, greenish-yellow ; ca-
rapace granular, reticulated with prominent
lines ; ends acute or denticulate ; eye-spot
oblong; length 1-480".

BIBL. Ehrenberg, Infus. p. 257 ; Dujar-
din, Infus. p. 373.

GLENOMORUM, Ehr.— The Glenomo-
rum tingens of Ehrenberg (PL 24. fig. 14),
which consists of aggregated revolving groups
of green bodies, with two anterior cilia, and
a red (eye-)spot, has been shown by Weise
and Stein to form the young state of CHLO-
ROGONIUM, which itself appears probably to
be a stage of development of PROTOCOCCUS.

GLENOPHORA, Ehr.— A genus of Ro-
tatoria, of the family Ichthydina.

Char. Free; eyes two, frontal; rotatory
organ circular and frontal; tail truncated,
without toes.

G. trochus (PL 34, fig. 36). Body ovato-
conical, colourless, the turgid front and the
narrowed foot truncated; eyes blackish;
length 1-576"; aquatic.

BIBL. Ehrenb. Infus. p. 391.

GLOBULINA, Turp. = GLCEOCAPSA.

GLOBULINE. — An animal substance
nearly allied to albumen, existing within
the coloured corpuscles of the blood and the
crystalline lens. It is amorphous.

BIBL. See CHEMISTRY, ANIMAL.

GLCEOCAPSA, Kutz.— A genus of Pal-
mellaceae (Confervoid Algae), instituted by
Kiitzing to receive certain forms, distributed
among Heematococcus, Microcystis, Soro-
spora, &c. by various authors. As we have
adopted it, it is distinguished from Palmella
by the persistence of the coats of the parent-
cells as envelopes enclosing their progeny of
several generations, to the number of 4, 16,
64, or more generations, the membranes
becoming confluent subsequently, however,
by solution, into a gelatinous mass. From
Coccochloris the chief distinction seems to
be in the persistence of the lamellae of the
parent- cells in the membranous condition,
and the globular instead of cylindrical or
elliptical form of the cells ; while the habit
is to form rather flat, irregular strata than
globose or papillose masses. From Proto-
coccus it is distinguished by the persistent
gelatinous investment.

We give such of Kiitzing's species as are
British, with the synonyms as stated by
him; but they require further investiga-
tion.

1. G. confluens. Stratum gelatinous,
green. Diam. of cell-contents, 1-1200 to
I-6(W".=.H(ematococcus minutissimus, Has-
sall?

2. G.montana. Stratum gelatinous, green;
vesicles concentrically striated; cell-con-
tents 1-1000 to 1-500"' in diam.=H.mero-
sporus, Hass.

3. G. granosa. Stratum green, firm;
vesicles concentrically striated; cell-con-
tents 1-300"' in diam. = H. granosus,

4. G. polydermatica (PL 3. fig. 4). Stra-
tum hardish, olivaceous, somewhat compact
or granular; concentric lamellae evident,
thick ; cell-contents 1-800 to 1-500'" in diam.
=H. rupestris, Hass.

5. G. ceruginosa. Stratum gray-aeruginous,
granular-crustaceous ; vesicles large (1-100
to 1-60'"), irregular; cell-contents 1-1000
to 1-600'".= #. (Bruginosus, Hass.

6. G. limda. Stratum dirty olive or black-

GLCEONEMA.

[ 293 ]

GNETACEJ3.

ish, soft, but tubercular ; cell-contents seru-
ginous; 1-/00'". //. lividus, Hass.

7- G. Magma. Stratum purplish-black,
crustaceous, granular; cell-contents 1-500'"
to 1-320"'. Sorospora montana, Hass.

8. G. sanguinea. Stratum black ; internal
cells deep blood-red ; cell-contents 1-600 to
1-400'". = Hcematococcus sanguineus, Ag.,
Hass.

9. G. Shuttleworthiana. Stratum dirty
red ; internal cells orange ; cell- contents
1-1000 to 1-900'".

10. G. Ralfsiana. Stratum dirty purple ;
internal cells rosy - purple ; cell-contents
1-750 to 1-400'".= Sorospora Ralfsii, Hass.

In PI. 3. fig. 13 is represented a form we
have met with among freshwater Algae,
which appears to agree with Kiitzing's G.
ampla.

Those resting forms of Euglena where the
encysted groups are devoid of a firm outer
coat, bear considerable resemblance to a
large Glaocapsa.

BIBL. Kiitzing, Phyc. generalis, p. 173,
Sp. Alg. 216, Tab. Phyc. pis. 19 et seq.;
Hassall, Brit. Freshwater Algce, pi. 79, &c.

GLCEONEMA, Ag. \— Names of Diato-

GLOIONEMA, Ag. J maceous genera no
longer retained. See ENCYONEMA.

GLGEOSPORIUM, Moutagne.— A genus
of Sphaeronemei (Coniomycetous Fungi) de-
veloped beneath the surface of leaves, and
bursting through, forming a kind of rust on
the surface.

1. G. paradoxum (Myxosporium para-
doxum, De Notar.) occurs on ivy.

2. G. Lobes. Aster oma lobes, Berk.
Brit. Fungi.

3. G. concentricum (CyUndrosporum con-
centricum, Grev. Sc. Crypt. Flor. pi. 27)
forms a white rust upon cabbage-leaves.

BIBL. Berk. & Br. Ann. Nat. Hist. 2 ser.
v. p. 455 ; Berkeley, Hort. Trans, vi. p. 121.

GLOIOSIPHONIA, Carm.— A genus of
Cryptonemiaceae (Florideous Algae), the sin-
gle British representative of which is a rare,
feathery, red sea-weed, 3-12 inches high,
with a semi-gelatinous tubular frond. The
spores are in dense masses, scattered among
the radiating jointed filaments which clothe
the periphery of the branches.

BIBL. Harvey, Brit. Mar. Alg. p. 152.
pi. 21 A, Eng. Bot. pi. 1219.

GLYCERINE— Is the sweet principle of
thefats. It may be prepared by boiling any fat,
as tallow, butter, olive oil, &c., with oxide of
lead and water, the water being from time to
time removed, and replaced by fresh. The

aqueous solutions are freed from the lead by
sulphuretted hydrogen, the filtered liquid
evaporated to the consistence of a syrup,
and finally in vacua over sulphuric acid.

Glycerine, when pure, is a colourless,
highly refractive, syrupy liquid, of a sweet
taste ; it mixes in all proportions with alco-
hol and water, but it is insoluble in aether.
The property possessed by glycerine of con-
stituting a liquid which does not become dry,
and mixes with water, has caused it to be
used for the preservation of microscopic ob-
jects, especially those which will not permit
of being dried. It renders objects as trans-
parent as Canada balsam.

We prefer solution of chloride of calcium
for all preparations except those of insects ;
as the larvae, &c. and starch.

GLYCIPHAGUS, Hering.— A subgenus
of Acarus.

We omitted in the art. ACARUS to add
the heads under which certain species of
Acarus, Latr. are noticed. Thus, Acarus
scabiei = Sarcoptes scabiei ; Acarus equi =
Psoroptes eq.; Ac.folliculorum = Demodex
foil.

GLYPHOMITRIUM, Bridel.— A genus
of Orthotrichaceous Mosses, deriving its
name from the grooved calyptra. Glypho-

Fig. 287.

Glyphomitrium Daviesii.
Teeth of the peristome. Magnified 150 diams.

mitrium Daviesii, Brid. is found in Wales
and Ireland on rocks, mostly near the sea.
It is peculiar to Great Britain and Ireland.

GNAT. See CULEX and CULICID^E.

GNETACE^E.— A family of Gymnosper-
mous Flowering Plants remarkable for their
jointed stems, composed of wood marked
with circular disks. (See WOOD.) The
flowers of these plants are also very remark-
able, the male consisting merely of a calyx
containing one-celled anthers united by their
filaments; the female, of a naked ovule with
two involucral scales, originally with two
coats, but subsequently with a third which

GOMPHONEMA.

[ 294 ]

GONATORRHODON.

grows up between the inner of the first two
and the nucleus, and after fertilization pro-
jects out of the exostome as a tubular pro-
cess with a fimbriated extremity.

BIBL. Lindley, Vegetable Kingdom, art.
GnetacecB.

GOMPHONEMA, Ag.— A genus of Dia-
tomacese.

Char. Frustules mostly single or binate,
attached by a filiform stipes, wedge-shaped
in front view ; valves with a median line and
a nodule at the centre and at each end, and
striated with transverse or slightly radiating
lines resolvable into dots. Aquatic and
fossil.

Conjugation has been observed in several
species.

Kiitzing describes thirty-eight species,
Smith admits twelve as British. The form
of the frustule is subject to great variety,
and the specific characters are probably of
little value.

The most common species are :

G. acuminatum (PL 12. fig. 34, a, b, c).
Frustules in front view simply cuneate, or
inflated in the middle ; valves attenuated at
the base, ventricose in the middle, beyond
which they are again expanded; ends acumi-
nate, or truncate with an acuminate pro-
longation; striae distinct; length of frustules
1-360". (San Fiore deposit.)

G. geminatum. Valves ventricose in the
middle, constricted and rotundo-truncate
towards each end; striae distinct; stalks
long, thick, densely interwoven; length of
frustules 1-216 to 1-180".

G. olivaceum. Densely crowded, forming
a mucous mass; frustules broadly cuneate
(fr. v.) ; valves obovato-lanceolate ; striae
distinct; length of frustules 1-1020".

G. curvatum. Frustules curved; valves
obovato-lanceolate; striae faint; length
1-720".

BIBL. Ehr. In/us, p. 215; Kiitzing, Ba-
cill. p. 84, and Sp. Alg. p. 63 ; Smith, Brit.
Diatom, p. 77; Ralfs, Ann. Nat. Hist. 1843.
xvi. p. 459.

GONIDIUM.— The name applied to cells
which in the Thallophytes perform an office
analogous to that of the GEMMAE of the
higher Cryptogams, and the separating bud-
structures, such as bulbils, stolons, &c. of
the Flowering Plants ; being cells developed
from the vegetative tissues, ultimately thrown
off, and capable of propagating the indivi-
dual. The gonidia of the Lichens are glo-
bular cells with green contents developed in
the central layers of the thallus, afterwards

set free by the destruction of the cortical
layer ; they appear capable of multiplication
by subdivision before growing out into the
filaments which form the foundation of the
new thallus (see LICHENS). The gonidia
of the Fungi are usually termed CONIDIA
(see that article, and FUNGI). The gonidia
of the Algae are best known in the CONFER-
VOIDS, where they are formed from the cell-
contents, and generally present themselves
ciliated, as ZOOSPORES. The tetraspores of
the Florideae are probably the homologues of
gonidia.

GONATOBOTRYS, Corda.— A genus of
Mucedines (Hyphomycetous Fungi), the fer-
tile filaments of which present at intervals
swollen articulations, on which are attached
simple ovate spores (figs. 288, 289).

BIBL. Corda,

Fig. 288.

Fig. 289.

Gonatobotrys simplex.

Fig. 288. A fertile filament. Magn. 100 diams.
Fig. 289. A sporiferous joint, with most of the spores
removed. Magn. 600 diams.

GONATORRHO- Fig. 290.

DON, Corda. — A
genus of Mucedines
( Hyphomycetous
Fungi), the fertile
filaments of which
have at intervals
swollen articulations,
whence arise monili-
form chains of spores
(fig. 290).

BIBL. Corda,
Prachtfl. Europ.
ScMmmelb. pi. 3.

Gonatorrhodon speciosum.

Fertile filaments with swollen joints bearing chains of
spores. Magn. 100 diams.

GONIOTHECIUM.

[ 295 ]

GORGONIA.

GONIOTHECIUM, Ehr.— A genus of
fossil Diatomaceae.

Char. Frustules geminate, terete, with a
median (longitudinal) constriction (suddenly
attenuate and truncate at the ends, hence
appearing angular). Corresponding to Pyxi-
dicula, constricted in the middle, and trun-
cate at the ends.

Found in America.

The characters of the nine or ten species,
as well as in fact those of the genus, have
been very imperfectly described.

BIBL. Ehrenberg, Abhandl. d. Eerl. Akad.
1841. p. 401, and Ber. d. Eerl. Akad. 1844.
p. 82; Kiitzing, BacilL p. 51, and Sp. Ala.
p. 23.

GONIUM, Miiller.— A genus of Volvo-
cineae (Confervoid Algae) forming microsco-
pic, square, flat fronds, either ciliated and
endowed with a power of motion, or devoid
of cilia and motionless ; it is possible that
these two conditions are only stages of deve-
lopment in species active at one time and
resting at another. The perfect fronds are
composed of usually sixteen cells enclosed
in wide, colourless coats (young fronds but
four cells, some kinds have more than six-
teen), united together into flat, square masses
by adherence at various points of their cir-
cumference; a light vacuole in the sub-
stance of the cell-contents may often be ob-
served to exhibit a rhythmical contraction and
expansion, as mVolvox; the cells of the active
forms having each a pair of vibratile cilia,
which run out from the central protoplasmic
mass, through the hyaline envelope, and
project as free processes, rowing the frond
about in the water. They are commonly
observed to increase by division, a frond
composed of sixteen cells breaking up into
four fronds, each composed of four cells, &c.j
but it is probable that other kinds of deve-
lopment exist, and that the motionless forms
are resting states of active species. Gonium
pectorale is an exceedingly interesting micro-
scopic object, not uncommon in freshwater
pools. Ehrenberg, who regards them as
Infusoria, describes the following species.

1. G. pectorale (PI. 3. fig. 11). Frond
square, composed of sixteen bright green
cell-masses, enclosed in hyaline envelopes,
each with a pair of cilia ; size of green masses
1-1960 to 1-1150"; frond not exceeding
1-280". In clear water, salt and fresh, near
the surface.

2. G. punctatum. Cells sixteen; cell-
masses green, with black granules; diam.
1-4600"; frond of sixteen, 1-576".

3. G. tranquillum (PL 3. fig. 12). Cells
sixteen; cell-masses green, diam. 1-2880";
frond of sixteen, 1-144 to 1-288", sometimes
twice as broad as long; the cell-masses
found in division (binate or quaternate),
motionless. (Possibly not a Gonium, but a
Palmellacean) (Tetraspora?).

4. G. hyaUnum. Cell-masses hyaline,
diam. 1-3000"; frond of twenty or twenty-
five, 1-600". In stagnant water.

5. G. glaucum. Cell-masses bluish-green,
from four to sixty-four in a frond, diam.
1-7000 to 1-4200", ditto of frond not ex-
ceeding 1-570". In sea-water.

The remarkable organism SARCINA re-
sembles the motionless Gonia in structure,
but its peculiar habit would rather lead to
its being placed among the Fungi. The
genus TETRASPORA among the Palmellaceae
is closely related here. MERISMOPJEDIA
seems to be an unnecessary genus, as the
species may fall under one or other of these.
BIBL. Ehrenberg, Infusionsth. p. 55 ;
Cohn, Nova Acta, xxiii. p. 169. pi. 18.
GORDIUS, Linn. — A genus of Entozoa.
Char. Body very long and slender, fili-
form ; alimentary canal with a single orifice;
sexes distinct.

G. aquations, the common hair-worm, is
from 7 to 10" in length and about 1-25 to
1-20" in breadth, of a brown or blackish co-
lour, and is found in water or damp places.
The mouth is very indistinct ; the tail of the
male is bifid, that of the female simple and
rounded.

The ova, agglutinated in long strings, are
deposited in water, and being devoured by
insects, undergo development within their
bodies.

These animals frequently coil themselves
into a knot-like form, whence the name.
See MERMIS.

BIBL. Dujardin, Hist. nat. d. Helminth.
p. 296, and Ann. des Sc. nat. 1842. xviii.
p. 142; Siebold, Lehrb. d. VeryL Anat.,
Entomol. Zeitung, 1842-43, and Erich son's
Archiv, 1 843. ii. p. 302 ; Berthold, Ueber den
Ban d. Wasserkalbes, 1842.

GORGONIA, Linn.— A genus of Polypi,
of the order Anthozoa.

Char. Polypidom attached by a kind of
root, consisting of a central, branched, horny
and sometimes anastomosing flexible axis,
coated with a soft andfleshy polypiferous crust .
The species, of which there are four Bri-
tish, are popularly known as sea-fans ; they
are not microscopic, often attaining very
considerable dimensions.

GOSSYPIUM.

[ 296 ]

GRAMMONEMA.

The polypidom, as well as the crust, con-
tain spicula of various forms imbedded in
them, a specimen of which is exhibited in
PI. 33. fig. 27.

BIBL. Johnston, Brit. Zoophyt. p. 166.
GOSSYPIUM. See COTTON.
GOUT-STONES. See CHALK-STONES.
GRACILARIA, Grev.— A genus of Rho-
dymeniaceae (Florideous Algae), with feathery
fleshy-cartilaginous fronds, 6 to 12" or more
long, of a red or purplish colour, the central
substance of which is composed of large
cells, the cortical of closely-packed hori-
zontal filaments. The spores are formed
in tubercles consisting of a thick coat com-
posed of radiating filaments, containing a
mass of minute spores on a central placenta.
The tetraspores are imbedded in the cells of
the surface. G. confervoides is the only
common species; it grows from 3 to 20"
long, and as thick as small twine.

BIBL. Harvey, Brit. Mar. Alg. p. 128.
pi. 16 C, Engl. Bot. pi. 1668.

GRAMMATONEMA, Ag.— A genus of
microscopic plants, sometimes placed among
the Diatomaceae, either as distinct or included
under Fragilaria. But the membrane is
scarcely siliceous, and does not withstand
heat or acids. Kiitzing places it among the
Desmidiaceae.

Char. Cells quadrangular, very narrow,
closely conjoined into an elongated fila-
ment.

G. striatulum, K. ( Grammonema Jurgensii,
Ralfs) is slender, yellowish -brown; the cells
three to eight times longer than broad,
slightly attenuated to each end, and sepa-
rated at the angles. It does not change
colour in drying ; its variety, /3. diatomoides,
turns green in drying. Marine.

BIBL. Kiitzing, Sp. Alg. p. 187 ; Ralfs,
Ann. Nat. Hist. xiii. p. 457. pi. 14. fig. 5.

GRAMMATOPHORA, Ehr.— A genus of
Diatomaceae.

Char. Frustules in front view rectangular,
at first adnate, but afterwards forming zig-
zag chains ; vittae two, longitudinal, inter-
rupted in the middle and more or less curved.
Marine. Valves furnished with transverse
striae, in most invisible by ordinary illumi-
nation, and in a few so difficult of detection
that the valves have been regarded as TEST
OBJECTS.

Kiitzing describes thirteen species.

G. marina (PL 1. fig. 14; PI. 12. fig. 35 ;

PL 14. fig. 37). Striae invisible by ordinary

illumination; vittae near the middle semi-

circularly curved outwards; valves linear,

gradually attenuated towards the obtuse
ends; length 1-108 to 1-420".

The form and structure of the frustules
and valves appears greatly to vary. Some-
times the frustules are nearly square, at
others six times as long as broad. In some
specimens the valves are suddenly, at others
uniformly inflated at the middle (PL 1. fig.
14 b; PL 12. fig. 35 c), some have the ends
capitate. Again, in some valves there is a
median line and a small central nodule
(PL 12. fig. 35 c), in others there is neither
median line nor nodule, but a large internal
ring (PL l.fig. 14 b). Lastly, in some valves
the striae extend over the whole of the valves,
while in others they are deficient at their ends.
Some of these variations have formed the
basis of distinct species, but probably with
little reason.

A variety, G. subtilissima, Bail. (PL 14.
fig. 38 a, b), has been pointed out by Prof.
Bailey, in which the form of the frustules
and valves agrees with the above characters,
but in which the transverse striae are ex-
tremely difficult of detection when mounted
in balsam.

G, serpentina. Striae distinct; vittae large,
serpentine, with the end curved inwards to
form a kind of hook ; length 1-200".

BIBL. Ehrenberg, Ber. d. Berl. Akad.
1839. p. 126, and Ber. ejusd. 1840, &c.;
Kiitzing, Sp. Alg. p. 120; Ralfs, Ann. Nat.
Hist. 1843. xi. p. 449; Bailey, Silliman's
Journal, vii.

GRAMMITIDE^E.— A sub-tribe of Poly-
podaeous Ferns, with naked sori, containing
three genera :

I. GRAMMITIS. Sori linear or roundish,
seated on certain arms of the veins. Veins
simple or forked, scarcely anastomosing.

II. SELLIGN^SA. Sori linear or roundish,
seated on certain arms of the veins. Veins
very much branched, anastomosing in
more or less regular meshes, without free
veins.

III. SYNAMMIA. Sori oblong, seated
on the back of the lowest venule. Veins
branched, anastomosing into more or less
regular meshes, with free venules.

GRAMMITIS, Swartz.— A genus of
Grammitideae (Polypodaeous Ferns), synony-
mous with Ceterach. Grammitis ceterach, or
Ceterach ojficinarum,is an indigenous species;
the back of the fronds is densely clothed
with chaffy scales and hairs, composed of
cellular tissue.

GRAMMONEMA, Ag. = GRAMMATO-

GRANTIA.

[ 297 ]

GRAPHIS.

GRANTIA,Fleming. — Agenus of Sponges.

Char. Form variable; firmish and inelastic,
usually white, with a close but porous tex-
ture, and composed of a gelatinous base, with
imbedded calcareous spicula; orifices distinct.
Marine.

Spicula simple, radiate or stellate, com-
posed of carbonate of lime ; hence easily
distinguished from the siliceous spicula of
other sponges by their dissolving with effer-
vescence in a dilute acid. The organic basis
is stated not to be fibrous as in most other
sponges.

The seven British species are found grow-
ing upon or from rocks, sea-weeds, shell-fish
and zoophytes, between tide-marks. They
vary in size from about the 1-10 to 3 or 4".
Gemmules have not been found in them.

BIBL. Johnston, Brit. Sponges, Sfc.
p. 172; Grant, Outlines of Compar. Anat.
and Edin. New Phil. Journ. i. and ii.

GRANULE-CELLS. — This term has
been applied to cells found in animal solids
and liquids, containing a number of globules
of fat or oil (PL 30. figs. 7, 16a, 17 c). They
are of variable size, perhaps the average may
be placed at 1-2000"; and are easily recog-
nized by the dark margins and light centres
of the globules, which are insoluble in acetic
acid and solution of potash. The cells some-
times contain a nucleus, at others not. The
term granule-cells should properly be limited
to cells of new formation, as those found in
inflammation, cancer, &c. ; but it has been
so generally applied to cells of whatever
kind, containing fatty globules, that it has
no pathological signification.

See DEGENERATION, FATTY, and IN-
FLAMMATION.

GRAPE-FUNGUS.— See OIDIUM.

GRAPHIDE^E.— A family of Gymnocar-
pous or open-fruited Lichens, characterized
by irregularly-formed, mostly elongated
apothecia, with the margins closed in, or the
disk covered with a veil in the earliest state.
The excipulum either special or formed by
the thallus.

Synopsis of British Genera.

I. OPEGRAPHA, Ach. Thallus crusta-
ceous or membranous. Apothecia (lirellce]
elongated, simple, or branched, sessile ; ex-
cipulum carbonaceous, entire or surrounding
the sides and base. The disk chink-like or
channelled with a proper border.

II. GRAPHIS, Ach. Thallus crustaceous
or membranous. Apothecia lirellseform, im-
mersed ; excipulum carbonaceous, halved or

confined to the side, the base being naked;
disk channelled, surrounded by a proper
border and an accessory one from the thallus.

III. HYMENODECTON, Leighton. Thal-
lus crustaceous or membranous. Apothecia
lirellseform, immersed; excipulum a very thin,
black, cartilaginous membrane, entire or sur-
rounding the sides and base; disk broad,
plane, smooth, surrounded with a very
slender proper border and an accessory one
derived from the thallus.

IV. CHiOGRAPHA,Leight. Thallus mem-
branaceous. Apothecia lirellseform or sub-
discoid, sessile; excipulum carbonaceous,
entire or surrounding the sides and base ;
disk plane, broad, surrounded by a proper
border and an accessory derived from the
thallus.

V. AULOCOGRAPHA, Leighton. Thallus
membranaceous. Apothecia lirellseform,
subimmersed, prominent ; excipulum carbo-
naceous, halved or confined to the sides,
palmatifid, the base naked ; disk chink-like,
closed, surrounded with a proper longitudi-
nally-furrowed border, and an accessory one
derived from the thallus.

VI. LECANACTIS, Eschweiler. Thallus
crustaceous. Apothecia lirellseform or sub-
discoid, immersed ; excipulum carbonaceous,
entire or surrounding the sides and base;
disk plane, open, pruinose, surrounded with
a proper border.

VII. PLATYGRAMMA, Leight. Thallus
crustaceous. Apothecia lirellseform, almost
simple or radiate; excipulum none; spori-
ferous layer free ; disk plane, open, naked,
without any margin.

VIII. ARTHONiA,Ach. Thallus cartila-
gineo-membranous. Apothecia roundish or
difformed, tumid, innately sessile, covered
with a subcartilaginous membrane, subgela-
tinous within, containing immediately under
the surface a series of pear-shaped thecse ;
no excipulum ; disk nearly plane, without a
border, black and rough.

IX. CONIOCARPON, D.C. Thallus crus-
taceous. Apothecia appressed, roundish-
deformed or elongated, covered with a sub-
cartilaginous membrane, which ultimately
breaks up into a fine powder, subgelatinous
within, containing a series of pear-shaped
thecse ; no perithecium ; disk flat, depressed,
without a border, pruinose.

BIBL. Leighton, Monoar. of Brit. Gra-
phidete, Ann. Nat. Hist. 2nd ser. vol. xiii.
1854.

GRAPHIS, Ach.— A genus of Graphideae
(Gymnocarpous Lichens), containing several

GRASSES.

[ 298 ]

GRIFFITHSIA.

British species very variable in their appear-
ance ; mostly whitish or yellow, papery ex-
pansions on bark, beset with irregular black
markings like writing.

BIBL. Leighton, Ann. N. H. 2 ser. iii. 264.

GRASSES.— A family of Monocotyledo-
nous Flowering Plants remarkable in many
respects for their microscopic structures,
especially the siliceous EPIDERMIS and the
STARCH grains in the ENDOSPERM, for
which see thpse heads.

GRATELOUPIA, Ag.— A genus of Cry-
ptonemiaceae (Florideous Algae), represented
by a very rare British species, G. filicina,
rarely growing more than 2 inches high
with us. Fructification minute, immersed,
favellidia opening by a pore, and cruciate
tetraspores vertically placed among the fila-
ments of the periphery.

BIBL. Harv. Brit. Mar. Alg. p. 137.
pi. 17 A; Grev. Alg. Brit. pi. 16.

GREGARINA, Dufour. — The curious
organisms of which this genus consists, are
placed provisionally among the Entozoa;
they have as yet been insufficiently examined,
and authors are not agreed as to their struc-
ture and nature.

They exist as parasites within the bodies
of animals, and inhabit the intestinal canal,
or the cavity of the abdomen. Most fre-
quently they are met with in insects, espe-
cially their larvae; but sometimes also in
Annelida, both aquatic and marine (Lumbri-
cus, &c.), in the Crustacea and Mollusca.

They are microscopic and colourless ;
mostly round, oval, fusiform or cylindrical
(PL 16. figs. 25, 28, 34) ; and consist of a
smooth transparent cell-wall, enclosing a
granular, more or less liquid mass, with one
or more nuclei and nucleoli. Sometimes
they exhibit a constriction in the middle, or
are divided by a transverse septum. In
some a process resembling a head is situated
at one end ; this may be short, round and
obtuse or pointed, or more elongated and
furnished with reflexed hook-like processes.
The Gregarina are capable of motion, which
is either that of slow progression, ensuing
without contraction of the body, or produced
by irregular contraction of the membrane or
substance of the body.

Vibratile cilia have been detected both
upon the outer and the inner surface of the
membrane, and the internal granules often
exhibit molecular motion, especially after
the addition of water. One or more long
motionless filaments sometimes arise from
the outer surface.

The membrane and its contents, except
the nucleus, are soluble in acetic acid.

Their method of propagation, if such it be,
represents a form of conjugation, and takes
place as follows. Two individuals coming
into contact by corresponding portions of
the body (PI. 16. fig. 34), become shortened
and firmly united. A transparent capsule
is next formed around the two individuals,
which encloses them in a cyst (figs. 26, 30),
the adjacent portions of the cell-membranes
are absorbed, and the substance of the two
bodies becomes intimately fused. Globules
or cells are then formed in the contents of the
cell, which subsequently assume the form of
Naviculee, and have been called pseudo-
naviculae (erroneously navicellce] (figs. 31,
32, 33) ; these are supposed to represent
the germs of new Gregarince, which become
liberated by the bursting of the cell ; their
further development has not been traced.

It has been supposed that the pseudo-
naviculae might really represent Naviculce,
and that the cysts containing them were
sporangia ; but this view does not appear
probable, neither do the pseudo-naviculae
possess a coat of silex.

In some cases it appears that the contents
of the two cells in conjugation remain di-
stinct until the pseudo-naviculse are formed ;
but it is not certain whether each single cell
in these instances has not arisen from the
fusion of two others.

A very large number, more than eighty
species, of Gregarina have been described
and arranged in numerous genera, &c., as
is so usual where little more than the form
of the organisms is known.

BIBL. Dufour, Ann. d. Sc. nat. 1837. vii.;
Stein, Miiller's ArcUv, 1848, Ann. Nat.
Hist. 1850. v., and Infus.; Frantzius, Obser-
vationes de Gregarinis, 1846 ; Henle, Mul-
lets Archiv, 1835. 1845 ; Siebold, Beitr. z.
Naturg. d. wirbellos. Thiere, 1839 ; Kolliker,
Siebold fy Kolliker' s Zeitschr., 1848 & 1849.

GRIFFITHSIA, Ag.— A genus of Cera-
miaceae (Florideous Algae), with feathery
fronds 3 to 6" long, composed of delicate
dichotomously-branched filaments consisting
of a single row of cells, the branchlets often
whorled ; colour crimson or rosy red. The
fructification consists of spores, antheridia
and tetraspores, all produced in similar situ-
ations, namely, at the articulations, where
they are surrounded by a kind of involucre
formed of short ramelli, to which the tetra-
spores and antheridia are attached. The
antheridia consist of a kind of shrubby tuft

GRIMMIA.

[ 299 ]

GUEMBELIA.

of extremely minute filaments arising from
an axial filament which arises from a ramellus
of the involucre. Fig. 291 represents a
branch terminating in an involucre of whorled
ramelli bearing tetraspores; the lowerfigure is

Fig. 291.

Griffithsia spluerica.

Fig. 291. Fragment of a frond bearing an involucre with
tetraspores. Magn. 20 diams.

Detached ramellus of the involucre, showing the attach-
ment of the tetraspores. Magn. 40 diams.

a portion of a ramellus, showing the mode of
attachment of the tetraspores. In the an-
theridial involucres, the plumose antheridial
structure is attached in exactly the same
way. Seven British species are recorded, of
which one or two are not uncommon.

BIBL. Harvey, Brit. Mar. Alg. p. 167.
pi. 23 B ; Decaisne, Ann. des Sc. nat. 2 ser.
xvii. p. 353. pi. 16 ; Thuret, Ann. des Sc.
nat. 3rd ser. xvi. p. 16. pi. 5 ; Derbes and
Solier, ibid. xiv. p. 276. pi. 36 ; Enol. Bot.
pi. 1479 & 1689.

GRIMMIA, Ehrhart.— A genus of Ortho-
Fig. 292.

Grimmia.
Teeth of peristome. Magnified 150 diameters.

trichaceous Mosses, containing numerous
British species.

Many of the species of Trichostomum of
Hedwig and Schwa3grichen are placed here
by Bruch and Schimper and C. Miiller.

GROMIA, Duj.— A genus of Infusoria.

Char. Carapace brownish-yellow, mem-

branous, soft, globular or oval, with a small
round orifice, from which very long, filiform,
branched expansions with very delicate ex-
tremities protrude.

Dujardin places this genus in the Rhizo-
poda; Ehrenberg among the Foraminifera.
It belongs properly to the Arcellina.

G. oviformis. Carapace globular, with a
short neck; marine; size 1-25 to 1-12".
Found among marine plants.

G. fiuviatilis (PL 24. fig. 15). Carapace
globular or ovoid, without a neck ; aquatic ;
breadth 1-280 to 1-100". Found upon Ce-
ratophyllum.

Schlumberger describes an aquatic Gromia
(hyalina), differing from the last in size
(1-860 to 1-520"), and in the carapace being
colourless ; hence it probably represents the
young state of G. fiuviatilis.

BIBL. Dujardin, Ann. d. Sc. nat. 1835.
iv. In/us, p. 252 ; Schlumberger, Ann. d. Sc.
nat. 1845. iii. p. 255.

GUANO. — As is well known, guano is
imported into this country in large quantities
as a manure. It consists principally of the
excrement of birds, in a more or less decom-
posed state. It affords the microscopist a
means of procuring the foreign marine Dia-
tomacea3, the frustules and valves of which
are often contained in it in large numbers.
The Diatomacea3 may be obtained from
guano as recommended at page 202.

GUEMBELIA, Hmp.— A genus of Or-

Fig. 293. Fig. 294. Fig. 295.

Guembelia fontinaloides.

Fig. 293. A fertile shoot.

Fig. 294. Capsule with calyptra. Magn. 10 diams.

Fig. 295. Teeth from the peristome. Magn. 150 diams.

thotrichaceous Mosses, including various
species, separated from Grimmia on account
of the peculiar calyptra, and also the Cincli-
dote of P. Beauvais.

GUM.

[ 300 ]

GYRINUS.

G. orbicularis, Hmpe.= Gnwmm orbicu-
laris, Br. Eur.

G. riparia= Cinclidotus riparia, Wils.

G. fontinaloides (figs. 293-5) = Cincl.
fontinaloides, P. B.

GUM. — A name applied to various viscid
(not oily) secretions of plants. Gums have
no microscopic structure when pure and
clean, but often exhibit under the microscope
traces of structures, such as debris of cellular
tissue, filamentous Fungi, &c., which have
become imbedded in them while soft. Gum-
arabic has been used sometimes for mounting
objects, in the same way as Canada balsam,
but it is not a satisfactory material. Sections
of very soft tissues or very minute objects may
be made by imbuing them with or immersing
them in solution of gum and allowing the
whole to dry up to a tough, semisolid mass,
capable of being sliced with a razor. The
slices are freed from gum by soaking in water.

GUTTA-PERCHA.— A kind of gum-resin
produced by the evaporation of the milky
juice of the Isonandra gutta, one of the
family of the Sapotaceae, a native of Sumatra
and the neighbouring regions. Its relation
to the microscope arises from its use in a
solid form and as cement, in mounting mi-
croscopic objects in cells. See CEMENTS
and PREPARATIONS.

GYGES, Bory.— Described by Ehrenberg
as a genus of Volvocineae, having neither
eye-spot, tail, nor flagelliform filament ; the
carapace(cell-membrane) simple, subglobose.

Motion very slow. He gives two species :

G. granulum (PI. 41. fig. 14). Ovate or
subglobose, internal granular mass dark
green; diam. 1-1150". Aquatic.

G. bipartitus. Nearly spherical, internal
mass yellowish-green, frequently bipartite;
diam. 1 -480". Aquatic.

So far as appears from the descriptions
and figures, these do not seem to differ from
PROTOCOCCUS.

(For G. sanguineus, Shuttleworth, see
RED SNOW.)

BIBL. Ehr. Infus. p. 51.

GYMNOGONGRUS, Mart.— A genus of
Cryptonemiacese (Florideous Algae), with
horny branched fronds, the divisions cylin-
drical or compressed, a few inches high, of a
purplish-red colour. The substance of the
branches presents three layers of closely-
packed filamentous cells, the central longi-
tudinal, the intermediate curved, and the
peripherical horizontal and monilif orm . The
spores have not been observed; the tetra-
spores (cruciate) are arranged in monili-

form rows, in wart-like thickenings of the
branches.

BIBL. Harvey, Brit. Mar. Alg. p. 145.
pi. 18 B ; Engl. Bot. pi. 1089 & 1926.

GYMNOGRAMMA, Desv.— A genus of
exotic Gymnogrammeae ( Poly pod aeousFerns ),
some of the species of which are remarkable
for a yellow or white pulverulent appearance
on the back of the fronds, owing to the
presence of abundance of microscopic cellu-
lar hairs, ex. gr. G. Calomelanos, G. chryso-
phvlla, ochracea, &c.

GYMNOGRAMMEJE.— A. sub-tribe of
Polypodaeous Ferns, containing several in-
teresting exotic genera.

I. GYMNOGRAMMA. Sori on the backs
of all the veins and venules. Veins pinnate
or forked, scarcely anastomosing.

II. HEMIONITIS. Sori on the backs of all
the veins and venules. Veins very much
branched, anastomosing in more or less
regular meshes.

III. ANTROPHIUM. Sori imbedded in the
back of all the veins and venules. Veins
very much branched, anastomosing in more
or less regular meshes.

GYMNOMITRIUM, Corda.— A genus of
Jungermannieae (Hepaticaceae), containing
one British alpine species, the Jungermannia
concinnata of the British Flora.

BIBL. Hook. Brit. Jungerm. pi. 3; Ekart,
Synops. Jungerm. pi. 8. fig. 63; Engl. Bot.
pi. 1022.

GYMNOSPERMIA.— A division of the
Flowering Plants (see VEGETABLE KING-

DOM),includingtheCoNIFER^E,GNETACE^E,

and CYCADACE^E ; deriving this name from
the mode of development of the OVULES.

GYMNOSPORANGIUM, D. C. — A
genus of Cseomacei (Coniomycetous Fungi,
see also UREDINEI). G. Juniperinum grows
upon living branches of the common Juniper,
appearing at first like an exanthema on the
bark, which in wet weather swells up into an
orange-coloured tremelloid, plicate mass,
which readily dries up, however, and then is
scarcely visible. Somewhat rare, but when
present generally copious.

BIBL. Berk. Brit. Flora, vi. part 2.
p. 361 ; Fries, Syst. Myc. iii. p. 505.

GYMNOSTOMUM, Schwagr.—A genus
of Mosses, now distributed into PYRAMI-
DIUM, PHYSCOMITRIUM and other genera.

BIBL. Miiller, Syn. Muscorum ; Bruch
and Schimper, Bryologia Europeea.

GYRINUS, Geoffr.— A genus of Coleo-
pterous insects, of the family Gyrinidae.

G. natator, one of the eight British spe-

GYRINUS.

[ 301 ]

GYROSIGMA.

cies of this genus, is very commonly seen in
groups performing its gyrations upon the
surface of pools or rivers, whence it has re-
ceived the popular name of whirligig.

The body is ovate, or elliptic and de-
pressed, the elytra black and shining. The
antennae are short and retractile within a
cavity in front of the eyes ; the basal joint mi-
nute, the second large, globular, and furnished
externally with an ear-like joint fringed with
colourless, flattened, hair-like processes ; the
remaining seven joints form a clavate mass,
being very short and closely united, the first
commencing by a very narrow base or pe-
dicle. The eyes are divided into two parts
by a transverse septum, the upper of which
serves for viewing objects in the air, the lat-
ter those in water; by some authors these
insects are described as possessing four di-
stinct eyes. The terminal segment of the
abdomen is furnished with two retractile
ciliated lobes. The two fore-legs are long,
and of the ordinary form, whilst the four
hind legs (PI. 27. fig. 5), which are used as
oars, are short, flat, and dilated ; the femur

(d) and tibia (c) somewhat triangular, the tibia
also fringed with short spines and long, flat-
tened filaments ; in the middle pair of legs

(e) the latter exist on both margins, whilst
in the hind legs these are present only on the
outer margin. The tarsi (a) are five-jointed,
the three basal joints produced on the inside
into long, flat, leaf-like lobes fringed with
spines ; the fourth joint is of about the same
size, and semicircular, the fifth being very
short and attached to the fourth near the
end, and both are fringed on their outer
margin with flattened filaments resembling
those upon the tibia; all the tarsi are fur-
nished with two distinct claws.

The anterior tarsi of the male differ
from those of the female, as in Dytiscus.
The circulating currents can be seen in the
hind legs.

The larva (PI. 28. fig. 19), which is aquatic,
is of a dirty-white colour, long, narrow, and
depressed, resembling a small centipede ; it
consists of thirteen segments including the
head. Its antennae are filiform and four-
jointed ; the eyes numerous and tubercular,
grouped on each side of the head. The
three pairs of legs are attached to the eight
anterior segments of the body ; the remain-
ing segments are furnished on each side with
a branchial filament, excepting the last,
which has two of them, and four minute
conical points, bent downwards, and used by
the insect when in motion.

BIBL. Westwood, Introduction, fyc. i.
p. 105.

GYROPUS, Nitzsch.— A genus of mandi-
bulate Anoplura (Insects), of the family
Liotheidae.

Char. Tarsi two-jointed, with a single claw.

Mandibles without teeth ; maxillary palpi
conical and four-jointed ; labial palpi none ;
antennas four-jointed; thorax two-jointed;
abdomen ten-jointed.

G. ovalis (PI. 28. fig. 8). Head ferrugi-
nous, transverse, with a lateral produced
lobe on each side ; thorax and legs ferrugi-
nous ; abdomen nearly orbicular, yellowish-
white ; claws long, curved and strong ; length
1-48".

Found upon the guinea-pig (Cavia co-
bay a).

G. gracilis. Head and thorax ferruginous ;
abdomen elongate, segments with a transverse
striated band at each suture ; ungues very
short and minute ; length 1-36".

Found also upon the guinea-pig.

BIBL. Denny, Anoplur. Monographia.

GYROSIGMA, Hass. (Pleurosigma, Sm.).
— A genus of Diatomacese.

Char. Frustules single, free, longer than
broad; front view linear or linear-lanceolate;
valves navicular, sigmoid, with a longitudinal
line, and anodule in the centre and at each end.

The group of species arranged in this ge-
nus should properly form a subgenus of
Navicula, inasmuch as the sigmoid form of
the valves, upon which the distinguishing
character is founded, does not exist in all
the species of Gyrosigma to a greater extent
than that in which it occurs in some species
of Navicula ; in some, its only indication is
a slight inequality in the two halves of the
valves. The median line and nodules consist
of an internal thickening of the valves at the
corresponding parts, the line is best seen in the
front view (PL 11. fig. 16) ; it is occasionally
found in afractured valve, projecting as a solid
highly refractive rod, the thinner adjacent
portions of the valve being broken away ;
for brevity, it may be called the keel.

The valves exhibit spurious striae, arising
from the existence of rows of dots (depres-
sions), of which we have already treated
under DIATOMACESE. These striae and dots
are in most species very difficult to detect,
requiring the use of oblique light, and the
stops; the principles which should guide in
the search for them have been explained
under ANGULAR APERTURE ; the prelimi-
nary preparation of the valves is also essen-
tial (DlATOMACE^B, p. 202).

GYROSIGMA.

[ 302 ]

GYROSIGMA.

Most of the species are found in salt or
brackish water; a few are aquatic. They
often abound upon the surface of mud.
Conjugation or the formation of sporangia
has not been observed. The frustules are
sometimes found enveloped in amorphous
mucus, and those of one species have been
found within gelatinous tubes.

Many species have been described, of
which those that have been used as TEST-
OBJECTS will be enumerated. We must,
however, express our belief that they cannot
truly be regarded as distinct species, unless
of microscopic objects, if the term may be
permitted. The measurements are mostly
those of the Rev. Mr. Smith and Mr. Beck,
with which our own have coincided as nearly
as could be expected. The species are
arranged according to the fineness of the
markings, which coincides withthe difficulty
with which they are detected and resolved
into dots ; and the appended figures express
the number of striae or rows of dots in
1-1000".

Stria oblique (dots alternate or quin-
cuncial, PI. 11. fig. 40).

G. formosum (PI. 11. fig. 25). Broadly
linear, attenuated towards the ends; si^-
moidure evident; keel oblique ; length 1-60';
striae 36. Marine.

G. decorum (PI. 11. fig. 26). Rhomboid-
linear; attenuated; sigmoidure very evident;
keel oblique ; length 1-90"; striae 36. Marine.

G. speciosum (fig. 28). Linear-lanceolate;
sigmoidure resulting from the curvature of
one margin of each half of the valve, the
opposite margin of each respective half being
nearly straight; keel in each half forming two
curves, very oblique near the end; length
1-90"; marine; striae 44. The halves of
the valves resemble the blade of a pocket-
knife.

G. strigosum (fig. 29). Linear-lanceolate,
ends rather obtuse, sigmoidure slight ; keel
nearly straight in the middle, curved near
the ends; length 1-90"; striae 45. Marine.
Fig. 40 represents the striae resolved into
dots.

G. quadratum (fig. 34). Rhomboidal,
acuminate at the ends ; sigmoidure evident
towards the ends ; keel curved, nearly me-
dian; length 1-150"; marine; striae 45.

G. elongatum(Pl. 11. fig. 31, and PI. 1. fig.
18). Linear-lanceolate, acuminate ; sigmoid-
ure slight, uniform; keel median; length
1-80''; marine; striae 48.

G. rigidum (fig. 30). Linear-lanceolate,

obtuse at the ends ; sigmoidure slight ; keel
nearly median; length 1-70"; marine; striae
48.

G. angulatum (Navicula angulata) (PL 11.
fig. 33). Rhomboid-lanceolate or angular-
lanceolate ; sigmoidure evident ; keel nearly
median; length 1-110"; marine; striae 52.
PI. 1. fig. 16 represents a valve with the striae
resolved into dots ; PI. 1 1 . fig. 41 represents
the dots more highly magnified.

PL 1 1 . fig. 33 a represents a specimen with
the endochrome and nucleus.

/3 (fig. 33 b). Simply and narrowly lan-
ceolate, ends acute.

y (fig. 33 c). Ends beaked, abruptly
flexed.

G. (Bstuarii (fig. 35). Lanceolate ; ends
abruptly tapering, short and beak -like ; sig-
moidure evident ; keel not median ; length
1-250"; marine; striae 54.

G. intermedium (fig. 36). Narrowly linear -
lanceolate, acute; sigmoidure none, or merely
indicated by a slight inequality in the oppo-
site margins of the valves; keel nearly
straight and almost median; length 1-140";
marine ; striae 55.

ft G. nubecula. Ends obtuse; slightly
more lanceolate, and shorter ; marine ;
striae 55.

G. delicatulum (fig. 32). Very narrowly
linear-lanceolate; sigmoidure evident; keel
nearly central; marine; length 1-130";
striae 64.

G. obscurum (fig. 27). Linear, attenuated
near the ends ; sigmoidure slight, principally
arising from the curvature of one margin of
each half of the valve; keel not median,
especially near the ends; marine; length
1-200"; striae 75.

Strife longitudinal and transverse (dots
opposite, PL 11. figs. 39, 42).

In most of the following species or forms
the dots are not equidistant in the longitu-
dinal and transverse rows.

G. strigilis (fig. 12). Linear-lanceolate ;
sigmoidure evident; keel nearly median,
flexure double ; marine ; length 1-75 ; striae :
longitudinal 40, transverse 36.

G. balticum (fig. 10). Broadly linear,
narrowed at the ends ; sigmoidure apparent
at the ends only, and produced principally
by the curvature of one margin only ; keel
not median, flexure double ; marine ; length
1-80" ; striae, both sets, 38. Fig. 39, piece
of valve, showing dots.

^. Gradually tapering towards the ends ;
striae obscure.

H^MATINE.

[ 303 ]

H^EMATOIDINE.

G. Hippocampus (fig. 13). Narrowly
lanceolate, gradually attenuated towards the
broad, very obtuse ends; sigmoidure evi-
dent ; keel nearly median; marine or brackish
water; length J-160"; striae: long. 32,
tr. 40.

G. attenuatum (fig. 15, PL 1. fig. 17).
Linear-lanceolate, with obtuse ends; sigmoid-
ure slight ; keel nearly median ; marine and
aquatic; length 1-120"; stria;: long. 30, tr.<40.

G. lacustre (fig. 18). Linear-lanceolate,
ends rather obtuse ; sigmoidure evident ;
keel almost median ; aquatic; length 1-130";
striae, both sets, 48.

G. tenuissimum (fig. 24). Narrowly linear,
attenuate towards the ends ; sigmoidure evi-
dent; keel nearly central; aquatic; length
1-180"; striae, both sets, 48.

G. Spencerii (fig. 17). Linear-lanceolate ?
sigmoidure evident ; keel nearly median ;
aquatic; length 1-200"; striae: long. 55,
tr. 50.

G. littorale (fig. 19). Lanceolate, ends
somewhat prolonged; sigmoidure evident;
keel median; aquatic; length 1-180"; striae :
long. 24, tr. 50. Fig. 42 represents the dots
upon part of a valve.

G. acuminatum (fig. 14). Linear-lanceo-
late, acuminate; sigmoidure evident; keel
median; aquatic; length 1-150"; striae:
long. 40, tr. 52.

G. fasciola (fig. 21). Linear-lanceolate,
with linear beak-like ends ; sigmoidure evi-
d$nt; marine; length 1-200; striae: long.
(?), tr. 64.

G. prolongatum (fig. 23). Very narrowly
linear -lanceolate, acuminate, with linear
beak-like ends; sigmoidure present in the
ends only; keel nearly median; marine;
length 1-200"; striae : long. (?), tr. 65.

G. distortum (fig. 20). Lanceolate; ends
slightly produced and beak-like ; sigmoidure
evident; keel central ; marine ; length 1-300";
striae : long. 65, tr. 75.

G. macrum (fig. 22). Very narrowly
linear-lanceolate; ends produced into long
beak-like processes; sigmoidure produced
by the ends of the beaks only ; keel median ;
length 1-100"; striae, long. (?), tr. 85.

BIBL. Hassall, Freshwater Algce, p. 435;
Smith, Brit. Diatom, i. p. 61; Kiitzing, Sp.
Alg. and Bacill. ; Rabenhorst, D. susswass.
Diat.

H.

H^EMATINE.— The red colouring matter
of the blood, in the globules of which it

exists combined with globuline. It possesses
no morphological characters.

BIBL. See CHEMISTRY.

HLEMATOCOCCUS. See PROTOCOC-
cus and GL^OCAPSA.

ELEMATOIDINE.— This substance, to
which Virchow first drew attention, is not
unfrequently met with in masses of extrava-
sated blood which have remained for some
time in the living bodies of the Vertebrata, as
in old apoplectic clots, sanguineous extrava-
sations resultingfrom contusions and wounds,
the effusions accompanying the rupture of
the Graafian vesicles, &c.

It occurs in the form of granules, globules,
and distinct crystals. These are somewhat
highly refractive, and mostly of a ruby-red
or yellowish-red colour ; they are stated also
to have been found colourless. The most
common forms are represented in PL 9. fig.
16, and they appear to belong to two distinct
systems, — the oblique rhombic prismatic,
and the regular system.

The properties of haematoidine are as in-
constant as the crystalline form, and it is
probable that several different substances
have been ranged under the above title, or
perhaps modifications of the same substance
in different states of hydration ; for so insu-
perable has been the difficulty of obtaining
haematoidine in quantity and a state of purity,
that its true nature has not been satisfactorily
determined.

It is mostly insoluble or difficultly soluble
in water, alcohol, aether, acetic and dilute
mineral acids, and solution of potash. Some-
times it is soluble in acetic acid with a
yellow colour, at others readily so in water.

An amorphous, colourless proteine-sub-
stance is sometimes separated from the cry-
stals by the action of mineral acids.

There seems to be but little doubt that
haematoidine consists principally of the hae-
matine of the blood in a crystalline form ; it
is also related in composition to bilifulvine
(see BILIFULVINE).

Haematoidine may be artificially procured
from various sources ; perhaps most readily
from the blood of fishes by spontaneous
evaporation. The blood of the spleen of the
horse changes almost entirely into prismatic
crystals of it in drying. In obtaining the
crystals, the presence of the serum is preju-
dicial, and it should be washed away with a
small quantity of water. If recently dried
blood be treated with a vegetable acid (acetic,
oxalic acid, &c.), a drop of the solution be
placed upon a slide, covered with thin glass,

ILEMATOPINUS.

[ 304 ]

HAIR.

and kept at a temperature of 80° to 100° F.,
the crystals may also be obtained. This re-
action might be of use in judicial investiga-
tions. The addition of water, and a little
alcohol or aether to the blood, sometimes
favours the separation of the crystals.

Crystals of haematoidine have been found
within the blood-globules prior to the addi-
tion of reagents.

Their preservation is difficult ; it is best
effected by washing them with alcohol, or
this liquid somewhat diluted with water, and
drying them under the air-pump, or over
sulphuric acid.

BIBL. Virchow, Ann. d. Chem. u. Pharm.
1851, June (Chem. Gaz. 1852); Funke,

Zeitsch. f. rat. Med. 1851. i. p. 172, 1852.
ii. pp. 199 & 288; Kunde, ibid. 1852. ii. p.
271 ; Lehmann, Journ.f. prakt. Chemie,lv.

p. 65 (Chem. Gaz. 1852, x. p. 273) ; Ber.
d. Gesellsch. d. Wiss. z. Leipzig, 1852. p. 78
(Chem. Gaz. 1853. xi. p. 442), and Physiol
Chemie; Sanderson, Edinb. Monthly Journ.
xiii. pp. 216. 521 ; Kolliker, Mikrosk. Anat.;
Teichmann, Zeitsch. f. rat. Med. 1853. iii.
p. 375.

H^MATOPINUS, Leach.— A genus of
Insects, of the order Anoplura, and family
Pediculidae.

Char. Legs all formed for climbing ; tho-
rax generally narrower than the abdomen,
and distinctly separated from it ; abdomen
composed of eight or nine segments.

This genus contains several species, which
live as parasites upon various animals, — the
field-mouse, rat, dog, ox, horse, ass, calf,
hog, rabbit, hare, squirrel, &c.

H. suis (PI. 28. fig. 4; fig. 4*, anterior leg).
Dusky ferruginous ; abdomen grey or ashy-
yellow, flat and membranaceous, with a black
horny excrescence surrounding each of the
white spiracles ; legs long and thick ; femur
transversely striped ; tibia very abruptly cla-
vate, dark-coloured at the end ; tarsi with a
large fleshy pulvillus.

Found upon pigs out of condition ; length
1-10 to 1-6".

BIBL. Denny, Monogr. Anopl. Brit. p.
24 ; Gervais, Walckenaer's Apteres, iii. 301.
H^EMOCHARIS,Sav.(PwcicoZa,Blainv.).
A genus of Annulata.

H. piscium (Piscicola geometra) is a
leech-like animal, found upon the carp,
tench, roach, &c. Length 1 to 2",

BIBL. Leo, Mutter's Archiv, 1835; Ley-
dig, Siebold and Kb'lliker's Zeitschr. i. ;
Brightwell, Ann. Nat. Hist. 1842. ix. 11.
HJ3MOPIS, Sav.— A genus of Annulata.

H. sanguisorba, the common horse-leech.
In this animal the teeth are less numerous
and more obtuse than in the medicinal leech
(Hirudo ojficinalis).

HAIL. — The microscopic structure of
hail-stones does not appear to be uniform.
In some a central nucleus surrounded by
concentric layers has been noticed; in others
the nucleus is enveloped by a radiating cry-
stalline crust ; or again, the entire mass has
been found to consist of little spheres of ice.
When hail-stones liquefy, a copious evolution
of gas takes place. Hail-stones may best be
collected for examination in a blanket, which
being a bad conductor of heat, retains them
longest in the solid state. Connected with
the structure and formation of hail-stones, is
the composition of spherules of condensed
vapour. These are generally believed to
consist of films of water enclosing portions
of air, but Dr. Waller's observations have led
him to the conclusion that they are simply
composed of water. If the former view were
correct, those hail-stones which consist of
aggregations of icy spherules, should contain
air within them, which does not appear to be
the case; but in deciding this question,
attention must be paid to the principles laid
down in the INTRODUCTION, p. xxxii, /.,
which will afford a simple means of deciding
the point.

In some liquefied hail-stones, the spores
of fungi and algae, with infusoria, have been
found.

BIBL. Pouillet, Elemens de Physique, ii.;
Waller, Phil. Trans. 1847. p. 23; id. Phil.
Mag. 1846. xxix. p. 103 and 1847. xxx. p.
159 ; Harting. Skizzen aus d. Natur.

HAIR, OP ANIMALS. — The structure of
the hair of animals is very complicated, and
requires careful manipulation for its investi-
gation. We shall commence with the hair
of man, in which it has been the most per-
fectly examined.

Human hair. When a hair is viewed
under a low power, it appears black at the
sides and light in the middle, so as to convey
a notion of its being a tube ; such is not,
however, the case, although this notion was
long admitted.

The hairs are secreted by the skin, and
consist of modified epidermic formations.
Each is implanted in a cutaneous depression,
termed the hair-follicle (fig. 296), at the
bottom of which it is fixed by a dilatation
called the knob or bulb of the hair (c). The
free portion, or that projecting beyond the
skin, is the shaft or scape (a); and that above

HAIR.

[ 305 ]

HAIR.

the bulb but contained within the follicle, is
Fig. 296.

I

Magnified 50 diameters.

A hair of moderate size, contained in its follicle, a ,
shaft ; b, root ; c, bulb or knob ; d, cuticle of the hair ; e,
inner sheath of the root ; /, outer sheath of the root ; g,
structureless membrane of the hair-follicle ; h, transverse
and longitudinal fibrous layer of the same ; i, papilla ; k,
excretory ducts of the sebaceous glands or follicles, with
their epithelial and fibrous layer ; I, cutis of the orifice of
the hair-follicle ; m, rete mucosum ; n, cutaneous epi-
dermis ; o, termination of the inner sheath of the root.

the root (b). The bulb encloses or surrounds
a conical or rounded body (i), the papilla or

iree varieties of hair are met with upon
different parts of the body : 1, consisting of
long, soft hairs, from 1 to 3" and more in
length; as the hair of the head ; 2, short,
rigid and thicker hairs, from 1-4 to 1-2" in
length, as in the eye-lashes; and 3, short,
very slender hairs, from 1-12 to 1-6" in
length, as in the down or woolly hairs of the
face, the back and extremities.

When the shaft of a hair is examined

under the microscope by transmitted light,
two structures are mostly distinguishable, a
median, more or less black, somewhat irre-
gularly granular and linear portion—the
medulla or pith ; and an outer, fibrous-
looking portion, mostly more or less coloured,
according to the colour of the hair, the cortex,
cortical or fibrous portion.

The cortical portion is that upon which
the firmness, elasticity, and colour of the
hair depends, and constitutes the greater
portion of its bulk. It exhibits numerous
longitudinal stria?, or interrupted dark lines
and dots. When acted upon by strong sul-

Fig. 297.

Magnified 350 diameters.

Plates and cells of the cortical substance of a hair, after
treatment with acetic acid. A, separated cells : 1, front
view (three of them isolated, two united) ; 2, side view.
B, a layer, composed of several cells.

X

HAIR.

[ 306 ]

HAIR.

phuric or some other acid at a gentle heat,
it becomes at first resolved into plates or
fibres (fig. 297 B) of the most varied sizes,
both as to length and breadth ; but if the
action of the acid be continued, these fibres
become separated into cells (fig. 297^).
These cells present uneven surfaces, and a
more or less elliptical outline, their true form
being spindle-shaped ; but they are mostly
flattened and angular, or curved from mutual
pressure, resulting from their aggregation
into the shaft of the hair. The cells are
about 1-300 to 1-500" in length, and from
1-6000 to 1-2200" in breadth. They mostly
contain elongated, dark-looking nuclei,
1-400 to 1-1 100" in length; these are well
seen in a colourless hair, heated with soda or
potash (fig. 298 Ab, and B) ; in coloured

Fig. 298.

Magnified 350 diameters.

A, Portion of a white hair after treatment with soda.
«, nucleated cells of medulla, free from air ; b, cortical
substance with fibrillation and linear nuclei ; c, cuticle.
B, three isolated nuclei from the cortex.

hair they also contain pigment-granules, to
which the colour of the hair is principally
owing. The pigment-granules are exceed-
ingly minute, about 1-50,000" in diameter,
rounded, and as existing in the hair, are
mostly arranged in linear groups, their
colour and number varying with that of the
hair. The pigment-granules are best sepa-
rated by the action of caustic potash or soda,
and they frequently exhibit molecular motion.

The striated and dotted appearance of the
shaft of hairs is not produced simply by the
nuclei, nor by the pigment, but arises in
part also from the unequal refraction of the
light by the various parts of the cells, and
from the presence of minute spaces filled
with air. The nature of each can always be
determined by attention to the principles
laid down in the INTRODUCTION.

Towards the bulb, the cells of the cortex
are more distinct, less elongated, and as well
as the nuclei more easily isolated when
treated with acids (fig. 299) ; whilst in the

Fig. 299.

Fig. 300.

Magnified 350 diameters.

Fig. 299. Two striated cells from the cortex of the root

close aboTe the bulb, with nuclei.
Fig. 300. Cells from the deepest portions of the bulb :

a, from a coloured bulb, with pigment- granules and

partly concealed nuclei ; b, from a white hair, with

distinct nuclei and a few granules.

bulb itself they are round (fig. 300), 1-4000
to 1-1800" in diameter, closely crowded, and
sometimes containing only a colourless
nucleus, at others pigment-granules.

The medulla, like the cortex, consists of a
number of cells. Its structure is best ob-
served in a hair which has been treated with
soda or potash. The cells are then seen to
be arranged in one or more linear series
(fig. 298 a] ; they are angular or rounded,
1-2000 to 1-1000" in diameter; and if the
action of the alkali has not been too long
continued, they exhibit a nucleus ; they fre-
quently also contain one or more granules
or globules of fat (fig. 302). In the shaft
and upper part of the root of the hair, these
cells contain air, which gives them a dark or
black appearance by transmitted light ; and
it was the generally received opinion, until
we pointed out the error several years ago,
that this darkness or blackness arose from
the presence of pigment. The contrary,
however, may be easily proved by macerating
the hair in oil of turpentine or any liquid,
when the air escapes in bubbles and becomes

HAIR.

[ 307 ]

Fig. 301.

Magnified 250 diameters.

Portion of the root of a dark hair, slightly acted upon by soda :
a, medulla, the cells still containing air ; b, cortex with pigment ;
c, inner cuticular layer ; d , outer cuticular layer ; e, inner layer
of the inner root-sheath ; /, outer perforated layer of the same.

HAIR.

consisting of flat, imbricated, epi-
thelial scales. In the natural state
of the hair, the existence of these
scales is only indicated by the

Fig. 303.

•Wtt

Magnified 160 diams.

A, surface of the shaft of a white hair, the
curved lines indicating the free margins of the
epidermic scales. B, scales isolated by the action
of soda.

displaced by the liquid ; moreover, on drying
Fig. 302.

Magnified 360 diameters.

Medullary cells with pale nuclei and fatty granules,
from a hair treated with soda.

the hair, the air and black appearance return.
PI. 22. fig. 1 represents a white hair, in
which the medullary cells of the lower part
are filled with Canada balsam, whilst those
of the upper portion still contain air. Again,
examination by reflected light is equally con-
clusive, for under it the black medullary por-
tions become white, which would not be the
case did the blackness arise from pigment.
PI. 22. fig. 9 illustrates this in the hair of
the Lion ; where a represents the hair as
seen by transmitted, and b, by reflected light.
Cuticular coat. The shaft and root of the
hair, above the termination of the inner
root-sheath, are coated externally by a firmly
adherent, thin, simple, membranous layer,

presence of irregularly transverse and ana-
stomosing lines seen upon the surface, or
slight dentation of the margin (fig. 70 A).
But when the hair has been treated with an
acid or an alkali, the scales become sepa-
rated. Their free margins are directed to-
wards the unattached end of the hair. The
scales are much more distinct without treat-
ment in the hair of the newly-born infant
(PI. 22. fig. 3). They are very transparent,
somewhat quadrangular, flattened or curved
cells (fig. 303 B), not containing a nucleus ;
their margins or edges are often black, and
as the other parts are transparent, they are
apt to be overlooked. They are about
1-700 to 1-500" in length, and one-half or
one-third of this in diameter.

In the lower part of the root, below the
termination of the root-sheath, the cuticular
coat is double, or consists of two layers.
The above-mentioned cuticle of the shaft
and upper part of the root forms the con-
tinuation of the innermost of these, which
possesses nearly the same structure, except
that the scales of which it consists are some-
what longer, and directed more obliquely out-
wards. These layers are best seen in a hair
treated with an alkali, especially with the aid

x2

HAIR. [ 3<

of pressure; they then become separated
(fig. 301 ), the inner, with the root of the hair,
assuming an undulating form, and remaining
firmly adherent (c); whilst the outer (d} re-
mains attached to the inner root-sheath, its
cells also being broad and without nuclei.
At the bulb, both these layers become trans-
formed into soft cells, broader than long,
with transverse nuclei, finally becoming fused
with the round cells of the bulb.

The hair-follicles are pouches, about 1-10
to 1-4" in length, pretty closely surrounding
the hairs, and extending in the short hairs
into the substance of the upper layer of the
cutis ; but in the long hairs, into its deepest
portion, or even into the subcutaneous cel-
lular tissue. They may be regarded as pro-
longations of the skin, with its components,
the cutis, basement-membrane, and epider-
mis. Hence three parts are distinguishable
in them : an external, fibrous, very vascular
portion, the proper hair-follicle, a basement-
membrane, and a non- vascular cellular coat,
— the epidermis of the follicle, or, because it
surrounds the root of the hair, the root-
sheath.

The fibrous portion of the follicle consists
of two layers or membranes. The outer one
(fig. 296 h) is the thicker, and contains ves-
sels and nerves. Its inner surface is con-
nected with the inner layer ; externally it is
attached to the surrounding areolar tissue ;
and above it is continuous with the outer
layer of the cutis. It consists of common
areolar tissue, the fibres of which are longi-
tudinal, with elongated, spindle-shaped nu-
clei. The inner layer (fig. 304 a) is much
more delicate, and only extends from the
base of the hair-follicle to the orifice of the
sebaceous follicles. It consists of a single
layer of transverse fibres, with long and nar-
row nuclei, resembling unstriated muscular
fibres.

The third layer (fig. 304 6), or basement-
membrane, is transparent and structureless,
and extends from the base of the follicle,
without apparently covering the papilla, as far
as the inner root-sheath, and perhaps higher.
It presents delicate transverse anastomos-
ing lines, producing a fibrous appearance.

The pulp or papilla of the hair (fig. 296 i)
belongs to the follicle, and corresponds to a
papilla of the skin. It is rounded or oval,
1-96 to 1-480" in length, is connected with
the fibrous coat of the follicle by a kind of
stalk, and consists of indistinctly fibrous
areolar tissue with nuclei and granules of
fat, but contains no cells.

Magnified 300 diameters.

Portion of the inner fibrous coat and basement-mem-
brane of a hair-follicle: a, inner coat with transverse
fibres and elongated transverse nuclei ; d, basement-
membrane, seen as it were in section ; r, its lacerated
margins ; d, fine lines (fibres ?) on its inner surface.

The two root-sheaths consist of the epi-
dermic covering of the hair- follicle. The
outer (fig. 296/) is the continuation of the
rete mucosum of the skin, and lines the en-
tire follicle. Its lower part is in contact
externally with the basement membrane of
the follicle; but above the termination of
the inner transverse layer of the follicle, it is
in direct contact with the outer or longitu-
dinal layer. It consists of several layers of
nucleated cells, resembling those of the rete
mucosum of the skin, the outer having their
long axis perpendicular to that of the hair ;
the others, especially towards the bulb, being
rounded. This outer root-sheath is most
distinct in the follicles of the skin of the
negro, from which it may be withdrawn with
the epidermis after maceration.

The inner root-sheath (fig. 301, e, /) forms
a transparent, very firm and elastic, yellowish
membrane, extending from near the base of
the hair-follicle to near the mouths of the
sebaceous follicles, where it terminates ab-

HAIR.

[ 309 ]

HAIR.

ruptly with a jagged margin. Externally it
is connected with the outer root-sheath, in-
ternally with the outer layer of the cuticle
of the hair ; hence no interval exists natu-
rally between it and the hair. At first sight
it appears as a perfectly homogeneous mem-
brane, but on closer examination it is seen
to be distinctly cellular; it consists of two
or three layers of polygonal, longish, trans-
parent cells, with their long axis parallel to
that of the hair. The outermost (Henle's)
layer (figs. 301 /, 305 A] consists of long,

Fig. 305.

Magnified 350 diameters.

Elements of the inner root-sheath. A, external layer :
1, isolated plates ; 2, the same in connexion, showing the
interspaces (a) between the cells (b). B, cells of the inner
non-perforated layer. C, nucleated cells of the lower
part of the inner sheath, which consists of a single layer
only.

flattened, non-nucleated cells, from l-/00to
1-500'' in length, with fissures between them,
forming a fenestrated layer. The innermost
(Huxley's) layer (figs. 301 e, 305 B) consists

of one or two layers of shorter and broader
polygonal cells, from 1-1200 to 1-600" in
length ; their nuclei, which exist in the lower
part only of the coat, are often broader at
the ends than in the middle, sometimes
curved and pointed. At the base of the
hair-follicle, the inner root-sheath consists
of a single layer only of beautiful, polygonal,
nucleated cells (fig. 305 c) ; these becoming
soft, delicate and rounded, gradually pass
into the outer layers of the round cells of
the bulb.

In regard to development, the rudiments
of the hair appear as processes of the rete
mucosum descending into the substance of
the cutis. These are solid and consist of
cells, the internal of which become horny
and form first a small slender hair in the
axis of the process, next an inner sheath
surrounding the former, whilst the outer
cells remain soft, and form the outer sheath
and the cells of the bulb.

After birth the foetal hair appears to be
completely shed, new hairs being formed in
the old follicles, which displace the first set,
as shown in figs. 306, 307.

Fig. 306.
A.

Fig. 307.

Magnified 20 diameters.

Eye-lashes of a child a year old. A exhibits a process
(TO) of the bulb or outer root-sheath, in which the central
cells are elongated, and form a cone distinct from the
outer cells. B, one more advanced, in which the inner
cone has become developed into a hair and an inner root-
sheath : a, outer, b, inner root-sheath of the young hair ;
c, pit for the pulp ; d, bulb ; e, shaft of the old hair ;
f, bulb, g, shaft, A, summit of the young hair ; f, sebaceous
follicles ; k, three sudoriparous ducts opening into the
upper part of the hair-follicle.

HAIR.

[ 310 ]

HAIR.

The hairs sometimes found developed upon
mucous membranes, and within encysted
tumours and ovarian cysts, possess the nor-
mal structure in every respect.

Of the morbid states of the human hair,
we need mention only the loss and change
of colour, and the presence of fungi. When
the colour entirely vanishes, and the hair
becomes white or grey, the cells of the me-
dulla contain abundance of air. This arises
from a kind of degeneration or impaired nu-
trition ; the liquid contents of the cells are
not supplied in sufficient quantity; they
therefore evaporate, and the cells being pre-
vented from collapsing by their adhesion to
each other and to the firm cortex, become
filled with air, which replaces what would
otherwise constitute a vacuum. Fungi are
found in FAVUS upon the cortex of the hair,
within the follicles, and even within the hair
itself, as is stated. In Porrigo decalvans also,
fungi are stated to occur in the hairs ; we
can affirm positively that this is not correct,
even when the disease has lasted for years.

The principal differences between the hair
of man and of animals, and that of animals
from each other, relate to — 1, the size; 2,
the relative proportions of the cortical and
medullary structures ; 3, the locality of the
pigment ; 4, the arrangement of the medul-
lary cells; 5, the comparative amount of
true hair, and woolly hair, down, or wool;
and 6, the size and projection of the super-
ficial cortical cells or scales, upon which the
valuable property of felting depends. Of
these we shall give a brief sketch (PL 1.
figs. 1-3, and PL 22).

The hair of the Mammalia generally is
formed upon the same plan as that of man ;
great variety, however, exists in its com-
plexity of structure and the arrangement of
the component parts.

Quadrumana (PI. 22. figs. 4 & 5). In the
monkey (Indian) (fig. 4), the hair presents
much of the same structure as in man ; the
pigment is confined to the cortex, but the air-
cells of the medulla are larger and less
crowded ; this is seen to a greater extent in
the hair of the lemur (fig. 5).

Cheiroptera. In the bats (PL 1. fig. 2;
PL 22. figs. 6 & 7), a striking character is
the peculiar development of the cortical
scales of the surface. In the hair of the
common bat (PL 1. fig. 2), which is one of
the TEST-OBJECTS, and Australian bat (PL
22. fig. 7), this character is not so striking
as in that of the Indian bat (PL 22. fig. 6),
in which the scales are grouped in whorls at

pretty regular intervals along the shaft, and
project considerably beyond the surface.
The pigment is principally confined to these
whorled scales. In some of the white hairs
of the bat, the individual scales are very
beautifully seen (PL 1. fig. 2 c).

Insectivora. The hair of the mole (fig. 8)
bears some resemblance to that of the bats ;
but the cells of the medulla are very distinct.
(See SPINES).

Carnivora (figs. 9-13). In this Class the
structure of the hair varies considerably. In
the lion (fig. 9) the cortical cells are distinct,
but not projecting ; the medullary cells
are very numerous, and the air-spaces mi-
nute, but closely aggregated, as we often
find them in the human hair. In the bear
(fig. 10), the large hairs present much the
same structure as in the lion ; the wool-hairs
differ strikingly from these, however, in the
distinctness of the cortical and medullary
cells.

Pachydermata (figs. 14-17). In this Class
the hairs present a development correspond-
ing with that of the skin ; being very thick
and complex in structure. In the elephant
(fig. 15, transverse section), each hair resem-
bles a number of hairs fused together.
Scattered through its substance are pale spots
formed by cells containing little or no pig-
ment, with an irregular perforation in each,
probably arising from rupture of the cells.
Surrounding these medullary centres are
innumerable cortical cells loaded with pig-
ment. In the pig (fig. 16), the distinction
between the cortex and medulla is not well
marked, and the cells assume a radial direc-
tion, as indicated by those which contain
most pigment. In the Cheiropotamus (fig.
17) the distinction is more evident.

Ruminantia (figs. 18-22). In this Class
the hair presents great variety. In the camel
(fig. 18) and dromedary (fig. 19), the true
hair exhibits much the same structure as
that of the higher classes ; whilst in the
deer (fig. 20, moose-deer; fig. 21, musk-
deer) the medullary portion is enormously
developed at the expense of the cortical
portion ; in no hairs is the cellular structure
more distinct than in the two latter, the
medulla closely resembling a piece of vege-
table cellular tissue. The wool-hair in this
class presents the characteristic structure.
That of the camel (fig. 18 b) agrees in struc-
ture with the type of wool from the sheep
(fig. 22) in its softness, flexibility and wavi-
ness, and in the distinctness of the cortical
cells.

HAIR.

[ 311 ]

HAIR.

Edentata (figs. 23 & 24). The difference
between the hair of the three-toed sloth
(fig. 23) and that of the armadillo (fig. 24)
is well-marked. In the former , the cortical
cells take a remarkably oblique or radiating
course, whilst in the latter they run longitu-
dinally.

Rodentia (figs. 25-35). In this Class the
pigment is met with sometimes in the me-
dulla, at others in the cortex. The arrange-
ment of the air-cells is often very beautiful,
and has rendered these hairs favourite micro-
scopic objects. Portions of a mouse-hair in
various parts of its length are represented in
fig. 27, a forming the free end. Fig. 28 dis-
plays two portions of the same hair as ana-
lysed by treatment with solution of potash.
The cortical parts have not been resolved into
their component cells ; whilst those of the
medulla have assumed their rounded and
natural form, and exhibit minute granules of
pigment, with larger globules of fat. The
arrangement of the medullary cells in two
rows is seen in fig. 286. The pigment
within the cells in situ is seen in fig. 31 b,
from the rabbit. The wool presents its cha-
racters in a marked degree ; the projection
of the outer layer of cortical cells, and the
distinctness of the medullary air-cells being
very evident.

Marsupialia (figs. 36 & 37). In this
curious class the hair greatly resembles that
of the rodents. That of the Kangaroo pre-
sents very beautifully imbricated cortical
cells (fig. 36).

Monotremata. The structure of the hair
of the Ornithorhynchus is as peculiar as that
of the animal in general. It presents that of
hair and wool combined (fig. 38). The basal
portion resembles wool, and is very long and
narrow ; the structure of two pieces in dif-
ferent parts of its length is seen in fig. 38 c
and d. At the end of this portion is attached
the proper hair containing the pigment
within the cortical substance (b) ; fig. 38 *
represents the surface-view of the hair,
showing the imbricated scales.

In Birds the hair is replaced by FEATHERS.

The hair of the Invertebrata does not
present the same structure as that of the
higher animals. Some physiologists have
therefore limited the term hair to the filiform
epidermic formations of the Mammalia;
whilst others admit the occurrence of hair in
all classes of the animal kingdom. At all
events, the hairs of the Invertebrata are not
usually composed wholly of epidermis. They
consist of an outer cortical or epidermic

layer, frequently coloured, and upon which
their firmness depends ; lining this, is
sometimes a prolongation of the cutis ; at
others a colourless substance, which, when
the hair is dried, presents an irregular cell-
like appearance and contains air, so as to
resemble the air-cells of the hair of the
Mammalia. In other instances the hair is
completely solid, but exhibits no trace what-
ever of cell-structure. It remains to be
shown whether the latter may represent the
epidermis hardened in an amorphous state ;
and whether those lined with cutis may be
regarded as epidermic formations upon an
exserted papilla of the skin; whilst those
presenting the air-cells when dried correspond
to an outer hardened epidermic layer, and an
inner retaining its distinctly cellular state.
In those lined with cutis, the circulation can
sometimes be observed.

We have only space to notice a few in-
stances of variety of form, many of which
occur, and have long rendered these hairs
interesting and elegant microscopic objects.
Thus, in some of the Arachnida they are
feathery, giving off slender lateral branches,
as in Lycosa (PI. 22. fig. 41), Epeira (PL 2.
fig. 8 a), Acarus (PI. 2. fig.l b), &c.; in others
these branches are directed forwards near the
middle of the shaft, but recurved at the end,
as in My gale (the bird-catching spider) (PL
22. fig. 4 1 ); or while the branches on the shaft
resemble the above, the end of the hair is
thickened, cylindrical and longitudinally stri-
ated, with minute setae arising from the striae,
as in fig. 42; again, some of them are simple,
but furnished with spiral striae (Epeira,~PL2.
tig. 86); in Trombidium they are sometimes
very elegantly feathery.

In Insects, Arachnida, &c., they often ap-
pear to arise from a bulb at the base, but
the bulb is annular, not solid, and bears no
resemblance in structure to the bulb in the
Mammalia; it consists of a thickening or
fold of the epidermis of the skin, not of the
hair, from which it is separated by a white
ring, indicating thinness of this coat, and
often corresponding to a joint; the hair
arises from the base of a depression situated
within the annular bulb. The hair of the larva
of Dermestes is very beautiful, and is used as a
TEST-OB j ECT. Two forms are met with : in
one (PL 1 . fig. 1 c) the shaft is simply covered
with densely aggregated, minute, spinous,
secondary hairs; in the other (PL 1. fig. 1
a, b), the spines or scales upon the shaft are
narrow, acute, and placed in pretty regular
whorls ; in the uppermost whorl they are

HATR.

[ 312 ]

HAIRS.

broader, the spines remaining as midribs,
whilst the margins are more developed, the
whole resembling a flower with four or five
petals ; but at the end of the hair, the scales
are longer, narrower, and recurved, each
midrib being terminated below by a little
knob.

The examination of the hair, and its dis-
section can only be effected by the aid of
chemical reagents, especially sulphuric acid,
solution of potash or of soda. These should
first be used cold, and if no separation of
the components ensues, heat even to boiling
must be applied ; the subsequent addition of
water is sometimes advantageous. Sections
of hair can be made with a razor, a bundle
of hair being fixed between two flat pieces of
cork, or between two cards. Transverse
sections of the human hair can be obtained
by shaving a second time, an hour or two
after the first ; the sections should then be
washed in water. The cortical cells are most
beautifully seen in white hairs which have
been thoroughly soaked in oil of turpentine,
and mounted in Canada balsam. The air-
cells of the medulla are best observed in
hairs which have been mounted in balsam
without the previous application of turpen-
tine. The sheaths of the hair keep best in
solution of chloride of calcium.

Many of the structures of the hair of the
Mammalia may be well observed in the large
hairs or bristles (whiskers) of the ox, &c. ;
in these also the pulp is seen to contain
blood-vessels, which have not been detected
with certainty in that of man.

The hairs of some animals polarize light.
An interesting object of this kind may be
made by placing two series of the white
hairs of a horse in balsam, so as to cross
each other at an angle, and viewing them
by polarized light (PI. 31. fig. 39).

In regard to the discrimination of the
hairs of one animal from those of another,
we believe that the examination of individual
hairs can in general be but little depended
upon; whilst a comparison of their form,
length and breadth, with the proportion of
the true hair to that of the wool, conjoined
with the consideration of the internal struc-
ture, might sometimes enable an observer to
arrive at a satisfactory conclusion.

BIBL. Kolliker, Mikrosk. Anat. i.; Eble,
Die Lehre v. d. Haar. in d. gesammt. orga-
nisch. Nature Henle, Allgem. Anat., and
Fror. Notiz. 1840; Todd & Bowman, Phys.
of Man; Erdl, Abh. d. Akad. in Miinchen,
Bd. iii. ; Paget, Brit, and For. Med. Rev.

1842, &c.; Huxley, Med. Gaz. 1845; Grif-
fith, Med. Gaz. 1848; Heusinger, System
d. Histologies Gurlt, Mull. Archiv, 1836;
Aikin, Arts and Manufactures; Donders,
Mulder's Physiologische Chemie.

HAIRS, OF PLANTS. — The term hair is
applied in botany to filamentous productions
upon the surface of the organs of plants,
consisting of one or more cells arising out
of and constituting part of the epidermal
structure. Hairs of plants present a great
variety of conditions ; in the simplest kind,
those composed of a simple, cylindrical, co-
nical, bifurcated or stellate cell, they may be
varied inform by the peculiar shape of the
constituent cell, in individual character by
the presence or absence of special secretions
in the cell-cavities, and in their collective
character by the mode of arrangement on
the epidermis, since they may be few and
scattered, or so numerous as to form a vel-
vety coat. Compound hairs, namely those
composed of a number of cells, vary in like
manner, and, moreover, in the examples
where the cell-walls acquire considerable
thickness, pass gradually from pure hairs
into bristles, and thence into the structures
called THORNS (distinguished from true
spines by being appendages of the epider-
mis). The stellate forms also present many
variations intermediate between hairs proper,
and SCALES.

These structures are interesting to the
microscopist on account of the variety and
often extreme elegance or curiosity of their
forms. They likewise strongly attract the
attention of the physiologist from the sim-
plicity of their organization and their free
condition, allowing the phenomena pre-
sented by the cell-contents to be readily ob-
served under the microscope. In reference
to their characters as microscopic objects, it
will suffice to indicate their principal modi-
fications, and state a certain number of ex-
amples. For this purpose they may be
classified as follows : —

Simple hairs : unbranched. Cabbage-leaf
(Brassica, fig. 308), (Enothera, Dictamnus
(PL 21. fig. 39 a), Anchusa (PI. 21. fig. 17) ;
bifurcated, Capsella (PI. 21. fig. 36), Draba
(fig. 311); inflated or capitate, Antirrhinum
(fig. 310 and PL 21. fig. 34), Salvia (fig. 309) ;
Helleborus fcetidus ; branched, in many Cru-
ciferae, as Sisymbrium Sophia (PL 21. fig. 35),
Alternanthera axillaris (PL 21. fig. 37);
stellate, Alyssum (fig. 312). Very often hairs
composed of a single cell are supported upon
a short cell, and then developed horizontally

HAIRS.

[ 313 ]

HAIRS.

in two directions, as in Grevillia lithido-
phylla (PL 21. fig. 29); in several so as to
form a star, as in Deutzia scabra (PL 21.
fig-26); Alyssum (Pl.21.fig.28). Structures
analogous to the last occur upon the septa
of the air-cavities of the Nymphaeacese. such
as Nuphar lutea (PI. 21. fig. 15), Victoria,
&c.

Fig. 308. Fig. 309.

Fig. 310.

Hairs of:—
Brassica (leaf). Sal via (calyx). Antirrhinum (corolla).

Fig. 311.

Fig. 312.

Draba (leaf). Alyssum (leaf).

Magnified 100 diameters.

Compound hairs. These exhibit a similar
diversity of character, and often imitate, on
a larger scale, the forms of the simple hairs ;
they may be unbranched, as in the hairs of
the garden Pelargonia (PL 21. fig. 18), and
a large proportion of ordinary silky hairs
upon the epidermis of plants. COTTON is a
striking example, consisting of the hairs of
the seeds of Gossypium (PL 21. fig. 1).

Commonly these hairs are cylindrical, but
not unfrequently one or more of the upper-
most or all the component cells are expanded
into a more or less globular form. Capitate,
glandular, hairs often occur on corollas, and
particularly on the inner scales of leaf-buds ;
examples: the bulbils of Achimenes (PL 21.
fig. 32), the corolla of Digitalis (PL 21. fig.
33), Lysimachia vulgaris (PL 21. fig. 40),
Scrophularianodosa (PL 21. fig. 41), Bryonia
alba (PL 21. fig. 42), the inner scales of the
winter leaf-buds of the ash, &c. Or the
hairs are torulose, as in Lamium album, the

common white Dead-nettle; or moniliform
or necklace-shaped, as on the stamens of
Tradescantia (fig. 315), the Marvel of Peru
(Mirabilis, fig. 313). The transition from
these to the branched forms are presented
commonly in the simpler forms of the pappus
of the Composite, as in that of the Ground-
sel, which has toothed hairs ; in other exam-
ples the lateral teeth grow out into branches,
as in the species of Hieracium and other
Composite, presenting pinnate or plumose
forms, according to the extent of ramifica-
tion. Verbascum Lychnitis (PL 21. fig. 19)
has compound hairs branched at the joints.
Compound hairs likewise exhibit the hori-
zontal development ; the hairs of the garden
Chrysanthemum are horizontal, navicular
cells, supported on a tall articulated pedicle
(PL 21. fig. 30)j the stellate hairs of the Ivy
(PL 21. fig. 27) are compound, and sup-
ported on a short stalk-cell. The last form
a transition to the scales of the Eleagnaceae
and many ferns.

Fig. 313.

Fig. 314.

Fig. 315.

Hairs of : —

Mirabilis. Antirrhinum (calyx). Tradescantia v stamen).
Magnified 100 diameters.

The hairs above noticed are mostly soli-
tary. In the Malvaceae (Hibiscus] tufted or
stellate groups of hairs are met with, and in
the air-cells of Utricularia are seen curious
groups of four hairs. Marrubium creticum
is another example of this kind of structure
(PL 21. fig. 47).

Almost all of the above- described forms
of hair may contain merely watery, colour-
less or coloured contents ; or they may have
one or more of the component cells filled
with special, oily, resinous or saccharine secre-
tion. In the latter condition they are termed
glandular hairs. The character of these
organs are spoken of under the head of
GLANDS andSECRETiNcORGANS of Plants.
It has not been thought worth while to sepa-
rate them in this article.

HAIRS.

[ 314 ]

HAIRS.

Some of the hairs with watery cell-con-
tents present favourable opportunities for ob-
serving the ROTATION of the protoplasm; for
example, the young hairs of the stamens of
the Tradescantia (or spider-wort of gar-
deners) before they have acquired their mo-
niliform character and dark contents; the
stinging hairs of nettles also show this when
young, and probably it might be observed
in all young hairs, where sufficiently trans-
parent and uninjured. One precaution
greatly facilitates the observation, namely,
to dip the hairs into alcohol for an instant,
and immediately plunge them in water;
after this operation, the structure is readily
wetted by water, and no longer obscured by
the abundance of air-bubbles that remain
entangled with and adherent to the surface
of the fresh hairs. These young hairs like-
wise exhibit at their apices the various con-
ditions of the contents (nucleus, protoplasm,
&c.) of cells multiplying by division (PL 38.
figs. 8 & 9). The circulation takes place in
the dark streaks represented as forming a
network connected with the nuclei (ri).

Stings, such as those of the Nettle (PI. 21.
fig. 8), consist of simple cells having a
bulbous base enclosed in a cellular case,
formed by the growing-up of the epidermis
round the base of the hair ; the latter tapers
away upward to near the apex, where it
again expands into a little globular head.
The walls are rather thick and spirally stri-
ated. The bulbous base is filled with the
irritating liquid, which exudes when the
knob-like head is broken off, through the
tension of the cellular investment of the sac.

The intimate structure of the hairs of
plants presents many points of interest. The
cells are of course composed of a cellulose
wall, with contents varying according to age
and other circumstances. When young,
they are always densely filled with protoplasm
(PL 38. figs. 8 & 9), which becomes gradu-
ally excavated by vacuoles, and expanded
so as to form a mere reticulation or a few
streaks upon the wall, mostly connected with
an evident nucleus. The cavity of the cell
is then filled, in hairs proper, with watery
cell-sap, sometimes coloured, as in the petals
and stamens of many flowers, by the same
liquid colouring matter as the cells beneath
the epidermis ; stings are filled with acrid,
watery juice ; glandular hairs with various
secretions, which, like the watery juices, ap-
pear at first in vacuoles, gradually occupying
the place of the protoplasm, which follows
the expanding cell- walls.

Hairs, being epidermal structures, possess
a more or less evident cuticular layer, which
may be detached by the action of acids
(fig. 203. p. 237) ; sulphuric acid often causes
this to separate and expand as a kind of vesicle
from the surface of the hair, as is shown in
fig. 13. PL 21 (Siphocampylus) ; the cuticle
of the full-grown moniliform hairs of Tra-
descantia may be separated in like manner
(see EPIDERMIS). This cuticle also exhi-
bits in many cases the same markings which
occur on the surface of the epidermis of cer-
tain plants, as Helleborus, Cakile, &c. (PL 21.
figs. 9 & 10), consisting of elevated spots,
ridges, reticulations, &c., composed entirely
of thickenings of the cuticular layer. This
is well seen in the hairs of the Boraginaceae,
e.g. Anchusa (PL 21. fig. 17), the Cruciferae,
as of Farsetia, Cheiranthus, &c., or Delphi-
nium (PL 21. fig. 16). The spiral strige on
the sting of Urtica urens (PL 21. fig. 8) ap-
pear to be of similar nature.

Finally, it is necessary to mention the
remarkable structure of the hairs upon the
surface of the seeds and pericarps of certain
plants among the Acanthaceae, Polemo-
niaceae, Labiatae, Compositae, &c. Those of
the ACANTHACE^E have been spoken of
partly under that head and under ACANTHO-
DIUM. They are hairs composed of cylin-
drical cells, simple (Ruellia, PL 21. fig. 21),
or conjoined into a compound and branched
hair (Acanthodium, PL 21. fig. 24), the cell-
walls of which receive when young a spiral
(fig. 24) or annular (fig. 21) fibrous deposit,
and subsequently become partially disor-
ganized; so that if placed in water in the
mature state, the primary cell-wall almost
dissolves into a kind of jelly, and the spiral-
fibrous structure expands with elasticity.
The conditions are similar in Collomia ( PL 2 1 .
fig. 22), and according to Schleiden, in Gilia,
Ipomopsis, Polemonium, Cantua, &c. among
the Polemoniaceae, and somewhat the same in
many species of Salvia (PL 21. fig. 23), Ocy-
mum, Dracocephalum moldavicum,&c. among
the Labiatse. In Cobcea scandens, the spiral-
fibrous hairs take rather the form of minute
scales, and they do not spontaneously ex-
pand elastically (PL 21. fig. 20). Among
the Compositae, these spiral-fibrous hairs
have been observed on the pericarp of Ruc-
keria, some species of Trichocline, Euriops,
Mesogramma, Doria Cluyticefolia, Oligothrix
gracilis, and some species of Senecio. Spiral
cells also occur on the seed of Hydrocharis.
The best way to observe the elastically ex-
panding hairs is to place a thin slice of the

HALICHONDRIA.

[ 315 ]

HALYMENIA.

skin of the seed on a slide, in a little alcohol,
which does not soften the cell- wall; when
the object is focused, the addition of a little
water causes the gelatinous softening of the
cell-walls, the spiral fibres fly out from the
surface of the seed-coat, and show clearly
the character of these beautiful objects.
The primary membrane may be detected even
in its gelatinous state, by adding sulphuric
acid and iodine, which produce a purplish
or violet colour. Further remarks on this
head will be found under SPIRAL STRUC-
TURES.

The hairs on the stigma of Campanula
are remarkable for the intussusception which
is observed to take place in mature hairs.
The filiform processes growing from the
under surface of the frondose Hepaticacea3,
the thallus of Lichens, the prothallium of
Ferns, &c., are commonly called radicle
hairs. In most cases they present no re-
markable points of structure ; in Marchantia,
however, peculiar spiral markings have been
detected (see MARCHANTIA).

BIBL. General Works on Structural Bo-
tany; Meyen, Secretions-organe der Pflan-
zen, Berlin, 1837, Pflanzen -physiologic ;
Cohn, de Cuticula, Linncea, xxiii. 337, 1850 ;
Schleiden, Beitriige zur Phytogenesis, Miil-
ler's Archiv, 1838, Beitr. z. Botanik, Leip-
sic, 1844, i. p. 121 (Transl. in Scientific Me-
moirs) ; Decaisne, Ann. des Sc. nat. 2 ser.
xii. 251. pi. 4; Leighton, Ann. Nat. Hist.
vi. p. 257; Brongniart, Ann. des Sc. nat.
2 ser. xii. p. 244. pi. 4.

HALICHONDRIA, Flein.— A genus of
SPONGES.

HALIDRYS, Lyngb.— A genus of Fuca-
cese (Fucoid Algae), containing one British
species, H. siliquosa, common on rocks and
stones somewhat above low-water mark. It
is readily distinguished by its pod-like, sep-
tate air-vessels. The fructification, which is
terminal on the branches, much resembles
that of Fucus, except that the interior of
the receptacles is filled up with firm poly-
gonal cellular tissue. The antheridia, more-
over, are terminal on their pedicels, often in
tufts, short in form, and intermixed with
spore-sacs in the same conceptacle.

BIBL. Harvey,JBr.M«r.^%.p.l5.pl.lC;
Thuret, Recherches sur les Antheridies, Ann.
des Sc. nat. 3 ser. xvi. p. 8. pi. 3.

HALIONYX, Ehr.— A genus of Diato-
maceae.

Char. Frustules single ; valves equal, or-
bicular, surface radiate, a certain number of
the rays not commencing at the umbilicus ;

no internal septa ; umbilicus not reached by
the rays. Marine.

H. senarius. Rays six, the intervening
spaces with shorter rays of equal length pa-
rallel to the larger, and with transverse laxly
cellular lines; umbilicus punctate, entire;
diam. 1-720".

H. duodenarius. Rays twelve.

Probably forms of Arachnoidiscus.

BIBL. Ehr. Ber. d. Berl. Akad. 1844.
p. 198.

HALISERIS, Tozzetti. — A genus of Dic-
tyotaceae (Fucoid Algae), containing one Bri-
tish species, with a brownish-olive, some-
times forked frond, with a midrib, from 4" to
1' high, having a very powerful, offensive
smell when fresh. The fructification is pro-
duced in sori, arranged in lines on each side
of the midrib, or scattered, containing large
spores. (This requires further examination.)

BIBL. Harvey, Br. Mar. Alg. p. 36.
pt. 6 B.

HALTERIA, Dujj.— A genus of Infusoria,
of the family Keronia.

Char. Body almost spherical or top-
shaped, surrounded by long, very delicate,
retracting cilia, which, by becoming adherent
to the slide, and suddenly contracting, cause
it to change its place suddenly, as if by leap-
ing. A row of oblique very large cilia situ-
ated at the circumference of the body.

H. grandinella (=Trichodina grandinella,
Ehr.) (PI. 41. figs. 11, 12). It has two kinds
of appendages on its surface : 1, straight,
excessively delicate, radiating cilia, which
appear to be the cause of its movements,
which are so sudden, that, even with the
utmost attention, it cannot be ascertained
how they are produced ; 2, very large cilia,
arranged obliquely at the circumference of
the body. Aquatic. Greatest breadth.
1-850".

Stein points out the resemblance of this
animalcule to the swarm-germs of&nAcineta
found upon Cyclops.

BIBL. Dujardin, Infus. p. 414; Stein,
Infus. p. 54.

HALYMENIA, Ag.— A genus of Cry-
ptonemiaceae (Florideous Algae), containing
one British species, found on the southern
shores. It is a somewhat palmate, mem-
branous, rose-coloured sea-weed, usually
from 6 to 12" long, composed of a double
membrane, the layers being separated by a
loose network of jointed filaments. The
fructification consists of favellidia buried in
the frond, attached to the inner surface of
the membranous laminae ; scattered all over

HAPLARTA.

[ 316 ]

HELIOPELTA.

the frond, appearing to the naked eye like
red dots.

BIBL. Harvey, Brit. Mar. Ala. p. 148.
pi. 19 D.

HAPLARIA, Link.— See BOTRYTIS gri-
sea.

HAPLOMITRIUM, Nees.— A genus of
Jungermannieae (leafy Hepaticacese), contain-
ing one British species, H. (Jungermannia)
Hookeri, an . Alpine plant, which has been
carefully studied by Gottsche. It is remark-
able for having leaves (without amphigastres)
inserted on all sides of the stem. The ter-
minal capsule emerges at length from a large
oblong fleshy epigone (fig. 332). The an-
theridia (fig. 327) occur in the axils of the
leaves. They have a double coat, the inte-
rior of which consists of reniform cells (fig.
326), which become isolated and more or less
dissolved. The spermatozoids, produced in
minute vesicles (fig. 328), resemble those of
the Mosses.

BIBL. Hooker, Brit.Jungermannite, pi. 54 ;
Ekart. Synops. Jung. pi. 8. fig. 65 ; End-
licher, Gen. Plant. No. 474-3; Gottsche,
Nova Acta, xx. p. 265. pis. 13-20.

HAPLOTRICHUM, Link.— A genus of
Mucedines (Hyphomyce- p-
tous Fungi), intermediate
in structure between Bo-
try tis and Aspergillus.
The spores are developed
from a capitate cell termi-
nating the septate erect „
fertile filaments (fig. 482). /Q

BIBL. Corda, Icon, y^f
Fung.-, Nees,Syst.d.Pilze,
pi. 4; Fries, SummaVeget.

P- 470. Haplotrichum roseum.

Magn. 200 diams.

HARVEST-BUG. TROMBIDIUM au-

tumnale.

HASSALLIA, Berk.— See SIROSIPHON.

HAVERSIAN CANALS. See BONE.

HEART.— The muscular fibres of the
heart present certain peculiarities. The
primitive bundles are more slender than
usual ; they frequently anastomose, and con-
tain normally a few minute granules of fat ;
the transverse striae are also often indistinct.
In disease the fatty matter is often extremely
abundant (PL 30. fig. 14 a), and the striae
are more or less obliterated.

BIBL. Kolliker, Mikroskop. Anat. ii. ;
Forster, Handbuch d. path. Anat.; Wedl,
Grundz. d. path. Histol. ; Quain, Med. Chi.
Trans. 33; Rokitansky, Handb. d. path.
Anat.

Fig. 317.

HEDWIGIA, Hook.— A genus of Mosses.
See ZYGODON.

HELICOMA, Corda.— A genus of De-
matiei (Hyphomycetous Fungi) with the
spores curled into a spiral. Mr. Berkeley
considers the distinction between Helicoma
and Helicosporium scarcely tenable, and
Fries includes Helicoma Miilleri, Corda,
under Helicosporium. This plant has been
found on dead wood in this country.

BIBL. Corda, Icon. Fung. i. pi. 4. fig. 219 ;
Berkeley and Broome, Annals Nat. Hist.
2nd ser. vii. 98 ; Fries, Summa Veget. p. 500.

HELICOSPORIUM, Nees.— A genus of
Dematiei (Hyphomycetous Fungi), growing
on decayed wood, nearly related to Helicoma
and Helicotrichum. Helicoma and Helico-
sporium are described as having erect fertile
filaments, Helicotrichum creeping branched
filaments, but the distinctions are obscure,
as also those between Helicoma and Helico -
sporium, the first of which should have the
spirals closed, the latter open. Fries and
Berkeley both include Helicotrichum under
Helicosporium. Br. species

1. H. pulvinatum, Fr.
(fig.317). Formingablack-
ish or olive pulvinate stra-
tum over wood, with slen-
der branched filaments,
bearing yellowish- green
strings of sporidia coiled
up into a spiral of about
three turns, very fugacious
(Helicotrichum pulvina-
tum, Nees).

2. H.vegetum,¥r. Wide-
ly pulvinate-effused, sub- Helicosporium puM-
olivaceous, at length black ; natum.
fertile filaments erect, stiff, Maen; 20° diams-
subulate ; spores coiled into a ring, 3-sep-
tate, greyish green.

BIBL. Berk. Hook. Brit. Fl. vol. ii. pt.2.
p. 335 ; Ann. Nat. Hist. vi. 434, 2nd ser.
vii. p. 98 ; Fries, Syst. Myc. iii. p. 353,
Summa Veg. 500 ; Corda, Sturm. Deutschl.
Flora, 3 ser. ii. pi. 15 & 16; Nees, Nova
Acta, ix. 246. pi. 5. fig. 15, Sy sterna My col.
p. 68. fig. 69.

HELICOTRICHUM, Nees. See HELI-
COSPORIUM.

HELIOPELTA, Ehr.— A genus of Dia-
tomaceae.

Char. Frustules single (?), orbicular in
side view, internally furnished with imper-
fect radiating septa, the alternate interme-
diate portions of the valve being depressed ;
valves angular and not furnished with mark-

HELLEBORUS.

[ 317 ]

HEMIAULUS.

ings in the centre, but with as many large
submarginal apertures (?) as there are rays,
and with numerous erect opposite submargi-
nal spines on each side. The spines connect
the pairs of young frustules !

H. metii. Frustules with six septa and
rays, three of the intervals raised and coarsely
cellular, the alternate ones impressed with
fine decussating lines, the limb of the radiate
margin broad ; marginal spines in the middle
of each cellular interval one or three, in the
others two or four ; umbilical star slightly
angular; diameter 1-370". Bermuda.

Three othev species, with a different num-
ber of rays.

The different appearances of the markings
upon the elevated and depressed portions of
the valves evidently arise from the existence
of the ordinary depressions seen naturally by
oblique and direct light.

BIBL. Ehrenberg, Ber. d. Berl. Akad.
1844. p. 262.

HELLEBORUS, L.— A genus of Ranun-
culaceae. The cuticular layer of the epider-
mis of the leaves of H.fcetidus exhibits cu-
rious waved ridges (PI. 21. fig. 9). See
EPIDERMIS, of Plants.

HELMINTHOSPORIUM, Link.— A ge-
nus of Dematiei (Hyphomycetous Fungi)
growing on rotten wood, &c., of which nu-
merous species are found in Britain. The
mycelium is often somewhat gelatinous or
indistinct ; on it arise (often aggregated)
erect, rigid, septate filaments (fibres), on the
summits of which stand large, often club-
shaped septate spores. Br. species :

1. H. macrocarpum, Grev. (Grev. Sc.
Crypt. FL pi. 148. fig. 1).

2. H. subulatum, Nees (Nees, Nova Ac-
ta, ix. pi. 5. fig. 13).

3. H. Clavariarum, Desm. (Desmazieres,

Ann. des Sc. nat. 2 ser. ii. pi. 2. fig. 2).

(Grev. -Sc. Crypt.
FL pi. 148. fig. 2).

4. H. velutinum, Link (<

5. H.fusisporium, Berk. (Br. F/ora,vol. ii.
part 2. p. 336).

6. H. nanum, Nees (Nees, Nova Acta, ix.
pi. 5. fig. 13 B ; System, fig. 65).

7. H. simplex, Kunze (Nees, I. c. fig. 11).

8. H. Tilite, Fr. (Berkeley, Annals Nat.
Hist, vi.pl. 13. fig. 18).

9. H. folliculatum, Corda (Corda, Icon.
Fung. i. pi. 3. fig. 180).

10. H. obovatum, Berk. (Ann. Nat. Hist.
vi. pi. 13. fig. 19).

11. H. delicatulum, Berk. (I. c. fig. 20).

12. H. Smithii, Berk. & Broome (Ann.
Nat. Hist. 2 ser. vii. pi. 5. fig. 5).

13. H. turbinatum, Berk, and Br. (I. c.
fig. 6).

14. H. Rousselianum, Montagne (Ann. des
Sc. nat. 3 ser. xii. p. 300).

15. H. sticticum, Berk, and Br. ( Ann. Nat.
Hist. 2nd ser. xiii. pi. 15. fig. 10).

BIBL. Berkeley, Brit. Flora, iii. pt. 2.
p. 336 ; Fries, Systema, iii. p. 354, and Sum-
ma Veget. p. 500, and the works above cited.

HELMINTHOSTACHYS, Kaulf. — A
genus of Ophioglossaceous Ferns, distin-
guished by the complex spikes bearing
crested sporanges.

Fig. 318.

Fig. 319.

Helminthostachys zeylanica.

Fig. 318. Fragment of a spike with sporanges. Magni-
fied 10 diams.
Fig. 31Q. A portion still more magnified (20 diams).

HELVELLACEL— A family of Ascomy-
cetous Fungi, approaching to the Hymeno-
mycetes in outward form, but distinguished
at once by their fructification. See Asco-
MYCETES, SPATHULEA, LEOTIUM, STIC-
TIS, PROPOLIS.

HEMELYTRA. — The anterior pair of
wings of the Heteropterous division of the
Hemiptera. See INSECTS.

HEMEROBIUS, Linn.— A genus of Neu-
ropterous Insects.

Hemerobius ( Chrysopa] perla, one of the
lace- winged flies, has very thin, transparent,
and beautifully netted iridescent wings, in
which the circulation can be well observed ;
the wings also exhibit well the tracheae in
the veins. The larva feeds upon Aphides.

BIBL. Westwood, Introduction &c. ;
Bowerbank, Entom. Mag. iv.

HEMIAULUS, Ehr.— A genus of Diato-
maceae.

Char. Frustules single, compressed, sub-
quadrate, with two tubular processes on each
side, the ends of those (the shorter) on one
side being open, the others closed ; not con-
stricted at the sides.

HEMIONITIS.

[ 318 ]

HEPATICACEJE.

H. antarcticus (PL 19. fig. 3).

The species (two) appear to consist of
EiddulphicB, with the ends of two of the pro-
cesses broken off. Ehrenberg remarks that
in one specimen he could not detect the
apertures, perhaps on account of the position
not being suitable !

BIBL. Ehrenberg, Eer. d. Berl. Akad.
1844, p. 199.

HEMIONITIS, Linn.— A genus of Gym-
nogrammese (Polypodaeous Ferns) with a
very elegant reticulated arrangement of the
sori.

HEMIPTERA.— An order of INSECTS.

HEMIPTYCHUS, Ehr.— See ARACH-

NOIDISCUS.

HEMITELIA, Presl.— A genus of Cya-
thaeous ferns. Exotic.

HEMIZOSTER, Ehr.— A genus of sili-
ceous fragments of some unknown substance
or body !

BIBL. Ehrenberg, Eer. d. Eerl. Akad.
1844. p. 199.

HEMP.— The ordinary name of the fibre
of Cannabis sativa, consisting of the liber-
fibres of this plant (PI. 21. fig. 6). It is ap-
plied to some other substances used for the
same purposes, e. g. Manilla-hemp (the fibre
of MUSA) &c. See TEXTILE FIBRES and
LIBER.

HENDERSONIA, Berkeley (Sporoca-
dus, Corda, in part). A genus of Sphaero-
nemei (Coniomycetous Fungi), interesting
as having furnished one of the earliest dis-
covered examples of two forms of fructifica-
tion, leading to the abolition of the distinc-
tion between Coniomycetous and Ascomyce-
tous Fungi (CONIOMYCETES). Mr. Berke-
ley has seen two conditions of spores in H.
mutabilis, and he states that Fries informs
him of the observation of asci and septate
naked spores conjointly in Hendersonia Sy-

Fig. 320.

Hendersonia.

Spores on the perithecium.
Magnified 200 diams.

ringa. Several British species have been

described. They form dark spots or patches
on the stems of herbs or twigs of trees ; the
dark matrix having a perithecium excavated
in it, lined by a gelatinous stratum, on which
stand stalked fusiform septate spores (fig,
320).

1. H. elegans, Berk. (Ann. Nat. Hist. vi.
pi. xi. fig. 9). On the culms of reeds.

2. H. macrospora, Berk, and Broome (I. c.
2nd ser. v. p. 3/3). On dead twigs of Phi-
ladelphus.

3. H. arcus, Berk, and Br. (I. c.). On Box
twigs.

4. H. mutabilis, Berk, and Br. (I. c.). On
dead twigs of Plane.

5. H. polycystis, Berk, and Br. (/. c.). On
dead twigs of Birch.

6. H. macropus, Berk, and Br. (I. c.). On
dead leaves of Carex.

7. H. typhoidearum, Desm. (Desmazieres,
Ann. des Sc. nat. 3rd ser. xi. 344). On dead
leaves of Typha, &c.

8. H. Stephensii, Berk, and Br. (Ann. Nat.
Hist. 2 ser. viii. p. 95). On dead stems of
Pteris aquilina.

9. H. fibriseta, Berk. (Hooker's Journal
of Botany, iv. p. 43). On Birch planks.

BIBL. Berkeley and Berk, and Broome,
Annals Nat. Hist. 1. c. ; Hooker's Journal
of Botany, iii. 319; Fries, Summa Veget. 416.

HEPATICACE^E. — An order of the
Muscales (Cryptogamous Plants), consisting
of plants of "small size, varying much in
structure, inhabiting damp spots on the
ground, rocks, or trees, or floating on water.

The vegetative structure of the lowest
forms consists simply of a patch of green
membrane, spreading over the ground, com-
posed of a single (Anthoceros leevis) or dou-
ble (Sphcerocarpus terrestris) layer of cells
containing chlorophyll. In Marchantia
(see MARCHANTIA) there is an advance;

Fig. 321.

Fig. 322.

Fimbriaria fragrans.

Fig. 321. Lobe of a frond. Nat. size.
Fig. 322. Section of frond, showing two immersed
antheridia. Magnified 40 diams.

the frond not only exhibits more definitely
characterized lobes, but also a considerable

HEPATICACE.E. [ 319 ] HEPATICACE^.

meet, if prolonged across the stem, in the
form of a V (fig. 324).

The leaves are very frequently imbricated,
and they overlap in two ways : either each
leaf covers with its lower edge a little of the
leaf below it, or each leaf overlaps a little of
the base of the leaf above it. In the first
case, the leaves are called succubous (fig.
324), in the second, incubous (fig. 325). The
leaves vary much in form, and are often
deeply toothed or bilobed, and form exceed-

Fig. 324. Fig. 325.

thickness and a complexity of internal struc-
ture, since it possesses an epidermis invest-
ing both surfaces, and containing stomates
on the upper (see STOMATES). The lower
epidermis is also provided with numerous
radical hairs (see HAIRS and SPIRAL STRUC-
TURES). Fimbriaria (fig. 322), Lunularia
(fig. 323), &c., likewise possess thick cellular
fronds. In Riccia the frond also presents
a reticulated upper face provided with sto-

Fig. 323.

*%*

Lunularia vulgaris.
A frond in fruit. Nat. size.

mates, but the form of the entire frond is
usually elongated and bifurcated, and a slight
groove runs along the middle line, almost
like a mid-nerve. This central line exhibits
a difference in the internal cellular structure,
since it is composed of elongated cells, while
the surrounding green substance is composed
of spherical cells, such as constitute the en-
tire mass enclosed between the upper and
lower epidermis of the frond of Marchantia.
The groove on the upper face (of Riccia)
corresponds to a rib on the lower face, from
which arise most of the radical filaments,
while they are scattered indiscriminately
over the lower face of Marchantia; and
from this line also arise the little bodies re-
sembling minute leaves, called amphigastres.
If we suppose the frond of Riccia elongated
and the mid-nerve more strongly marked,
we have the likeness of Bfytia Lyellii (fig.
63, p. 87) ; while if this latter were notched
down to the rib at intervals along each side,
we should have the stem with two parallel
rows of leaves, as in the Jungennanniese.

The line of insertion of the leaves is sel-
dom exactly parallel with the axis of the
plant, and very rarely at right angles. In
most cases it is more or less oblique, and
the obliquity is in reverse direction at the
two sides of the stem, so that the lines of
insertion of two succeeding leaves would

Fig. 324. Radula complanata. Magn. 5 diams.
Fig. 325. Plagiochila undulata. Magn. 5 diams.

ingly elegant objects under the microscope.
The leaves are accompanied in many cases,
chiefly in the Jungermannieae, by stipule-like
leaflets, called amphigastres, situated at the
under side of the stem.

These plants are reproduced by dust-like
grains called spores, by minute cellular no-
dules called gemmce, and by innovations, i. e.
new lobes growing out from the margins of
the old fronds, or buds in the axils of leaves,
or on confervoid branches sent out from the
stem.

The gemmce of Marchantia polymorpha are
produced in elegant membranous cups, with
a toothed margin, growing on the upper
surface of the frond, especially in very damp
and imperfectly lighted situations ; they are
little cellular nodules at first attached by a
stalk, and at a certain period fall off and
grow up into a new frond. (See MARCHAN-
TIA.)

The spores are produced in sporanges or
capsules, the formation of which is preceded
by special anatomical and physiological phae-
nomena demonstrating the existence of di-
stinct sexes in these plants. The organs

HEPATICACE/E.

[ 320 ]

HEPATICACE^E.

which represent the anthers of flowering
plants are called antheridia, those which re-
present the ovules, and produce the spore-
cases, are called archegonia or pistillidia.
The antheridia are small globular or oval
bodies, more or less stalked, which in the
Jungermanniese are composed of a double
layer of cells forming a membranous sac,
which, when ripe, bursts and discharges
numerous minute globular cellules, each of
which again bursts and discharges an ex-
tremely small filament, which moves about
actively in water (figs. 327 & 328). These

Fig. 326.

Fig. 327.

Fig. 328.

Haplomitrium Hookeri.

Fig. 326. Axillary antheridia. Magn. 30 diams.
Fig. 327. Fragment of wall of antheridia ; the reniform
loose cells belong to the inner layer. Magu. 200 diams.
Fig. 328. Spermatozoids from ditto. Magn. 200 diams.

organs mostly occur in the same situations
as the archegonia, and in some of the fron-
dose forms, such as Anthoceros, Eiccia,
Fimbriaria (fig. 322), &c., they are imbedded

Fig. 329. Fig. 330. Fig. 331.

Marchantia polymorpha.

Archegonia in various stages.

Magnified 100 diameters.

in the substance of the frond ; in others, as
in Marchantia, they are immersed in the
upper part of special male stalked receptacles
(see MARCHANTIA) ; in the leafy forms,
they are free in the axils of the leaves (fig.
327).

The archegonia or pistillidia are likewise
developed in various places, indicated here-
after in the tabular view of the families.
They consist of a kind of flask-shaped cellu-
lar case (figs. 329 to 331), enclosing at first a
single cell (embryonal cell), which subse-
quently grows into a sporange, apparently
after one or more of the spiral filaments of
the antherids have come in contact writh it,
by passing into the neck of the flask-shaped
sac (epigone). The embryonal cell becomes
increased by cell-division into a globular
cellular mass, which acquires various forms
in the different genera and families. The
epigone enlarges for a long time with the
growing capsule, completely enclosing it
(fig. 332), but after a time the latter bursts

Fig. 332.

Haplomitrium Hookeri.

Young sporange enclosed in the epigone.

Magnified 20 diameters.

through the top of the epigone, which thus
forms a kind of sheath round the base of the
sporange or its stalk, and is called the vagi-
nule. The epigone may tear irregularly, so
as to form an irregular vaginule or calyx, or
regularly, so as to present a circle of teeth ;
or it may be slit horizontally in a circle, and
half of it carried up by the sporange, which
it thus surmounts as a hood or calyptra.
This epigone is sometimes surrounded by
another envelope called the perigone. This
originates at a later period and in a different
way, since it gradually springs up as a cir-
cular sheath around the base of the epigone,
and by continued growth comes to surround
it as a kind of cup, like the corolla of a
flower (fig. 324). In Marchantia, only one
archegone is found in each perigone; the

HEPATICACE^E.

[ 321 ]

HEPATICACE.E.

perigones of Jungermanniese always enclose
several, but only one is developed into a
sporange. In some kinds, as Sarcoscyphus,
there are always several archegones in a
perigone, and two or three produce sporanges.
Sometimes the archegones, with or without
perigones, are solitary ; more frequently they
are in groups. Whether solitary or grouped,
they may have a further envelope composed
of slightly modified leaves, free or confluent
together; these are the pericheetial leaves,
and constitute the perichcete. When both
perichate and perigone exist, it is easy to
determine which is which, but when only
one exists, the history of development alone
gives the key ; the perichaete is always de-
veloped before the archegones it encloses,
while the perigone, as already stated, grows
up round the archegone during its develop-
ment into a sporange, being absent at the
time of the first appearance of that organ. In
fig. 324 the base of the pedicel is seen to rise
out of a toothed vaginule (calyx or epigone},
which is enclosed in a tubular perigone, out-
side of which are two bilobed perichaetial
leaves.

The sporange developed from the embry-
onal cell of the archegone varies much in
its perfect condition. In Jungermanniese it
is mostly an oval body borne on the extre-
mity of a delicate thread-like stalk springing
out of the vaginule (fig. 324). The oval
body splits down from the summit, when ripe,
into four valves, which spread open more
or less in the form of a cross (figs. 324-5).
The cells of these valves exhibit very elegant
spiral-fibrous structure, like that of the walls
of anthers (see SPIRAL STRUCTURES). This
kind of sporange discharges minute spores
(see SPORES) and elaters, slender tubular cells
containing a spiral filament (PI. 32. fig. 38),
both forming very interesting microscopic
objects.

In the different frondose forms the sporanges
present very varied conditions. The arche-
gones of ANTHOCEROS send up a filiform
sporange, which is two-valved and contains
a columella (fig. 26, p. 49). In TARGIONIA
and some others the capsule is almost sessile,
and bursts irregularly. In RICCIA, where
the archegones are imbedded in the frond,
the sporange is a sessile globose body, with
the calyptra adherent, never bursting regu-
larly, but emitting the spores by decay. In
SPH^ROCARPUS, also, the calyptra is per-
manent as a cellular sac, inside of which the
sporange ripens into an indehiscent globular
body, emitting the spores only by decay.

In Marchantia, Fegatella, Lunularia, Gri-
Fig. 333. Fig. 334.

Lunularia vulgaris.

Fig. 333. Section of a receptacle, unripe.
Fig. 334. More advanced sporange, emerged from the

epigone.
Fig. 335. A burst sporange.

Magnified 20 diameters.

maldia, &c., the archegones are produced on
fleshy receptacles elevated upon stalks, and

Fig. 336. Fig. 337.

|\

Grimaldia barbifrons.

Fig. 336. Fertile plant. Magn. 2 diams.

Fig. 337. Section of the receptacle, with an abortive
archegone on the left side, and a half-ripe sporange still
enclosed in the epigone on the right. Magn. 20 diams.

Fig. 338.

Fig. 339.

Fimbriaria tenella.
Fig. 338. Receptacles with closed epigones. Magn. 10

diams.

Fig. 33Q. Two perigones, one with the epigone closed,
the other with the teeth of the epigone open, showing
the bursting sporange. Magn. 20 diams.

Y

HEPATICACEJE.

[ 322 ]

HERCOTHECA.

the sporanges are formed on the under side
of these receptacles (fig. 223, p. 257, figs. 334,
337, 339), which are of varied forms, &c. The
sporanges on these either burst by valves
(fig. 335), or by circumscissile dehiscence
throw off a lid, as in Fimbriaria (fig. 339).

The frondose forms do not all produce
elaters, and have not all the spiral fibres in
the cells of their walls. The exceptions are
the Riccieae, and the elaters of Anthoceros
are rudimentary. In Marchantia the elaters
are highly developed (PL 32. figs. 36, 37),
also the spiral tissue of the valves of the
capsules (PL 32. fig. 35). TARGIONIA has
branched elaters.

The spores mostly have a double coat, but
not always (e. y. Marchantia) ; they germi-
nate by protruding a pouch-like process,
which becomes a filament, from which the
new fronds or leafy stems arise.

The peculiarities of the different groups
above referred to will be better understood
after reading the following characters.

Synopsis of the Families.

A. Vegetation frondose, i. e. leaf and stem
confounded.

1. ANTHOCEROTE^B. The vegetative
portion consists of a minute green membra-
nous or slightly fleshy body, growing on
damp ground, not exhibiting any distinct
mid-nerve; it is at once known by its peculiar
fruits or sporanges, consisting of slender
stalk-like bodies springing up irregularly
from the upper surface of the frond, which
forms little sheaths (vaginule) around their
bases. These stalk-like fruits burst when
ripe, splitting down the middle from the tip,
and display a central bristle-like column
(columella), to which adhere the minute hair-
like bodies (rudimentary elaters) which are
mingled with the spores.

2. MARCHANTIE.E. The vegetative por-
tion is here also a succulent leaf-like expan-
sion, mostly exhibiting a more or less lobed
form, and without any conspicuous mid-
nerves in the lobes. The fruits are more
complicated structures than those of Antho-
ceroteae. From notches in the lobed frond
arise slender stalks terminating at the top in
an expanded structure (receptacle], resembling
in some cases a conical cap, in others a star
with a number of thick rays like the spokes
of a wheel, &c. The spores are formed in
membranous sacs attached on the under
surface of the cap or star-like body, and they
are accompanied by elaters of considerable
size exhibiting highly developed spiral bands.

The sporanges have no columella, and burst
at the tip with more or less regular tooth-
like valves.

3. RICCIE^I. Vegetative portion an ex-
ceedingly delicate cellular leaf-like structure,
more or less lobed, with an evident mid-
nerve. The sporanges are either imbedded
in the substance of the frond, or only ele-
vated on a very short stalk, and surrounded
by a membranous sheath derived from the
upper surface of the frond. The sporanges
have no columella and no elaters.

4. PELLIE^E. Vegetative portion a leaf-
like frond, mostly with an evident mid-nerve,
from which arise the sporanges, consisting
of capsules, usually bursting by four valves,
more or less elevated on a thread-like stalk.
Sporange without a columella; spores ac-
companied by elaters.

B. Vegetation foliaceous, i. e. leaves and
stem distinct.

5. JUNGERMANNIE.E. Vegetative portion
a thread-like stem clothed with green mem-
branous leaves more or less overlapping at
their bases. Sporanges springing from the
end of the stem, raised on more or less
evident stalks, bursting by four valves and
spreading in the form of a cross; spores with
elaters, which often adhere to the valves of
the sporange. The leafy stem of Junger-
mannieae is generally readily distinguishable
from that of the Mosses by the peculiar
mode of insertion of the leaves which pro-
duces a peculiar flattened arrangement.

BIBL. Hooker, British Jungermanniee,
1816 ; G. W. Bischoff, Bemerk. uh. die
Lebermoose, Nova Acta, xvii. p. 909. pi. 67-
71. 1835, Bemerk. zur Entwickl. der Leber-
moose, Bot. Zeit. xi. 113, Ann. des Sc. nat.

3 ser. xx. 57 ; Lindenberg, Monographic
der Riccien, Nov. Acta, 1836, Synops. Hepa-
ticarum, 1844 ; Nees ab Esenbeck, Natur-
gesch. der Europ. Lebermoose, Berlin, 1836 ;
Ekart, Synopsis Jungermanniarum, Coburg,
1832 ; Greenland, Memoire sur le germination
de quelques Hepatiques, Ann. des Sc. nat.

4 ser. i. 5; Hofmeister, Vcrgleich. Unter-
suchungen uber Kryptogamen, fyc., Leipsic,
1851.

HERCOTHECA, Ehr.— A genus of Dia-
tomaceae.

Char. Frustules single, valves unequal,
turgid ; connecting membrane of the valves
continuous, not cellular, dividing beneath an
integument which is mostly veined, or
beneath free setae which occupy the place of
the integument and are persistent. Hence

HERPETIUM.

[ 323 ]

HIMANTHALIA.

the corpuscles in the adjoining upper margin
of each valve appear to be crowned or
covered by setae or opposite membranes.
These forms divide in the siliceous manner
of the Melosiree, but not beneath a deciduous
integument (hoop).

H. mammillaris. Valves not striated, with
about twenty simple opposite setae at the
middle of the base, longer than the mammillae
and inserted into their margin, obvallate ;
diameter 1-810". Bermuda.

BIBL. Ehrenberg, Ber. d. BerL Akad.
1844, p. 262.

HERPETIUM, Nees.— A genus of Jun-
germannieae (leafy Hepaticaceae), distin-
guished by the incubous bilobed leaves not
being folded together, and by the obtusely
three-angled perigone. Two Brit, species :

1. H. reptans (Lepidozia, Dumortier).
Leaves squarish, acutely two or four-toothed
at the end. Woods and shady places. Jun-
germannia reptans, Hook. Brit. Jungerm.
pi. 75,

2. H. trilobatum (Mastigobryum, Nees).
Leaves ovate, three-toothed at the summit.
Moist alpine spots. J. trilobatum, Hook.
Brit. Jung. pi. 76.

BIBL. Hooker, Brit. Jungermannia, I. c. ;
Endlicher, Gen. Plant, nos. 472-9; Ekart,
Synops. Jungermann. pi. 3. figs. 21, 22.

HETEROMITA, Duj.— A genus of Infu-
soria, of the family Monadina.

Char. Body globular, ovoid, or oblong,
with two filaments arising from the same
point in front ; one, more delicate, and with
an undulatory motion, causing progression ;
the other thicker, and floating freely behind,
or adhering here and there to the slide, so
as to produce by its contraction sudden mo-
tion backwards.

Distinguished from Anisonema and Hete-
ronema by the absence of a tegument, shown
by the glutinous appearance of the entire
mass of the body, the facility with which it
adheres to other objects and becomes drawn
out, and the presence internally of certain
corpuscles which can only have entered by
vacuolae formed on the surface.

Found in both fresh and salt water.

H. ovata = Bodo grandis, E. (PI. 23. fig.
18 a).

H. granulosa. Body globular, surface
granular; marine; length 1-2300".

H. angusta. Body lanceolate, slightly
sigmoid; aquatic; length 1-980".

BIBL. Dujardin, In/us, p. 297.

HETERONEMA, Duj.— A genus of In-
fusoria, of the family Euglenia.

Char. Form variable, oblong, irregularly
expanded posteriorly ; with a slender flagel-
liform filament, and a thicker trailing, re-
tracting filament.

Tegument obliquely striated.

Differs from Heteromita in the presence of
a tegument, and from Anisonema in the tegu-
ment being contractile.

H. marina (PI. 24. fig. 17). Filaments
longer than the body; length 1-4300".

BIBL. Dujardin, Infus. p. 370.

HEXAMITA, Duj.— A genus of Infusoria,
belonging to the family Monadina.

Char. Body oblong, rounded in front,
constricted and bifid or indented behind;
two or four flagelliform filaments arising
separately from the anterior margin, the two
posterior lobes being prolonged into flexuous
filaments.

H. nodulosa (PL 24. fig. 20). Oblong,
with three or four longitudinal rows of no-
dules; motion vacillating ; length 1-1800".
In decomposing marsh-water.

H. inflata.

H. intestinalis. Fusiform, prolonged into
a bifid tail; length 1-2100". In the intes-
tines and peritoneal cavity of the Batrachia
and Tritons.

BIBL. Dujardin, Infus. p. 296.

HILDENBRANDTIA, Zanardini. — A
genus of Nulliporous Corallinaceae (Flori-
deous Algae), containing one British species,
H. sanguinea, Kiitz. (H. rubra, Meneghini) :
common, in the form of a bright or dark
red membranous crust, at first circular, after-
wards spreading irregularly over smooth
stones and pebbles. The frond is about 1-20"
thick in the middle and thinner toward the
edges, and composed of minute globose cells,
partly vertically, partly horizontally arranged.
It is not stony. It has immersed concep-
tacles, pierced by a pore (fig. 254. p. 266),
containing tetraspores and paraphyses.

BIBL. Harvey, Brit. Mar. Alg. p. 110.
pi. 14 C, Phycolog. Britann. pi. 250, Ann.
Nat. Hist. xiv. pi. 2. (as Rhododermis
Drummondii) ; Kiitz. Phyc. generalis, pi. 78.
fig. 5.

HILUM.— This name is applied to the
surface of attachment of the funiculus of
seeds, which is seen as a kind of scar, more or
less distinct. Sometimes it coincides with
the chalaza or organic base of the seed,
sometimes, where a raphe exists, it is near
the micropyle. (See OVULE.)

HIMANTHALIA, Lyngbye.— A genus of
Fucacese (Fucoid Algae), remarkable for the
peculiar forms of the frond and receptacle,

HIMANTIDTUM.

[ 324 J

HOLOPHRYA.

the latter consisting of a repeatedly forked,
strap-shaped cord, from 2 to 10' long,
springing from the top-shaped frond, which
is about an inch high. The dark olive-green
thong-like H. lorea is common on rocky sea-
shores. The receptacle is pierced by nume-
rous pores leading to immersed conceptacles
resembling those of Fucus, containing either
parietal spore-sacs or antheridia, the plants
being dioecious. The centre of the receptacle
is filled with mucous matter traversed by
jointed filaments. The antheridial sacs of
Himanthalia are double, and contain sper-
matozoids of flattened, ovoid or spherical
forms, with an orange granule and two cilia,
like those of Pycnophycus and Halidrys.

BIBL. Harvey, Brit. Mar. Alg. p. 20.
pi. 2 B ; Thuret, Ann. des Sc. nat. 3 ser.
xvi. p. 54 et seq. ; Greville, Alg. Brit. pi. 3;
Engl. Sot. pi. 569.

HIMANTIDIUM, Ehr.— A genus of Dia-
tomaceae.

Char. Frustules resembling those of Eu-
notia, connected by their sides into a fila-
ment. Aquatic.

Kiitzing describes thirteen species, some
of which are fossil.

H. pectinate (Fragilaria pect. Ralfs) (PL
12. fig. 36). Frustules in side view constricted
at the curved and rounded ends ; one side
slightly raised and flat, the other slightly
excavated or flat; striae evident; length
1-180".

/3. Convex margin of side view undulate
or with two indentations (fig. 36, b}.

Mr. Ralfs remarks a difference of form
between the newly-forming and the parent
frustules, the lateral margins of the former
in the front view being rounded (fig. 36, c).

H. arcus. Frustules rectangular in front
view; valves linear-arcuate, ends rounded,
subrecurved; striae evident; length 1-300
to 1-132".

H. monodon (Eunotia mon. Ralfs). Frus-
tules in side view subarcuate, convex on one
side, concave on the other, ends broadly
rounded ; striae evident ; length ?

BIBL. Ehrenberg, Ber. d. Berl. Akad.
1840 ; Kiitzing, Bacill. p. 36, Sp. Alg. p. 8 ;
Ralfs, Ann. Nat. Hist. xii. p. 107, xiii. p. 459.

HIMANTOPHORUS, Fabricius. — A
genus of Infusoria, of the family Euplota.

Char. Head not distinct from the body ;
hooks numerous; neither styles nor teeth
present.

Long curved hooks, almost in pairs, form
a broad band on the ventral surface, and are
the organs of locomotion; also a row of cilia

extending from the mouth a considerable
distance backwards.

H. Charon (PI. 24. fig. 18, under view;
fig. 19, side view). Body hyaline, plane,
elliptical, anterior end somewhat obliquely
truncate ; cilia small, hooks slender and long.
Marine. Length 1-180".

BIBL. Ehrenberg, Infus. p. 375.

HIPPARCHIA, Fabr.— A genus of Lepi-
dopterous Insects.

Char. Wings more or less rounded,
middlelongitudinal nerve of fore- wings giving
off posteriorly four nerves ; antennae with an
elongate, compressed and curved club ; head
small.

H. Janira, the meadow-brown butterfly,
in which the wings are brown, and the ante-
rior pair exhibit a blackish-brown round
spot with a white eye or centre, is common
in meadows. The scales (PI. 1. fig. 9) are
sometimes used as TEST-OBJECTS.

BIBL. West wood, Introduction, tyc., and
British Butterflies.

HIPPURIC ACID.— This acid occurs in
small quantity in human urine, especially
after a vegetable diet ; more largely in that
of the horse and other herbivora, as the ox,
the goat, the sheep, the hare, &c. ; also in
that of some reptiles.

It is readily soluble in boiling water and
alcohol ; less so in cold water and in ether.

It crystallizes in prisms or needles (PI. 7 '•
fig. 18), belonging to the right rhombic
prismatic system, some of which bear resem-
blance to those of the ammonio-phosphate
of magnesia, from which it is readily distin-
guished by its solubility in potash or hot
water. It" is sometimes obtained under the
same circumstances as benzoic acid, from
which it differs in its greater solubility in
ether, and in the thickness and solidity of
its prisms, those of benzoic acid being thin
and plate-like. Its crystals are beautifully
analytic ; which property is deficient in those
of benzoic acid.

It may best be procured from cow's urine,
by boiling with slaked lime for some time,
filtering and supersaturating with muriatic
acid; and it may be purified by repeating the
process and using animal charcoal.

BIBL. See CHEMISTRY.

HISTOLOGICAL ANALYSIS. See IN-
TRODUCTION, p. xxxvi.

HISTOLOGY or HISTIOLOGY, is the
doctrine of the structure of animal and vege-
table tissues in relation to their development.

HOLOPHRYA, Ehr.— A genus of Infu-
soria, of the family Enchelia.

HOLOTHYRUS.

[ 325 ]

HORMOSPORA.

Char. Body covered with vibratile cilia,
oblong-ovate, cylindrical or globular, rounded
or truncate in front; no lips nor teeth.

Cilia arranged in longitudinal rows.

Ehrenberg admits five aquatic species ; to
these Dujardin, who places this genus in the
family Paramecia, adds one marine.

H. ovum, E. (PL 24. fig. 22). Body ovate,
subcylindrical, ends subtruncate; internal
substance green; length 1-576 to 1-216".

H. brnnnea, D. (PL 24. fig. 21). Body
brown, cylindrical, becoming globular when
distended with food and then changing in
colour; length 1-120''.

The encysting process has been observed
in two of the species.

BIBL. Ehrenberg, In/us, p. 314; Dujardin,
Infus. p. 493 ; Cohn, Siebold and Kolliker's
Zeitschr. iv. ; Stein, Infus.

HOLOTHYRUS, Gerv. — A genus of
Araclmida, of the order Acarina and family
Gamasea.

H. cocdnella is nearly as large as a lady-
bird (Coccinella], and is found in the Isle of
France.

BIBL. Gervais, Walckenaer's Apteres,
iii.

HOMCEOCLADIA, Ag.— A genus of Dia-
tomaceae.

Char. Frustules linear, elongate, arranged
in tufts within gelatinous tubes, which form
a filiform branched frond. Marine.

The nature of the markings upon the
valves is doubtful. Kiitzing admits the ex-
istence of median and terminal apertures
(nodules), and places the genus in the same
family as Navicula, &c. ; but these are not
represented in his figures ; neither are they
mentioned bv Ralfs.

H. Martiana, Ktz. (H. anglica, Ralfs) (PL
14. fig. 15; a, portion of frond; b, part of
a filament containing two frustules ; c, front
view of single frustules, with endochrome ;
d, side view of empty frustule). Filaments
tufted, polychotomous, setaceous, terminal
branches corymboso-fastigiate, acute ; fasci-
cles of frustules closely approximated ; frus-
tules very long, narrowly linear, obtuse,
transversely striated ; length 1-96 to 1-90" ;
entire plant 1 to 2" high.

H. anglica, Ktz. Filaments tufted, seta-
ceous, di-trichotomous, branches equal and
acute at the apex, fascicles of frustules
closely approximated ; frustules very long,
exactly linear, obtuse, transversely striated ;
length 1-84"; entire plant 1" high.

Six other species.

BIBL. Kiitzing, Bacillar. p. 110, and Sp.

Alg. 97; Ralfs, Ann. Nat. Hist. 1845, xvi.
109.

HOOF.— The hoofs of animals consist of
the same structure as horn.

HOOKERIA, Smith.— AgenusofHypnoid
Mosses. Brit, species :

1. Hookeria late-virens, Hook, and Tayl.

2. Hookeria lucens, Sm.

HOP.— The hop plant (Humulus Lsupulus)
is remarkable for the glands containing the
resinous secretion imparting the aromatic
odour. These occur upon the lower face of
the leaf, upon the calyx, and, above all, on
the scales of the fruit and the seed-coat.
They have been examined by Meyen and
others, most recently by Personne. They
are little stalked cups (PL- 21. fig. 14) com-
posed of a single layer of cellular tissue,
concave above at first, but as the secretion
increases in quantity, the cuticle becomes
detached in a plate from the upper surface,
except at the rim of the cup, and is pushed
up so as finally to form a convex papilla on
the top, like the nut projecting from an
acorn-cup. The secretion appears to be
formed in the cells, and poured out beneath
the cuticular pellicle, which is marked with
lines corresponding to the side-walls of the
cells. Solution of potash and alcohol clean
away the resinous secretion and render the
structure clear. When the fresh glands are
placed in water, they swell and finally burst,
the cuticular lid usually separating by a cir-
cumscissile dehiscence.

The hop is subject to a peculiar mildew, a
minute fungus, for which see ERYSIPHE
(Spharotheca}.

BIBL. Meyen, Secretions - Or gane der
Pflanzen, p. 38. pi. 5. figs. 17-21; Personne,
Ann. des Sc. nat. 4 ser. i. p. 299. pi. 17.

HOPLOPHORA, Koch. — A genus of
Arachnida, of the order Acarina and family
Oribatea.

Char. Body and general habit those of
Galumna, but no wing-like appendages to
the pseudo-thorax.

Two species ; not British (?).

BIBL. Koch, Deutschl. Crustac. fyc. ;
Gervais, Walckenaer's Apteres, iii.

HORMOSPORA, Brebisson.— A genus of
Palmellaceae (Confervoid Algae), with a frond
consisting of simple or branched gelatinous
confervoid cords enclosing rows of oval or
spherical cells; they appear to the naked
eye like greenish filaments; found floating
among Confervae or other aquatic plants.
These plants do not appear to consist of
septate filamentous tubes like the Conferva,

HORN.

[ 326 ]

HYALOSIRA.

but of rows of individual cells imbedded in a
filiform gelatinous tube (fig. 340), analogous

Fig. 340.

Fig. 341.

Hormospora transversalis.

Fragments of gelatinous filaments, with the cells grouped
in fours.

Magnified 350 diameters.

in its nature to the gelatinous coat investing
the linear rows of cells of Hyalotheca, &c.
The cells multiply by transverse division,
the rows thus becoming elongated; these
cells contain green contents arranged in a
granular, lamellar, or radiating form. Bre-
bisson describes obscurely another mode of
increase, in which the "endochrome becomes
concentrated and organized into vesicles or
zoospores. The corpuscles then become
larger, and the filament becoming as it were
dislocated, the corpuscles group themselves
in several rows, and without regular form "
(fig. 341). In H. transversalis there is an
especial tendency to a grouping of the cells
in fours. Three species have been described;
1 and 3 are known as British.

1. H. mutabilis, Breb. Filaments simple;
cells ovoid or subspherical ; cell-contents
lamellar. Aquatic. Breb. Ann. des Sc. nat.
3ser. i. pl.l. fig. 1.

2. H. transversalis, BreT>. (figs. 340,341).
Filaments simple; cells ovoid or fusiform,
transverse; contents granular. Aquatic. Breb.
I. c. fig. 2.

3. H. ramosa, Thwaites. Filaments
branched ; cells oval or spherical ; contents
radiated. In a pool to which salt water had
access. Harvey, PJiyc. Brit. pi. 21 3.

BIBL. Brebisson, Ann. des Sc. nat. 3 ser.
1; Harvey, Brit. Mar. Alg. p. 235. pi. 27 B,
Phyc. Brit. pi. 213; mge^Einzell.Alg. p. 7.
pi. 3. fig. B.

HORN. — The horns of animals are of
three kinds ; those composed of bone, those
consisting of epidermic formations, and
those in which both are present. The former,
properly called antlers, agree in minute struc-
ture with bone, and therefore require no
special notice. The horn of the rhinoceros
may be taken to represent the structure of
the second kind. It consists of an aggrega-

tion of horny fibres, each of which is made
up of a series of concentric layers. These
layers are composed of cells tangentially flat-
tened, and sometimes containing pigment.
The cells may be separated by macerating
the horn in solution of potash. Cracks
filled with air are frequently visible between
the layers. The centres around which the
laminae are arranged, probably correspond to
papillae of the cutis.

The horn of the buffalo agrees essentially
in structure with that of the rhinoceros.

The third kind of horn is exemplified by
that of the cow. In its centre is a process
of bone, surrounding and extending beyond
which is the proper horn, consisting of con-
centric layers, in the natural state composed
of flattened, irregular, angular nucleated cells
(PL 17. fig. 29 a), which assume their primi-
tive forms under the action of potash (6) ;
some of them contain pigment (c). Be-
tween the laminae cracks containing air are
also met with (f).

Sections of horn made at various angles to
the axis form very beautiful polarizing ob-
jects; the gorgeous colours seen in those of
rhinoceros's horn cannot be excelled, nor can
drawings represent them faithfully (PI. 31.
figs. 37, 38). The horn of the buffalo also
forms an interesting object of the same
kind.

BIBL. Bonders, Mulder's Physiolog. Che-
mie ; Owen, Brande's Diet., Art. Cornua.

HORSE-LEECH. See H^MOPIS.

HYALODISCUS, Ehr. = CvcLOTELLA,
Kiitz. in part.

H. Ifsvis = Cyclotella Itevis.

H. patagonica = Cycl. patagon.

BIBL. Ehrenberg, Ber. d. Berl. Akad.
1845, pp. 78 & 155; Kiitzing, Sp. Alg. p. 20.

HYALOSIRA, Kiitz.— A genus of Diato-
maceee.

Char. Frustules concatenate, rectangular,
tabulate; with alternate vittae, interrupted
in the middle, and connected with those of
the opposite side by fine lines ; lowermost
frustule attached by a stipes which is affixed
to one angle. Marine.

The fine lines at the end of the vittae give
the latter a forked appearance. The frus-
tules are often partly separated, so as to be
connected with each other by one angle only.

Four species, probably not really distinct.

H. rectangula (PI. 13. fig. 1). Stipes
short, frustules subconcatenate, in front view
subquadrate, rectangular; length 1-1380".

BIBL. Kiitzing, Bacillar. p. 125; Sp.
Alg. p. 115.

HYALOTHECA.

[ 327 ]

HYDRA.

HYALOTHECA, Ehr.— A genus of Des-
midiacese.

Char. Cells united into an elongated, cy-
lindrical filament, which is surrounded by a
gelatinous sheath ; cells in front view slightly
constricted, so as to give the margins a cre-
nate appearance ; or having a grooved rim
surrounding one end, and forming a biden-
tate projection ; end view orbicular.

The filaments are not twisted, and are
always of the same apparent breadth. Spo-
rangia orbicular, smooth.

H. dissiliens (PL 10. fig. 1, front view of
filament; 2, end view). Filament fragile,
margins crenate; breadth of filament 1-1300
to 1-800". The transparent sheath of this
beautiful object is so delicate as to be easily
overlooked. Sporangia (figs. 3, 4) situated
within the connecting tube.

Not uncommon in clear boggy pools.

H. mucosa. Filament scarcely fragile;
joints not constricted, surrounded at one end
by a minute furrowed rim, forming in the
front view a bidentate projection; breadth
of filament 1-1250 to 1-1100".

The furrowed rim of each cell is on the
same side as that of the contiguous cell.

BIBL. Ralfs, Brit. Desmid. p. 51.

HYDATlNA,Ehr.— A genus of Rotatoria,
of the family Hydatinsea,

Char. Eyes absent ; jaws two, teeth nu-
merous, free ; foot forked.

H. senta (PL 34. fig. 37; fig. 38, teeth).
Body conical, hyaline ; margin of rotatory
organ ciliated ; foot robust; aquatic; length
1-48 to 1-36".

This animal forms a favourable subject
for the examination of the typical struc-
ture of the Rotatoria; and is that which
Ehrenberg used as the basis of his investiga-
tions upon their organization.

H. brachydactyla. Segments of foot short;
body suddenly narrowed at the base of the
foot; aquatic; length 1-144".

BIBL. Ehrenberg, Infus. p. 412.

HYDATIN.EA.— A family of Rotatoria.
Char. Neither carapace nor enveloping
sheath present ; rotatory organ multiple, or
more than bipartite.
18 genera.

Eyes absent.

No teeth Enteroplea.

Teeth present.

Jaws with numerous teeth Hydatina.

„ with a single tooth Pleurotrocha.

Eyes present.
Eye single.

Eye frontal Furcularia.

,, cervical.

Foot styliform Monocerca.

„ forked.

Frontal cilia, no hooks nor styles Notommata.
„ styles present . . Syncheeta.

,, hooks Scaridium.

Foot absent ; with cirrhi or fins. . Polyarthra.

Eyes two.
Eyes frontal.

Foot forked Diglena.

„ styliform.

With cirrhi Triarthra.

Without cirrhi Rattulus.

Eyes cervical Distemma.

Eyes three.
Eyes not stalked.

Eyes cervical Triophthalmus.

Two eyes frontal, one cervical . . Eosphora,
Two frontal eyes stalked, one cervi-
cal not stalked Otoglena.

Eyes more than three in a single group Cycloglena.
„ ,, two groups. . Theorus.

BIBL. Ehrenberg, Infus. p. 410.

HYDNEL— A family of Hymenomyce-
tous Fungi, characterized by bearing their
basidiospores on tubercles or spine-like pro-
cesses on the under side of a discoid, cup-
shaped or funnel-shaped, stalked or sessile
pileus. The basidiospores are seen by making
cross sections of the spines, &c. See BASI-
DIOSPORES, HYMENOMYCETES.

BIBL. Berkeley, On the Fruct. of Hyme-
nomycetous Fungi, Ann. Nat. Hist. i. 81 ;
Leveille, Sur I'Hymenium des Champignons,
Ann. des Sc. nat. 2 ser. viii. 32.

HYDRA, Linn. (Freshwater Polype).—
A genus of Polypi, of the order Anthozoa
and family Hydrina.

Char. Locomotive, single, naked, gelati-
nous, subcylindrical, but very contractile and
variable in form ; the mouth surrounded by
a single row of filiform tentacles. Propaga-
tion by the formation of gemma3 and ova
upon or within the substance of the body
of the animal.

1. Hydra viridis (PI. 33. fig. 21, adhering
to the radicles of duck-weed (Lemna) ). Body
leaf-green, cylindrical or insensibly narrowed
towards the base; tentacles 6 to 10, shorter
than the body.

Common in ponds and still waters. Ten-
tacles narrowest at their origin.

2. H. vulgaris. Body orange-brown, yel-
lowish or red, cylindrical ; tentacles 7 to 12,
as long as or longer than the body.

Tentacles tapering to the free ends.
Found in weedy ponds and slowly running
waters.

3. H. attenuata. Body pale olive-green,
attenuated below ; tentacles pale, longer
than the body.

In ponds ; rare.

4. H. fusca. Body brown or greyish,

HYDRA.

[ 323 ]

HYDRA.

lower half suddenly attenuated; tentacles
several times longer than the body.

Still waters ; rare.

The characteristic forms of the body can
only be judged of when fully extended in
search of prey ; for when the animals are
touched, shaken, or in any way disturbed,
the body assumes very variable forms, be-
coming rounded, ovoid, &c.

The structure of the body of Hydra has
been much investigated and discussed. By
some it has been regarded as consisting of
three layers — an internal and external coat,
and an intermediate muscular layer. The
true structure, however, has been pointed out
by Ecker. This author correctly regards the
animal as consisting of the substance deno-
minated sarcode by Dujardin, and neither
furnished with an outer nor an inner coat.
The transparent, gelatinous sarcodic sub-
stance forms the entire mass of the body and
tentacles ; on the surface it is frequently
irregularly rounded or nodular, or exhibits
spiral or other raised lines (PL 33. fig. 23 b);
and within it contains numerous vacuoles.
If a Hydra be crushed between glasses,
portions of the sarcode will be separated,
and assume a globular form, closely resem-
bling that of cells; the vacuoles will also
become greatly distended, just as occurs in
the substance of the Infusoria, and these
separated portions will often continue con-
tracting like an Am&ba. Two of them are
represented in PL 33. fig. 2.9 ; in a, a rather
small vacuole is present, whilst in b, this is
very large. Now in the latter instance, the
globule, as regards structure, forms a true
cell, consisting of a closed sac, with liquid
contents. Physiologically speaking, however,
it does not correspond to a cell, the entire
substance representing cell-contents, around
which a cell-wall has never been formed. A
number of these vacuoles exist naturally dif-
fused throughout the substance of the body.
The intermediate stratum, which is not
organically distinct, contains imbedded in it
a number of very minute green or otherwise
coloured granules ; these are of a rounded
form, and present a double outline, as if
composed of cells. In the uninjured Hydra.,
they exist in the inter-vacuolar substance,
thus giving the tissue an elegantly reticular
appearance. We believe that these granules
consist of chlorophyll ; they are insoluble in
potash ; they become coloured purplish red-
brown by iodine and sulphuric acid, after
treatment with potash ; and the green
granules of Hydra vulgaris are rendered

bluish-green by sulphuric acid, in the same
manner as the chlorophyll of leaves. The
colour of Hydra has been differently
accounted for. Laurent states that he suc-
ceeded in colouring them blue, white and
red, by feeding them with indigo, chalk and
carmine, — whilst Hancock has shown that
the colouring is much affected by exposure
to light ; those not exposed to light, from
living under stones, &c., having the natural
colour, whilst those exposed to the light
became bleached. It is generally admitted,
however, that the colour depends upon or is
modified by the nature of the food ; but
exact experiments are wanting to decide this
question. Towards the inner surface of the
body, the granules are brownish or blackish.
Imbedded in the superficial portions of
the substance of the Hydra are certain cu-
rious bodies, termed the stinging organs (PI.
33. fig. 23 a). These are best seen upon the
tentacles ; they consist of an oval, truncate,
firm capsule (PL 33. fig. 226) of compara-
tively considerable thickness, as indicated by
its marked double outline. Within the cap-
sule is contained a very long and slender
filament, at the base of which are four minute
spines. In the undisturbed state of the
Hydra, the filament with the spines is coiled
up in the capsule (fig. 22 a) ; but when the
animal is touched, pressed or heated, the
filament with the spines flies out with extra-
ordinary rapidity, so that we have not been
able to determine exactly how the spines are
arranged within the capsule. Most probably
the spines, while within the capsule, are
directed forwards and in close contact, and
then in assuming their recurved position,
they are the means of projecting the filament
forwards. A capsule, containing an unex-
panded filament and spines enclosed within
a detached globule of sarcode, is represented
in fig. 22 d. When these capsules are heated
with a solution of nitrate of silver, a portion
of the silver is reduced to the metallic state.
This action is a property of formic acid;
hence when it is considered that these organs
closely resemble in structure those of the
Acalephse, which possess an urticating power
like stinging-nettles, arising from the pre-
sence of formic acid, and that in Hydra
these filaments are driven into and wound
the prey, it may appear probable that they
secrete and contain formic acid. But as
many other substances reduce salts of silver,
and as the sarcode, from which it is perhaps
impossible to separate these bodies, may
produce this effect, the point must be con-

HYDRA.

[ 329 ]

HYDRA.

sidered as doubtful and requiring further in-
vestigation. In addition to these stinging
organs, we have found other very minute
capsules (fig. 22 c), containing a filament
curved even when emitted, the nature of
which is obscure.

A third kind of organ is said to have been
met with also in the surface of the body,
consisting of ovate capsules or bodies, from
which a stout and short filament projects.
These appear to resemble the organs of ad-
hesion of the Acalephse ; but as their size is
not stated, nor the diameters of the figures ex-
pressed, we have been unable to identify them.

The body and tentacles of Hydra are hol-
low. The prey, which consists of Entomos-
traca, small Annulata, &c., when caught by
one or more of the tentacles extended for
the purpose, is slowly brought to the mouth,
and forced into the cavity of the body, in
which it is digested ; the undigested portions
being evacuated through the mouth. It is
still a question whether a posterior outlet to
the cavity of the body exists. The posterior
part of the body is more or less dilated into
a flattened disc, which, by its suctorial power,
enables the animal to attach itself to various
bodies. Hancock has seen excrementitious
matter passing through the body at this
part and the disc ; but most, if not all, pre-
vious observers have denied the existence of
a canal. The cavities of the tentacles have
been described as containing a semifluid sub-
stance, undergoing a kind of circulation;
and the cavity of both the tentacles and the
body have been stated to be lined with cilia.

The extraordinary power which Hydra
possesses of reproducing lost parts is truly
wonderful. Thus, if the body be cut into
two or more, or even forty parts, each con-
tinues to live, and developes a perfect new
animal. If the section be made lengthwise,
so as to divide the body all but the end, the
two portions become resoldered and form a
perfect being ; if the pieces be kept asunder,
each becomes a Hydra, the two possessing
but one posterior end; if the section be
made from the tail towards the head, the
two bodies will be perfected and remain
attached to the one head. If a tentacle be
cut off, a new animal is formed from it.
When one end of the body of a Hydra is
introduced into the body of another, the two
unite and form one. The head cut off one,
may be engrafted upon the body of another
which wants one. And when the body is
turned inside out, the outer surface which
has thus become the inner wrill perform the

ordinary digestive functions, and the animal
will continue to live.

The ordinary mode of reproduction of
Hydra is by gemmation ; a minute swelling
forms upon some part of the surface of the
body, this enlarges, and gradually assumes
the form of the parent, while remaining
attached to it. Sometimes several of these
are formed upon a single individual at the
same time, and so, remaining adherent, they
give the animal a branched appearance (PI.
33. fig. 21).

At certain seasons of the year, as at the
end of summer or in the autumn, reproduc-
tion takes place by the formation of sperma-
tozoa and ova. The spermatozoa are formed
within spermatic capsules. These arise as
minute conical tubercles a little beneath the
base of the tentacles, one on each side (PI.
33. fig. 24 a) ; and the spermatozoa are libe-
rated from them by bursting. The sperma-
tozoa in the figures resemble those of the
Mammalia, except that the tails are undu-
late. The ova are furnished with a thick
coat, and are formed in the substance of the
lower part of the body (fig. 24 i). They
subsequently separate from the body, ana"
appear to be capable of spontaneous motion,
but whether from the presence of cilia or
not is undecided. The sac of the ovum then
becomes ruptured, and the new animal es-
capes (fig. 25).

Hydrce are very common. The best me-
thod of procuring them is to collect a number
of water-plants from any clear pool or slow
stream, and bring them home in an india-
rubber bag (sponge-bag). On placing the
plants subsequently in a glass jar (con-
fectioners' jar) containing water, they will be
found at the end of some hours with the
tentacles fully extended in search of prey,
when they are easily recognized. They
usually adhere to the sides of the glass, or
to the stems or under sides of the leaves of
the plants; but sometimes they are seen
suspended from the surface of the water by
the sucker, which is protruded just above it
so as to become partly dry. A number of
small Entomostraca should be added to the
water, as they are very voracious.

Some of the species of Hydra are occa-
sionally covered with minute parasitic Infu-
soria, viz. Kerona polyporum (PL 41. fig. 13),
which is found upon H. vulgaris andfusca ;
and Trichodina pediculus (PL 24. fig. 16),
which occurs upon H. vulgaris and viridis.
It is an interesting sight to see these running
up and down the tentacles and surface of the

HYDRACHNA.

[ 330 ]

HYDRODICTYON.

body of the polypes, when we recollect that
their surface is covered with the stinging
organs. These lice are not, however, found
upon perfectly healthy polypes ; impurity of
the water and an unhealthy state being
generally denoted by their presence.

BIBL. Leeuwenhoeck, Phil Trans. 1703,
xxiii.; Trembley,M<?m.s .l.Polyp.d'eau douce;
Ehrenberg, Corall. d. roth. Meer. ; Laurent,
Rech. s. VHydre, fyc. ; Corda, Ann. d. Sc.
nat. 2 ser. viii. ; Schaeffer, Die Armpolypen ;
Erdl, Miille^s Archiv, 1841 ; Ecker, Siebold
and Kolliker's Zeitschr. i. ; Johnston, Brit.
Zoophytes; A. Thomson, Todd's Cycl.Anat.
and Phys. iv. p. 1 7 ; Hancock, Ann. Nat. Hist.
2ser.v.p.28L; Allman,Microse.Jowrw.l854.

HYDRACHNA, Miill.— A genusof Arach-
nida, of the order Acarina and family
Hydrachna.

Char. Palpi tolerably long, third joint
longest, the fourth and fifth terminated each
by a claw ; mandibles ensiforin ; rostrum
long, scarcely shorter than the palpi ; body
rounded ; eyes distant ; vulva concealed by
a plate or shield.

When young, these little water- spiders
have three legs only, and in this state have
formed another genus, Achlysia.

H. cruenta, Miill. = H. alobula, Herm.
(PI. 2. fig. 29). Body subovate ; two pairs
of eyes at a moderate distance apart, reniform,
dark red ; skin covered with minute puncta.

The rostrum is broad and curved at the
base (fig. 29 c, the lower part directed to the
left), cleft above, so as to form a kind of
channeled sheath, containing the anterior
narrower portions of the two mandibles (b).
The palpi (c, upper organ) are inserted upon
the sides of the base of the rostrum and
curved downwards; the first joint is very
broad, the second much curved, the third
long, and flattened on one side and rounded
on the other ; the fourth joint is short, and
terminated by a short and thick claw; the
fifth also forms a claw, but the two claws do
not form a chela, their curves being parallel.
Of the legs (fig. 29 a), the three posterior
pairs are ciliated for swimming, and the
posterior are much longer than the anterior;
the coxae are flattened and form two groups
on each side; between the two posterior
coxae is the orifice of the reproductive organs;
the tarsi all have two claws, and are obliquely
truncated and concave at the ends (fig. 29 e).

The eggs are reddish-brown and deposited
upon the stems of water-plants; the nymphae
are found attached to aquatic insects (fig.
29/), as Nepa, Dytiscus, &c.

H. aeographica. Body spherical, black,
with spots and yellow points; palpi red,
acute; legs shorter than the body, black,
but red at the ends.

BIBL. Duges, Ann. d. Sc. nat. 2 ser. i. ;
Gervais, Walckenaer's Arachn. iii. ; Koch,
Deutschl Crustac., fyc.

HYDRIAS, Ehr.— A genus of Rotatoria,
of the family Philodinaea.

Char. Eyes absent ; neither proboscis
present, nor horn-like processes on the foot ;
rotatory organs two, placed at the ends of
two anterior processes of the body.

H. corniaera (PL 34. fig. 39). Body ovate,
hyaline ; foot narrowed into the form of a
slightly forked tail; aquatic; length 1-190".

Probably a young and imperfectly exa-
mined Philodina. Found in Egypt.

BIBL. Ehrenberg, In/us, p. 483.

HYDROCHARIDACE^.— A family of
Monocotyledonous Flowering Plants growing
in water, interesting to the microscopist as
affording very favourable opportunities of
viewing the circulation or rotation of the
cell-contents. The leaves of Vallisneria
spiralis, an Italian plant, which is readily
grown in jars of water indoors, are very fre-
quently used for this purpose ; the leaves and
sepals ofAnacharisA Isinastrum, a N .American
plant, now naturalized in streams in many
parts of Britain, also show the circulation
well. The extremities of the roots of Hydro-
charis morsus-rance, a plant common, floating
on the surface, in broad, permanent ditches,
are likewise adapted for the purpose. The
circulation consists of the flowing movement
of a layer of colourless protoplasm over the
inner surface of the walls of the cells. Where,
as in the leaves of Vallisneria and Anacharis,
the cells contain green globules of chlorophyll,
these mostly adhere to the circulating mass,
and are earned round with it. The phaeno-
menon may be observed in uninjured young
leaves simply immersed in water, by focus-
ing carefully; but in Vallisneria it is seen
more clearly in slices taken carefully parallel
to the surface of the leaf. The circulation
lasts a long time in these separate fragments
if they are kept wet. Sometimes it is arrested
by the preparation ; in such cases the appli-
cation of a gentle heat often causes it to re-
commence. It may be observed with a power
of 200 diameters, but a higher is requisite
for minute investigation. (See ROTATION.)
HYDRODICTYON, Roth.— A genus of
Siphonaceae (Confervoid Algae), containing
one species, H. utriculatum, found in fresh-
water pools in the midland and southern

HYDRODICTYON.

[ 331 ]

HYDRODICTYON.

counties of England. The frond consists of
a green open network of filaments attaining
a length of 4 to 6" when full-grown (fig. 342),
composed of a vast number
of cylindrical tubes (cells)
with rounded ends, adherent
together at their extremities,
the points of junction corre-
sponding to the knots or in-
tersections of the network.
The individual cells attain a
length of 4'" or more. The
organization of this plant and
its development are exceed-
ingly curious, and it has
lately been the subject of very
careful investigation by Al.
Braun and others. The cells
forming the links of the net
have a remarkably thick cel-
lulose coat when full-grown,
which exhibits several layers,
especially when treated with
sulphuric acid (PL 38. fig. 24
m). Weak sulphuric acid does
not affect the outer layer,
which may be termed the

Cuticle, while it Swells the in- of the largest size.

ner, and throws them into
waves, especially the innermost ; the subse-
quent addition of iodine colours the inner layer
blue, but not the cuticle. Strong sulphuric
acid acts differently; it detaches the cuticle
at many points, while the inner layer con-
tracts, so that the cuticle appears blown up
in vesicles ; the inner layers gradually soften
and dissolve. These last changes are similar
to what takes place at the dissolution of the
cell when the contents escape; and Cohn
states that the membranes give the bluish
reaction with iodine alone when thus par-
tially decomposed by natural causes. The
contents of the cell present several points of
interest connected with the phenomena of
cell-life, indicating a complexity in the or-
ganization of the internal structures not
formerly suspected, but which appears to
prevail pretty generally.

Immediately lining the wall is a mucilagi-
nous layer (PL 38. fig. 24 6), which Braun
has shown to consist of several lamellae : —
1 . An extremely thin, finely punctated layer,
coagulated and detached from the cell-
wall by the action of acids; this is the
primordial utricle of the cell. 2. The outer
mucilaginous layer, thicker than the primor-
dial utricle, but thinner than the next or
third layer. When separated from the first

layer, the outer surface appears rough and
wavy, and it is connected with the third layer
by mucilaginous cords; it contains indi-
stinctly defined colourless granules. 3. The
inner mucilaginous layer, the thickest of the
three, is rough on the outside and waved on
the inside from the projection of granules
imbedded in it ; this is the only green layer,
appearing of a homogeneous green colour (like
the spiral bands of Spirogyrd) when the cells
are in their prime, besides which it contains
innumerable green granules, sometimes in
rows, more frequently uniformly scattered.
Thislayer likewise contains starch-corpuscles,
such as occur in the green substance of the
Confervoids generally, causing the cell-
contents to exhibit a vast number of bril-
liant points. In imperfect cells the green
layer sometimes appears in patches, not
completely investing the surface of the outer
mucilaginous layer ; this is also common in
young cells. The fluid in the cavity of the
cell is clear and watery.

The reproduction of the fronds of Hydro-
dictyon is effected by the conversion of the
contents of the individual cells into complete
new nets like the parent, which sets them
free by dissolution. The following is a brief
history of this remarkable process. The
first stage is the solution of the starch-grains;
the green layer becomes more opake ; lighter
spots appear on the inner part of the muci-
laginous layer, excavated in its substance
and surrounded by the chlorophyll-globules,
which separate from each other, forming
dark boundary lines round the light spots.
The bright green then gives place to abrowner
tinge. The light spots already observed, the
centres of the nascent gonidia, exerting an
attraction as it were on the chlorophyll -glo-
bules, become severally enveloped in a layer of
them, and then separate from each other, so
that they then appear like dark spots with
an intervening reticulation of bright lines.
The dark spots (gonidia) are now polygonal,
mostly six-sided, about the 1-2500" in ilium .
The parent cell-membrane now begins to
soften and swell up ; the gonidia, thus ac-
quiring more space, become rounded, and
soon present a slight tremulous oscillatory
movement. The cuticle of the parent-cell
then cracks, allowing the inner softened
layers to swell out ; the gonidia commence
an active trembling and jerking motion, not,
however, moving far from one spot ; after a
time they again come to rest, and become
united at certain points of their circumfe-
rence ; the green granules become fused into

HYDROGASTRUM.

[ 332 ]

HYMENIUM.

a homogeneous mass, and the rudiment of the
first starch-granule soon appears, while the
gonidia grow out into a tubular form, acquire
a cellulose membrane, and collectively form
a new net, which becomes free by the total
solution of the parent-cell. These gonidia
appear to possess four short cilia ; their mo-
tion lasts about half an hour ; from 7000 to
20,000 occur in one cell. They are di-
stinguished by Braun as macrogonidia, from
other gonidia of smaller size and longer
shape, which he calls microgonidia, furnished
with four long cilia and a red parietal spot.
These have a different history. From 30,000
to 100,000 appear in the parent-cell, their
development presenting the same character
up to the time when the motion begins.
Then, the microgonidia, unlike the net-form-
ing macrogonidia, leave their parietal posi-
tions with a whirling motion, and move
through the entire cavity of the parent-cell,
until at length the membrane of the latter
bulges out in one or more places and bursts,
and the microgonidia leave the cavity in a
swarm. According to Cohn, they are at first
enclosed in a thin mucilaginous pellicle pro-
truded before them [like the swarming spores
of PEDIASTRUM]. However, they escape,
become free in the water, and swim about for
a long time. At length they come to rest,
sink to the bottom, and remain there heaped
in green masses, like cells of PROTOCOCCUS,
for a long period. Their farther history is
unknown.

The rapidity of the growth of the Hydro-
dictyon-net by the above process is wonder-
ful ; the component cells of the net increase,
under favourable circumstances, to 600 times
their original length in a few weeks. In cul-
tivated specimens, the whole history, from
the origin of a net to the production of a
new one, passes over in three or four weeks.
The original size of the cells is about 1-2500",
in the fully developed condition they are
about 1 to 4'' long. No development of
spores or resting-sporeshasyetbeen observed.

BIBL. Vaucher, Conserves, p. 82. pi. 9;
Areschoug, Linncea, xvi. p. 127. pi. 5 (1842);
Hassall, Brit. Freshw. Alg. p. 225. pi. 58 ;
Al. Braun, Verjungung, fyc. (Rejuvenescence,
Sfc.}, Ray Soc. Vol. 1853, passim; Cohn,
Nova Acta, xxiii. 207. pi. 19.

HYDROGASTRUM, Desv. = BOTRY-

DIUM.

HYDROMORINA, Ehr.— A family of
Infusoria.

The two genera of which it consists, Poly-
toma and Spondylomorum, appear to be

Monads (species of Algae) undergoing divi-
sion. See these genera.

BIBL. Ehrenberg, Ber. d. Berl. Akad. 1848.

HYDROPHILUS, Geoff. See HYDROUS.

HYDROPHORA, Tode.— A genus of
Mucorini (Physomycetous Fungi). Mildews
growing on the dung of animals, distin-
guished by the indurated persistent peridiole
and the conglobated spores. Two species
are described as British.

H. stercorea, Tode. Fleecy ; filaments
simple, very long, fugacious, white ; peridioles
spherical, yellow, subsequently black. Com-
mon on dung after much rain.

2. H. murina, Fr. Filaments scattered,
short, simple, persistent, white ; peridioles
yellow, subsequently opake. On rats' dung.
(Mucor fulvus, Sowerby, pi. 400. fig. 4.)

BIBL. Berkeley, Hook. Brit. FL ii. pt. 2.
331 ; Fries, Syst. My col. iii. p. 314, Summa
Veget. p. 87.

HYDROUS, Linn.— A genus of Coleop-
terous Insects, of the family Hydrophilidse.

H. piceus is one of the largest aquatic
British beetles. We have selected the head
to illustrate the structure and arrangement
of the trophi, &c. in the Coleoptera (see
INSECTS). The perfect insect is about H"
in length. The full-grown larva is about 3"
long ; it has no lateral branchiae, but two
filiform branchial appendages at the end of
the body.

BIBL. Westwood, Introduction, fyc. ; Du-
meril, Consid. gen. s. I. Insectes; Stephens,
British Beetles.

HYDRURUS, Ag.— A genus of Confer-
void Algae which we have placed for con-
venience among the PALMELLACE^E, but
it seems to form a link between these and
the ULVACE^E. The frond consists of a
branched, feathery, very gelatinous expan-
sion, the branchlets set with minute pro-
cesses or ramelli (PI. 3. fig. 8 a) ; in the ge-
latinous substance are imbedded minute cells
with homogeneous green contents, most
closely set in the ramelli, more scattered in
the older part of the frond (PI. 3. fig. 8 b).
H. Ducluzelii, Ag., grows to a length of from
1 to 6'', and from 2 to 4'" in diameter,
attached to stones in mountain brooks and
rivers ; the recent frond is of brownish-olive
in mass, green when dried. When fresh it
has a very offensive smell. Reproduction not
described.

BIBL. Harvey, Brit. Alg. (1 ed.) p. 180 j
Hassall, Br. Freshw. Alg. p. 302. pi. 77.
fig. 3 ; Kiitzing, Tab. Phycol. pi. 34. fig. iii.

HYMENIUM.— The term applied to the

HYMENODECTON.

[ 333 ]

HYMENOMYCETES.

layer of cellular tissue upon which are seated
the basidia of the higher FUNGI.

HYMENODECTON, Leighton. — A
genus of Graphideae (Gymnocarpous Li-
chens), separated from Opegrapha. H. (Op.)
dendritica and its varieties occur on the
bark of beech trees.

BIBL. Leighton, Ann. Nat. Hist. 2nd ser.
xiii. p. 387; Eng. Bot. pi. 1756.

HYMENOMYCETES. — The highest
order of Fungi, characterized scientifically
by the peculiar mode of arrangement of the
spores, which are borne in groups of four on
the exposed surface of a more or less mem-
branous or sometimes gelatinous layer called
the hymenium. The fruit, called the sporan-
gium, varies extremely in form. In most of
the Tremellini it is an irregular jelly-like or
waxy expansion, borne, however, on a round-
ish support in Tremella ; in the Clavati it
forms a club-shaped, mostly branched, fleshy
or leathery stalk-like body (called the hyme-
nophore), which is clothed at its ends by the
sporiferous-membrane or hymenium, forming
a smooth layer. In the Auriculati and
Hydnei the sporangium is either an ex-
panded irregular crust-like, membranous or
leathery mass, or has the form of a club, a
funnel, or of a hat or cap, the sporiferous
membrane clothing either the upper or under
surface as a warty, spiny or comb like stratum.
In Polypori and Agarici the sporangium
is a discoid (often laminated), bell-shaped,
or dish-formed, fleshy body, more or less
coloured and tuberculated on the upper side,
mostly borne on a columnar stalk inserted
on the under side, while the sporiferous layer,
or hymenial structure, presents itself as a
conspicuous layer on the under side, con-
sisting of a number of paper -like lamellae, or
vertical tubes or pits, closely packed, on the
lateral surfaces of which are borne the spores.
The younger stages of development of most
Hymenomycetes do not exhibit all these
characters, since the sporange is at first en-
closed in a sac-like body arising from the
mycelium, so that the external appearance is
similar to that of one of the Gymnomycetes
(as in very young mushrooms); this sac
finally bursts, to allow of the expansion of
the sporangium.

The cellular structure of this family is
simple, in spite of the varied outward forms ;
the whole mass, from the filamentous myce-
lium up to the sporiferous membrane or hy-
menium, is made up of interwoven branched
cellular filaments, of great tenuity. In the
Tremellini these filaments are imbedded or

dissolved into an amorphous waxy or gela-
tinous substance ; in other cases they form
a dry, corky structure, but the consistence is
generally fleshy. In a few cases among the
Agarici and Polypori, vesicular or elongated
branched cells are met with, of considerable
size, containing a milky juice (in the gills
of Ag.deliciosus, &c.). The spores are short
terminal branches of roundish or elongated
cells, called basidia, clothing the free surface
of the hymenial structure (see BASIDIO-
SPORES). They may be seen in thin cross
sections cutting the laminae of the Agarics
or the tubes of the Polypori at right angles,
requiring a high power for their observation.
Four spores are formed on each basidium,
from which they fall off when mature. The
Agarics exhibit on the hymenium, among
the basidia, peculiar projecting vesicles filled
with opake fluid (pollinaria,Corda; cystidia,
Leveille; utricles, Berkeley), which some
have called anthers, but which appear to be
paraphyses, that is, undeveloped or abortive
(bare) basidia. The spores are mostly ex-
ceedingly minute, of various forms and co-
lours, and consisting of simple cellules.
Tulasne has recently shown that the Tre-
mellini produce spermatia as well as basidio-
spores ; in Tremella, and other genera, they
arise from distinct branches of the hymenial
filaments ; in Dacrymyces they are produced
in germination from some of the detached
basidiospores lying upon the mycelium (see
TREMELLINI).

The structure of these Fungi must be in-
vestigated in all stages of development, since
very great changes of size and form take
place at different epochs, simply from expan-
sion or solution of the cellular textures.

Synopsis of the Tribes.

1. AGARICINI. Sporange like a round or
flat cap, borne on a stalk. Hymenium form-
ing vertical plates or folds on the under
surface.

2. POLYPOREI. Sporange like a round
or flat cap, disk, cup, or funnel, sometimes
stalked, with a porous (formed of tubes) or
reticulated hymenium on the under side.

3. HYDNEI. Sporange like a round or
flat cap, cup, or funnel, sometimes stalked,
with the hymenium on the under side exhi-
biting awl-shaped processes or tubercles.

4. AURICULARINI. Sporange tubular,
cup- or funnel-shaped, with the smooth or
papillose hymenium on the under surface.

5. CLAVATI. Sporanges club-shaped,
simple or branched like a shrub, with the

HYMENOPHYLLACE^E.

[ 334 ]

HYPHOMYCETES.

hymenium covering the tips and sides of
them.

6. TREMELLINI. Sporange vague, or
cup-shaped, often gelatinous at first, harden-
ing by drying up. Hymenium confounded
with the structure of the sporange, on the
upper, under, or both surfaces ; basidia ter-
minating the branches of hymenial filaments,
accompanied sometimes by branches bearing
spermatia. The detached spores often lie
imbedded in the gelatinous surface of the
hymenium, and sometimes produce spermatia
there.

BIBL. Berkeley, Lindley's Vegetable
Kingdom, Hooker's Brit. Flora, vol. ii. pt. 2,
Ann. Nat. Hist. i. 81, and ix. p. 1 ; Leveille,
Ann. des Sc. nat. 2 ser. viii. p. 321 ; Fries,
Summa Veget. p. 267 ; Tulasne, Ann. des Sc.
nat. 3 ser. xix. p. 193.

HYMENOPHYLLACE.E.— A family of
Ferns, distinguished by the delicacy of the
structure of their leaves and the composition
of the sori or fruits. The leaves are of the
utmost simplicity of organization, consisting
merely of a single layer of cellular tissue,
traversed by scalariform tubes constituting
the veins. There is no distinction of epi-
dermis and parenchyma, and no stomates.

Genera.

I. Trichomanes. Sporanges sessile around
the base of an exserted filiform column,
formed by the prolongation of a vein beyond
the margin of the leaf, surrounded by a cup-
shaped indusium continuous with the leaf
(fig. 343).

Fig. 343.

Fig. 344.

Trichomanes humile.

Hymenophyllum bivalve.

Fig. 343. Fragment of a leaf, with sori.
Fig. 344. Ditto.

Magnified 10 diameters.

II. Hymenophyllum. Sporanges sessile up
to the summit of a similarly formed column
projecting from the margin of the leaf, sub-
elevated, but not exserted beyond the indu-
siura, which is two-valved (fig. 344).

III. Loxsoma. Sporanges stalked, in-
serted up to the summit of a sub-elevated,
exserted column arising in a similar way
within the margin of the leaf, surrounded by
an indusium, somewhat within the margins
of the fissures between the teeth of the leaf,
with a truncated mouth, entire.

HYMENOPHYLLUM, Smith. — Filmy
Ferns. The typical genus of Hymenophyl-
laceous Ferns, remarkable for their delicate
structure and often almost moss-like habit.
Two dwarf species are natives of Britain,
H . tunbridgense and H. Wilsoni.

Fig. 345.

Fig. 346.

Fig. 347.

Hymenophyllum ciliatum.

Fig. 345. Fragment of a leaf. Magn. 10 diams.
Fig. 346. Sorus with one valve removed. Magn. 20

diams.
Fig. 347. Sorus. Magn. 20 diams.

HYPEROMYXA, Corda. See CHEIRO-

SPORA.

HYPHEOTHRIX, Kiitz.— A genus of
OSCILLATORIACE^E (Confervoid Algae). No
British species recorded.

HYPHOMYCETES.— An order of Fungi
composed of microscopic plants, growing as
moulds over dead or living organic sub-
stances. The vegetative structure or myce-
lium creeps over or among the structures
infested as a collection of delicate, simple or
branched, continuous or septate filamentous
cells ( flood}, and produces the spores either
on lateral pedicels (from which they soon
fall off, becoming intermingled with the my-
celium), or in heads at the swollen or rami-
fied extremities of usually erect filaments

HYPHOMYCETES.

[ 335 ]

HYPHOMYCETES.

(figs. 348, 349, 350 & 351). These filamen-
tous pedicels in most cases exhibit a con-
traction just below the point of origin of the
spore, giving them the same appearance as
the pedicels of basidiospores. The spores

Fig. 348.

Fig. 349.

Fig. 348. Cephalothecium roseum. Magn. 200 diams.
Fig. 349. Botrytis nutans. Magn, 200 diams.

are round (PI. 20. fig. 15), oval (fig. 351, and
PI. 20. figs. 5, 6), spindle-shaped (Fusisro-
RIUM), spiral (HELICOSPORUM), and iso-
lated or connected (fig. 350) in beaded lines

Fig. 350.

Cephalotrichum Caput-Medusse.
Magnified 200 diams.

(PENICILLIUM, ASPERGILLUS), or grouped
in a stellate form. In the Isariacei and Stil-
bacei the erect pedicels are composed of a
number of conjoined filaments (fig. 354) ; in
the other families the pedicels are simple
filaments. Some authors include among
these plants theMucorini(PHYSOMYCETEs),
regarding the vesicular envelope of the spores

there as a mere veil, not a true cell producing
the spores in its interior. This family is of

Fig. 351.

Fig. 352.

Clonostachys Araucaria.

Fig. 351. Magn. 200 diams.

Fig. 352. A fertile branch. Magn. 400 diams.

especial interest from containing so many
moulds and mildews, and various parasitical
Fungi to which the diseases of plants, and in

Fig. 353.

Fig. 354.

Ceratocladium microspermum.
Fig. 353. Magnified 200 diams.
Fig. 354. Spores magnified 400 diams.

some cases of animals, have been attributed.
Further particulars respecting these will be
found under the Families, also PARASITIC
FUNGI.

HYPNEA.

[ 336 ]

HYPOCREA.

Synopsis of the Families.

1. ISARIACEI. Receptacle clavately-
branched, composed of filaments closely at-
tached in their whole length ; spores simple,
attached to simple pedicels arising in all
parts (fig. 353).

2. STILBACEI. Receptacle wart-like or
clavate above, stalked below, composed of
filaments closely packed, coherent, termina-
ting singly in free spores.

3. DEMATIEI. Mycelium filamentous,
spores compound or simple, arising from the
apices of erect, solid, corticate, subopake
filaments (fig. 350), or produced by the so-
lution of the plants.

4. MUCEDINES. Mycelium filamentous,
spores solitary, or crowded on articulated or
branched, tubular and pellucid filaments
(fig. 348, 349), soon separating and mingling
with the mycelium, or adherent in chained
rows.

5. SEPEDONIEI. Mycelium filamentous,
spores usually found heaped together resting
on the mycelium, and apparently springing
out of it directly, i. e. without erect spori-
diferous pedicels.

HYPNEA, Lamouroux. — A genus of Rho-
dymeniaceae (Florideous Algae), the only
British species of which, H. purpurascens,
is a common purplish-pink feathered or
shrubby sea-weed, the lobes being cylindri-
cal, filiform and cartilaginous, growing from
6" to 2" in height, with the filaments about
V" in diam. On stones, rocks, &c. between
tide-marks. The fructification consists of
coccidia, tubercles immersed in the ramuli,
each containing a mass of small spores ; and
tetraspores, immersed in the lesser branches,
of .separate plants.

BIBL. Harvey, Brit. Mar. Ala. p. 130.
pi. 16 D; Phyc. Brit. pi. 116; English
Botany, pi. 1243.

HYPNOIDE.E.— A family of Pleurocar-
pous Mosses of large extent. Leaves with
the cells prosenchymatous, dense or lax,
smooth or papillose. Alar cells at the bases
of the leaves diverse : 1, square, flattish or
ventricosely impressed, pellucid or yellow-
ish, or fuscescent ; 2, few, vesicular, placed
at the very base, of a delicate yellow or hya-
line ; 3, obsolete, scarcely any, placed at the
very base, fugacious, hyaline, vesicular ; 4,
many, square, in papillose leaves, but mostly
not very conspicuous. Leaves 0-5-nerved.
Nerves binate, diverse: 1, divergent from
the base, distinct, very callous at the back of
the leaf and prominent in the form of a spine
from the dorsal surface ; 2, flattened down,

scarcely callously prominent ; 3, in leaves
where the alar cells are vesiculiform, the
nerves obsolete, indicated by a pair of very
short striae, mostly inconspicuous.

British Genera.

a. Internal peristome without interposed cilia.

I. NECK ERA. Calyptra dimidiate. Pe-
ristome double, single or absent, the internal
or the external or both being occasionally ob-
solete. External : 16 equidistant or more or
less geminate teeth, lanceolate, trabeculate,
with a longitudinal line composed of a double
layer, arising below the orifice, sometimes
split into several irregular arms. Internal :
similar to the above or capillary, placed on a
more or less exserted membrane, conjoined
by transverse appendages, very often wholly
or partly cancellate. No interposed cilioles.

II. PILOTRICHUM. Calyptra mitriform.
Peristome, &c. as in NECKERA.

b. Internal peristome with interposed cilia.

III. HOOKERIA. Calyptra mitriform.
Peristome double ; external teeth lanceolate-
subulate, with a more or less broad longitu-
dinal median line, trabeculate ; internal on a
more or less deep, keeled membrane, subu-
late, scarcely ciliiform ; rudimentary cilia in-
terposed, hardly conspicuous or more rarely
perfect.

IV. HYPNUM. Calyptra dimidiate. Peri-
stome double. External teeth sixteen, lan-
ceolate, trabeculate, with a more or less
broad longitudinal line, more rarely a fissure,
with more or less crest-like prominent tra-
beculae within. Internal teeth on a grooved
reticulated projecting membrane, lanceolate,
articulated, grooved, solid or perforated in
the middle, or altogether gaping and sepa-
rating. Cilia one to four, interposed, very
often rudimentary.

HYPNUM, Dill.— A large genus of Hyp-
noideae (Pleurocarpous Mosses). The British
species, amounting to nearly a hundred, are
too numerous to be dwelt on here. Many
of them are extremely common in all woods,
growing on trunks of trees, banks, &c. ; others
grow in water or in bogs, &c. The distinc-
tions of the species are taken in great part
from the forms, &c. of the leaves, which re-
quire the use of a microscope for their accu-
rate determination.

BIBL. Hooker, Taylor and Wilson, Mus-
cologia Britannica; Hooker, Brit. Flora,
vol. ii. pt. 1 ; Miiller, Synops. Muscorum.

HYPOCREA, Fr.— A genus of Sphaeriacei

HYPODERRIS.

[ 337 ]

HYPOPUS.

(Ascomycetous Fungi), with a horizontal,
sessile, or indistinct stroma, filiform asci and
simple spores. The species of this genus,
like those of Hypoxylon, as given by Fries,
are partly referred to Sphceria by other au-
thors ; the distinctions will be best explained
by taking all these genera under SPH^ERIA.
HYPODERRIS, R. Brown.— A genus of
Cyathaeous Ferns, with very prettily fringed
indusia. Exotic.

Fig. 355.

Hypoderris Brownii.

Sorus, with fringed indusium.

Magnified 25 diameters.

HYPOGLEL— A family of Gasteromyce-
tons Fungi, characterized by their resem-

Fig. 356.

Hydnangium c .indicium.

Basidiospores upon the hymenium.

Magnified 400 diameters.

Fig. 357.

Hysterangium clathroides.

Section of hymenium with oval basidiospores.

Magnified 400 diameters.

blance to the Truffles ( Ascomycetes) in grow-
ing underground, and by their fleshy mde-

hiscent sporange, which is excavated into sinu-
ous cavities lined with basidiospores, which
are sometimes smooth and sometimes tuber-
culated (figs. 356, 357).

BIBL. Tulasne, L. R. & C., Fungi Hypo-
gcei, Paris, 1851 ; " Rapport " on that work,
Ann. des Sc. nat. 3 ser. xv. 267, and Ann.
Nat. Hist. 2 ser. vol. viii. 19.

HYPOPTERYGIACExE.— A family of
Pleurocarpous Mosses with a peculiar ar-
rangement of the leaves, which are placed
in two opposite straight rows united on the
upper side of the stem, with a third median
row of smaller stipuliform leaves on the

Fig. 358.

Fig. 359.

Hypopterygium .

Fig. 358. Natural size.

Fig. 359. A leafy branch. Magnified 5 diams.

under side, bearing a resemblance to the
intermediate leaves in Selaginella (figs. 358 &
359). The cells of the leaves are parenchy-
matous and equal in all parts. The genera
are all exotic, viz. Hypopterygium, Cyatho-
phorum and Helicophyllum.

HYPOPUS, Dug.— A supposed genus of
Arachnida, of the order Acarina, and family
Acarea.

Char. Body ellipsoidal, coriaceous ; palpi
absent; labium oblong, prolonged in the
form of a rostrum, and furnished with two
long anterior rigid setse. The species are
numerous, and are found as parasites upon
both animals and plants; as Arvicola (the
field-mouse), Bombus (the humble-bee),
Musca (fly), some Myriapoda; also upon
ferns, &c. Dujardin has rendered it pro-
bable that they are young forms of Gamasus.
They have no mouth nor digestive organs.

PL 2. fig. 15 represents a Hypopus mus-

z

HYPOTHECIUM.

[ 338 ]

ILLOSPORIUM.

carum, which we found upon a house-fly
(Musca domestica).

BIBL. Duges, Ann. d. Sc. nat. 2 ser. i.
p. 20, ii. p. 37; Gervais, Walckenaer' s
Arachn. iii. p. 265 ; Dujardin, Ann. d. Sc.
nat. 3 ser. xii. pp. 243 & 259.

HYPOTHECIUM.— The term applied to
the layer of cellular tissue, on which are
attached the thecae or spore-sacs of the fruits
of the LICHENS.

HYPOXYLON,Fries.— A genus , of Sphse-
riacei (Ascomycetous Fungi), distinguished
by a sessile stroma, separate and distinct
from the matrix (see SPH.ERIA). The Hy-
poxyla of Bulliard with an erect stroma be-
long to XYLARTA.

HYSTERIUM, Tode.— A genus of Pha-
cidiacei (Ascomycetous Fungi), distinguished
by the elliptical or elongated perithecia (figs.
360 & 361), bursting by a simple longitu-
dinal slit. The species are numerous, grow-
ing upon (usually dead) bark, stems and
leaves of various plants. H. rugosum has
been placed by some authors among Lichens
(as Opegrapha macularis, epiphega, Eng.
Bot.). It is common on smooth living
branches of oak and beech. H. pulicare,

Fig. 361.

Fig. 360.

Hysterium degenerans.
Fig. 360. Natural size.
Fig. 361. Perithecium. Magnified 10 diameters.

Fig. 362.

Fig. 363.

Fig. 362. Hysterium foliicolium )3 Hederse. An ascus
containing eight spores, magnified 100 dia-
meters ; with loose spores, magnified 200
diameters.

Fig. 363. Hysterium elongatum. Spores. Magnified
400 diameters.

H. Rubi, H.Pini, a.n&H.culmigenum,t}ie grass
Hysterium and If. foliicolium growing on
leaves of hawthorn, ivy or oak, are common.
The species with septate spores (fig. 363)
form the genus Hysterographium, Corda.

BIBL. Berk. Hook. Br. Flora, vol. ii. pt. 2.
p. 293 ; Ann. Nat. Hist. 2 ser. vii. p. 185 ;
Fries, Summa Veget. p. 368 ; Greville, Sc.
Crypt. Fl. pis. 24, 26, 72, 87, 88, 129 & 167.

I.

ICHTHYDINA, Ehr.— A family of Rota-
toria.

Char. No carapace; rotatory organ single,
continuous, not lobed nor divided at ^the
margin.

The rotatory organ is in the form of a circle
in Ptygura and Glenophora ; in Ichthydium
and Chcetonotus it is long, band-like, and
placed upon the ventral surface.

The family is thus divided :

Eyes absent.
No hairs present.

Tail-like foot simple and truncate Ptygura.

„ forked Ichthydium.

Having bristly-hairs.

Tail simple, truncate Dasydytes.

Tail forked Chcetonotus.

Eye single, frontal Sacculus.

Eyes two, frontal Glenophora.

Dujardin places Ichthydium and Chatonotus
among the Infusoria ; and Ptygura among
his Melicertina.

BIBL. Ehrenberg, In/us, p. 386; Dujardin,
In/us.

ICHTHYDIUM, Ehr.— A doubtful genus
of Rotatoria, of the family Ichthydina.

Char. Eyes absent; body without dorsal
hairs ; pediform tail forked.

Locomotion is effected by cilia placed
upon the ventral surface.

Dujardin places this genus among his
symmetrical Infusoria.

I. podura (PI. 24. fig. 23). Body linear-
oblong, often slightly constricted near the
anterior turgid and sometimes trilobate end;
foot short; aquatic; length 1-140".

BIBL. Ehrenberg, Infus. p. 388.

ILLICIUM. See WINTERED.

ILLOSPORIUM, Mart.— A genus of Stil-
bacei (Hyphomycetous Fungi), mostly rose-
red gelatinous bodies growing upon Lichens,
described as consisting of irregular spores, at
first involved in a globule of mucus, and
afterwards glued together in simple, mealy
patches (these plants seem very obscure).
Four species are described as British :

1. I. roseum, Fr. (Grev. -Sc. Crypt. Fl.
pi. 51).

2. I. carneum, Fr. (Corda, Icon. Fung. iii.
fig. 1).

3. I. corallinum, Rob. (Desmaz. Exsicc.
no. 1551).

4. I. coccineum, Fr. (Cord. I. c. fig. 3).
BIBL. Op. cit. and Berkeley, Brit. Flora,

ii. pt. 2. p. 328, Ann. Nat. Hist. 2 ser. v.
466 ; Fries, Summa Veget. 482, Syst. My col.
iii. 259.

ILLUMINATION.

[ 339 ]

INFLAMMATION.

ILLUMINATION.— So much has been
said in the Introduction (p. xxv), and in the
articles ANGULAR APERTURE, DIATO-
MACE.E, POLARIZATION and TEST-OB-
JECTS, upon the subject of illumination in
general, and of the effects of various kinds
of illumination in rendering evident the dif-
ferent structural peculiarities of objects, that
we shall merely add here two illustrations of
the importance of attention to the physiolo-
gical effects of a variation in the relative
amount of light transmitted by or reflected
from the parts of an object, or of contrast
as it is popularly called.

If two candles, the flames of which are
of equal size and height, be placed parallel
to and 2 or 3 feet from a painted wall
or other un coloured surface, and a piece of
string be suspended at an inch or two from
the wall, and opposite the interspace between
the two candles, on lighting one of the latter,
the surface of the wall will be illuminated
at all points except those corresponding to
the shadow of the string. But on lighting
the other candle, two shadows will become
visible, the second lying in the direction of a
line drawn from the second candle through
the string to the wall. Thus by throwing an
increased amount of light upon all parts of
the wall except the line corresponding to the
shadow of the second candle, this line will
appear dark or even black; whereas it might
have been expected that this portion would
have appeared to the eye as light as it was
before, which is not the case. Again, if we
take a section of the shell of a hen's egg or
any similar object, and illuminate it by re-
flected light, all the more opake parts will
appear white and luminous ; but on trans-
mitting light from the mirror through the
object, the reflected light being unchanged,
the whole appearance will be altered, the
parts which were before white will now
become black, and vice versa.

These experiments show that it cannot be
concluded from the dark appearance of parts
of an object that light is not reflected from or
transmitted through them ; for parts may be
made to appear dark or black by simply
throwing more light upon the surrounding
parts, so that darkness may indicate either
absolute or comparative absence of light.
This important point must always be borne
in mind in determining the cause of the
appearances of objects under different kinds
of illumination.

INDIAN RUBBER, or CAOUTCHOUC.—
This substance occurs naturally in globules

suspended in the milky juices of many plants,
especially of the Orders Euphorbiacese, Ur-
ticaceae and Apocynaceae. The form of the
globules is varied. In PI. 39. fig. 23 is
represented part of a milk-vessel of Euphor-
bia antiquorum with two caoutchouc globules.
When such milky juices are evaporated, the
globules become blended into a uniform
elastic mass, the India-rubber.

Solution of caoutchouc is sometimes used
as a cement for closing glass cells, but its
chief importance in this respect depends on
its forming a constituent of marine glue (see
CEMENTS).

INDIGO. — This well-known vegetable
substance is chiefly obtained from plants of the
genera Indigofera and Isatis, and Polygonum
tinctorium, but may be found in many others.
It has also been found in human urine, of
which it is probably a normal constituent.
Its best marked character is that of subliming
in flattened prisms and plates (PL 6. fig. 14).
Indigo is sometimes used as a colouring
matter for injections ; and is also very
useful for colouring the internal cavities of
Infusoria which swallow the granules; for
rendering visible ciliary motion (see INTRO-
DUCTION, p. xxxi); &c. The simplest mode
of employing it is to rub it from a water-
colour cake of indigo very gently with a
little water. The Infusoria require to be
left in the coloured mixture some time, and
it is well to remove them into clean water
for examination.

BIBL. See CHEMISTRY.
INFLAMMATION.— The phenomena of
inflammation are best studied in one of the
lower animals, as in the web of the frog's
foot, the mesentery of the frog, the tail of
the tadpole, or of the larva of the water-
newt (Triton), the process being excited by
the application of a hot needle, a solution of
common salt, ammonia, dilute spirit or vola-
tile oil.

The first thing noticed is a contraction of
the capillaries, amounting to about one-third
of their calibre, the blood flowing through
them with increased velocity. The capillaries
then become dilated, redder and more full of
blood, but the current is still uniform. In
the next stage, the flow of blood becomes
irregular and oscillatory ; that is, the blood
goes forwards and backwards, sometimes
stopping for a time and then resuming its
onward course. At last the circulation
entirely ceases, the capillaries appearing
fully distended, and frequently tortuous and
varicose. When the stasis is perfect, the

z2

INFLAMMATION.

[ 340 ]

INFLAMMATION.

capillaries appear filled with a red mass, in
which the outlines of the globules may be
distinctly perceived, but the liquid portion
of the blood begins to acquire a red colour,
and upon puncturing one of the vessels, the
globules are found cemented together.

Lastly, the liquor sanguinis exudes through
the walls of the vessels, sometimes accom-
panied with extravasation of blood-corpuscles
from rupture of the capillaries. The con-
traction of the capillaries appears to result
from a vital contractility; the dilatation from
increased attraction between the blood and
the parenchyma. It does not appear that
the stasis is caused by an increase in the
number of colourless corpuscles, and their
adherence to the sides of the vessels, as has
been supposed.

Soon after the exudation is poured out
from the vessels, it usually begins to coagu-
late, and the changes which it subsequently
experiences, vary according to the intensity
of the inflammation, and the part in or upon
which it is deposited.

The principal forms assumed by inflam-
matory exudation are —

1. The gelatinous or molecular. After
coagulation has taken place, the more solid
portion remains as a gelatinous structureless
mass, or exhibits numerous molecules, gra-
nules, and homogeneous globules, immersed
in its substance, and consisting of proteine-
compounds or fatty matter.

2. The fibroid and fibrous. Two forms of
this occur. In one, the fibroid, the mass
exhibits rather a fibrous appearance than a
true fibrous structure, presenting ill-defined
striae, principally following one direction, the
mass containing also numerous molecules
and granules. Some of these striae indicate
commencing separation into fibres; others are
indications of folds produced by manipula-
tion. This variety constitutes a common
form of recent false-membrane. In the
other, the true fibrous, the mass consists of
very minute, crowded, pale and slender
fibres, interlacing in all directions or running
parallel with each other. Sometimes the fibres
are united into bundles; at others, one part of
the mass is found to consist of the fibroid
structure, another of true fibres. As the
lymph or exudation becomes older, the fibres
become firmer and more distinct. In some
instances, the fibroid and fibrous tissue forms
a loose mesh-work, containing a liquid sub-
stance— colloid tissue of exudation; this
consists of fibrine, not gelatine.

These two forms of tissue consist chemi-

cally of proteine-compounds. They are
mostly rendered more transparent by and
swell in acetic acid; but sometimes this
reagent slightly coagulates them.

3. The corpuscular. The corpuscles of
inflammatory exudation are of four kinds :
a, exudation-corpuscles or granule-cells; b,
pyoid corpuscles ; c, pus-corpuscles, and d,
fibro-plastic corpuscles. These names have
been variously applied by different authors,
so that their signification has become vague.

a. Exudation-corpuscles or granule-cells
(PI. 30. fig. 7)» sometimes called granular
cells, or granular corpuscles, are spherical or
rounded corpuscles, of very variable size,
perhaps on an average from 1-4000 to
1-1500" in diameter. They are sometimes
solid, at others consist of cells, and always
contain numerous globules of fat, sometimes
also a nucleus. Their outline is usually very
faint, and often no outline is perceptible,
except that formed by the globules. They
are scarcely affected by acetic acid, whilst
solution of potash disintegrates them and
liberates the fatty globules. They are
sometimes aggregated into masses — com-
pound granular masses. The exudation in
which they are contained always exhibits
numerous free globules of fat, arising from
their disintegration. They closely resemble
in appearance cells of tissues which have
undergone fatty degeneration.

b. Pyoid corpuscles, sometimes called
plastic corpuscles, and c, pus-corpuscles, are
described under Pus ; and d, fibro-plastic
corpuscles, under TISSUE, FIBRO-PLASTIC.

The relative proportions in which these
elements are contained in various exu-
dations depends upon the acuteness, stage,
duration and locality of the morbid process.
Thus, in wounds undergoing cure by the first
intention, the exudation is at first gelatinous,
then fibroid and ultimately fibrous. Upon
the surface of serous membranes, the above
forms occur mixed with pyoid and granule-
corpuscles, and sometimes those of pus. The
same applies to mucous membranes, but
here the corpuscles predominate, and are
mostly mixed with epithelial cells. In the
substance of organs, the granule-cells gene-
rally predominate ; and in inflammation of
the brain, these are formed outside the walls
of the vessels, and care is required to dis-
criminate the compound granular masses
from fatty globules deposited in the walls
of the vessels.

BIBL. Works on Medicine; Lebert, Phy-
siol. PathoL-, Wed},PathoLHistolog. ; Forster,

INFUSORIA.

[ 341 ]

INFUSORIA.

Pathol. Anat.; Bennett; Edinb. Monthly
Journ. 1850. x. p. 150; W. Jones, Guy's Hosp.
Reports, 1850 ; Paget, Lectures on Inflam-
mation ; Gluge, Atlas d. Path. Anat.

INFUSORIA.— An order of Animals.

Char. Microscopic animals not furnished
with either vessels or nerves, but exhibiting
internal spherical cavities ; motion effected
by means of cilia, or variable processes
formed of the substance of the body, true
feet being absent.

(Body composed of proteine compounds ;
soluble in solution of potash.)

Every one who has examined with a micro-
scope a drop of water containing animal or
vegetable matter which has been set aside
for a time, or a drop from any pool or ditch,
must have observed numerous minute beings
in active motion, resembling some of those
figured in Pis. 23, 24 & 25 ; these are Infu-
soria, or the animalcules of infusions.

Perhaps no question has been more dis-
cussed than that of the structure of the
Infusoria. Ehrenberg regards them as
being highly organized, and furnished with
distinct organs like the higher animals ;
whilst more recent authors consider them as
representing simply a nucleated cell. Unfor-
tunately the facts are not accordant with
either of these views; the question must at
present be considered as still sub judice.

The structure of the Infusoria is not the
same in all the families. In the Amcebsea,
in which the simplest form of animal struc-
ture occurs, the entire substance of the body
consists of a glutinous, homogeneous or
slightly granular diaphanous sarcodic mass
(PI. 23. fig. 9 a), in which no trace of organs
can be detected. In the substance of the
body a number of rounded moving spaces
are frequently visible, containing foreign
particles serving as food, and derived from
the surrounding water (fig. 96). The entrance
of these particles takes place, or has been
described to take place, in two ways ; either
by the tentacular expansions of the body
surrounding them, and forcing them towards
the interior, where they are digested whilst
surrounded by the inverted outer portion of
the body, or they are urged into the sub-
stance itself, just as a marble might be
forced into a mass of jelly or paste, and
being moved through the body by the
general contraction of its substance, are ulti-
mately expelled. In the next simplest
family, in the Arcellina, the sarcodic mass is
contained within a distinct envelope or cara-
pace, from an orifice in which the tentacular

expansions are protruded (PI. 23. fig. 39 ;
PI. 25. fig. 24).

These two families have been separated
from the Infusoria by some authors (Rtiizo-
PODA) ; but the same structure exists in
many of those which are left by these
authors among the Infusoria.

In other Infusoria the outer portions of
the body appear to be firmer than the inner;
hence these may be said to have an outer
coat. In others again, a fine pellicle invests
the surface, which is distinctly separable ;
whilst in the last form, the body is more or
less enclosed in a carapace or shell, to which
it is to a greater or less extent attached.
We shall examine the further structure of
the Infusoria, by considering the parts in
order and separately, to prevent confusion.

Integument. — The carapace must be viewed
as a secretion from the body of the animal,
and not as corresponding to an integument.
This structure has been noticed under
CARAPACE ; in Arcella it is undissolved
by potash, even on boiling; and it is not
coloured red by Millon's test, nor blue by
sulphuric acid and iodine ; hence it does not
appear to consist of either a proteine-com-
pound or cellulose ; perhaps it is composed
of chitine.

In some Infusoria a distinct outer coat is
present, as in Paramecium. It often becomes
visible when the Infusoria are kept in a small
quantity of water upon a slide, the globules
of sarcode which escape from rupture of the
body carrying it before them. It is fre-
quently beautifully marked with minute
depressions (PI. 25. fig. 1), regularly arranged,
and from each of which a cilium arises.
Dujardin distinguishes a contractile and a
non-contractile integument; but in many
instances, this author does not distinguish
with sufficient clearness between the carapace
and the integument, and his non-contractile
integument frequently corresponds to the
carapace. Beneath the outer coat, the
substance of the body frequently appears
thicker, although no distinct layer can be
separated; and it is doubtful whether the
markings are situated in the outer coat, or
whether the latter derives them from being
moulded upon the inner coat, to which they
properly belong. The structures here exhibit
some analogy with those of the cell-contents
of the cells of certain Confervoid Algae. The
outer pellicle may correspond to the primor-
dial utricle or external mucilaginous layer.
The next coat, when distinguishable, is not
so well defined ; it is strictly bounded on the

INFUSORIA.

[ 342 ]

INFUSORIA.

outside, but internally appears to pass gra-
dually into the softer substance of the central
mass, like the protoplasm in vegetable cells.
Like this again, it often appears to be pro-
longed in irregular processes across the
central mass, forming septa or cross parti-
tions, so that the softer substance occupies
only as it were cavities hollowed out in
the firmer reticular sarcodic mass ; hence
arises a cellular appearance. The existence
of the outermost coat or pellicle is demon-
strated by the phenomenon of ecdysis, which
occurs in certain species. But these mem-
branes or pseudo-membranes do not appear
to exist in all cases, for in some Infusoria the
body adheres readily to the glass of the
slider on which it is viewed under the micro-
scope, and is torn up into fragments in the
endeavour to free itself.

The structure of these parts will be again
discussed in the sequel.

Dr. Allman has lately pointed out the
occurrence of minute cilia-like filaments
attached at the base to cells (?) or rounded
bodies, imbedded in the integument, and
resembling the stinging organs of Hydra, &c.

Locomotive organs. — No distinct muscular
structure can be detected in the Infusoria,
but a contractile power is possessed by the
general substance of the body. In Vorticella
(PL 25. figs. 21 a & 27) and some others,
the contractile substance is prolonged
through the hollow pedicle, thus forming a
spurious muscular band.

The other directly or indirectly locomotive
organs are thus distinguished. 1, cilia :
these are the most common, and form the
fine, short, very transparent, hair-like fila-
ments projecting from their surface. In
some they entirely cover the surface, whilst
in others they are arranged in one or more
rows round the mouth, or upon the ventral
surface, &c., as described under the genera.
During life they are seen actively vibrating, and
in some their motion appears constant; whilst
in others it is interrupted at intervals, appa-
rently under the influence of a will. They
are most distinctly seen when the Infusoria
are dried (see CILIA). 2, flagelliform fila-
ments (PI. 24. fig. 59) ; which are long
anterior cilia, the ends only of which are
vibratory and moveable in all directions ;
they are usually one or two only. 3, retract-
ing cilia or filaments (PI. 23. figs. 12, 18 a ;
PL 24. fig. 17) : these are single, long,
flexuous and directed backwards ; they fre-
quently become adherent to the slide, and
produce a sudden, backward motion of the

animal. 4, setae or bristles (PL 24. fig. 53) :
these are rigid, filiform, straight and move-
able, but not vibratile, and are sometimes
provided with a bulb at the base ; they can
be slowly raised or depressed, and serve for
support, walking or climbing. 5, styles
(PL 25. fig. 17), are thick, straight, very
moveable setae, without bulbs ; they neither
rotate nor vibrate. 6, uncini or hooks (P1.41.
fig. 13) are short, thick, curved setae, serving
for prehension, climbing or creeping; and
are bulbous and usually very thick at the base.

Nervous system. — None has been dis-
covered. In the naked Infusoria, the sense
of touch is diffused throughout the substance
of the body. In others, it is particularly
developed in the snout-like appendages of
the body, and in the longer cilia, setae, &c.
The Infusoria are probably all sensible to
light, and many of them exhibit near the
anterior part of the body, one or more
coloured (mostly red) specks, which have
been considered as eyes ; but they contain
no distinguishable cornea, nor lens, nor are
they connected with any appreciable sub-
stance comparable to nervous matter; and
similar specks occur in the same situation in
the spores of many Algae; moreover, the
eye-specks are most distinct in those genera
which are doubtful Infusoria. Hence it might
be denied that they represent eyes. Yet
they bear considerable resemblance to the
eyes of the Rotatoria, and some Annelida;
so that their true nature must be considered
as problematical.

Digestive system. — On attentively exami-
ning Infusoria under a high power (1-4 to
1-8), a number of roundish spots are gene-
rally visible in the substance of the body ;
they are sometimes filled with a whitish
granular matter, at others they contain Des-
midiaceae, Diatomaceae, or other algae, or
bodies existing in the surrounding water.
These have been called gastric vesicles, cells,
spaces or sacculi. They are only visible
from their contents, and no membrane can
be distinguished in them. If a little indigo
or carmine be added to the water containing
the Infusoria, these cavities will soon become
filled and will be rendered very distinct ; in
the plates they are represented as filled with
these pigments.

On attentively watching them, they will
appear to move around the body of the
animalcule, sometimes two of them appear-
ing to become fused into each other, or the
contents of one to pass into another.

Finally, the pigment will be seen to escape

INFUSORIA.

[ 343 ]

INFUSORIA.

at some part of the surface of the body,
when the spots will vanish. Different views
have been entertained in regard to the nature
of these spots or cavities. By the older
observers, they were regarded as internal
cavities, into which water was admitted with
any particles accidentally suspended in it,
forming a means of bringing a greater extent
of surface of the substance of the animalcule
into contact with the water, and thus aiding
in respiration.

Ehrenberg regards them as dilated caeca
or portions of a true alimentary canal
(PL 24 a) ; whilst Dujardin considers them
as vacuoles arising in the same manner as
those found in sarcode, from whatever source
derived; others have viewed them as cells
floating loosely within the body. Most
observers deny that they are portions of an
alimentary canal, and that such canal exists,
but seem inclined to adopt the opinion that
they are cavities irregularly formed in the
substance of the body by the introduction of
the foreign matters, which are urged through
it by its contractions, or moved onwards by
its circulation. They are certainly not
cells, otherwise they could not so readily
admit particles of colouring matter, &c., nor
could their contents become fused together,
as is sometimes seen to occur. They do not
appear to be simply vacuoles filled in the
ordinary manner by the surrounding liquid,
because the pigment is accumulated in them
in greater proportion than it exists in the
liquid. In many Infusoria, the particles are
admitted at a definite orifice, representing a
mouth; this is round or oval, sometimes
situated at the anterior end of the body,
sometimes more posteriorly, or even at the
commencement of the posterior third of the
body, and it is generally indicated by a
circle, fringe or some other definite arrange-
ment of the cilia, which bring the particles
towards it. The course which the particles
(apparently the gastric cavities) take is
usually irregular, but sometimes tolerably
definite, down one side of the body and up
the opposite. The manner in which the
undigested particles are evacuated is also an
unsettled question; for whilst Ehrenberg
admits either the existence of a distinct
excretory orifice, or evacuation by the mouth,
other authors assert that these particles may
be evacuated at any part of the surface of the
body.

The question then must remain, whether
there is a distinct alimentary canal, the walls
of which are invisible on account of their

extreme delicacy, or whether the particles
drawn in by the cilia are urged at random
through the substance of the body. The
fact that distinct walls cannot be detected, is
of no great weight in opposition to the for-
mer view, because the radiate contractile
vesicles of Paramecium exhibit no walls, and
are quite invisible when contracted ; and the
excretory vessels ofDistoma, although having
distinct walls, are seen to contract, and then
to vanish completely (Van Beneden).

It may easily be ascertained by experiment
that some Infusoria will imbibe bisulphuret
of mercury as readily as indigo or other
matters, and thus would appear to be entirely
deprived of any selecting power governed by
a sense of taste ; but some kinds would seem
to have a sense of taste : Coleps, for in-
stance, greedily devours the substance of
crushed Entomostraca and their ova, be-
coming greatly deformed in the operation.

The vacuoles or digestive cavities are fre-
quently very distinct when the animalcules
are dead, and especially when dried. If the
animalcules be fed with colouring matter, on
drying them, the vacuoles thus rendered di-
stinct will be found to contain the pigment,
which is in favour of Dujardin's view.

Surrounding the mouth in some Infusoria,
as Nassula, Prorodon, Chilodon, and Chla-
midodon, is a horny cylinder of rod-like bo-
dies, called teeth (PI. 23. fig. 27 a, b; fig.
29; PL 24. figs. 40. 45. 72) ; they do not
appear to exert any triturating power, and
their true signification is unknown. In some
Infusoria a kind of oesophagus is also pre-
sent, as in Vorticella, Carchesium, Epistylis,
Oxytricha, &c., consisting of a mostly fun-
nel-shaped tube, often lined with cilia.

A coloured gastric juice has been described
by Ehrenberg as existing in the gastric cavi-
ties. The colour has, however, been ac-
counted for by Siebold, as produced by re-
fraction, and the presence of aggregations of
pigment-granules mistaken for gastric cavi-
ties. This explanation we believe to be in-
admissible; and in some instances at least (PL
23. fig. 19), the reddish-violet colour is real,
and arises from the presence of solution of
the chlorophyll of Oscillatorice, which is often
different by reflected and transmitted light.

Circulating system. — On closely watch
ing almost any of the Infusoria, minute,
mostly rounded, clear spots are seen in the
substance of the body, disappearing and re-
appearing at pretty regular intervals. These
are of variable size, but about that of the
gastric cavities. The nature of their con-

INFUSORIA.

[ 344 ]

INFUSORIA.

tents, which is a colourless liquid, is doubt-
ful. Dujardin regards it as consisting of
water, and as existing in vacuoles similar to
the vacuoles or gastric cavities ; whilst Sie-
bold finds here a kind of rudimentary circu-
lation of a nutritive fluid, comparable to the
circulation of the blood. In certain Infu-
soria, as Paramecium (PL 24. fig. 56), this
phenomenon is observed to take place be-
tween a central rounded and several elon-
gated and radiating cavities ; and the liquid
contents are seen to be propelled from the
former into the latter, and vice versd. These
contractile or pulsating vesicles or spaces,
as they are called, never contain foreign
particles ; they are tolerably constant in po-
sition in the same species of Infusoria ; and
they do not rotate nor move like the gastric
cavities ; all which facts are opposed to the
notion of identity with the latter. Yet they are
found in some Algae, as Volvox, which would
negative their relation to an animal circulation.
Ehrenberg regarded them as seminal vesicles.
Another kind of circulation takes place in
some of the larger Infusoria. This is a rota-
tion of the mass of the internal substance of
the body, situated between the outer coat and
a central space occupied by a thin liquid, in
which the nucleus lies. It has been observed
in Paramecium, but only in those specimens
having green corpuscles imbedded in the outer
coat. It is best understood by comparing it
with the circulation in a cell of CHARA.

Nucleus. — In the substance of the bodies
of most of the Infusoria may be perceived a
solid granular-looking body, of variable form,
mostly rounded, elongate, or curved (PI. 23.
fig. 53 ; PI. 24. figs. 37. 56 ; PL 25. fig. 26),
sometimes branched (PL 25. fig. 25), which
those who regard the Infusoria as consisting
of simple cells, consider as a true nucleus ;
whilst Ehrenberg regarded it as a testis.
The latter it certainly is not, but it is con-
nected with reproduction, as stated below.

When almost any of the Infusoria are
allowed to remain upon a slide until most of
the water has evaporated, certain rounded
and somewhat highly refractive globules will
become evident at their margins (PL 25. fig.
2 a) ; these consist of semifluid gelatinous
sarcode, and they possess a remarkable ten-
dency to the formation of vacuoles or cavi-
ties in their interior, which apparently be-
come filled with the surrounding water.
This fact is perhaps the strongest in favour
of the formation of the gastric cavities and
contractile vesicles within the body of the
living animals, in the same manner as sup-

posed by M. Dujardin ; which is, however,
opposed, in the case of the contractile vesi-
cles, by their tolerably constantly uniform
position, and especially their remarkable
form (as in the stellate vesicles of Parame-
cium, &c., PL 24. fig. 56), and the manner
in which the contents in the latter instance
are propelled from one to the other, or
from the radiate to the rounded vesicles.

The argument that structures similar to
those of the higher animals cannot be de-
tected because they are proportionately small
in agreement with the small size of the ani-
mals themselves, does not probably hold
good; because the elementary tissues of the
lower animals are generally even larger than
in the higher ; thus, the elementary fibrillae
of the muscular fibres of a fly are larger than
those of a horse, the difference in size of the
muscles depending upon the number of them
forming a muscle ; and in the Infusoria we
might expect them to be single, or in small
number, but still distinct. It would be well
to prepare some of the larger Infusoria in
the same manner as the muscular structure
is prepared to exhibit the ultimate fibrillee.

In regard to the cell-nature of the Infu-
soria, such can scarcely be conceived to exist
in- bodies surrounded by an integument
which is being continually ruptured at va-
rious points by the admission or expulsion
of drops of water. Again, the existence of a
distinct mouth, or part at which foreign bo-
dies are admitted, seems inconsistent with
the notion of a cell. The occurrence of
stinging organs in the outer surface, should
it be confirmed, would still further oppose
this view. The remarkable manner, also, in
which the substance of the crushed bodies
and the ova of the Entomostraca attract and
are consumed by Coleps, shows evidently
that these animals have a distinct sense of
taste ; for they are not only attracted by it,
but they may be seen to gorge themselves
until they become quite altered in shape
from distension. If the contractile vesicles
are the same as the gastric cavities, it is dif-
ficult to understand why, when containing
water, they should be contractile, and when
containing water and foreign bodies, they
should not be so, and should move about.

Propagation. — Distinct sexual organs are
unknown in the Infusoria ; and their modes
of propagation resemble in many respects
those of plants, especially the Algae; although
it must be remembered that the intermediate
generations of some of the higher animals
are often developed upon the same plan. It

INFUSORIA.

C 345 ]

INFUSORIA,

may be mentioned that Ehrenberg regards
the Infusoria as hermaphrodite; the male
organs consisting of the contractile vesicles
and the so-called nucleus ; whilst the ova-
ries and ova are represented by colourless or
coloured corpuscles imbedded in the sub-
stance of the body, and which are found to
vary in number periodically, being sometimes
absent, at others forming filiform meshes
comparable to the ovaries of Insects and the
Trematoda. Undoubtedly, many of the co-
loured corpuscles seen in the bodies of the
Infusoria are granules of chlorophyll, or
other matters derived from without; but
some of them may consist of chlorophyll-
granules formed within the body, as in Hydra.
Division. — Spontaneous division is either
longitudinal (PI. 25. fig. 37), or transverse
(fig. 38). In both the nucleus undergoes
division, as well as the body. In the longi-
tudinal division the process commences at
one end of the body, from which the cilia
usually are retracted or disappear ; a notch
is first perceived, which afterwards becomes
deeper, until the body is completely cleft ;
the two halves then acquire cilia, and assume
the functions of perfect animals. In the
transverse division, a median constriction
appears first, followed by perfect separation,
as in the last. During these processes of
division, the animals sometimes continue
their movements as usual ; at others this is
more or less interfered with. In Vorticella
(PL 25. fig. 21 a), in which the process of
longitudinal division may be conveniently
watched, on account of the comparative fix-
ture of the animals by a pedicel, when the
division is nearly completed, a ring of cilia is
formed near the attached end of the body,
by the movements of which the new Vorti-
cella is separated from the parent. The
process is completed in about an hour.

Gemmation — is not a general process in the
Infusoria. It is well seen in Vorticella (PI.
25. fig. 26). The buds arise from near the pos-
terior end of the body, and, when fully deve-
loped, liberate themselves by the formation of
a posterior ring of cilia, as above mentioned.
Diffluence. — Some authors have described
a mode of increase in Infusoria, where the sub-
stance of the body breaks up into a number
of fragments, each of which is capable of
becoming a perfect individual. The exist-
ence of this process, called diffluence, is
questioned by later observers, and is said to
have arisen from a confusion with the phse-
nomena accompanying the increase of the
encysted forms.

Encysting Process. — Many of the Infusoria
are observed to alter their form at certain
periods, become rounded, lose or retract their
cilia (PI. 25. fig. 27), and to secrete all over
then* surface gelatinous matter, forming a
coat or cyst enclosing them. While thus
encysted, the substance of the body becomes
divided, and gives origin to a number of in-
dividuals, which are discharged by the burst-
ing of the cyst. They do not always re-
semble the parent in form (PI. 25. fig. 34).
In some cases the progeny or brood become
individually encysted within the parent cyst;
it appears, however, that they are not dis-
charged in this condition, but escape first
from their own cyst and then from the pa-
rent, in which they leave their own exuviae.
Stein thinks that it was such broods that
Ehrenberg mistook for the results of the
increase by diffluence.

The encysted forms also propagate by
giving birth to germs by a process of internal
or external budding; this connected with the
Acineta-formation. — The most remarkable
point connected with the reproduction of the
Infusoria is the phenomenon of the ALTER-
NATION OF GENERATIONS. Many kinds
which propagate by subdivision, or gemmation
from the surface, in their ordinary course of
life, as Vorticella, Paramecium, &c., undergo
a metamorphosis leading to a different mode
of increase. They lose their characteristic
form, become rounded and encysted, and
then push out tentacular processes at various
points, so as to acquire the shape which has
given rise to the foundation of the genus
Acineta. Occasionally the Vorticellce of this
form, which after becoming encysted are
detached from their pedicels, become again
attached by a foot, and in this case present
the appearance of a Podophrya. The nucleus
and the contractile vesicle are clearly di-
stinguishable in this stage. The nucleus
then gives birth to a new individual, by bud-
ding, which becomes free and independent
in the interior of the Acineta parent, and is
ultimately expelled. This process may be re-
peated many times. Propagation also occurs
in these Acineta or Podophrya forms by a bud-
ding out from the surface, or the conversion
of the whole contents into new individuals.

We may sum up the modes of increase
of the Infusoria as follows : — 1. The perfect
characteristic form of the animal may in-
crease by simple division, or by gemmation
from the surface. 2. This form may be-
come rounded and encysted ; the encysted
mass is then («) converted entirely into a

INFUSORIA. [

variable number of new individuals, discharged
by the bursting of the parent- cyst ; or (b)
new individuals are formed singly or in small
numbers by a process of internal budding,
the new individuals becoming free within
the parent, and then escaping from the cyst;
or (c) the simple encysted form is metamor-
phosed into the Acineta (free) or Podophrya
(stalked) form, by the protrusion of tuber-
cular processes ; in this state it gives origin
to new individuals by internal budding (from
the nucleus). Colpoda afford examples of
the processes 1 and 2, a and b ; the Vorti-
cellte of all three together, with the two
modifications of 2 c.

When the Vorticellcs are about to become
encysted, they draw in their ciliated disk and
contract their bodies into a ball, at the same
time secreting around them a gelatinous mass
which solidifies into a firmer elastic covering.
Sometimes this occurs whilst adherent to the
stalk, which latter then soon dies away and
disappears, this process being first indicated
by the breaking up of the muscular band
into separate portions. More frequently,
however, it becomes detached from the stalk
first, and a ring of cilia is developed near the
end of the body of the Vorticella, which be-
comes encysted whilst swimming. The Aci-
neta or Podophrya forms are further metamor-
phoses of the gelatinously encysted forms.

Conjugation. — A process of union of the
bodies of distinct individuals has been ob-
served in the Infusoria, in the ordinary
forms as well as in the Acineta and Podo-
phrya conditions (PI. 25. fig. 33). So far as
the point is ascertained, however, this phae-
nomenon does not seem to be connected
with reproduction. The blending of the
individuals does not become complete ; it is
rather a cohesion, and the lines of demarca-
tion may always be traced. Three, four, or
even more have been observed united
together. Conjugating pairs might be taken
for a dividing body if hastily viewed. But
the distinction is not only perceptible by the
reverse order of the changes seen on watching
the object, the bodies becoming more and more
blended instead of separated, but the frequent
diversity in the condition of the bodies, as to
transparency, &c., and above all, the nuclei,
clearly mark the characters. The nucleus
of a dividing body is ordinarily extended
longitudinally at right angles to the line of
division, being divided across by this. In
conjugation the two nuclei are generally
found lying parallel to each other and (at
some distance) to the surface of union.

16 ] INFUSORIA.

Some observers have attempted to prove
that Infusorial animals and plants are derived
from the direct transformation of organic
matters ; thus the molecules of the ultimate
fibrilla3 of muscle, when separated by the
effect of decomposition, acquire the appear-
ance and motion of Bacteria. These obser-
vations, however, prove nothing to the point,
because the bodies are so much alike as to
be undistinguishable by mere appearance,
and without the use of chemical reagents.
These have been entirely neglected. Repe-
tition of the experiments with the aid of
acetic acid and solution of potash, shows
readily that these notions are entirely erro-
neous.

When we consider that the multiplication
of the Infusoria by division takes place
according to a geometrical progression, also
that they need only become encysted to
produce swarms of germs, we can easily
understand their rapid propagation in liquids;
when also they will resist a degree of cold
= 8° F,, and an elevated temperature of
260° F., or even desiccation, without destruc-
tion, and when their minute size is added,
we can readily understand their almost uni-
versal diffusion.

As we have stated, a drop of water can
scarcely be found which does not contain
some Infusoria. Many of them will only
live in fresh or sweet water, whilst others
are found only in decomposing and even
putrid water containing decomposing animal
and vegetable substances ; others, again, are
only met with in salt or brackish water.
Those existing in fresh water may be col-
lected in ordinary wide-mouthed bottles,
a drop of which may be removed by the
dipping-tube ; any individual one perceptible
to the eye may be withdrawn by the same
means. Their natural movements are best
watched in the live-box; but these move-
ments greatly interfere with the observance
of the contractile vesicles, and general mi-
nute structure, which is best seen when they
are simply confined between the slide and
cover, in a small quantity of water. A good
plan for arresting their motions is that of
warming the slide containing them over a
candle or lamp for a short time. Many In-
fusoria live only in particular kinds of infu-
sions, just as certain plants live only upon
particular kinds of soil ; and these infusions
should be prepared by adding cold fresh
water to the vegetable or animal substances,
the water being in considerable excess, and
allowing the mixture to remain for a time.

INFUSORIA.

[ 347 ]

INFUSORIA.

Even in infusions of many powerful poisons,
as of Nux vomica, Cevadilla, &c., they will
not be found absent ; and Dujardin has no-
ticed that their development is greatly pro-
moted by the addition of certain salts to the
solutions, as phosphate and carbonate of
soda, phosphate, nitrate, and oxalate of am-
monia ; and this author is inclined to believe
that some of these salts become decomposed
in the presence of the organic matters,
yielding nitrogen to the Infusoria; he also
states that oxalate of ammonia disappears
entirely under these circumstances. We
believe, however, that a process of oxidation
goes on in many of these cases, unconnected
with the presence of the Infusoria, and thus
salts of vegetable acids become converted
into salts of more highly oxidized acids, as
into carbonates, &c.

The following are the most common of
the Infusoria found in natural waters or infu-
sions of vegetable or animal matters : —

Amphileptusfasciola.
Bodo saltans.

socialis.

Chilodon cucullulus.
Chilomonas parame-

cium.
Chlamidomonas pul-

visculus.
Coleps hirtus.
Colpoda cucullus.
Cyclidium glaucoma.
Euplotes charon.
Glaucoma scintillans.
Leucophrys carnium.

pyriformis.

Monas crepusculum.
gliscens.

Monas guttula.

termo.

Oxytricha pellionella.
Paramecium aurelia.

chrysalis.

colpoda.

milium.

Polytoma uvella.
Stylonichia pustulata.

mytilus.

Trachelius lamella.
Trichoda pura.
Trichodina grandi-

nella.

Uvella glaucoma.
Vorticella convallaria.
microstoma.

Some of the Infusoria are phosphorescent,
and impart a luminous property to sea-
water. The following are the species in
which this has been distinctly observed : —
Prorocentrum micans ; Peridinium michaelis,
P. micans, P.fusus, P.furca, and P. acu-
minatum ; Synchceta baltica, and a doubtful
species of Stentor.

Slender needle-like crystals of sulphate of
lime have been observed affixed to the bodies
of the Infusoria, probably derived from the
water in which they live.

The Infusoria are difficult of preservation.
Some of them will exhibit their characters
when dried; the cilia and vacuoles remaining
very distinct, as also the striae upon the in-
tegument. Others are but little changed
by a concentrated solution of chloride of

calcium. Solution of chromic acid or of
bichloride of mercury will answer with some
of them, although they are rendered some-
what opaque by these reagents, which is
sometimes an advantage where they are
naturally very transparent.

The systematic arrangement of the Infu-
soria is in an unsettled state. The characters
of the genera and species laid down by Eh-
renberg are mostly founded upon analogies
more than upon observation. Those pro-
posed by Dujardin, on the other hand, are
far more accordant with observation, and
consequently more simple and practical.
But unfortunately the latter author has so
altered the names proposed by Ehrenberg,
and since generally adopted, — raking up old
and long-forgotten names, which are, more-
over, often doubtfully identical with those for
which they are substituted, and sometimes
using similar names for totally different ge-
nera and species, — that great confusion has
been produced, and the two systems are not
at present reconcilable. We are therefore
compelled to give both of them.

In descriptions of genera and species, the
anterior part of the body is that near which
the eye-specks are situated, and which is
directed forwards ; the surface towards which
the eye-specks are nearest forms the back or
dorsal surface. A narrowing of the body
posteriorly, so as to give rise to a prolonga-
tion, forms a tail ; and an anterior prolon-
gation of the dorsal surface is described as a
forehead or upper lip, according to its situation .

Ehrenberg1 s Classification. — Ehrenberg
divided the Infusoria into two classes, — the
Rotatoria, which now form a distinct class
of the Invertebrata, being much more highly
organized than the Infusoria ; and the Poly-
gastrica, which correspond to the Infusoria
as at present recognized, excluding, however,
the following families.

The MONADINA we leave as doubtful;
but they consist beyond a doubt of the zoo-
spores of Algae, or the lower forms of Algae,
and the germs of true Infusoria.

The CRYPTOMONADINA and HYDROMO-
RINA probably consist of Alga3, like some
of the last.

The VOLVOCINA form a family of Con-
fervoid Algae.

The VIBRIONIA are included among the
OSCILLATORIACE^E (Confervoid Algae).

The CLOSTERINA form a subfamily of
DESMIDIACE^E (Confervoid Algae).

The BACILLARIA' correspond to the DES-
and DIATOMACE^E (Algae).

INFUSORIA. [ 348 ] INFUSORIA.

The remaining families are arranged in
the subjoined table according to Ehrenberg's
system, although it must not be forgotten

A. Intestinal tube absent. Anentera.

Body emitting foot-like expansions.

that the characters relating to the gastric
apparatus are not generally admitted to be

correct.

Expansions absent.

Not furnished with cilia or setae on the surface.
Form of body variable.

Carapace present ...................................... DINOBRYINA.

Carapace absent ...................................... ASTASI^EA.

Cilia or setae present on the surface of the body or the carapace.

Carapace present ...................................... PERIDIN^A.

Carapace absent ...................................... CYCLIDINA.

B. Intestinal tube present. Enterodela.
Orifice single. Anopisthia.

Carapace none ........................................ VORTICELLINA.

Carapace present ...................................... OPHRYDINA.

Two orifices at opposite ends of the body.

Carapace absent ...................................... ENCHELIA.

Carapace present ...................................... COLEPINA.

Orifices differently placed. Allotreta.
Carapace none.

No tail ; a proboscis present .......................... TRACHELINA.

Tail present, mouth anterior .......................... OPHRYOCERCINA.

Carapace present ...................................... ASPIDISCINA.

Orifices ventral. Catotreta.
Carapace absent.

Motion effected by cilia .............................. COLPODEA.

Motion effected by organs ............................ OXYTRICHINA.

Carapace present ...................................... EUPLOTA.

According to Dujardin's system, the Infusoria are arranged as follows (excluding those
certainly belonging to the Algae).

Body asymmetrical, or not composed of two similar lateral portions.
Sect. 1. Furnished with variable expansions.

* Expansions visibly contractile, simple or frequently branched.
Fam. I. AMCEB^A. Naked, creeping, incessantly changing their form.

Fain. 2. RHIZOPODA. Creeping or fixed; secreting a more or less regular shell or
carapace, from which incessantly changing expansions are exserted (Arcellina,
Ehr.).
** Expansions very slowly contractile, always simple.

Fam. 3. ACTINOPHRYINA. Animals almost immoveable (Acinetina, Ehr.).

Sect. 2. Furnished with one or more flagelliform filaments which serve as locomotive
organs ; no mouth.

* No integument.

Fam. 4. MONADINA. Swimming or fixed.
** With an integument.

$ . Aggregate. Floating or fixed.

Fam. 5. DINOBRYINA. Teguments connected at one point, forming a branched poly -
pidom.
$ $ . Isolated. Swimming.

INJECTION.

[ 349 ]

INJECTION.

Fam. 6. THECAMONADINA. Tegument not contractile (Cryptomonadina and some

AstasicB, Ehr.).

Fam. 7. EUGLENIA. Tegument contractile (Astasicea, pt. Ehrenb.).
Fam. 8. PERIDIN^A. Tegument not contractile, a furrow occupied by vibratile cilia.

Sect. 3. Furnished with cilia, no contractile tegument. Swimming.

* Naked.

Fam. 9. ENCHELIA. No mouth ; cilia scattered without order (not Enchelia, Ehr.).
Fam. 10. TRICHODINA. Mouth visible or indicated by an oblique row, or oral ring of

cilia ; no cirrhi.
Fam. 11. KERONIA. Mouth present; an oblique row of cilia, with cirrhi or stouter

cilia in the form of styles or hooks.
** With a carapace.

Fam. 12. PL^SCONINA. Carapace diffluent, or decomposable like the rest of the body.
Fam. 13. ERVILINA. Carapace true, persistent. A short pedicle.

Sect. 4. Ciliated; furnished with a lax, reticular, contractile tegument, or the presence of a
tegument indicated by the regular serial arrangement of the cilia.

* Always free.

Fam. 14. LEUCOPHRYINA. No mouth.

Fam. 15. PARAMECIA. With a mouth, no oral fringe of cilia.

Fam. 16. BURSARINA. A mouth and an oral fringe of cilia.

** Fixed, either voluntarily, or by their organs.
Fam. 17. URCEOLARINA. Fixed voluntarily.

Fam. 18. VORTICELLINA. Fixed, at least temporarily, by their organs or by some part
of the body.

Symmetrical Infusoria.

* Several types having no relation with each other.

Gen. : Planariola. Coleps. Chcetonotus — Ichthydium.

BIBL. Miiller, Animalcula infusoria, 1 786;
Ehrenberg, Die Infusionsthierchen als vol-
kommen Organismen; id.Abhandl.undBericht
d. Berl. Akad. passim ; id. Ueber d. Geolog.
d. unsichtbar. kleinen Lebens ; id. Ueb. d.
Formbestandigkeit, fyc., organisch. Formen ;
Dujardin, Hist. nat. d. Zoophytes ; Pineau,
Ann. d. Sc. nat., Zool. 3rd ser. iii. v. ix. ;
Stein, Wiegmann's Archiv, 1849; id. Sie-
bold und Kolliker's Zeitschr. iii. ; Die Infu-
sionsthiere,Ijeips\.c, 1854; Peltier, L'lnstitut,
1836 ; Focke, Isis, 1836, and Physiolog.
Studien ; Kutorga, Naturgeschicht. d. In-
fusionsth.; Meyen, Miiller' s Archiv, 1839;
Pritchard, History of Infusorial Animalcules;
R. Jones, Ann. Nat. Hist. 1839. iii.; Werneck,
Ber. d. Berl. Akad. 1841 ; Erdl, Muller's
Archiv, 1841; Griffith, Ann. Nat. Hist. 1843.
xii. ; Siebold, Lehrb. d. Vergleich. Anat. ;
Cohn, Siebold und Kolliker's Zeitschr. iii.
260; Kolliker, Sieb. und Kolliker's Zeitschr.
i. 198 ; Claparede, Wiegmann's Archiv, Dec.
1854, transl. Ann. Nat. Hist. 2 ser. xv.
p. 211 ; Schneider, ibid, p. 191, transl. ibid,
xiv. p. 322.

INJECTION.— The art of filling the
vessels and other minute tubular organs of

animals with coloured substances, by which
their relative size, arrangement, and relation
to the surrounding parts may be made ma-
nifest. The substances used for injections
consist of powders, mostly insoluble, mixed
with some liquid which holds them in sus-
pension or solution ; and while in this state
they are driven into the vessels by a syringe
or some similar contrivance. We shall first
give a sketch of the apparatus requisite, and
the method of making the liquids for inject-
ing the tissues of the Vertebrata, before
treating of the process itself.

Syringe. Two or three syringes are requi-
site, of various sizes, adapted to the volume
of injection to be thrown into the vessels, or
the size of the animal or part to be injected.
In most cases, one holding 6 drms. or 1 oz.,
and another holding about 2 oz. will be
found most generally useful. Each syringe
must be provided with two rings at the
upper part next the handle, so that it may
be firmly and easily held. The syringes
when in use should be surrounded by a roll or
two of flannel fastened with string, to prevent
their rapid cooling, and the flannel should
be kept as dry as possible during the process.

INJECTION.

[ 350 ]

INJECTION.

Sometimes a much smaller syringe, called
an oyster-syringe, is useful for injecting very
small and soft animals.

The plug of the piston is adapted to the
tube of the syringe by two pieces of wash-
leather, the method of replacing which must
be learnt at the time the syringe is bought,
for it is difficult of description. The plug
must work air-tight in the tube, which may
be proved by depressing the handle as far as
possible, then closing the nozzle of the sy-
ringe with one finger, withdrawing the han-
dle to its fullest extent, and letting it go,
when it should fly entirely home. If this
does not take place, the plug must be re-
leathered.

The handle of the syringe should be gra-
duated, i. e. transverse lines should be
scratched upon it with the end of a file, or
in some other way, so that when its descend-
ing movement is so slow as not to be felt
by the hand, it may be indicated to the
eye.

The syringes, and in fact all the mechani-
cal apparatus requisite for injection, may be
purchased of Mr. Neeves, High Street, Hoi-
born, or of Mr. Ferguson, Giltspur Street,
Smithfield.

The syringe must accurately fit the stop-
cocks and pipes.

Injecting pipes. — These must be of various
sizes, to suit those of the vessels into which
they are to be introduced ; they are furnished
with two short transverse arms, by which
they may be tied to the vessel. The smallest
pipes which are made easily become stopped
up unless thoroughly cleansed after use ; to
remove any obstruction, a very fine kind of
needle made of watch-spring is required,
and may be procured of Mr. Ferguson as
above.

Stop-cocJcs. — One or two of these are use-
ful in stopping the injection from returning,
when the syringe is removed, or force ceases
to be applied to it.

Forceps. — One or two pairs of small tena-
culum forceps must be at hand; these are
noticed in the INTRODUCTION, p. xxii.

Jars or other vessels for holding the in-
jection. These may consist of confectioners'
jam-pots, or may be made of tin. The for-
mer have the advantage of retaining the heat
for a considerable time. When in use, the
jars must be placed in a water-bath, or in a
tin vessel containing water, and placed over
a stove.

Stirring -rods. — These must be made of
wood.

Size. —The colouring matters used for in -
jection are mostly insoluble powders. These
are usually mixed with size or some form of
solution of gelatine, which holds them in
suspension better than water. The author
of the application of this substance to in-
jecting purposes we believe to be Mr. Goadby,
and very valuable it is.

The size mostly used is that termed Young's
patent size, and it is sold in the shops. It
should be clear and fresh. Those who can-
not obtain this may prepare its equivalent
by dissolving 1 part of glue in 8 or 10 parts
of water with the aid of heat.

The principal liquid injections used may be
arranged according to their colours. In re-
gard to the proportions of the colouring mat-
ter to that of the size, it must be remarked
that these vary as used by different injectors;
and that, in general, when the vessels to be
injected are very minute, the size should be
somewhat thinner, and the proportion of
pigment rather less than under the opposite
conditions. When the injection is directed
to be strained, this must be done through a
piece of new flannel wrung out of hot water,
or through a ' tammy sieve,' which is more
convenient. In preparing the injections,
great care must be taken that the jars are
perfectly clean, and that no old injection
remains adherent to them. The colouring
matters, whether dry or dissolved, should be
added to the size previously warmed in the
water-bath, or the tin vessel mentioned
above, and the whole should be stirred until
thoroughly incorporated. When trituration
is spoken of, it must be understood that the
rubbing in a mortar should be continued for
a long time, until the substance is reduced
to the finest possible state of powder.

Harting recommends preparing a stronger
size than that mentioned above, containing
1 part of glue to 4 of water, and that the
chemical substances be dissolved in the ad-
ditional water requisite before being added
to the size, which would seem to be prefer-
able ; but we have found the method recom-
mended to answer every purpose, and it has
the advantage of greater simplicity.

Red Injection. — This is best made with
vermilion (bisulphuret of mercury), which
before use should be carefully examined as
to its purity from minute colourless crystal-
line particles, by viewing it by reflected light,
when they are easily detected. When the
vessels to be injected are very minute, the
vermilion is best previously levigated, i. e.
triturated in a mortar with a small quantity

INJECTION.

[ 351 ]

INJECTION.

of water, the whole being afterwards thrown
into a large amount of water, and allowed to
settle for a few seconds, so that the coarser
particles still left may subside; the upper
portions of the liquid, containing the finer
parts of the powder, are then poured off and
allowed to settle, the supernatant water
being again poured off, and either allowed
to dry slowly, or mixed while moist with the
size.

The ordinary proportions for this injection
are —

Vermilion lioz. 1 /* • i • • n\
Size ! lb | (Avoirdupois weight).

or —

Vermilion 164 grs. (Apoth. wt.)
Size .... 4 oz, (Avoird. wt.)

Stir the colouring matter well with the
warmed size, then strain.

Other red colouring matters have been
used, but they cannot be recommended.
Among them may be mentioned, — the basic
chromate of lead, prepared by boiling the
neutral chromate with caustic or carbonate
of potash ; the biniodide of mercury, formed
by decomposing bichloride of mercury with
iodide of potassium in atomic proportions ;
the oxysulphuret of antimony; solution of
carmine in ammonia.

Yellow Injection. — This is prepared with
the chromate of lead (chrome yellow), as
follows : —

Take of—

Acetate of lead 380 grs.

Bichromate of potash . . 152 grs.
Size 8 oz.

Dissolve the lead salt in the warm size,
then add the finely powdered bichromate of
potash.

As thus prepared, some of the chromic
acid remains free, and is wasted, which may
be obviated by preparing the chromate of
lead with the chromate of potash, in the
proportions of —

Acetate of lead 190 grs.

Chromate of potash (neutral) 100 grs.
Size . .... 4 oz.

Acetate of lead 196 grs.

Bichromate of potash 76 grs.

Carbonate of potash 41 grs.

Size 4 oz.

The chromate of lead prepared from the

bichromate of potash alone has the deepest
colour, and is that generally used.

No better yellow injection than this can
be found, or is requisite.

White Injection. — The best white injection
is made with carbonate of lead, thus : take
of—

Acetate of lead 190 grs.

Carbonate of potash 83 grs.

Size 4 oz.

Dissolve the acetate of lead in the warm size
and filter ; dissolve the carbonate of potash
in the smallest possible quantity of water,
and mix it with the size.

143 grains of carbonate of soda may be
substituted for the above amount of carbo-
nate of potash.

A white injection (very inferior) may also be
made with carbonate of lime, by taking of —

Fused chloride of calcium .... Ill grs.

Carbonate of potash 167 gr.

Size 4 oz.

286 grs. of carbonate of soda may be substi-
tuted for the carbonate of potash.

Blue Injection. — In whatever manner pre-
pared, this cannot be in general recom-
mended; for blue pigments reflect so little
light, that the injections made with them
appear almost black. The only one worthy
of mention is prussian blue suspended in
oxalic acid, which may be prepared with —

Prussian blue 73 grs.

Oxalic acid 73 grs.

Size 4 oz. ;

the oxalic acid being first finely triturated in
a mortar, the prussian blue and a little water
afterwards added; and the whole then
thoroughly mixed with the previously warmed
size.

General method. — When the part for
injection has been selected, the first pro-
ceeding is to fix the pipe in some vessel, and
the larger this is the more easily will the
pipe be inserted and fixed. When the vessel
has been isolated, if it has been cut across, the
pipe should be introduced at its end, pushed
up as far as possible, and a piece of not too
thin silk-thread passed beneath and tied
around it, enclosing of course the nozzle of
the pipe; the ends of the silk should then
be wound around the arms of the pipe
and again tied, so that the pipe may
remain firmly fixed in the vessel. If the
vessel be not divided, a longitudinal slit
should be made in it for the introduction of
the pipe, the thread being passed around it

INJECTION.

[ 352 ]

INJECTION.

by a curved needle, the eye of which
carries the thread. As soon as the pipe
has heen fixed in the vessel, all other vessels
communicating with it should be tied around
with silk-thread or closed in some other way
that the injection may not escape; some-
times it is requisite to enclose a part of the
tissue itself in the ligature; in other instances
their closure may be effected by fusion of
the tissue at the spot from which the injec-
tion might escape by the application of a
red-hot iron.

The organ or part to be injected is then im-
mersed in warm water, in order that it may
become heated throughout; and if it be
large and of considerable thickness, this may
take some time, and fresh warm water must
be added at intervals to keep it at the same
temperature, which should be about as great
as can be borne by the hand. If the water
be too hot, the vessels and tissues will
be rendered brittle, and the whole will be
spoiled. Moreover, the part should not be
kept longer in the water than is absolutely
requisite, for the same reason. While the
tissue is becoming heated in the water, the
injection should be prepared, or be heated if
previously prepared, and kept constantly
stirred ; the stop-cocks should also be
immersed in hot water.

As soon as all is ready, the stop-cock
turned open is fixed to the syringe and
some hot water is drawn into and expelled
from the syringe two or three times, so that
it may become properly heated. It is next
filled with the injection, taking especial care
that no air be allowed to enter, to avoid
which it must be filled, emptied and refilled
several times, the nozzle being kept beneath
the surface of the injection. The syringe is
then taken in the hand, a little of the injec-
tion being forced out at the nozzle of the
stop-cock, which is next loosely inserted into
the pipe, and some of the injection being
urged into it by depressing the handle, the
pipe is filled and the nozzle introduced into
it. Very gentle pressure is then made upon
the piston, so that the injection may be
driven into the vessels, and this must be
continued until the piston ceases to be felt
to move, or is seen not to enter the syringe
further, by watching the graduations on its
handle. When this is found to be the case,
firmer pressure must be made and the effect
noticed. But practice can alone guide as to
the time at which the pressure should cease,
or when as much injection has been forced
into the preparation as is required. Some

judgement may be made from the colour
assumed by the preparation; or, the stop-
cock being turned off, and the syringe sepa-
rated from it, the preparation may be exa-
mined with a low power, while laid upon a
large glass plate.

During the continuance of the process,
the preparation, the injection, and the pipes
must be kept at the original temperature ;
and should any part be found to become
cool, the stop-cock must be turned off, the
syringe separated, the injection returned to
the jar, fresh warm water added to the pre-
paration, and the whole process recommenced
as at first.

If, during the process, there should be an
escape of the injection from any part, this
need not cause alarm if slight; should it,
however, be considerable, it must be stopped
by one of the means pointed out above ;
perhaps by the orifice of the vessel and sur-
rounding parts being grasped by the tena-
culum-forceps, and the whole included in a
ligature. If the preparation be small, not-
withstanding a considerable escape of the
liquid, a very good injection may often be
made.

As soon as the injection is completed, a
ligature should be placed around the vessel
into which the pipe is inserted beyond its
nozzle ; the pipe is next removed, and the
preparation should be immersed in clean
cold water, and kept in it for an hour or two
at least. It may then be withdrawn and
sections made of it with a knife, razor, or
some other instrument.

Large pieces of injected preparations are
best preserved in a stoppered bottle contain-
ing dilute spirit of wine (1 spirit to 2 water,
or equal parts). See also MOUNTING and
PRESERVATION.

When two or more sets of vessels are to
be injected, the process should be continued
uninterruptedly until completed, *. e. as soon
as the injection of one set has been com-
pleted, another pipe should be at once
inserted into one of the other set, and so on.
Or what is better, if possible, the pipes for
the two or three sets should be introduced
and fixed at once, before the process is com-
menced.

As regards the period after death at which
the injection should be commenced, this
varies with the kind of organ or tissue ; if it
be delicate, the sooner the better ; whilst if
the vessels be comparatively large, by some
little delay, the tissue becomes somewhat
softer and more yielding.

INJECTION.

[ 353

INJECTION.

When a tissue has been successfully in-
jected, the vessels appear plump and well
filled by reflected light. But if they be not
so, the preparation has its value ; for it will
perhaps well display the relative positions of
the capillaries to the surrounding tissues
when viewed by transmitted light; often
even better than when the injection has
been what is termed successful. In fact,
when the vessels are well filled, little more
can be seen in general than the relative
situation of the vessels to each other.

The choice of the kind of injection is not
a matter of much importance, except as
regards the facility with which the vessels
are traversed. The arteries are in general
filled with red injection; the veins with
yellow and the ducts (as the urinary tubules)
with white. The chromate of lead is perhaps
the finest injection and runs best, except
that made with prussian blue and oxalic
acid, which does not reflect enough light
where the vessels are to be viewed by re-
flected light, although when these are very
minute and can be conveniently viewed by
transmitted light, it may be preferred.

It may be remarked, that if it be required
to use a yellow (the chromate) injection
and a white (the carbonate of lead) for two
sets of vessels in one preparation, the chromic
acid in the former must previously be com-
pletely neutralized, otherwise it will render
the white (carbonate of lead) yellow. This
may, however, be avoided by substituting
the carbonate of lime for that of lead.

As microscopic objects, nothing can exceed
the beauty of injected preparations, and to
be seen in their greatest perfection, they
should be dried, moistened with oil of tur-
pentine and mounted in Canada balsam. At
the same time it must not be forgotten that
when dried and preserved in this manner,
the real arrangement of the vessels is more
or less distorted, those lying in different
planes being brought into the same, and so on.

In Plate 31. figs. 33, 34 and 35, we have
given representations of three injections
viewed by reflected light; fig. 35 being taken
from the liver of a cat, in which injection
made with vermilion was thrown into the
portal vein, and that with chromate of lead
into the hepatic vein. Fig. 34 is a portion
of the lung of a toad injected with vermilion;
and fig. 35 is a portion of the kidney of a
pig, the arteries and Malpighian tufts
(KIDNEY) being filled with the red (vermi-
lion) injection, and the urinary tubules with
the white (carbonate of lead).

The tissues of the Invertebrata are so soft,
that the ordinary syringes and pipes can
rarely be used for injecting them, and re-
course must be had to a finer and lighter
form of apparatus. One recommended by
Rusconi consists of a kind of trochar, con-
sisting of a needle and the quill of a crow,
partridge, or some small bird. In using it,
the small vessel through which the injection
is to be thrown is held with forceps against
the extremity of the trochar, and punctured
with the needle. The quill is next directed
into the puncture, and the needle withdrawn.
The small nozzle of a syringe is then intro-
duced into the upper end of the quill, and
the injection thrown in. A form proposed
by Harting consists of a common glass pi-
pette of moderate width, and of a caoutchouc
tube, the smaller end of which is fastened by
means of thread to the broader end of a fine
curved glass nozzle. In using this apparatus,
the pipette is first filled with the injection,
and its lower portion introduced into the
broader end of the caoutchouc tube, which,
from its conical form, it accurately closes.
The caoutchouc tube may be made by rolling
a piece of sheet caoutchouc around a glass
rod, and cutting the superfluous portions
away with scissors ; the freshly divided sur-
faces will adhere by a little kneading with
the nails, and they may be secured by solu-
tion of caoutchouc or gutta percha in oil of
turpentine.

Different liquids for injection are also usu-
ally requisite, and many have been recom-
mended ; among these may be mentioned, —
1, indigo triturated with oil, and diluted
with oil of turpentine ; 2, oil-paints diluted
with oil of turpentine; 3, infusion of log-
wood (H&matoxylon) ; 4, solution of carmine
in size or in ammonia ; and 5, solution of
alkanet in turpentine.

A considerable escape of the injection is
often unavoidable in these cases, and must
not therefore be heeded.

Some injectors simply introduce the in-
jection into the dorsal vessel or lacunae,
whence it is propelled to all parts of the
body by the circulation. Thus M. Agassiz
says that if the indigo injection (1) be intro-
duced in this way into insects, it is seen to
circulate almost instantaneously in every
part of the body, and on subsequently open-
ing the insect, all parts of the body are found
to be coloured. We believe that M.Blanchard
also adopts this method. Probably the best
injections for this purpose would consist of
the alkanet and turpentine (5).

2 A

INJECTION.

[ 354 ]

INJECTION.

The perfect injection of an organ or an
entire animal of considerable size is a tedious
and fatiguing process. We have therefore
contrived a very simple piece of apparatus,
which any one can prepare for himself, and
which effects the object by mechanical means.
It consists of a rectangular piece of board,
2' long and 10" wide, to one end of which
is fastened an inclined piece of wood, sup-
ported by two props, as shown in fig. 364.

Fig. 364.

The inclined portion is pierced with three
holes, one placed above the other, into either
of which the syringe may be placed; the
uppermost being used for the larger, the
lowermost for the smaller syringe ; and these
holes are of such size as freely to admit the
syringe covered with flannel, but not to allow
the rings to pass through them. The lower
part of the syringe is supported upon a semi-
annular piece of wood, fastened to the upper
end of an upright rod, which slides in a
hollow cylinder fixed at its base to a small
rectangular piece of wood ; and by means of
a horizontal wooden screw, the rod may be
made to support the syringe at any height
required. The handle of the syringe is let
into a groove in a stout wooden rod con-
nected by means of two catgut strings with
a smaller rod, to the middle of which is fast-
ened a string playing over a pulley, and at
the end of which is a hook for supporting
weights, the catgut strings passing through
a longitudinal slit in the inclined piece of
wood.

In use, the part to be injected is placed in
a dish of some kind containing warm water,
supported at a suitable height beneath the
end of the syringe by blocks of wood. The
syringe is then filled with injection, passed
through the proper aperture in the inclined
board, and fitted to the pipe, the stopcock
being turned off. The rod and strings are
next adjusted, and a suitable weight being
added, the stopcock is very slowly turned
on, and the effect watched. If the handle

of the syringe do not move, more weight
must be added, the stopcock always being
turned off when this is about to be done.

A great advantage of this apparatus is,
that it sets at liberty the hands, so that an
escape of injection may be arrested, or fresh
warm water added, without interruption of
the process.

When it is not required to fill the capilla-
ries, but only the smaller arteries or veins,
the colouring matters need not be prepared
by double decomposition, and the following
substances may be used : —

Red. — Size 1 Ib. (avoirdupois wt.),
vermilion 2 oz. (avoird. wt.).

Yellow. — Size 1 Ib., King's yellow
(orpiment), or chrome-yellow, 2£ oz.

White.— Size 1 Ib., flake-white 3£ oz.

Blue. — Size 1 Ib., fine blue smalt 6 oz.

Black. — Size 1 Ib., lamp-black 1 oz.

Injections may be preserved either in the
dry or wet state. For the former, sections
should be made, thoroughly dried upon
slides, then moistened with oil of tur-
pentine, and mounted in balsam. For pre-
servation in the wet state, they must be
mounted in cells while immersed in dilute
spirit, Goadby's B. solution, or in chloride
of zinc (see MOUNTING and PRESERVA-
TION).

We have not space to give a list of in-
jected preparations ; they are all very beau-
tiful, but we can only notice a few of the
most interesting. For practice in the art of
injecting, we may recommend the kidney of
a sheep or pig ; one system of vessels being
alone filled with red or yellow injection, and
this should be the arterial. Afterwards, in
another kidney, the urinary tubules may be
injected first, with white injection, and sub-
sequently the arteries with red or yellow.
A portion of the small intestine, exhibiting
the general capillaries, with the plexuses of
the villi, forms a beautiful object, as pre-
pared from the rabbit, the rat, &c. Among
other preparations, may be mentioned the
liver of various animals, as the cat, the rab-
bit, &c.; the lungs of the cat, rabbit, &c., in
which the capillaries are very minute ; those
also of the reptiles, as of the frog, triton,
boa and other snakes, in which they are
coarser, but very beautifully arranged ; the
lungs of birds ; the kidneys of the frog and
triton ; the web of the frog's foot ; the ciliary
processes and choroid coat of the eye ; the
gills of the eel and other fishes ; the lungs
of kittens, &c. which have not breathed,

INOMERIA.

[ 355 ]

INSECTS.

the air-cells being injected from the trachea ;
the skin of the frog, and especially of the
triton, &c.

BIBL. Berres, Anat. d. mikrosk. Gebild.
d. Menschl. Kb'rp. ; Rusconi, Ann. des Sc.
nat. 2 ser. xvii. ; Tulk and Henfrey, Anat.
ManipuL; Doyere, Comptes Rend. 1841;
Harting, Het Mikroskoop, fyc., abstracts in
Ed. Monthly Journ. 1852; Robin, Du Mi-
croscope, 8fc.', Quekett, on Injections ; Goad-
by, in Wythes' 'The Microscopist.'

INOMERIA, Kiitz.— A genus of Oscilla-
toriaceae (Confervoid Alga3) with calcareously
hardened, incr u stin g frond s, growing on stone s
in fresh water. The fronds are composed of
vertical, parallel, whip-shaped filaments, with
the sheaths obscure, connected together, and
decomposed into very slender fibrils above.
Kiitzing supposes his I. Rameriana to be
synonymous with HassalPs Lithonema crus-
taceum.

BIBL. Kiitz. Spec. Alg. p. 343, Icon. Phys.
ii. pi. 83 ; Hassall, Brit. Fresh-to. Alga, p. 266.
pi. 65. fig. 3.

INSECTS.— A class of invertebrate arti-
culate animals.

Char. Head distinct, furnished with two
antenna3 ; respiratory organs consisting of
tracheae ; cutaneous skeleton composed of
chitine.

Insects are distinguished from the Arach-
nida, by the head being distinct from the
thorax, and the presence of antennae ; and
from the Crustacea by the respiratory organs
consisting of tracheae.

Most insects have three pairs of legs, and
the body consists usually of thirteen seg-
ments; one for the head, three for the
thorax, and nine for the abdomen, the legs
being attached to the second, third and
fourth segments. But in some (Myriapoda)
the segments of the body and the legs are
very numerous.

The cutaneous skeleton or integument of
insects probably consists of three layers, an
outer epidermic, an intermediate pigment-,
and an internal fibrous layer ; but consisting
as it does of chitine, it is very imperfectly re-
solvable into its elementary components.
The epidermic layer often presents a distinct
cellular aspect (PI. 28. fig. 30 a); sometimes
the cells appearing as if flattened and over-
lapping (PI. 28. fig. 30 c), and their free
margins fringed with minute hairs (fig. 30 b).
In other instances, the epidermis appears
uniform and structureless. In its deeper
portion, the epidermis is often strongly im-
bued with a resinous pigment, which is

removable by prolonged maceration hi solu-
tion of potash or in oil of turpentine.
Beneath these imperfectly separable layers,
is another representing probably the cutis,
and consisting mostly of numerous second-
ary layers made up of fibres, running parallel
or interlacing, and leaving fissures between
them, sometimes presenting a stellate ap-
pearance : these fibres may be separated by
maceration in caustic potash.

The outer surface of the integument of
insects is usually furnished with processes of
various kinds, as tubercles, ban's, spines,
scales, &c. (see HAIRS and SCALES). The
inner surface also gives ofl7 processes, which
form a kind of internal skeleton, serving for
the attachment of muscles, &c. In sketch-
ing the various parts of which the skeleton
is composed, it must be understood that
they are not always equally distinct, and that
upon their degree of development, form
and general structure, the characters of the
families, genera, and species are mainly
founded.

The head (fig. 365 a) consists of an upper
anterior portion (PL 26. fig. 1 d), the clypeus,
and an upper posterior portion (fig. 1 b), the
epicranium or vertex, which are sometimes
separated by a suture; a posterior portion
or occiput (fig. 24-), by which the head is
articulated with the prothorax ; and a pos-
terior inferior portion (fig. 3 n), the gula.

The eyes are situated upon the upper, an-
terior, or lateral parts of the head, and are
of two kinds, simple and compound. The
simple, called ocelli or stemmata (PI. 28. fig.
2 a ; PL 26. fig. 24 6), are usually from one to
three in number, but sometimes very numerous
in larvae ; they appear like shining smooth
specks (PL 26. fig. 4), and usually form a
triangle behind or between the compound
eyes. They consist of an arched, round, or
elliptical cornea, behind which is a conical
or cylindrical lens. The optic nerve forms a
cup- shaped expansion for the reception of
the lens, which is surrounded by a layer of
pigment of various colours, resembling a
choroid membrane.

The compound eyes (fig. 365 b) are two,
large, usually round or kidney - shaped
(PL 26. figs. 1 c, 3 c), situated upon the
upper and outer part of the head, and are
sometimes so large (as in the Diptera,
Libellulce, &c.) as almost or quite to
touch each other in front. They may be
regarded as composed of numerous simple
eyes closely aggregated ; their corneae vary
in thickness, are but slightly arched, qua-
2A2

INSECTS.

[ 356 ]

INSECTS.

drangular or hexagonal in form, and in im-
mediate contact laterally. Hence their com-
pound cornea, when viewed from before
or behind, presents the appearance of a

membrane with numerous, beautifully regu-
lar six- or four-sided facets (PL 26. figs.
5a, b). The facets are very variable
in number, but often many thousands are

Fig. 365.

Diagram showing the principal parts of the cutaneous skeleton of a grasshopper.

a the head, with the eyes b and the antennse c ; d, the thorax, consisting of e the prothorax, to which the first pair
of legs/ is attached ; g, the mesothorax, to which the first pair of wings h, and the second pair of legs i are attached ;
k, the metathorax, to which the second pair of wings /, and the third pair of legs m are attached ; n, abdomen ;
m, femur ; o, tibia with its spines, and p tarsus with its claws.

present. The facets are sometimes broader
in front than behind, and they are some-
times doubly convex (as in the Lepidoptera),
at others concavo-convex (in Libellula, PI.
26. fig. 6 c), but usually the surfaces are
parallel. The cornea possesses a laminated
structure.

Behind each cornea is a transparent cone
(PI. 26. fig. 6/), representing a crystalline lens,
the apex of which is imbedded in a transparent
mass corresponding to a vitreous humour ;
and this is surrounded by a cup-shaped
expansion of a branch of the optic nerve.
The length of the lens is variable, in the
Diptera being very short, whilst in the Coleo-
ptera and Lepidoptera it is five or six times
as long as broad ; and in Libellula it even
exceeds this length. The compound cone,

consisting of the lens and vitreous humour, is
surrounded by a sheath of pigment, forming
a choroid membrane (PI. 26. fig. 6#), in
which numerous tracheae ramify; this ex-
tends over the front of the base of the cone,
leaving, however, a small pupillary space or
pupil, which is separated from the back of
the cornea by an anterior chamber (fig.
6df).

The antenna are noticed under ANTENNAE.

The trophi or organs of the mouth vary
in structure in the different orders, but the
following form the typical parts : an upper
central single piece, the labrum or upper lip
(PI. 26. figs. \e, 3e, 22 a), forming the
upper boundary of the mouth, and articu-
lated at its base with the clypeus. A lower
single piece, forming its lower margin, called

INSECTS.

[ 357 ]

INSECTS.

the labium or lower lip (PI. 26. fig. 2 i, I, m).
This consists of several parts : the most
posterior is the mentum (fig. 3 1), which is
articulated posteriorly with the gula (fig. 3 ri).
Sometimes an intermediate portion occurs,
the submentum (fig. 3 w), at others this is
consolidated with the occiput (fig. 2 m). The
most anterior portion is the ligula (figs. 2,
3 i), which is frequently notched or lobed ;
and is sometimes furnished with two lateral
portions called paraglossae (fig. 2 * ) . Between
the ligula and the mentum or submentum
are the palpigers, one on each side (fig.2i);
these are sometimes united, and to them
the labial palpi (figs. 2, 3 k) are attached.
Below the labrum are the mandibles, one on
each side, forming two strong curved jaws,
and frequently furnished with powerful
teeth (figs. 3 /, 22 b) ; these are the proper
organs of manducation. Below the mandi-
bles are two other lateral organs, the maxillae
(figs. 1, 2, 3g ; fig. 22 c) ; they are usually
less firm than the mandibles, and serve to
hold and convey the food to the back of the
mouth. Each maxilla is furnished with a
jointed palp (figs. 1, 2, 3 h), and sometimes
with an appendage called the galea or
helmet (fig. 22 *) ; and an inner curved and
acute portion termed the lacinia or blade
(fig. 22 f). In some insects there is a di-
stinct soft and projecting organ, forming the
floor of the mouth, the lingua or proper
tongue (fig. 22 d) ; the tongue of the cricket
(fig. 23) is a favourite and beautiful micro-
scopic object.

These structures are best examined in the
Coleoptera or Orthoptera, in which the parts
we have described are most distinct. In the
other orders they are altered in structure to
adapt them to the nature of their food.
Thus in the Lepidoptera, the labrum and
mandibles are reduced to three minute tri-
angular plates; the maxillae are elongated
to form the antlia (ANTLIA), at the base of
which a pair of minute palpi are often to be
detected. The labium is small, triangular
and furnished with a pair of large palpi
clothed with long hairs or scales, and serving
for the defence of the antlia.

In the Hemiptera (PI. 26. figs. 26, 27),
the labrum is short and pointed, and over-
laps the root of the rostrum ; the mandibles
and maxillae are transformed into slender
lancet-like organs (the maxillary palpi being
obsolete), enclosed within the equally elon-
gated horny and jointed rostrum or labium,
the labial palpi also being obsolete.

In the Diptera (PI. 26. figs. 29, 30),

the five upper organs, together with the
internal tongue, are elongated into lancet-
like organs, the maxillary palpi being
attached to the base of the maxillae. These
six organs are enclosed in a fleshy thickened

C' see (the labium), often terminated by two
ge lobes which act as suckers. In many
species, however, some of these lancet-like
organs are obsolete. This kind of mouth is
termed a proboscis.

These varieties are further noticed underthe
heads of the genera selected for illustration.

Behind the head we have the thorax. This
consists of three rings or pieces, each of
which supports a pair of legs (fig. 365, e, g,
k). The first ring is called the prothorax
(e), the second the mesothorax (g}, and the
third the metathorax (*). Each of these
rings consists of a dorsal and a sternal piece ;
the dorsal half-rings are called the pro-
notum, mesonotum, and metanotum ; the
ventral or sternal, the prosternum, meso-
sternum, and metasternum. In the four-
winged insects, the anterior wings are
attached to the central piece or mesothorax
(g), the posterior wings to the metathorax
(k). In the Diptera, the wings are attached
to the mesothorax, and the halteres to the
metathorax. Various other subdivisions
have been made of these parts, but they are
too numerous to mention here. It may be
remarked, however, that the epimera are the
pieces to which the basal joints of the legs
are directly attached ; that the under part of
the thorax or pectus is sometimes furnished
with an elongated acuminate appendage, the
sternum ; and that the scutellum or shield
is a piece existing at the upper and back
part of the mesonotum, and extending be-
tween the wings.

The legs are placed on the under side of
the body, and are joined to its segments at
an articular cavity existing between the
sternum and the epimeron, called the aceta-
bulum. Each leg usually consists of five
parts. The first is the hip or coxa (PL 28.
fig. 9 g) ; but sometimes there is a small,
very moveable piece between the epimeron
and the coxa (PI. 28. fig. 9, between/ and g),
called the trochantin; this is, however, gene-
rally absent or consolidated with the coxa.
The second joint is the trochanter (PL 28.
fig. 9 h); it is mostly small, and annular.
The third is the thigh or femur (fig. 365 m ;
PL 27. figs. 4, 5, 7 d), the thickest and
usually the largest joint of the leg. Next
comes the fourth, the tibia (fig. 365 o; PL 27.
figs. 4, 5, 6, 7 c), which is thinner, usually

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INSECTS.

compressed, and frequently furnished with
spines, spurs or other appendages, especially
at its end ; in the ant the tibiae have each a
beautiful pectinate process. The last portion
is the foot or tarsus (fig.365p; PI. 27. 6, 7 «),
which consists of several joints arranged in
a row. The number of these joints varies in
different insects; sometimes it is different
in the anterior and posterior pairs of legs ;
they are, however, most commonly five.
The last joint of the tarsus is usually fur-
nished with appendages, in the form of
hooks or claws, mostly two, and frequently
serrated, especially near the base. Some-
times also it has two or three delicate mem-
branous or fleshy cushions, called pulvilli
(PL 27. figs. 7 & 8) ; these are more or less
covered with hairs, which are sometimes
terminated by little disks (fig. 9), and by
which it is supposed that the insects are
enabled to ascend or adhere to polished
surfaces in opposition to gravity. In other
insects elegant brush-like appendages are
met with in the same situation. Disks of
the same kind but larger, and peculiarly -
arranged hairs, sometimes occur upon the
upper joints of the tarsus (PI. 27. fig. 6, DY-
TISCUS ; and fig. 4 a, APIS).

The structure of the legs of insects in the
larval state (PI. 27. figs. 32, 33) differs con-
siderably from that of the imago as de-
scribed above.

The wings are dry, membranous, and
transparent organs, consisting of two
laminae or plates, which are confluent at the
margins ; these plates may be regarded as
folds of the integument. Between them
run canals, commonly called veins, nerves or
nervures, which are more or less numerous
and ramified ; and upon their arrangement,
the distinguishing characters of the genera,
&c. are sometimes founded ( WINGS). The
veins are formed by two wide horny half-
canals in the upper and under plates, of
which the wings consist. The main veins
arise from the point of attachment of the
wings to the thorax, and gradually diminish
in diameter until they reach the extremity
of the wings. The veins convey the circula-
ting liquid, and contain each a tracheal
branch, which communicates with the tracheae
of the thorax. In flight they are said to be
distended, and the wings kept expanded by
air from the interior of the body. In some
kinds of wings the circulating currents are
not confined to narrow channels as in the
veins, but traverse a large part of the breadth
of the wings (COCCINELLA).

Most insects have four wings; but in
some, the males only are furnished with these
appendages. In the Diptera, the posterior
pair of wings are rudimentary, being replaced
by two little club-shaped bodies, called the
halteres, poisers, or balancers. In this order
also, and in some insects belonging to other
orders, a pair of small and rounded membra-
nous or scaly appendages are attached to
the back of the base of the first pair of
wings, called in the former the squamae
halterum, and in others, alulae or winglets.
The anterior pair of wings are in some
insects, as in the beetles, Coleoptera, hard,
horny and opake, forming wing-covers or
ELYTRA (fig. 371), and the lower wings,
which are usually larger, are folded together
beneath them, when at rest. In others, the
posterior wings disappear, and the elytra
coalesce at their inner margins. Sometimes
the anterior wings are horny or leathery at
the base, and membranous towards the
summit (fig. 370); these are called hemelytra.
At others, all the wings are thin, membra-
nous, and transparent, as in the Hymenoptera
and Neuroptera.

In the Lepidoptera, they are covered with
beautiful feathers or SCALES. In this order
also, there exists upon the upper side of the
prothorax, a pair of oval plates covered with
hairs, and called patagia or tippets. The
mesothorax also is furnished at its sides with
a pair of large triangular scales, called pte-
rygodes, paraptera, or tegulae; these are
attached to the upper part of the base of the
anterior wings, and they are often covered
with hairs or scales of a different colour
from those on the other parts of the thorax.

There exist also other modifications of
the wings of certain insects, adapting them
for special functions. In the Orthoptera
these modifications are the agents producing
the well-known chirping sounds, as in the
male cricket and grasshopper. In the common
house-cricket, Acheta domestica, each of the
upper wings or elytra exhibits a clear space
near the centre (PL 27. fig. 10 a), traversed
by a single vein only, or at least by a very
few veins. This space has received the name
of the drum or tympanum. Bounding it ex-
ternally is a large dark longitudinal vein,
provided with three or four elevated longi-
tudinal ridges. Immediately in front of the
tympanum, near the base of the elytra, is a
transverse horny ridge, tapering outwards
and furnished with numerous short trans-
verse ridges or teeth, and forming a kind of
file or bow (PL 27. fig. 106). When the

INSECTS.

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INSECTS.

two elytra are rubbed across each other, the
bow being drawn across the ridges gives
rise to the peculiar sound, the intensity of
which is increased by the tympanum acting
as a sounding-board. The apparatus of the
grasshopper is essentially of the same struc-
ture. It must be stated, however, that va-
rious other explanations of the origin of the
stridulating noise produced by these insects
have been given. Thus by some authors the
two bows are stated to work across each
other, whilst by others the legs are supposed
to act against the bow. This subject pos-
sesses interest for future observation.

In other insects, there is a peculiar mecha-
nism for uniting the anterior and posterior
wings of each side, so that they may be kept
steady and may act in unison during flight.
In the Lepidoptera, the moths only are pro-
vided with a minute hook arising from the
base of the costal nerve of the lower wing,
and inserted into a socket near the base of
the main nerve, on the under side of the
upper wing. In the Hymenoptera, there are
many such hooks arranged along part of the
costal nerve at the anterior and upper
margin of the second pair of wings (PI. 2/.
fig. 13). When the wings are expanded,
these attach themselves to a little fold on
the posterior margin of the anterior wing
(fig. 11 ri), along which they play freely
when the wings are in motion, sliding to and
fro like the rings on the rod of a window-
curtain. These hooks are somewhat twisted
towards their free end, recurved and some-
times notched at the point. They vary in
number in different genera and even in
the sexes. In the Hemiptera the whole
margin of part of the anterior wing is hooked
over a corresponding recurved part of the
posterior, so as to produce the same effect.

The abdomen (fig. 365 ri) forms the third
and terminal portion of the body of insects.
It usually consists of nine or ten rings or
joints, the posterior of which, however, are
sometimes so concealed, so small or so fused
with the others, that they appear to be
absent. The abdomen contains the prin-
cipal part of the alimentary canal and its
appendages, with the organs of reproduction.

The alimentary canal varies in length in
different insects, and even in the same insect
at various periods of its development. It
consists of the following parts : — 1 . The ceso-
phagus (PI. 28. fig. 2 b), a muscular organ
extending through the thorax ; it is some-
times dilated to form a crop or ingluvies, as
in the Lepidoptera, Hymenoptera, and Di-

ptera, and this occasionally forms a lateral
sac, connected with the oesophagus by a
narrower portion only, and called a sucking
stomach. 2. Next follows the muscular
stomach, proventriculus or gizzard (PL 28 c),
which is distinguished by the frequently
great development of its lining membrane
into plates, teeth or hooks of horny tissue
(PL 27. fig. 1) ; these serve to triturate the
food, and have long been known as beautiful
microscopic objects. 3. This is succeeded by
a long, cylindrical, true stomach or ventri-
culus (d), in which digestion takes place.
4. Behind this is a longer or shorter small
intestine (PL 28. fig. 2, between d and/),
terminating in 5, a dilated portion, forming
a large intestine or colon ; behind which is
a short rectum. The structure and length
of the parts of the alimentary canal vary
generally according to the nature of the
food, although this is not always the case in
regard to the latter.

The alimentary canal is covered by an
outer homogeneous peritoneal layer; beneath
which is a muscular coat, consisting of lon-
gitudinal and transverse fibres. Internally
it is lined by a homogeneous epithelial layer,
consisting, in part at least, of chitine. Be-
tween the latter and the muscular coat, at
the middle of the alimentary canal, is a layer
of cells, which probably perform a glandular
function. The large intestine or colon of most
insects in the imago state contains from four to
sixpeculiarorgansofdoubtfulnature,arranged
in pairs, either transversely or longitudinally.
These consist of transparent, rounded, oval
or elongated tubercles, projecting inside the
colon, sometimes with a horny ring at the
base, and traversed by tufts of tracheae.
These organs are most numerous in the Le-
pidoptera. They are never found in insects
in the larva- or pupa-state.

In most insects salivary glands are present
as one, two, or rarely three pairs of colour-
less sacs or tubes of very variable form and
length, sometimes scarcely extending beyond
the prothorax, at others accompanying the
alimentary canal into the abdomen. They
consist of an outer homogeneous envelope,
lined with colourless, nucleated cells, and
frequently have one or more distinct ducts,
sometimes containing a spiral fibre; they
terminate near the mouth, in some insects
the ducts previously expanding into a reser-
voir.

A distinct liver is not present in insects, its
function being performed by the glandular
cells in the walls of the true stomach. In

INSECTS.

[ 360 ]

INSECTS.

many insects, caecal appendages arise from the
latter, and also contain cells which secrete a
biliary liquid.

In some insects the small intestine is fur-
nished with glandular appendages in the
form of tubular caeca, probably representing
a pancreas.

Intimately connected with the digestive
and assimilative process is a curious organ
called the fatty body. This attains its maxi-
mum of development towards the end of the
larval period of existence. It consists of a
number of fat-cells imbedded in a reticular
or lamellar tissue (PI. 28. fig. 28), composed
of a number of somewhat angular lobes con-
nected by narrow processes having inter-
spaces between them. These are originally
formed from rounded, nucleated cells, which
have given off anastomosing processes (fig.
29). It is traversed by a number of slender
tracheae, and occupies the interspaces of the
various abdominal organs. Each lobe con-
siats of an outer structureless membrane,
enclosing the fatty matter imbedded in an
amorphous or granular substance. It ap-
pears to form a reservoir of nourishment for
the insect during the pupa state.

In most insects are found several slender
and elongated, mostly simple tubular glands,
opening by simple or united ducts into that
end of the true stomach corresponding to
the pylorus (PI. 28. fig. 2 e). Their free ends
are either caecal, or unite with each other.
They are'often very long, and much convoluted
around the intestines, sometimes presenting a
varicose appearance, and dilated near their
termination . These are theMalpighi an vessels,
and they probably perform the function of a
kidney, uric acid having been found in them.
They are usually yellowish or brownish, and
consist of a homogeneous outer coat, lined
with epithelial cells. Some authors, how-
ever, consider that the renal organ is repre-
sented by one or more long vessels convo-
luted upon the colon, and opening close to
the anus. And we have found in the cater-
pillar of the fox-moth, Lasiocampa rubi,
numerous long convoluted tubes, of a
milk-white colour, filled with perfect octo-
hedra and prisms of oxalate of lime.
These tubular organs terminated in the
rectum close to the anus by very slender
ducts, whilst at the upper ends, which
reached to about the anterior third of the
body, they were coiled upon themselves, or
united with each other.

Other glandular or secreting organs also
occur in insects. Thus, organs correspond-

ing to the cutaneous glands of the Vertebrata
are often met with as rounded glandular
cysts diffused beneath the integument, and
called glandulae odoriferae ; they open at the
junction of the segments of the body, or at
the joints of the legs, by very short ducts,
and pour out a strongly-smelling secretion.
In other insects, similar organs are concealed
at the posterior end of the body, and pour out
their secretion near the anus. Among the
Hymenoptera, the females are often furnished
with a glandular apparatus which secretes
the poison of the STINGS.

Spinning organs. A large number of those
insects which undergo perfect metamorpho-
sis are furnished in the larval state with
spinning organs, with the secretion of which
many larvae, before entering the pupa state,
weave a cocoon or enclose a cavity in which
to pass their period of rest, while others use
this secretion for agglutinating foreign
bodies to serve the same purpose. The
glands secreting the silk consist of two long,
tubular caeca (PL 27. fig. 16), which in a
more or less coiled state occupy the sides of
the body, and terminate anteriorly in two
narrow excretory ducts, dilated to form a
reservoir, and the common orifice of which
opens outside the mouth on a short tubercle
beneath the labium. The caterpillar is able to
compress the silken threads by the contraction
of an angle formed by the two capillary
tubes at their point of union, and is thus
enabled to suspend itself by the threads.
The material of the silk is always colourless,
and derives the colour which it presents in
certain instances from a varnish secreted in
the reservoirs, and issuing along with the
former.

The heart in insects exists as a long con-
tractile dorsal vessel, constricted at intervals.
This terminates posteriorly in a blind end,
and is narrower in front. The posterior
portion performs the functions of a heart,
whilst the anterior represents an aorta, and
conveys the blood from the heart to the
body. From the mouth of the aorta the
blood passes without any vascular walls in
regular currents taking all directions, and
running into the antennae, the extremities,
the wings and other abdominal appendages,
returning as a venous current. The blood
finally forms two principal lateral currents
directed towards the end of the abdomen,
and, accumulating in the neighbourhood of
the heart, is brought by its diastole through
the lateral valvular fissures existing in it;
whence it is again driven through the aorta

INSECTS.

[ 361 ]

INSECTS.

as before. The walls of the dorsal vessel
consist of longitudinal and transverse fibres,
surrounded externally by a very delicate pe-
ritoneal layer. The cavity of the heart is
lined by another delicate membrane, which
in the constricted parts forms internal val-
vular projections, whereby the dorsal vessel
is divided into as many chambers as there
are constrictions. Each of these cardiac
chambers is furnished at its front end, right
and left, with a fissure which can be closed
internally by a valvular membranous fold.
The cardiac chambers contract in regular
succession from behind forwards, and thus,
with the aid of the valvular apparatus, which
prevents the lateral exit of the blood, pro-
pel this liquid into the aorta. This is no-
thing more than a continuation of the most
anterior heart-chamber, and runs as a simple
narrow tube beneath the back of the thorax,
where it terminates either in a single aper-
ture, or divides into several short branches,
which also terminate suddenly in open ori-
fices. The number of chambers varies, but
very frequently there are eight.

In the antennae, legs, and other appen-
dages of the body of insects, the arterial and
venous currents may be seen running toge-
ther, whilst in the wings the currents are
distinct.

The blood of insects usually consists of a
colourless liquid containing rounded or oval,
colourless, nucleated corpuscles (PI. 40. fig.
33) ; but sometimes it is yellowish or green-
ish, and rarely red.

The respiration of insects is effected by
means of TRACHEAE, two or more large
trunks of which usually traverse the body
longitudinally, giving off branches which run
in all directions, and communicating with
the air by numerous short tubes, connected
at or near the sides of the body with orifices
termed SPIRACLES or stigmata. Of those
insects which live in water, some have stig-
matic orifices which are brought into rela-
tion with the air at the surface of the water ;
whilst others in the larval state respire the
air mixed with the water in which they live,
this process being facilitated by the presence
of external branchiae, or processes of the in-
tegument in the form of leaves, plates, or
hairs, through which numerous tracheae
ramify in every direction.

The nervous system of insects consists
essentially of a series of ganglia arranged in
pairs, one for each segment of the body, and
situated between the alimentary canal and
the under surface of the body. The ganglia

of each pair are mostly united with each
other, but sometimes distinct, and are con-
nected with those adjacent by longitudinal
cords. The uppermost pair of ventral ganglia
is connected by two lateral cords surround-
ing the oesophagus with a large cephalic gan-
glion or brain. From the ganglia branches
are distributed to all parts of the body. A
sympathetic system of nerves is also present.
Want of space compels us to limit the
notice of the reproductive organs to the
description of PI. 27. figs. 18 & 19.

Many insects undergo complete metamor-
phoses, between the period at which they are
hatched and that at which they attain their
full development. On first leaving the egg,
they assume a more or less worm-like form,
known as the larva, caterpillar, or maggot.
The next stage is that in which they usually
neither move nor take food, when they form
the nympha, pupa, or chrysalis. This state
is succeeded by that of the perfect insect
or imago. In other insects, however, among
the Orthoptera, Hemiptera, and Neuroptera,
the metamorphosis is incomplete, the body,
legs, and antennae of the larva are nearly
similar in form to those of the imago, but
the wings are wanting. In some insects,
also, of the above orders, the pupa con-
tinues to be active, differing only from the
larva in its larger size, and in having acquired
rudimentary wings (PL 28. figs. 15. 1?. 21).
In some insects the only change consists
in ecdysis, without material alteration in
structure.

Examination, fyc. The external parts and
organs of insects are usually examined as
opake objects, the animals being held in
the stage-forceps. This method is, however,
often very unsatisfactory ; and the best is
to press them as much as possible between
two slides, without crushing, and to fasten
the slides together with india-rubber bands
or fine string, so that the parts may dry in
the compressed form. When subsequently
soaked in oil of turpentine, and mounted in
balsam, they will become much more trans-
parent and distinct. By prolonged macera-
tion in turpentine, the whole of the pigment
may be removed, which enables the struc-
ture to be seen very distinctly. When the
organs are very hard and thick, they may be
softened by boiling water, or solution of
potash, before being pressed between the
slides.

The internal organs, which are very deli-
cate, must be brought to view by dissection
under water, the insect being fixed by pins

INSECTS.

[ 362 ]

INSECTS.

stuck into the leaded cork (!NTROD. p.
xxiii).

The smaller and more delicate insects,
aquatic larvae, &c., are best preserved in so-
lution of chloride of calcium or glycerine,
mounted in suitable glass cells.

To preserve insects for the future exami-
nation of the internal structure, they should
be kept in solution of chloride of zinc ; but
when very soft and fragile, they may be kept
in spirit and water.

Insects are divided into two sections, and
these into twelve orders, thus : —

Section 1. Apiropoda.

Char. Legs numerous ; thorax not sepa-
rated from the abdomen.

Ord. 1. Myriapoda. Wings absent; legs
numerous (24 or more), terminated by
a single claw; eyes collected into two
groups, variable in number, sometimes
absent (fig. 366).

Fig. 366.

lulus terrestris. Magnified 2 diameters.

Section 2. Hexapoda. Legs six ; thorax
distinct from the abdomen.

Ord. 2. Thysanura. Wings absent; not
undergoing metamorphosis ; not parasitic;
mouth furnished with mandibles and
maxillae ; eyes simple, in two groups ; ab-
domen mostly terminated by setae or a
bifid tail.

Ord. 3. Anoplura or Parasitica (Lice, PI.
28. figs. 3-8). Wings absent ; not under-
going metamorphosis; parasitic (eyes
two, simple, sometimes none). (See
errata.)

Ord. 4. Suctoria or Siphonaptera (Fleas).
Wingless ; metamorphosis complete ;
mouth suctorial; rostrum composed of
two serrated laminae and a thin suctorial
seta, included in a jointed two-valved
sheath.

Ord. 5. Strepsiptera or Rhipiptera. Males
with four wings ; anterior wings two small
moveable corpuscles; posterior wings
large, membranous, in the form of a qua-
drant of a circle, longitudinally folded like
a fan. Females, apterous, vermiform,
without legs. Metamorphosis complete ;
mandibles two, narrow, somewhat curved ;
palpi two, biarticulate, far apart, inserted
beneath the head (larvae, pupae, and
females living parasitically in Hymeno-
pterous insects).

Ord. 6. Dipt era (Flies). Wings two, with
alulets at the base ; two halteres ; mouth

suctorial ; labium not furnished with palpi,
prolonged into a proboscis or sheath, and
enclosing setae, variable in number ; palpi
(maxillary) two, at the base of the pro-
boscis ; metamorphosis complete.

Ord. 7- Hymenoptera (Bees, Wasps, &c.).
Wings four, membranous, posterior ones
smaller, and with fewer veins; maxillae
elongate, generally slender, sheathing the
labium ; abdomen of the females almost
always terminated by a borer or a sting ;
metamorphosis complete (fig. 367).

Fig. 367.

Tenthredo nassata.
Magnified 2 diameters.

Ord. 8. Lepidoptera (Butterflies, Moths).
Wings four, membranous, covered with
coloured scales; mouth furnished with

INSECTS.

[ 363 ]

INSECTS.

an involute, spiral tongue, composed of
the elongated maxillae; metamorphosis
complete (fig. 368).

Fig. 368.

Danais Plexippe.
Nat. size.

Ord. 9. Neuroptera (Lace-wings, Dragon-
flies, &c.). Wings four, membranous, ge-
nerally pellucid, reticulated, naked, very
often equal; mouth not suctorial, but
mostly made for manducation ; mandibles
in some obsolete ; females never furnished
with a sting, and but rarely with a borer or
exserted oviduct; metamorphosis mostly
incomplete, in some complete (fig. 369).

Fig. 369.

metamorphosis with few exceptions in-
complete (fig. 370).

Fig. 370.

Reduvius tuberculatus.
Nat. size.

Ore?. 11. Orthoptera (Grasshoppers, Crickets,
&c.). Wings four, the upper coriaceous,
veiny, the inferior membranous, longitu-
dinally plaited like a fan ; mouth serving
for manducation, with strong mandibles ;
maxillae furnished with a cylindrical hel-
met ; metamorphosis incomplete.

Ord. 12. Coleoptera (Beetles). Wings four,
Fig. 371.

Libellula depressa.
Nat. size.

Ord. 10. Hemiptera (Bugs, &c.). Wings four,
all membranous, or the anterior ones coria-
ceous at the base, and thicker ; mouth with
a jointed rostrum (labium), ensheathing
setae (mandibles and maxillae); palpi none;

Cerambyx eedilis.
Nat. size.

anterior hard, coriaceous or horny (elytra),
covering the posterior, which are membran-
ous and transversely folded; mouth formed
for manducation, furnished with mandibles,
maxillae, and palpi, both labial and maxil-
lary; metamorphosis complete (fig. 371).
BIBL. Newport, Todd's Cycl. Anat. and

INSILELLA.

[ 364 ] INTERCELLULAR SUBSTANCE.

Phys. art. Insects ; Kirby and Spence, Intro-
duction to Entomology ; Burmeister, Handb.
d. Entomolog. (tr. by Shuckard) ; Siebold,
Lehrb. d. Vergl. Anat. ; Straus-Durckheim,
Consid. general, s. I Anatomie Comp. d.
Anim. Articul. ; Westwood, Introduction to
the Classification of Insects (copious Bibl.) ;
id. Butterflies of Great Britain ; V. d. Hoe-
ven, Handb. d. Zoologie; Blanchard, New
French edition of Cuvier's Regne Animal ;
Stephens, Manual of Brit. Beetles-, Laporte
and Castleriau, Hist. nat. d. Insectes ; Spry
and Shuckard, Brit. Coleopt. Delineated;
Kirby, Monogr. Apum Anglice ; Curtis, Brit.
Entomol.; Panzer, Deutschlands InseJct.;
and the innumerable Memoirs in the Ann.
des Sc. nat., the Annals of Nat. Hist., and
the Linncean Transactions.

INSILELLA, Ehr. — A genus of Diato-
maceae.

Char. Frustules single, fusiform, with a
turgid ring (hoop ?) interposed between the
valves, which are equal. (Represents a fusi-
form Biddulphia.) Marine.

I. africana. Frustules with four constric-
tions, broader and subglobose in the middle,
diminishing in size towards the acuminate
ends ; no markings visible (by ordinary illu-
mination); length 1-530".

Found on the coast of Africa.

BIBL. Ehrenberg, Ber. d. Berl. Akad.
1845, p. 357; Kiitzing, Sp. Alg. p. 32.

INTEGUMENT or TEGUMENT.— The
cutaneous covering of the bodies of animals.

INTERCELLULAR PASSAGES, SPACES,
&c. OF PLANTS. — Where the cells of vege-
table tissue are of any but six- or twelve-sided
forms, interspaces must exist between them.
These are especially evident in parenchyma
formed of rounded cells, where there exist of
course, angular, intercommunicating, inter-

Fig. 372.

Vertical section of half a leaf of a Potamogeton, with
air-spaces I.

Magnified 200 diameters.

cellular passages. The stomates of LEAVES
always communicate with such intercellular

passages, larger in the lower part of the
parenchyma of leaves. Intercellular spaces
are lacunae of larger size, definite or indefinite
in form, bounded by a number of cells of
less capacity than the space itself. These
are especially large and abundant, as air-
receptacles, in aquatic plants, both in the
stems and leaves, as in the Nymphaeacese,
Naiadacese (fig. 372), and Hydrocharidacea3,
&c., but also common in most Monocoty-
ledonous plants, such as Juncacese (PI. 38.
fig. 18), Araceae, Grasses, &c.

Intercellular spaces and canals likewise
serve as RECEPTACLES for SECRETIONS,
as in the case of the glands of the Aurantia-
ceae (fig. 284) (see also GLANDS), and the
TURPENTINE-CANALS of the Coniferse. The
milk-vessels of plants appear to be formed
sometimes in intercellular canals, sometimes
out of cells (LATICIFEROUS TISSUE).

BIBL. General works on Structural Bo-
tany.

INTERCELLULAR SUBSTANCE, OF
PLANTS. — When we make fine sections of
many kinds of cellular structure, as for in stance
of the horny albumen of the seeds of Palms
(Areca, PI. 38. fig. 21 ) or other plants, of the
collenchymatous tissue beneath the epider-
mis of the Chenopodiaceae, &c., of the sub-
stance of cartilaginous Algae, of many woods,
&c., we find an appearance of intervals be-
tween the lines bounding the component
cells, which intervals are filled up with appa-
rently homogeneous substance. Thus seen
and no further investigated, the interposed
matter was formerly described as intercellular
substance, a peculiar form of vegetable orga-
nization, and some went so far as to imagine
that cells originated free in this, and subse-
quently became glued together and fixed by
the solidification of the whole (Unger and
Endlicher). The application of dilute sul-
phuric acid to preparations of this kind, with
iodine, generally shows clearly that the sup-
posed intercellular substance consists of
secondary deposits really inside the cells
(PI. 38. fig. 22). Recent observations go to
prove that the supposed intercellular sub-
stance, a matter secreted or otherwise pro-
duced between the cells of a tissue, is of
very rare occurrence, even if existing at all.
Many authors have written on the subject
during the last few years, and it is still one
of the vexed questions of Vegetable Ana-
tomy, standing in this respect beside the epi-
dermal or rather the cuticular structures,
with which it is very closely allied. The
following is a brief outline of those opinions

INTERCELLULAR SUBSTANCE. [ B65 ]

INTESTINES.

worth notice : — The existence of an inter-
cellular substance was first spoken of by
Moldenhawer and Agardh. Mohl gave it
this special name, and in 1836 declared
that it exists very generally, often in large
quantity. More recently he has shown that
most of what he formerly called by this
name consists of secondary deposits. But
a kind of cementing matter does seem to
exist in very small quantity in some cases,
as between the wood-cells of Pinus, &c.,
which resists all attempts to reduce it into a
condition wherein iodine will colour it blue.
Valentin regarded the so-called intercellular
substance as composed of a series of layers
deposited on the outside of the cell-wall.
Meyen at first described the solid masses
between the cells of collenchymatous tissue
as intracellular, subsequently, however, as
intercellular productions. Schleiden de-
scribes the so-called intercellular masses,
like the CUTICLE, as a secretion from the
outside of the cell-wall. Mulder and Harting
believe in the existence of this matter, but
doubt whether it exists universally. Hartig
regards it as an extracellular secretion.
Wigand denies the external secretion alto-
gether, and declares the so-called intercel-
lular substance to consist of the walls of the
parent-cells, more or less softened and con-
verted into a cement, analogous in its cha-
racter to the gelatinous matter of the fronds
of PALMELLACE.E. Cohn appears to be
of the same opinion. Schacht declares that
it exists universally as a cement fastening
the cells together, and describes it in the
wood of Coniferse, in the leaves of Mosses
and Hepaticae, &c., but acknowledges the
truth of Mohl's interpretation of the co]-
lenchyma and so-called intercellular sub-
stance of endosperms, &c., which indeed is
beyond all doubt. See EPIDERMIS and
SECONDARY DEPOSITS, WOOD and ALBU-
MEN.

BIBL. Mohl, the papers cited under CELL-
MEMBRANE; Valentin, Repertorium, 1836,
i. p. 96; Meyen, Pflanzen-physiologie, i.
p. 160, Wiegmann's Archiv, 1835, p. 151,
ibid. 1837, p. 30; Schleiden, Grundziige,
3rd ed. i. p. 330, Transl. (Principles) p. 112;
Unger, Grunzuge der Anat. u. Phys. der Pfi.
Vienna, 1846, p. 18; Mulder & Harting,
Physiological Chemistry (Edinburgh, 1849),
pp. 399, 469; Hartig, Ann. des Sc. nat.
2 ser. v. ; Wigand, Intercellular-substanz,
&c., Brunswick, 1850; Cohn, de Cuticula,
Linncea, xxiii. p. 337, 1850; Schacht, Pflan-
zen-zelle, Berlin, 1852, p. 76.

INTESTINES. — The intestines consist
of three coats, an outer peritoneal (PERITO-
NEUM), an inner or mucous membrane, and
an intermediate muscular coat.

The areolar tissue of the mucous mem-
brane is often indistinctly fibrous, especially
its inner portions, where it forms the base-
ment membrane; it contains scattered,
roundish, elongate nuclei, without elastic
tissue. Between the proper mucous mem-
brane and the submucous tissue, is situated
a layer of longitudinal and transverse un-
striped muscular fibres, frequently, however,
indistinct in man.

The epithelium of the intestines consists
of a single layer of cylindrical cells, contain-
ing a transparent oval nucleus, with one or
two nuclei, and granular matter.

The surface of the small intestines is
covered with VILLI, which are absent in the
large intestines,

Fig. 373.

Magnified 60 diameters.

Perpendicular section of the wall of the lower part of
the ileum of the calf, a, viUi ; b, Lieberkuhn's glands ;
c, muscular layer of the mucous membrane ; d, follicle of
a Peyer's gland ; e, subjacent portion of the submucous
tissue ; /, circular muscular fibres ; g, longitudinal ditto.

INTESTINES.

[ 366 ]

INTESTINES.

The elements of the muscular coat are
organic or unstriped muscular fibres, con-
sisting of pale, homogeneous, fusiform, flat-
tened cells, with an elongated nucleus. The
fibres frequently present knotty expansions,
and sometimes zigzag flexuosities.

The glandular organs of the small intes-
tines consist of Brunner's or the racemose
glands; Lieberkuhn's follicles or the tubular
glands ; Peyer's, the aggregate or agminate
glands ; and the solitary glands or follicles.

Brunner's glands are situated in the sub-
mucous tissue of the duodenum, extending
about as far as the orifice of the choledic
duct. If a portion of the intestine be kept
stretched, or distended with air, and the
muscular coat be dissected off, they are seen
as yellowish, flattened, roundish-angular
bodies, mostly about 1-50 to 1-25" in size,
the short ducts of which pass through the
mucous membrane. They secrete an alkaline
mucous liquid.

Lieberkuhn's follicles, or the tubular
glands (fig. 3/4), are distributed throughout

Fig. 374.

Magnified 60 diameters.

Lieberkuhn's follicles, from the pig. a, basement
membrane and epithelium j b, cavity.

the small intestines, extending through the
substance of the mucous membrane. They
are very numerous, straight, narrow, slightly
dilated at the ends, and rarely bifurcate.
They vary in length from 1-60 to 1-84", and
consist of a delicate basement membrane,
lined with epithelium.

Peyer's glands are rounded or elongated
flattened aggregations of glands, appearing
upon the inner surface of the intestine as
slightly depressed spots. They are most nu-

merous in the ileum, but are sometimes found
Fig. 375.

Magnified 10 diameters.

Portion of a Peyer's gland, human, a, follicles sur-
rounded by the orifices of Lieberkuhn's glands ; b, villi ;
c, scattered Lieberkuhn's glands.

in the lower part of the jejunum, or even its
upper part and the duodenum. They are
usually twenty, thirty, or more in number.
They vary in length from 1-25 to H". Each
consists of an aggregation of closed and
rounded follicles, from 1-70 to 1-12" in
diameter, partly seated in the mucous mem-
brane itself, partly in the submucous tissue.
The follicles are surrounded by a ring of
Lieberkuhn's glands, which, with villi, also
occupy the intervening portion of the mucous
membrane. Each follicle consists of a tole-
rably firm coat of indistinctly fibrous areolar
tissue, with scattered nuclei, enclosing a grey
soft substance, consisting of innumerable
nuclei and cells, from 1-3000 to 1-1500" in
diameter, with a few granules of fat. The
follicles are surrounded by a vascular net-
work, which sends off branches to their
interior.

The solitary glands agree in structure with
the individual follicles of Peyer's glands.
Their free surface is usually convex, and
covered with villi (fig. 376).

Fig. 376.

Solitary gland, covered with villi, from the jejunum.

The glandular organs of the large intes-
tines are Lieberkuhn's glands and the solitary
follicles.

The Lieberkuhn's glands agree in struc-

IODINE.

[ 367 ]

ISARIA.

ture with those of the small intestines, except
that they are larger and broader in propor-
tion to the greater thickness of the mucous
membrane. The solitary follicles also differ
from those of the small intestine in their
larger size, and in the circumstance that
each of the minute elevations of the mucous
membrane produced by them exhibits a
rounded or elongated opening, leading to a
depression in the mucous membrane over
the follicle (fig. 377). This, however, has

Fig. 377.

Magnified 45 diameters.

Solitary follicle from the colon of a child, a, tubular
glands ; b, muscular coat of the mucous membrane ; c,
submucous tissue ; d, transverse muscular fibres ; e, pe-
ritoneum ; /, depression in mucous membrane over the
follicle a.

no communication with the follicle.

The investigation of the structure of the
intestines is a matter of some difficulty. The
epithelium must be examined in a perfectly
fresh state. The glands are most readily
seen in portions hardened by absolute alco-
hol or chromic acid; whilst some have re-
commended boiling with acetic acid (80 per
cent.), then drying and making sections with
a Valentin's knife. The muscular elements
are rendered most distinct by maceration
with dilute nitric acid (20 per cent).

The capillaries of the intestines are very
beautiful when injected ; but great care is
required in securing the vascular branches
to prevent the escape of the injection.

BIBL. Kolliker, Mikrosk. Anat. ii. and
the Bibl. therein given.

IODINE. — Solution of iodine is often
useful for dyeing and rendering very trans-
parent objects more distinct, and for its
producing with some vegetable and animal
tissues and substances colours by which

they may be distinguished. The general
results of its action are enumerated in the
INTRODUCTION, p. xxxviii, and special re-
marks are made under the heads of the
tissues.

An aqueous solution of iodine is the best
for general use, but a solution in spirit is
much stronger. A very strong solution may
be made by dissolving iodine in a solution
of iodide of potassium. See also SCHULZ'S
LIQUID.

IRID^EA, Bory.— A genus of Cryptone-
miacese (Florideous Algae), containing one
British common species, I. edulis, a dull red
obovate, leaf-shaped sea-weed of fleshy-car-
tilaginous texture, 4 — 18" long, the central
substance composed of longitudinal filaments,
the cortical of closely-packed moniliform
perpendicular filaments. Fructification :
spores in spherical masses (favellidia), im-
bedded in the frond in wide patches near the
extremity; tetraspores in dense band-like
immersed sori.

BIBL. Harvey, Brit. Mar. Alg. 150. pi. 19,
A ; Phyc. Brit. pi. 97 ; Greville, Alg. Brit.
pi. 17; EngLBot.pL 1307.

IRIDESCENCE. See INTROD. p. xxx.

IRIS. See EYE, p. 252.

ISARIA, Hill. — A genus of ISARIACEI

Fig. 378.

Fig. 378. Isaria citrina. Plants on a fungus. Nat. size.

Fig. 379.

Fig. 379. Isaria citrina.
fruit. Magn. 20 diams.

A single plant, showing the

(Hyphomycetous Fungi), growing upon dead

ISARIACEI.

[ 368 ]

ISOETES.

insects, fungi or twigs or leaves of plants.
J. farinosa, Fries, grows to a height of
1 — 2" on dead pupae, spiders' nests, &c.
I. arachnophila, Ditton, intricate/, ¥r.,pube-
rula, Berk., and Friesii, Montagne, are also
British. I. citrina (figs. 378, 379) is a small
species, growing gregariously on vegetable
substances.

BIBL. Berk. Hook. Br. Fl. vi. pt. 2. p.464;
Ann. Nat. Hist. i. p. 259, vi. p. 132. pi. 12.
fig. 12. 2nd ser. v. p. 464 ; Fries, Summa
Veget. p. 464 ; Montagne, Ann. des Sc. not.
2 se'r. v. pi. 12. fig. 3.

ISARIACEI.— A family of Hyphomyce-
tous Fungi, growing on decaying animal
substances or larger Fungi, characterized by
a cellular receptacle formed of filaments ap-
proximated together and conjoined through-
out their whole length, each filament termi-
nating in a spore.

Synopsis of British Genera.

I. ISARIA. Receptacle clavately branched,
formed of densely interwoven coale scent
filaments, or cellularly-fleshy. Spores borne
on simple sporophores arising on all sides.

II. ANTHINA. Receptacle clavately
branched, formed of parallel filaments, loose-
ly interwoven or free, feathery or villous at
the summit only, where they form the simple
sporophores.

III. CERATIUM. Receptacle somewhat
horn-shaped, of a mucilaginous consistence,
sprinkled with filaments which collapse into
minute granules (conidia) and free sporidia.

BIBL. See the Genera.

ISOETES. — A genus of Psiloteae (Lyco-
podiaceae), consisting of plants, usually of
small size, growing at the bottoms of pools,
or in wet places. I. lacustris, the only
British species, occurs in mountain lakes.
Isoetes is very remarkable in its mode of
growth ; it is the only known plant possess-
ing a stem which never branches, moreover
the solid cone which supports the leaves
possesses a kind of cambium layer, from
which are produced successive layers of
woody structure, comparable in some mea-
sure with those of the Dicotyledons; besides
this, it has a striking peculiarity in the mode
of development of the (adventitious) roots,
the youngest of which are the lowest, the
older being gradually pushed upwards and
outwards towards the circumference.

The woody substance of the stem of Iso-
etes, like that of Lycopodiacese generally, is
a solid central body, without a pith; it is

surrounded by a thick parenchymatous rind,
which makes up the greater part of the mass
of the corm; the woody mass itself is cylindri-
cal above and somewhat semilunar below, the
convexity downward, and it has a layer of
cambium not only over the growing apex,
but over the convexity of the sides and lower
surface. Every year a new portion of wood
is added to the upper end, and also to the
outer angle of the convex lower mass. The
roots are produced in cycles of tens, some-
times one, sometimes two in a year ; in each
cycle the oldest root is the inmost ; but the
succeeding cycles appear in the middle of
their predecessors, and push them out, and
up to the side. The rind is renewed every
year by the cambium layer, and the latter in
its growth to increase the size of the corm,
by degrees covers up and encloses the re-
mains of the earlier roots (as the woody layers
of Dicotyledonous trees overgrow broken
branches, bury them, and convert them into
imbedded knots). The leaves are of delicate
organization, and contain four longitudinal
air-canals, with septa at intervals, and one
vascular bundle ; they are expanded at the
base, and contain the immersed sporanges.
DeCandolle says the epidermis has stomates;
this appears doubtful. The sporanges are
of two kinds, or rather bear two kinds of
spores, and there appears to be a periodicity
in their development. The fronds of I. la-
custris are discoverable in the interior of the
bud twelve months before they become fully
developed; the sterile originate in spring and
the earlier part of the summer, the fertile in
the autumn, while stunted fertile leaves ap-
pear even in the winter. If a vigorous leafy
plant is examined, it will be found to have a
few sterile leaves outside, then a circle of
leaves with oosporanges, next a circle of
anthero-sporanges, and in the centre of
the bud sterile leaves closing the annual cycle.
The sporanges are somewhat plano-convex,
longish-oval cases, with transverse processes
forming imperfect septa, dividing them into
several chambers (fig. 382). The cases are
sheathed by a membranous expansion of the
base of the leaf (fig. 381), to which they are
adherent by the back (fig. 382) ; the septa
arise opposite the point of attachment at the
back, and spreading out, join the front wall.
The different contents of the sporanges are
evident before they open, those with the
small spores having a smooth face, those
with large spores being rendered tubercular
from the protrusion of the wall by the under-
lying bodies. The wall of the capsule is

ISOETES.

[ 369 ]

ISOETES.

membranous and has no regular dehiscence,
the spores escaping by decay of the mem-
brane in front.

Fig. 380.

Fig. 381.

Fig. 382.

Isoetes setacea.
Fig. 380. Natural size.
Fig. 381. Base of a detached fertile leaf, seen in face.

Magn. 5 diams.
Fig. 382. Vertical section, from back to front of ditto.

Magn. 10 diams.

Fig. 383.

Isoetes setacea.

Fig. 383. Horizontal section, oosporange with macro-
spores. Magn. 10 diams.

The smaller spores resemble pollen grains;
they are usually of the shape of quarters of
a globe, more rarely tetrahedral, with an
outer coat presenting ridges at the angles, and
an inner which is a rounded sac. The outer
coat is finely dotted in I. lacustris. The
large spores are at first of a tetrahedral form
with rounded angles, but when ripe they
become globular. The delicate inmost layer
is enclosed in a thick exospore composed of
three layers; the innermost of moderate
thickness, brown colour, and glassy consist-
ence, exhibiting striae and three strong ridges
converging to a point at the angle where the
spore meets its three sister-spores ; the next
coat is thinnish, and of granular character
and yellow colour ; the outermost is a clear
and gelatinous layer ; the outer two follow
all the markings of the glassy coat, and are
especially thick over the three ridges.

The contents of the microspores are at
first merely granular protoplasm. About a
month after they are scattered from the
sporange, the primordial utricle becomes
divided into two or four portions, which
form cells, in each of which again are deve-
loped two vesicles, each producing a filament
coiled up spirally. The spores swell, the
daughter-cells burst,and the lenticular vesicles
escape ; the latter then open and emit the
spiral filaments, which are found to be co-
vered with cilia on the anterior turns of the
spiral, by means of which they move actively
through the water. They are the spermato-
zoids.

The macrospores, when they escape from
the sporange, contain only protoplasm with
oil-globules. In the course of a few weeks,
the internal cavity of the spore begins to
exhibit a development of cellular tissue, by
which it is subsequently filled up. This is
the prothallium. At the same time, the in-
ternal coat increases in thickness, and exhi-
bits several layers. The increase of size of
the prothallium causes the spore-coat to
burst at the apex where the three ridges
meet, so that three triangular valves turn
back, exposing the prothallium. On this
are developed the archegonia, the first on
the apex in the central point where the three
points of the spore-coat meet. If this is not
fertilized, others are produced around it.

2B

ISTHMIA.

[ 370 ]

IXODES.

The archegonium is of much the same cha-
racter, essentially, as that of the rest of the
higher Cryptogamous Plants, consisting of
a papilla with a central canal leading to the
embryo-sac. The four rows of cells forming
the neck of the archegone separate, and a
germ -cell is formed in the embryo-sac. This
is fertilized by the entrance of a spermato-
zoid into the embryo-sac.

In the development of the embryo in the
spore, it forms a cellular body, which gra-
dually displaces the cellular tissue originally
filling this up. The first leaf and roots are
developed while the rudiment is still within
the spore-coat, in opposite directions and
horizontally (right and left) in relation to
the apex of the spore. The young plant
somewhat resembles a germinating Mono-
cotyledon.

The woody structure of the stem of Isoetes
consists of spiral-fibrous cells, usually annular
or reticulated, but sometimes really spiral.

BIBL. Bischoff, Crypt. Gewachse, Rhizo-
carpen, Nuremberg, 1828. p. 70; Mohl, Verm.
Schrift. Tubingen, 1845. p. 122; Muller,
Botanische Zeit. vi. p. 297. 1848 (Ann. Nat.
Hist. 2 ser. ii. p. 81, &c.) ; Mettenius, Beitr.
z. Botanik. 1st heft, Heidelberg, 1850;
Hofmeister, Abhand. d. K. Sachs. Ges. d.
Wiss. iv. 123; A. Braun, Flora, 1847- p.
33.

ISTHMIA, Ag.— A genus of Diatomaceaj.

Char. Frustules depressed or subcylin-
drical, rhomboidal or trapezoidal in front
view, angles more or less produced ; frus-
tules coherent by the angles, basal frustule
stipitate ; surface of valves and hoop appear-
ing reticular or cellular. Marine.

The depressions upon the valves and hoop
are so large as to produce a distinct reticular
or cellular appearance when viewed by ordi-
nary illumination.

I. obliquata (nervosa, K.). Valves fur-
nished with linear thickenings, giving them
a coarsely reticular or veined appearance.
British.

I. enervis (PI. 13. fig. 2). Valves without
linear thickenings, uniformly covered with
depressions. British.

BIBL. Ehrenberg, Die Infus. p. 209 ;
Kiitzing, Bacill. p. 137, and Sp. Alg. p. 135 ;
Ralfs, Ann. Nat. Hist. 1843. xii. p. 270.

ITCH-INSECT. See SARCOPTES.

IVORY. — This substance, which consists
of the tusks of the elephant, possesses the
minute structure of bone.

IVORY,. VEGETABLE.— This substance,
consisting of the ALBUMEN of the seeds of a

Monocotyledonous tree, Phytelephas macro-
carpa, is composed of cellular tissue, with the
walls so thickened by horny secondary deposits
that the cavities of the cells are almost oblite-
rated. The pores of the secondary deposits,
however, remain uncovered throughoutall the
thickening, and thus are converted into tubes
or canals running to meet each other from
the small remaining cavities of contiguous
cells. In PI. 38. fig. 23 c represents a sec-
tion mounted in Canada balsam, which has
in part penetrated into the cavities ; the re-
maining cavities and pore canals are filled
with air and thus appear black (a).

IXODES, Latr.— A genus of Arachnida,
of the order Acarina, and family Ixodei.

Char. Palpi canaliculate, sheathing the
rostrum; mandibles 3-jointed, basal joint
internal, the second joint external and long,
the third short, denticulate ; labium covered
with reflexed teeth ; body very extensile, fur-
nished near the rostrum with a dorsal horny
shield ; legs with two claws and a caruncle.

These animals form part of those which
are popularly known as ticks. They are
commonly found in dense woods, upon
brushwood, briers, &c., from which they get
upon animals, as dogs, oxen, horses, &c.,
burying the rostrum deeply in the skin
and sucking the blood, so as to become dis-
tended to ten times their original size. They
are also found upon reptiles, birds, and occa-
sionally attack man.

The species are very numerous, and have
been arranged in several genera by some
authors.

I. ricinus, the dog -tick. Body oval, in
the gorged condition becoming globular and
blackish violet; legs and appendages brown.

I. reduvius. Pale yellowish red ; head
and legs black. Found upon sheep.

J. pictus. Back white, with brown spots ;
crenulate posteriorly; legs brown. Found
upon deer ; also upon mosses.

/. Dugesii (plumbeus, Dug.) (PI. 2. figs.
19-22). Oval, leaden grey, without spots.
Found upon dogs.

/. plumbeus, Leach. Shield heart-shaped,
slightly rugose; rostrum, palpi and legs
pale ferruginous ; body of a leaden colour ;
length 1-4". Found upon and in the nests
of the bank-swallow (Hirundo riparia).

BIBL. Gervais, Walckenaer's Apteres, iii.
p. 234; Hermann, Mem. Apterolog.-, Duges,
Ann. d. Sc. not. 2nd ser. ii. ; Leach, Linn.
Trans, xi. ; Koch, Uebers. d. Arachnid.
Syst. ; Denny, Ann. Nat. Hist. 1843. xii. ;
Gene, ibid, 1846. xviii. p. 160.

JANIA.
J.

[ 371 ]

JANIA, Lamouroiix. — A genus of Coral-
linaceae (Florideous Algae), calcareous fila-
mentous bodies, occurring in tufts, pale red
or purplish when fresh, on small Algae be-
tween tide-marks. The filaments are arti-
culated and dichotomously branched, impreg-
nated with a calcareous deposit. The fruit
consists of urn-shaped ceramidia, formed out
of the end joints of the branches, a dichoto-
mous continuation of which is represented
by a pair of minute divergent horns on the
ceramidium ; the latter is pierced by a pore
at the apex, and contains a tuft of erect
linear tetraspores. British species :

1. J.rubens. Joints of principal branches
cylindrical. Harvey, Phyc. Brit. pi. 252.

2. J. corniculata. Joints of principal
branches obconical and compressed, /. c.
pi. 234.

BIBL. Harvey, /. c. and Brit. Mar. Ala.
p. 107. pi. 13 D.

JATROPHA. See CASSAVA.

JENKINSIA, Hook.— A genus of Tzeni-
tidese (Polypodaeous Ferns). Exotic.

JUNGERMANNIA, Dill.— A genus of
Jungermannieae (Hepaticaceae), formerly
including the whole of these plants, but
now restricted to a certain number of species,
thus characterized : Fructification terminal.
Perichaetial leaves free or united only at the
base, like or unlike the stem-leaves. Peri-
gone membranous, tubular, plaited-denticu-
late at the apex, the mouth 3- or 6-cleft.
Vaginule membranous, included or rarely
exserted. Capsule 4-valved, splitting to the
base. Amphigastria present or absent.

This is the largest genus of the Jungerman-
nieae ; among the commonest species are J.
bicuspidata, L., J. albicans, L., J. barbata,
J. setacea, &c., found on wet bogs, banks,
rocks, &c.

BIBL. Hooker, Brit. Jungermanniea, Brit.
Flor. i. pt. 1. p. 112, &c.; Ekart, Synops.
Jungermann.', Nees v.Esenbeck, Lebermoose ;
Gottsche, Lindenberg and Nees, Synops.
Hepatic. Hamburg, 1844-47.

JUNGERMANNIEAE.— A family of He-
paticae, distinguished by possessing a distinct
stem, bearing leaves, often with stipule-like
bodies called amphigastria (fig. 384), with
terminal archegones and sporanges, bursting
by four valves (figs. 324 and 325), destitute
of a columella, containing elaters mixed with
the spores. In the older works, the tribe
comprehended only the genus Jungermannia,
in which were also included the Pellieae, but
Jungermannieae, as restricted to leafy stemmed

JUNGERMANNIE.E.

Fig. 384.

Jungermannia albicans.

Stem with succubous leaves and amphigastria, and a
lateral unopened perigone.

Magnified 10 diameters.

Liverworts, is now broken up into a number
of genera.

Synopsis of British Genera.

1. Leaves incubous (their bases covered by
the tips of those below).

* Leaves complicate, two-lobed.
•j* Amphigastria present.

I. LEJEUNIA. Perigone terete or an-
gular. Leaves not ciliated.

II. PHRAGMICOMA. Perigone depressed-
plane, subcordate, obtusely keeled in front.

III. FRULLANIA. Perigone compressed-
keeled.

IV. MADOTHECA. Perigone compressed,
two-lipped.

V. PTILIDIUM. Perigone terete. Leaves
ciliated.

VI. TRICHOCOLEA. Perigone wanting.
Leaves capillary-multifid.

t Amphigastria absent.

VII. RADULA. Perigone compressed.
** Leaves not complicate, two-lobed.

t Amphigastria present.

VIII. SENDTNERA. Perigone six-angled,
tubular, deeply multifid.

IX. SCHISMA. Perigone plicate, the
mouth almost equally erecto-laciniate, co-
vered by the perichaete.

X. HERPETIUM. Perianth triangular,
long, toothed at the mouth.

XI. CALYPOGEIA. Perianth oblong, sac-
like, fleshy, hairy, truncate, attached by one
side of its mouth to the stem.

2s2

JUNIPERUS.

[ 372 ]

KIDNEY.

ft Amphigastria wanting.

XII. PHYSIOTIUM. Fertile perigone
membranous, oblong-lanceolate, decurved.

2. Leaves succubous (the bases covering the
tips of those below).

* Amphigastria present.

XIII. SACCOGYNA. Perigone membra-
nous, saccate, pendulous, glabrous, mouth
with a membranous margin, by one side of
which it is attached to the stem.

XIV. CHEILOSCYPHUS. Perigone deeply
2-3 lobed, epigone chartaceous.

XV. LOPHOCOLEA. Perigone 3-lobed,
3-angular, lobes crest-toothed.

XVI. SPHAGINC^ETIS. Perigone terete
below, 3-angular above ; mouth denticu-
late ; amphigastria only on the gemmiferous
branches.

XVII. JUNGERMANNIA. Perigone tubu-
lar, plaited-denticulate, the mouth 3-6 cleft.
(Some species of Jungermannia have no am-
phigastria).

XVIII. ALLICULARIA. Perigone ter-
minal, adherent to and enclosed in the ur-
ceolate perichaete, the mouth regularly den-
ticulate.

** Amphigastria, absent.

XIX. PLAGIOCHILA. Perigone com-
pressed, truncate.

XX. SARCOSCYPHUS. Perigone adherent
to the perichsete, leaves 2-lobed.

XXI. GYMNOMITRIUM. Perigone want-
ing, ripe sporange included in the perichaete.

XXII. HAPLOMITRIUM. Perigone want-
ing, ripe sporange exserted.

JUNIPERUS, L.— A genus of CONI-
FERS (Gymnospermous plants), presenting
some interesting characters in the WOOD,
the POLLEN, and the development of the
OVULES.

JUTE.— The liber of Corchorus capsu-
laris, Willdenow, an East Indian plant be-
longing to the family of the Tiliaceae, so
many of which furnish fibrous substances
(such as the bast used for matting, the liber
of the lime-tree). Jute has a very long,
glossy fibre, and is now largely imported
into this country. PL 21. fig. 3 represents
the single liber-fibres (see TEXTILE SUB-
STANCES and LIBER).

BIBL. Hooker, Journal of Botany, vol. i.
25. 1849.

K.

KALLYMENIA, J. Ag.— A genus of
Cryptonemiacese (Florideous Algae), fleshy

membranous sea-weeds of red colour, with
ribless leaf-like fronds, having three strata
of cellular tissue, the central filamentous,
the intermediate of large round cells, the
cortical of minute cells in vertical rows.
Fructification : spherical masses (favellidia)
of spores half immersed in the frond, and
tetraspores, which are tetrahedrally subdi-
vided, and occur scattered. The two British
species, K. reniformis and Dubyi, are both
rather rare,

BIBL. Harvey, Brit. Mar. Alg. p. 150.
pi. 19 B ; Phyc. Brit. pi. 13. 123 ; Engl.
Bot. pi. 2116.

KAULFUSSIA, Blume.—
A genus of Marattiaceous
Ferns, with curious roundish
sori, formed of radiately co-
herent sporanges, opening by
a slit at the top (fig. 385).
Exotic.

Magn.25diams.

KERONA, Miill., Ehr— A genus of In-
fusoria, of the family Oxytrichina.

Char. Body covered with cilia, hooks also
present, but no styles.

K. polyporum (PI. 41. fig. 13). Body
whitish, depressed, elliptico-reniform, with a
row of longer cilia in front below the
mouth ; length 1-144". Parasitic upon
Hydra.

Dujardin unites the genera Stylonichia,
E., Kerona, E. and Oxytricha, E., in part, to
form his Kerona, with the following charac-
ters : Body soft, flexible, oval, depressed,
with cirrhi or thick non-vibratile cilia, in the
form of setse or styles, and with hooks. He
admits five species.

BIBL. Ehrenberg, In/us, p. 368; Du-
jardin, Infus. 422.

KERONIA.— A family of Infusoria (Duj.).

Char. Body irregularly ciliated, soft,
flexible, with a regular row of oblique vibra-
tile cilia leading to the mouth, and with
cirrhi in the form of styles or moveable, but
not vibratile hooks. This family nearly cor-
responds with the Oxytrichina of Ehrenberg.

Found in stagnant, fresh or salt water;
some more especially when the water has
become decomposed ; also in vegetable infu-
sions.

Three genera : Halteria, D., Oxytricha,
D. and Kerona, D.

KIDNEY. — The kidney consists of its
enveloping membranes, and the secreting
parenchyma.

The membranes are two : an adipose cap-
sule composed of loose areolar tissue abound-

KIDNEY.

[ 373 ]

KIDNEY.

ing n fat ; and a tunica propria, or albu-
ginea, which forms a whitish, thin, but firm
membrane, closely surrounding the kidney,
becoming connected with the pelvis and
vessels at the hilus, without being prolonged
into the interior of the organ, and consisting
of ordinary areolar tissue with numerous
fine networks of elastic tissue.

The parenchyma, in a transverse section,
appears to the naked eye to consist of two
parts, the inner or tubular substance, and
the outer or cortical. The tubular substance
is composed of 8-15 isolated conical masses
or pyramids, converging towards the hilus,
and then* apices forming the papilla ; whilst
the corticp.1 substance constitutes the outer
part of the organ, and fills up the interstices
between the pyramids. When microscopic-
ally examined, the cortical part also becomes
resolved into as many segments as there are
pyramids; hence the kidneys may be re-
garded as composed of a certain number of
intimately connected lobules.

Both the cortical and the tubular substance
consist principally of the urinary tubules.
These commence in each segment or lobule
by very numerous orifices in the surface of

Fig. 386.

Papilla of the kidney of a pig with the tubules injected,
showing their origins upon the surface.
Magnified 10 diameters.

the papillae, and pass through the pyramids,
running straight and nearly parallel with
each other (fig. 387 &)• During this course
they undergo repeated dichotomous subdi-
vision (fig. 387 I), the branches being given
off at a very acute angle, and at first with
considerable diminution in size ; and some-
times they divide into three or four branches,
so that ultimately a larger bundle of tubes
proceeds from them, producing the increased
breadth of the pyramids towards the exterior.

Towards thebase of the pyramids, theparallel
tubules become more loosely connected by

Fig. 387.

Perpendicular section of the injected kidney of a rabbit
through part of a pyramid. On the left the course of the
vessels, on the right that of the tubules is shown, a, in-
terlobular arteries, with their Malpighian tufts b, and
vasa efferentia c ; d, capillaries of the cortical portion ;
e, vasa efferentia of the outermost tufts passing to the
surface of the kidney ; /, vasa efferentia of the innermost
tufts running into the straight arteries, g,g,g; h, capil-
laries of the pyramids arising from the latter ; i, a straight
vein commencing at the papilla; A, origin of a urinary
tubule at a papilla ; I, o, branches of the same ; m, coiled
portion in the cortex ; n, the same at the surface of the
kidney; p, connexion with the Malpighian capsules.

Magnified 30 diameters.

the interposition of bundles of arteries and
veins, which run straight, and they diverge

KIDNEY.

in all directions, pursuing an undulating
course. On reaching the cortical substance,
this is still more the case, and the tubules
become inextricably interwoven, each finally
terminating in a Malpighian body. Those
which have not terminated in a Malpighian
body before reaching the surface of the kid-
ney, are reflected inwards until they do so ;
hence on viewing the outer surface of an
injected kidney, the loops of these tubules
are seen.

The urinary tubules are cylindrical, and
consist of a basement membrane (fig. 388 6)
lined with pavement epithelium, d. The base-
ment membrane is very transparent, but firm
and elastic. Within it is a single layer of
nucleated polygonal epithelial cells (fig. 388
d, e). These, when immersed in water, lose
their polygonal form, become rounded, and
appear to fill up the tubules entirely ; they
often also burst, and then the tubules appear
to contain nothing more than a finely gra-
nular mass with nuclei. These changes are
found to have taken place spontaneously, if
the kidney be not fresh. The epithelial cells
are larger in the convoluted than in the
straight tubules (fig. 388, 2).

[ 374 ] KIDNEY.

TJfe iMalpighian bodies may be regarded
as terminal dilatations of the tubules, each
containing a round plexus of vessels, the
Malpighian tuft.

The basement membrane surrounding the
tuft (fig. 388 a) is somewhat thicker than
elsewhere, and the epithelium lining it is
continued over the free surface of the tuft.
The Malpighian tufts consist of close convo-
lutions of fine vessels derived from branches
of the renal artery. The latter enter the
kidney between the pyramids, and continue
to divide until arriving at the cortical sub-
stance, where they give off a number of long
branches, mostly running towards the con-
vex surface of the kidney, between the lo-
bules, hence called interlobular arteries.
From these short, mostly lateral branches
are given off, each of which terminates in a
Malpighian tuft, forming its afferent vessel.
Each afferent vessel, on entering the Mal-
pighian body, divides into 5-8 branches, each
of which becomes subdivided into a tuft of
capillaries; these are variously convoluted
and interwoven, ultimately uniting to a sin-
gle vessel, the efferent vessel. The afferent

1 . A Malpighian body, A, with the urinary tubule B, C;
human, a, Capsule of the Malpighian body, continuous
with b, the basement-membrane of the tubule ; c, epi-
thelium of the Malpighian body ; d, that of the tubule ;
e, detached epithelial cells ; /, afferent vessel ; g, efferent
vessel; h, Malpighian tuft. 2. Three epithelial cells
from coiled tubules, one of them containing globules of
fat.

Magnified 300 diameters.

Fig. 389.

From a human kidney, a, end of an interlobular ar-
tery; b, afferent vessels; c, naked Malpighian tuft;
d, efferent vessels ; e, tufts enclosed in their capsules ;
/, urinary tubules arising from them.

Magnified 45 diameters.

KIDNEY.

[ 375 ]

KIDNEY.

and efferent vessels are usually situated near
each other, and opposite the origin of the
urinary tubule.

The efferent vessels, which, although
arising from the capillaries of the Malpighian
tufts, are rather small arteries than veins, in
import and partly in structure, terminate in
the capillary network situated in the cortical
substance and the pyramids. This network
surrounds closely the coiled tubules on all
sides, and forms a connected plexus through-
out the kidneys, the meshes of which are
roundish angular; but near the pyramids
the afferent vessels are larger, and differ
from the rest in their straighter course and
more sparing ramification.

The veins of the kidney commence on the
surface of the organ and at the apices of the
papillae by small branches connected with
the plexus ; these by their union form larger
ones, which accompany the larger arteries.

Mr. Bowman compares the solitary effe-
rent vessels of the Malpighian bodies to the
portal system of the liver, both serving to
convey blood between two capillary systems.
He describes these efferent vessels collect-
ively as the portal system of the kidney.

The interstices between the vessels, nerves
and tubules of the kidney are occupied by a
stroma of areolar tissue (fig. 390 c), containing
elongated nuclei, and which is much more
abundant in the medullary than in the cortical
portion. At the surface this frequently be-
comes condensed to form a very distinct

Fig. 390.

Transverse section of some cortical urinary tubules ;
human . a, divided tubules, with the epithelium removed ;
b, the same, containing the epithelium; c, stroma of
areolar tissue ; d, space corresponding to a Malpighian
body.

Magnified 350 diameters.

membrane, but loosely adherent to the fibrous
capsule, and which is connected by numerous
delicate processes with the inner stroma.

The pelvis of the kidney with the calyces
and the ureter consist of an outer fibrous, a
muscular, and a mucous coat. The fibrous
coat is composed of ordinary areolar tissue,
mixed with elastic tissue.

The muscular coat is strongest in the
ureter, and forms two layers of unstriated
fibres, the inner being transverse, the outer
longitudinal, but near the bladder an inner
layer of longitudinal fibres is added. The
muscular coat of the pelvis is as strongly
developed as that of the ureter, becoming,
however, less marked in the calyces, and
terminating where they embrace the pa-
pillae.

The mucous coat is thin, and not furnished
with glands or papillae. Its epithelium (fig.
391, B) is laminated, and remarkable for the
variable form and size of its elements (fig.
391, A), the deeper cells being roundish and
small, those in the middle cylindrical or
conical, and the uppermost roundish, poly-
gonal, and somewhat flattened. The cells
frequently contain two nuclei, and bright
rounded granules with dark margins.

Epithelium of the pelvis of the kidney ; human.

A . Isolated cells : a, small, b, large pavement-epithelial
cells ; c, the same containing the granules ; d, cylindrical
and conical cells from the deeper layers ; e, intermediate
forms. B. Cells in situ.

Magnified 350 diameters.

KIDNEY.

[ 376 ]

KONDYLOSTOMA.

In the Mammalia generally the structure
of the kidneys agrees essentially with that of
man.

In the lower Vertebrata they exhibit dif-
ferences which relate principally to the fol-
lowing particulars : — 1, the form, which in
birds, fishes, and reptiles is considerably
more elongated and frequently flattened;
2, the tabulation, which in the human adult
kidney is indistinct, although marked in the
foetus, whilst in that of other Vertebrata the
separate lobules are very distinct, sometimes
being connected only by the branches of the
ureter; 3, the Malpighian tufts, which in
birds, reptiles, and fishes consist of a single
convoluted vessel, and which in some (naked
reptiles) are larger, in others (osseous fishes)
smaller than in man ; whilst in birds (also
the sheep) they have been found inserted
into the sides of the tubules ; and 4, in the
structure and arrangement of the urinary
tubules; these are uniform in size in fishes;
furnished with ciliated epithelium in the
reptiles and fishes, and present varieties in
regard to the convolution, branching, and
termination in the ureter.

The epithelial cells of the urinary tubules
are not unfrequently found to contain the
ordinary urinary deposits, which are more
often still met with in the cavities of the
tubules. Many of these are probably, how-
ever, formed after death (see URINARY DE-
POSITS).

Among the morbid changes of the kidney,
passing over cancer, tubercle, variations in
the degree of vascularity, the presence of
calculi, and the ordinary products of inflam-
mation, may be mentioned the occurrence
of cysts. These are met with of various
size and in variable number. They may
contain a serous liquid, a yellowish colloid
substance, or a consistent albuminous mat-
ter with concentric bodies, and may occur in
a kidney otherwise healthy, or when affected
with Bright's disease. The walls of the
cysts do not differ in structure from those of
the tubules, except in being thickened; they
have been accounted for as arising from
dilatation of the tubules or Malpighian cap-
sules, in consequence of obstruction to the
escape of the urine, distension of the epi-
thelial cells of the tubules, and degeneration
of their nuclei, forming colloid cells. The
first is probably the general cause, and cer-
tainly an occasional one, the Malpighian
tufts having been found within the enlarged
cysts after injection. Sometimes the cysts
are those of Echinococci. In Bright's kid-

ney the tubules are found deprived of their
epithelium, the cells filled with albuminous,
fibrinous, or fatty matter ; in the advanced
stage both becoming undistinguishable in
some parts, whilst in others cells and tubules
are loaded with fatty globules, producing
the well-known granular appearance.

In examining the structure of the kidney,
sections must be made with a Valentin's
knife. The arrangement of the vessels may
be shown by injection, and the injected pre-
parations are very beautiful, and form ge-
neral favourites. The Malpighian bodies
are readily filled, the injection being thrown
into the artery, and they are readily recog-
nized by their resemblance to little apples
upon the branches of a tree, or bunches of
currants. The injection should be red. If
the injection be coarse, it will burst through
the capillaries of the tufts, and partially fill
the tubules, as in fig. 388 p ; but if it be
fine, it will fill the venous plexus. The uri-
nary tubules should be injected from the
ureter, white (lead) injection being used ;
and considerable force is required to make a
good injection, but this must be very gradu-
ally applied. PI. 1. fig. 35 is intended to
represent a portion of a kidney of a pig.
The kidneys of the smaller and lower ani-
mals are best injected from the heart.

BIBL. Kolliker, Mikrosk. Anat. ii. and
the Bibl. therein ; Bowman, Phil. Trans.
1842 ; Johnson, Todd's Cyclopaedia of Anat.
and Phys., art. Ren. ; Toynbee, Med. Chi.
Trans, xxx. ; Siebold and Stannius, Ver-
gleichend. Anat. ; Forster, Handb. d. Path.
Anat.; Frerichs, Die Brightsche Nierenkrank-
heit, 8fc. ; Gairdner, Edinb. Monthly Journal,
viii.

KNIFE, VALENTIN'S. INTRODUC-
TION, p. 23.

KOLPODA. SeeCoLFODA. We omitted
to state, under the latter head, that Du-
jardin places this genus in his family Para-
mecia.

KONDYLOSTOMA, Duj.— A genus of
Infusoria, of the family Bursarina.

Char. Body elongated, cylindrical, or
fusiform, slightly arcuate, the ends obtuse
and depressed, with a very large mouth
margined with stout cilia, and situated late-
rally at the anterior end ; surface obliquely
striated and ciliated.

K. patens (PI. 24. fig. 31 ; fig. 32, slightly
compressed). This appears to be the same
animal as Oxytricha caudata, E. It has a
moniliform nucleus. Marine.

BIBL. Dujardin, Infus. p. 516.

LABRELLA.

[ 377 ]

LAGEN.E.

L.

LABRELLA, Fr.— A genus of Phacidiacei
(Ascomycetous Fungi), growing upon living
leaves. L. Ptarmicee, Desm., grows upon
the leaves of Achillea Ptarmica.

BIBL. Berkeley, Ann. Nat. Hist. i. p. 208.
pi. 7- fig. 7 ; Fries, Summa Veg. p. 422.

LACE-BARK. See THYMELEACE^.

LACINULARIA, Oken. — A genus of
Rotatoria, of the family Floscularisea.

Char. Eyes two (when young); urceoli or
gelatinous sheaths aggregated into a spheri-
cal mass ; rotatory organ with two lobes.

L. socialis (PL 41. fig. 15). Urceoli ge-
latinous, yellowish; rotatory organ very
broad, in the form of a horse-shoe; aquatic;
length 1-36".

BIBL. Ehrenberg, In/us, p. 403 ; Huxley,
Microsc. Journ. 1852; !Leydig, Siebold and
Kolliker's Zeitschr. 1852; Ukedem, Ann.
des So. nat. 3 ser. 1851.

LACRYMARIA, Bory.— A genus of In-
fusoria, of the family Enchelia, E.

Char. Body rounded behind, not ciliated ;
with a long and slender neck, which is di-
lated at the end, and furnished with a ciliated
mouth and a lip, but no teeth (= Trachelo-
cerca without a tail).

L. proteus. Body oblong, turgid, colour-
less, with delicate oblique striae ; neck very
long; aquatic; length 1-140".

Two other species ; one (L. guttd) colour-
less and without striae ; the other (L. rugosa)
containing green matter, with the body
wrinkled.

Dujardin states that the body is ciliated ;
and unites the genera Trachelocerca,E. with
Lacrymaria, appending Phialina, and pla-
cing the extended genus in the family Para-
mecia.

BIBL. Ehrenberg, Infus. p. 309 ; Dujar-
din, Infus. p. 4 68.

LACTATES. See the bases, Lactate of
lime (PL 7- fig- 19), lactate of zinc (PI. 7.
fig. 20).

LACTEALS. See VILLI.

LADY-BIRD. See COCCINELLA.

LAEMARGUS, Kroyer. — A genus of
Crustacea, of the order Siphonostoma, and
family Cecropidae.

L. muricatus. Found upon the sun-fish
(Orthagoriscus molce). Length of female 1";
male much smaller.

BIBL. Baird, Brit. Entomostraca, p. 293.

LAGENJ2. — The systematic position of
the animals thus designated has not been
determined, in consequence of the structure

of the animal being unknown. They are
microscopic, contained within calcareous
shells, of a very curious flask-like form (PL
19. figs. 16-21), furnished with a longer or
shorter neck, and frequently with a tube
continued from it into the cavity of the shell;
sometimes also with a stalk-like process or
spine attached to the base. In some the
shells exhibit very minute foramina, resem-
bling those found upon the shells of the
Foraminifera, or are covered with distinct
depressions, and sometimes with longitudinal
ribs. Whether the animals agree in struc-
ture with the Foraminifera, or whether they
consist of Polypes, remains to be decided.
The former being the more probable, we
have arranged them provisionally with the
Protozoa. Mr. Clark considers that in the
natural state they are fixed by a spine-like
process at the base, the primary (basal) shell
to foreign bodies, the succeeding shells to
those beneath them in linear series; and that
the separate forms illustrated in the figures
referred to above, represent fragments of
the perfect organisms.

They are marine, and found living attached
to fuci, stones, &c., and fossil in sea-sand
and mud.

They have been divided into two genera,
Entoselenia and Lagena proper. The cha-
racters of the former are given under that
head.

Lagena. Cell calcareous, single, globular,
ovate or cylindrical, with a long, produced,
external neck, projecting from the upper
extremity ; cavity simple.

L. Icevis (PL 1.9. fig. 16 a; b, section).
Cell ovate or claviform, sometimes narrow
and much elongated, with a long, slender,
tubular neck, somewhat contracted near the
outer orifice, which is surmounted by a nar-
row rim ; surface smooth and shining, co-
vered with very minute foramina. Length
1-100 to 1-50".

/3 amphora. Cell elongated, with a spine
at the base, or fusiform. Length 1-50 .

L. gracilis (PL 19. fig. 17). Differs from
the var. /3 of the last in the surface being
marked with longitudinal striae. Length
1-55".

L. striata (PL 19. fig. 17). Cell ovato-
claviform or spherical, with parallel, coarse,
longitudinal striae or ribs. Varieties exist
in the length of the ribs. Length 1-100 to
1-50".

L. substriata. Striae very faint. Length
1-65".

BIBL. Williamson, Ann. Nat. Hist. 1848.

LAGENELLA.

[ 878 ]

LATEX.

i. 1 ; Clark, ibid. 1849. iii. 382, and 1850,
v. 166; D'Orbigny, Foraminif.fossiles.

LAGENELLA, Ehr— A genus of Infu-
soria, of the family Cryptomonadina.

Char. A red eye-spot present ; carapace
with a beak or neck like that of a bottle.

L. euchlora (PL 24. figs. 35 & 36). Ovate,
neck short, truncate ; carapace hyaline, con-
tents green. Aquatic; length 1-1150".

Dujardin places this organism in the genus
Cryptomonas.

It probably consists of the spore of an
Alga.

BIBL. Ehrenberg, In/us, p. 45 ; Dujardin,
In/us, p. 333.

LAMINARIA, Lamx. — A genus of Lami-
nariacese (Fucoid Algae), with large, flat, sti-
pitate fronds, several species of which are
common on rocky shores, attached to rocks
and stones. L. saccharina has a riband-
shaped frond, growing from 2 to 12 feet
long. L. digitata has a broad frond, 1 to 5
feet long, cut into a variable number of seg-
ments. The internal structure presents three
layers, the outermost forming a kind of epi-
dermis. The oosporanges(sTpores of anthers),
containing ciliated zoospores which repro-
duce the plant, are the only kind of fructifi-
cation yet observed. They are little elon-
gated sacs, nestling between epidermal cells
of peculiar structure, standing perpendicu-
larly upon the central substance of the frond.
In L. saccharina the presence of the spo-
ranges is denoted by a longitudinal brown
mark in the centre of the frond ; in L. digi-
tata they occur in flat patches on the extre-
mities of the digitations. The zoospores are
little olive-coloured bodies, with an anterior
and posterior cilium. Thuret has seen them
germinate.

BIBL. Harvey, Brit. Mar. Alg. p. 29. pi.
4; Phyc. Brit. pi. 192. 223. 241, &c.; Gre-
ville, Alg. Brit. t. 5 ; Thuret, Ann. des Sc.
nat. 2 ser. xiv. p. 240. pi. 30. fig. 1-4.

LAMINARIACE^.— A family of Fucoi-
deae. Olive-coloured inarticulate sea-weeds,
whose oosporanges are superficial, either
forming indefinite cloud-like patches, or co-
vering the whole surface of the frond.

Synopsis of the British Genera.

* Frond stalked, the stalk ending in an
expanded leaf-like portion.

I. ALARIA. .Lea/membranaceous, with a
cartilaginous percurrent midrib.

II, LAMINARIA. Leaf (simple or cleft)
without any midrib.

** Frond simple, leafless.

III. CHORDA. Frond cylindrical, hol-
low; the cavity interrupted by transverse
partitions.

LAOMEDEA, Lamx.— A genus of Po-
lypi, of the order Anthozoa.

Char. Polypidom rooted, erect, jointed at
regular intervals, the joints ringed and in-
crassated ; cells alternate, on short pedun-
cles, campanulate ; vesicles axillary ; polypes
hydriform.

Agrees very nearly with Campanularia.

Four British species, found upon marine
Algae, stones, &c., between tide-marks.

BIBL. Johnston, Brit. Zoophytes, p. 101.

LARVAE. — In animals which pass through
certain marked stages of development, or
undergo metamorphosis, as it is called, the
condition in the first of these stages is called
the larval state, and the animal itself is
called a larva.

The aquatic larvae of several insects are
well-known microscopic favourites, on ac-
count of their transparence, which allows
the action of the dorsal vessels, with the cir-
culation of the nutritive liquid, to be seen,
and their curious respiratory organs. A few
of the more common aquatic larvae and their
parts are represented in PL 28. figs. 1.
14-17. 19-22, 29; these are noticed more in
detail under their respective heads.

The aquatic larvae of some reptiles are
admirable objects for exhibiting the circula-
tion of the blood, the development of tis-
sues, &c., as those of the frog (tadpoles) and
of the Triton.

LASIOBOTRYS, Kz.— A genus of Peri-
sporacei (Ascomycetous Fungi).

L. LonicercB grows on the living leaves and
stems of various kinds of Honeysuckle,
forming little heaps seated on a tuft of ra-
diating filaments. The so-called peridioles
appear to be sclerotioid bodies, the superfi-
cial cells of which are converted into true
perithecia, becoming free on the surface;
these contain numerous asci when mature,
but the spores have not been observed.

BIBL. Berkeley, Brit. Flora, ii. pt. 2.
p. 324, Ann. Nat. Hist. 2 ser. ix. p. 386.
pi. 12. fig. 44; Fries, Summa Veg. p. 406;
Greville, Sc. Crypt. Fl. pi. 191.

LASTR^A.— A genus of Polypodaous
Ferns. See NEPHRODIUM.

LATEX.— The name applied to the pecu-
liar juices, becoming milky when exposed to
air, contained in the * milk-vessels/ or lati-
ciferous canals of plants, especially abundant
in Euphorbiaceae, Papaveraceae, Cichoraceae,

LATHILEA.

[ 379 ] LATICIFEROUS TISSUE.

&c. It appears to consist of a watery fluid,
with albumen in solution, in which float
globules of caoutchouc, or analogous gum-
resinous matter, of variable size, occasionally
mixed with starch-granules of peculiar forms,
as in Euphorbia (PI. 39. fig. 23). Schultz
attempted to show that there existed a regu-
lar circulation of the latex in plants, but the
idea is now abandoned by most observers.
See LATICIFEROUS TISSUE.

BIBL. Schultz, Sur la circulation et sur
les vaisseaux laticiferes dans les Plantes,
Paris, 1841; Von Mohl, Ueb. den Milchsaft,
&c., Botan. Zeit. 1843; Ann. Nat. Hist. xiii.
441.

LATHILE A. — A genus of Orobanchaceous
Flowering Plants. L. squamaria, a remark-
able plant, found here and there in beech-
woods in England, has been the subject of
much research as regards embryology, by
Schacht and others. See OVULE.

LATICIFEROUS TISSUE, DUCTS,
CANALS, or VESSELS. — These names are
applied to the tubular and often ramified
canals in which is contained the milky juice
or latex of many plants (figs. 392, 393). The

Fig. 392.

Fig. 393.

Fig. 392. Laticiferous tissue extracted by maceration
from Leontodon Taraxacum. Magn. 100
diams.

Fig. 393. Laticiferous tissue extracted from Chelido-
nium majus. Magn. 100 diams.

nature, or rather the origin of these canals is
still a matter of dispute, the recent researches
of Schacht more particularly having dis-
turbed all the formerly received notions.
The ducts present themselves in various
forms and conditions, especially in the rind

and pith in the Apocynaceae, Asclepiadaceae,
Moraceae, Urticaceae, Papaveraceae, Cucur-
bitaceae, Euphorbiaceae, Aroideae, &c. Sim-
ple unbranched milk-vessels occur in the pith
of the elder.

Schacht regards them all as liber-cells.
The opinion which we share with almost all
other vegetable anatomists is, that they are
intercellular passages, originally devoid of a
proper coat, but subsequently acquiring one
of variable thickness, derived apparently
from the secretion which they contain. Un-
ger, however, imagines that while some are
formed in this way, they are mostly deve-
loped out of confluent rows of cells, like the
dotted ducts. They require much further
investigation.

Canals bounded by a defined coat of cel-
lular tissue, forming intercellular canals or
ducts of very definite character, occur in the
Coniferae, the Guttiferae, Anacardiaceae, &c.
These will be spoken of under RECEPTA-
CLES FOB SECRETIONS.

Canals containing a milky juice occur in
some of the Fungi, as in the fleshy substance
of Agaricus deliciosus, quietus, and others
of the same section.

It was declared some years ago by Schultz
that a regular circulation of the latex takes
place through the ramified laticiferous ducts.
This was chiefly supported on observations
of movements of the latex which may be
made on tolerably transparent parts of living
plants containing these ducts. By bringing
the uninjured sepal of Convolvulus or a leaf
of Chelidonium under the microscope (placing
it in oil is advantageous in the latter case),
the branched latex-ducts may be made out,
and a flowing movement of the particles may
be seen occasionally. But this has been
shown to depend upon a disturbance of the
equilibrium by external causes, such as pres-
sure and heat, and may be produced at will
in any direction by making an incision, to-
wards which the juice flows.

BIBL. Schultz, Ueber Cy close der Lebens-
saftes, Sfc., Nova Acta, xviii. pt. 2 ; Sur la
circulation, fyc., Mem. des Sav. fyc., Paris,
1841, Mohl, Vegetable Cell, p. 94. London,
1852, Ueber den Milchsaft, $c., Bot. Zeit.
i. p. 553; Anonymous, Botan. Zeit. iv. p.
833 (1846) ; Schleiden, Principles of Botany
(London, 1849), p. 64 ; Unger, Grundzuge
der Anatomic und Physiologic (1846), p. 54;
Schacht, Botanisch. Zeit. ix. p. 513. 1851,
Die Pfianzenzelle, p. 210. Berlin, 1852;
Meyen, Secretions-Organe, p. 63. Berlin,
1837.

LAURENCIA.

[ 380 ]

LEAVES.

LAURENCIA, Lamx.— A genus of Lau-
renciaceae (Florideous Algae), containing
several British species, mostly common, of
yellowish-green, purple or pink colour, the
fronds pinnately branched, of solid paren-
chymatous structure. The ceramidia are
borne on the smaller branches, as are also the
antheridia ; the tetraspores are imbedded in
the ramuli(fig.394). The ceramidia contain

Fig. 394.

Laurencia dasyphylla.

Ramuli containing tetraspores.

Magnified 50 diameters.

tufts of pear-shaped spores ; the tetraspores
are tetrahedrally divided. The antheridia
are thus described (in L. tenuissima) by
Thuret : on the smaller branches, similar
to those which bear the ceramidia on other
individuals, occur greyish convoluted plates
of cellular tissue, of irregular form, bordered
by a line of roundish cells, containing gene-
rally a yellow liquid. Hyaline cells contain-
ing antherozoids are implanted vertically on
these plates, clothing both surfaces. The
antheridium has a sort of pedicel formed of
an ovoid cell, which also bears a dichotomous
hair, like those common over the branches of
this plant. The antherozoids are elongated-
ovoid, a little constricted at one extremity,
length about 3-5000". MM. Derbes and
Solier have observed them on L.pinnatifida
and other species.

BIBL. Harvey, Brit. Mar. Alg. p. 97.
pi. 12 C ; Phyc. Brit. pi. 55, &c. ; Grev. Alg.
Brit. p. 108. pi. 14 ; Derbes and Solier,
Ann. d. Sc. nat. 3 se'r. xiv. p. 276. pi. 37 ;
Thuret, id. xvi. p. 65. pi. 7, id. ser. 4. iii.
p. 19.

LAURENCIACEvE — A family of Flo-

rideae. Rose-red or purple sea-weeds with
a cylindrical or compressed, rarely flat, linear,
narrow, areolated, inarticulate or constricted
and chambered, branching frond, composed
of polygonal cells. Fructification : 1, con-
ceptacles (ceramidia) external ovate, fur-
nished with a terminal pore, and containing
a tuft of pear-shaped spores ; 2, tetraspores
immersed in the branches and ramuli,
scattered without order through the surface
cells ; 3, antheridia.

Synopsis of the British Genera.

I. BONNEMAISONIA. Frond solid, fili-
form (rose-red), much branched; the branches
margined with subulate, distichous cilia.

II. LAURENCIA. Frond solid, cylindri-
cal or compressed (purplish or yellowish),
pinnatifid ; the ramuli blunt.

III. CHRYSYMENIA. Frond hollow,
filled with watery mucus, neither constricted
nor chambered.

IV. CHYLOCLADIA. Branches hollow,
filled with watery mucus, constricted at
intervals and chambered.

LEANGIUM, Lk. See DIDERMA.

LEATHESIA, Gray.— A genus of Chor-
dariacei (Fucoid Algae), consisting of globose
or lobulated fleshy or horny structures,
growing upon rocks, either solid, or, by the
solution of the internal filamentous sub-
stance, ultimately hollow. The fronds are
composed of masses of dichotomous filaments
radiating from a point, in the olive-coloured
tufted species cohering laterally, and forming
the soft, fine coat of the lobes. The oospo-
ranges are oval sacs attached at the ends of
branches of the radiating filaments, between
which they nestle ; the trichosporanges, con-
sisting of short septate filaments occurring
in similar situations, are said by Thuret to
be more common, and the two kinds have
not been met with together.

BIBL. Harvey, Br. Mar. Alg. p. 48.
pi. IOC; Engl. Bot. pi. 1596; Thuret, Ann.
des Sc. nat. 3 ser. xiv. p. 237. pi. 26.
figs. 5-12.

LEAVES. — The microscopic structure of
leaves presents a wonderful variety of con-
ditions, from the most simple up to very
complex. Instances of the former are seen
in the MOSSES, JUNGERMANNIE^ and
other Flowerless plants where merely a
siir pie cellular plate exists. In the simpler
leaves of Ferns, such as HYMENOPHYL-
LUM, we have a cellular plate traversed by
vascular ribs. In SPHAGNUM among the
Mosses, the simple leaves have cells contain-

LEAVES.

C 881 ]

LECIDINE.E.

ing a spiral fibre. In the more complete
forms we distinguish an epidermis, above

Fig. 395.

ST

Vertical section of a leaf of a Melon.
E. S, superior epidermis ; P. S, subjacent close paren-
chyma ; M, infra-stomatal air-space ; L, intercellular
space ; F. v, fibro-vascular bundle (rib or vein) ; P. f,
inferior lax parenchyma ; E. i, inferior epidermis ; P,
hairs ; ST, stomate.

Magnified 100 diameters.

and below, often differing in character in the
two faces (see EPIDERMIS and STOMATES),
together with the diachyma or intervening
cellular mass, which varies in its characters
in different plants, and is traversed by the
fibro-vascular ribs or veins. The epidermis
exhibits GLANDS, HAIRS, &c., in different
conditions and forms, which cannot be enu-
merated again here, many of the most in-
teresting forms being mentioned under the
above heads. For observing the structure
of leaves, when consisting of more than a
simple cellular plate, horizontal and vertical
sections are required. The latter are easily
made with a sharp razor in thick and firm
leaves, but with delicate kinds it is necessary
to split a soft cork, to place the leaf care-
fully between the pieces and then to slice both
together, placing the fragments in water and
picking out the pieces of the leaf with a
needle. Many small simple leaves make
good objects by drying, soaking in turpen-
tine and mounting in balsam : the same may
be done with petals, sepals, &c. The leaves
of water-plants, such as of Vallisneria, Ana-
charis, Ceratophyllum, Hottonia, &c., are
very favourable for the observation of the
rotation of the cell-sap (see ROTATION).
They are of very simple cellular structure,
having no epidermis, stomates or fibro-vas-
cular ribs.

LECANACTIS, Eschweiler.— A genus of
Graphideae (Gymnocarpous Lichens), con-
taining one British species, L. lyncea=0pe-
grapha lyncea of the British Flora.

BIBL. Hooker's Brit. Flora, ii. pt. 1.
p. 148; Leighton, Ann. Nat. Hist. 2 ser.
xiii. p. 391. pi. 7. fig. 25.

LECANORA, Ach.— A genus of Leci-
dinese (Gymnocarpous Lichens), consisting
of numerous species growing chiefly on rocks,
stones and earth, distinguished from Lecidea
by the epithecia having a thickish border
formed of the crust and of the same colour.

BIBL. Hook. Brit. Flora, ii. pt. 1. p. 190;
Eng. Bot. pi. 949, 1792, &c.

LECIDEA, Ach. — A genus of Lecidineae
(Gymnocarpous Lichens), containing nume-
rous British species. The apothecia have a
border of the same colour as the disk.
Growing chiefly on rocks, sometimes on
bark. L. geographica, growing on subalpine
rocks, is a remarkable species.

BIBL. Hook. Br. Flora, ii. pt. 1. p. 177;
Engl. Bot. pi. 245, &c.

LECIDINE.E.— A family of Gymnocar-
pous or open-fruited Lichens, characterized
by free, circular, ultimately convex shields,
with the disk always open, and placed in a
special excipulum.

Synopsis of British Genera.

I. STEREOCAULON. Thallus cartilagi-
nous or somewhat woolly, branched and
shrubby. Apothecia top-shaped, sessile,
solid, flat, scarcely rising above the border ;
the disk at length spreading, covering the
border and reflexed.

II. CLADONIA. Thallus somewhat
shrubby, branched, rarely simple, rough with
scales, which are at length often evanescent;
branches cartilaginous, rigid, fistulose, all
attenuated and subulate, divided, fertile,
generally perforated in the axils. Apothecia
sessile, circular, convex, shaped like little
heads, not bordered, fixed by the circum-
ference, free beneath in the centre, the sides
reflexed, uniform within.

III. BCEOMYCES. Thallus crustaceous,
spreading, adnate. Apothecia circular, con-
vex, head-like, not bordered, sessile upon a
solid stalk.

IV. LECIDEA. Thallus crustaceous,
spreading, adnate, uniform. Apothecia cir-
cular, sessile, plano-convex, having a border
of the same colour as the disk.

V. UMBILICARIA. Thallus foliaceous,
coriaceous-membranous, pustuled, fixed by
the centre, peltate. Apothecia circular,

LECYTHEA.

[ 382 ]

LEMANIE.E.

somewhat concave, adnate, covered by a
black membrane, the disk at length tuber-
cled, with a border of its own substance.

LECYTHEA, LeV. See UREDINE^B.

LEECH. — Two species of the genus Hi-
rudo, which belongs to the class Annulata,
are used for medical purposes, viz. H. medi-
cinalis, in which the ventral surface is green-
ish, with black spots ; and H. officinalis, in
which these spots are absent.

The structure of the mouth of the species
of Hirudo is curious. The mouth is trian-
gular (PI. 17. fig. 25), and placed in the
middle of the anterior sucker. Each of its
three sides is furnished with a semicircular
jaw of cartilaginous consistence (fig. 26, side
view; fig. 27, view from above), upon the
convex margin of which are placed a large
number of partly calcareous teeth (fig. 26 b)
arranged in a row. The teeth (fig. 28, a side
view, b view from above) are flattened, some-
what triangular, and excavated at the base,
so as to exhibit two short prongs (d). They
are placed transversely upon the jaws, which
are moved by powerful muscles, and thus
produce the well-known wounds. And this
cross direction of the teeth is probably the
cause of the troublesome bleeding accompa-
nying the bite of a leech, in consequence of
the amount of laceration necessarily con-
nected with it.

The species of Hirudo have ten minute
eyes, arranged in the form of a horse-shoe
at the upper part of the anterior sucker.

The ova of leeches are deposited in a kind
of cocoon, composed of triangular fibres,
branched and interwoven so as to bear con-
siderable resemblance to a sponge, as which
one of them was formerly described.

BIBL. Brightwell, Ann. Nat. Hist. 1842.
ix. 11; Brandt and Ratzeburg, Mediz. Zoolog.
ii. ; Johnson, Treatise on the Medicinal
Leech, and Further Observ., fyc. ; Moquin-
Tandon, Monographie d. Hirudinees, &c. ;
Savigny, Descript. de VEgypte, xxi. ; Au-
douin and Milne-Edwards, Classif. des An-
nelides, 8fc. in Ann. d. Sc. nat. 1832-3, 27-
30 (separately printed); Bowerbank, Ann.
Nat. Hist. 1845. xv. 304 ; R. Jones, Outl.
of Animal Kingdom, p. 192.

LEIBLEINIA, Endl.— A genus of ma-
rine plants, placed among the Ectocarpacese
by Endlicher, and among Oscillatoriacese
(Confer void Algae) by Kiitzing, who includes
under it many of the species of Calothrix of
other authors. Endlicher cites only C. con-
fervicola, Ag., and another not British.

This is a minute, glaucous, tufted plant,

formed of short, rigid, erect, subulate fila-
ments, and is common, epiphytic on marine
filamentous Algae.

BIBL. Endl. Genera Plant. Supp. iii.
No. 69 ; Kiitzing, Sp. Alg. 276 ; Harvey,
Phyc. Brit. p. 223. pi. 26 C.

LE JEUNIA, Libert. — A genus of Junger-
mannieae (Hepaticaceae), containing several
rare British species, found in subalpine di-
stricts, viz. L. serpyllifolia, hamatifolia, mi-
nutissima, and calyptrifolia. The last is one
of the smallest of the British Jungermannieae,
and is remarkable for the peculiar form of
its leaves, which resemble the calyptra of a
moss (figs. 396, 397).

Fig. 396.

Fig. 397.

Lejeunia calyptrifolia.

Fig. 396. Stem with calyptriform leaves, an immature
plant (on the right), and a burst sporange.
Magn. 5 dianis.

Fig. 397. A leaf of ditto. Magn. 25 diams.

BIBL. Hook. Brit. Jung. pi. 42. 43. 51.
52, Brit. Flora, ii. pt. 1. p. 127.

LEM ANIE^E .—A family of Confervoidese .
Olive-coloured freshwater Algae, filamentous,
inarticulate, of cartilagineo-coriaceous sub-
stance, and compound cellular texture. The
fronds branched, hollow, bearing within at
irregular distances whorls of wart-like bo-
dies consisting of tufted, simple or branched
necklace-shaped filaments (fig. 398), arising

Fig. 398.

Lemania torulosa.

Section of filament, showing the tufts of fertile filaments.
Magn. 50 diams.

from the inner wall of the tubular frond,

LEMNA.

[ 383 ]

LEPTDOPTERA.

and finally breaking up into elliptical spores.
British genus :

LEMANIA. Character the same as of the
tribe. Two species have been found in Bri-
tain, L. torulosa, Ag. and L.fluviatilis. They
always grow in clear running streams. Mr.
Thwaites has made some interesting obser-
vations on the development of these plants.

BIBL. Hassall, Brit. Freshw. Alg. p. 68.
pi. 7-J Kutzing, Phyc. generates, p. 261;
Thwaites, Ann. Nat. Hist. 2 ser. i. p. 460.

LEMNA, L. — Duckweed. A genus of
aquatic Monocotyledonous plants, remark-
able for the simplicity of the structure, the
vegetative system being replaced by a mi-
nute leaf-like floating stem, with dependent
rootlets, furnished with a curious sheath
(pileorliize] at the end. They bear two monre-
cious imperfect flowers, and also propagate by
bulbils formed in the slits in the side of the
lenticular stems ; the young bulbils formed
in autumn sink when the parent dies, and
rise again in spring. Spiral vessels occur
abundantly in L. potyrhiza ; they are spa-
ringly present in the rest.

BIBL. Hook, and Arnott, Brit. Flor. p.
463 ; Schleiden, Beitr. zurBotanik. p. 229 ;
Weddell ( Wolffia], Ann. des Sc. nat. 3 ser.
p. 12. 155.

LEMON, ESSENTIAL OIL OF. — This is
sometimes used in microscopic examination
of pollen and other structures, which are
placed in it to render them more transpa-
rent, it being less diagreeable and less vola-
tile than oil of turpentine. Glycerine may
often be substituted.

LENTICELS.— Structures found upon
the surface of young stems, especially of
most of the Dicotyledonous shrubs and trees.
They first appear on the yearling shoot as
little specks, of a different colour from the
rest of the epidermis. Towards the winter,
or in early spring, the epidermis splits lon-
gitudinally over the lenticels, which become
then slightly projecting papilla?, frequently
divided into lips, as it were, by a median
furrow. The surface of the papilla is now
brown, and it is of corky character for some
little distance inward. As the branch grows,
the lenticels become drawn out laterally, so
as to appear like cross striae. They are sub-
sequently lost sight of by the bark splitting
through them, as in the apple or beech, or
by the bark peeling off" (plane).

Microscopic examination of sections shows
that they are mere cellular productions from
the mesophlaeum, or cellular envelope of the
BARK, and have no connexion with the liber

or cambium. DeCandolle imagined they
were root-buds, where adventitious roots
might arise under favourable circumstances;
but this was an error. Du Petit Thouars
thought they were breathing pores, replacing
the stomates of the epidermis ; but they are
not pores, and many trees, such as the Coni-
fers, Roses, Euonymus europaus, &c., have
none.

BIBL. DeCandolle, Ann. des Sc. nat. vii.
p. 5 (1826); Von Mohl, Vermischt. Schrift.
pp. 229. 233 ; Meyer, Linnaa, vii. p. 447 ;
Du Petit Thouars, Essais sur la Vegetation,
p. 20 ; Unger, Flora, 1836. ii. p. 577.

LEOCARPUS, Lk. See DIDERMA.

LEPADELLA, Bory.— A genus of Rota-
toria, of the family Euchlanidota.

Char. Eyes absent ; foot forked.

Three species. In two of them the jaws
have each a single tooth; in the other, each
two teeth.

L. emarginata (PI. 34. fig. 43). Carapace
depressed, oval, anterior portion broad,
emarginate at each end. Aquatic; length
of carapace 1-570".

Teeth of L. ovalis, PI. 34. fig. 44.

BIBL. Ehrenberg, In/us, p. 457.

LEPEOPHTHIRUS, Nordm.— A genus
of Crustacea, of the order Siphonostoma,
and family Caligidae.

Char. Fourth pair of legs slender, not
branched, formed for walking ; thorax with
only two distinct joints ; frontal plates des-
titute of sucking disks on the under surface.
Six British species, found upon various ma-
rine fishes, as the salmon, mackerel, sole,
brill, turbot, &c.

L. pectoralis (PI. 14. fig. 23). Female.
Carapace oval ; frontal plates small, notched
in the centre; antennas small; thorax as
long as the carapace, penultimate joint very
narrow, last joint nearly as long as the cara-
pace, almost quadrilateral and slightly lobed
posteriorly; abdomen short; caudal plates
small, terminal setae short ; sternal fork with
simple sharp-pointed branches; third pair
of foot-jaws large. Length about 1-2".

BIBL. Baird, Brit. Entomostraca, p. 273.

LEPIDOPTERA.— An order of Insects,
consisting of butterflies and moths.

Lepidopterous insects present several
points of interest to the microscopic ob-
server; among these may be mentioned
especially the proboscis or ANTLIA, the
hook connecting the wings (INSECTS, p. 359),
the wings themselves, and the beautiful
scales covering them (SCALES OF INSECTS,
TEST-OBJECTS). Their larvae or caterpillars

LEPIDOZIA.

[ 384 ]

LEPTOTRICHACE.E.

are favourable subjects for the examination
of the internal structure, — the tracheae with
their spiracles, the fatty body, the alimen-
tary canal, the spinning organs, the curious
legs, &c.

BIBL. See that of INSECTS, and espe-
cially the works of Newport, Siebold, and
Westwood.

LEPIDOZIA, Dumort. See HERPETIUM.

LEPISMA, Linn.— A genus of Insects,
of the order Thysanura, and family Lepis-
menae.

Char. Body elongated, flattened ; anten-
nae setaceous, with numerous very short
joints; palpi four, long; abdomen termi-
nated by three long filaments jointed near
their ends.

L. saccharina (PI. 28. fig. 18). Body
silvery-gray, not spotted, covered with nu-
merous scales; caudal filaments speckled
with reddish brown ; antennae about two-
thirds the length of the body.

This active little insect, which runs but
does not jump, is found (in the country)
upon the shelves of cupboards where sweets
and other eatables are kept, in window-
cracks, &c. Its habits are nocturnal. Its
beautiful silvery scales are used as TEST-
OBJECTS (PL 1. fig. 6).

There are many other species, the scales
of which probably exhibit the same struc-
ture.

BIBL. Gervais, Walckenaer's Apteres, iii.
p. 450.

LEPTOMITJE, Kiitz.— A supposed fa-
mily of filamentous Algae, probably consist-
ing of the mycelia of Fungi. See ALG^E.

BIBL. Ktitz. Spec. Alg. p. 148 ; Robin,
Ve'getaux parasitiques, 2 ed. p. 360.

LEPTOSTROMA, Fr.— A genus of Sphae-
ronemei (Coniomycetous Fungi), probably
consisting only of the younger stylosporous
states of species of HYSTERIUM or PHACI-
DIUM. Several species are recorded as
British, some common, occurring on the stems
and leaves of sedges, rushes, Pteris, &c.,
forming small round flat spots, from which
the upper part of the perithecium splits off,
leaving a little margined scar, in which are
seated the stylospores.

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 297 ;
Ann. Nat. Hist. i. p. 257, vi. p. 365 ; Tu-
lasne, Ann. Nat. Hist. 2 ser. viii. p. 114.

LEPTOTHRIX, Kiitz.— A genus of Os-
cillatoriaceae (Confervoid Algae), perhaps
doubtful whether distinct and perfect plants,
found on damp stones, among wet plants,
and in foul water.

L. ockracea, K. (Oscillatoria ochracea,
Grev.) is an obscure production, forming
yellowish brown flocculent masses, common
in boggy pools.

L. buccalis and L. insectorum, Ch. Robin,
probably belong to some Fungus (mycelia).

BIBL. Kiitz. Sp. Alg. 262, Tab. Phyc. i.
pi. 61. fig. 1 ; Robin, Vegetaux Parasitiques,
2nd ed. pp. 345. 355. pi. 1. figs. 1, 2. pi. 4.
figs. 1, 2.

LEPTOTHYRIUM, Kz.— A genus of
Sphaeronemei (Coniomycetous Fungi), ac-
cording to Fries, =Leptostroma, Fr., LEP-
TOTHYRIUM of later writers, is, according
to the same authority, the fruit of CRYPTO-
SPORIUM.

L. juglandis, Lib., has been found in Bri-
tain. Probably all these are imperfect forms
of Ascomycetes.

BIBL. Fries, Summa Veg. pp. 371. 423;
Berkeley, Ann. Nat. Hist. 2 ser. v. p. 371.

LEPTOTRICHACE.E.— Afamilyofoper-
culated Acrocarpous Mosses, branching by
innovations, or with the fertile summits se-
veral times divided. Leaves lanceolate or
awl-shaped, often canaliculate-concave, with
a nerve, mostly flattened, or terete; cells
prosenchymatous, often mingled with pa-
renchymatous, lax, or firmish, empty, not
unfrequently thickened at the apex, then
square. Capsule ovate or cylindrical, some-
times naked, sometimes erect, often stru-
mulose at the base; operculum conical or
subulate. Differing from Dicranaceae in the
absence of alar cells to the leaves.

Synopsis of British Genera.

I. BRACHYODUS. Calyptra mitriform ;
peristome simple ; teeth sixteen, very short,
broad, obtuse, irregularly torn, delicately
membranous, pale, very fugacious, equidis-
tant or a little confluent. Capsule elevating
a large annulus almost above the peristome.
Inflorescence monoecious.

II. CAMPYLOSTELIUM. Calyptra mitri-
form. Peristome simple, of sixteen teeth,
equidistant, lanceolate, purple, dicranoidly
bifid, on an emergent reticulated membrane.
Inflorescence monoecious. Capsule annu-
late.

III. SELIGERIA. Calyptra dimidiate.
Peristome absent or simple ; teeth sixteen,
equidistant, lanceolate, very flat, orange,
articulated, very smooth, sometimes perfo-
rated and fissile, or with a median line ren-
dering them fissile in the middle. Inflo-
rescence monoecious or dioecious.

IV. ANGSTRCEMIA. Calyptra hood-

LEPTOTRICHUM.

[ 385 ]

LEUCOPHRYS.

shaped. Peristome wanting, or simple;
teeth equidistant, more or less closely ap-
proximated at the base, bifid, dicranoid,
trabeculate below, arms articulate. Inflo-
rescence monoecious or dioecious.

V. LEPTOTRICHUM. Calyptra dimidiate,
narrow, twisted. Peristome simple; teeth
sixteen, equidistant, subulate, ciliiform with
a median line, or slit into cilia so as to con-
stitute thirty-two teeth approximated in
pairs, confluent at the base into a more or
less elevated membrane, reddish. Capsule
annulate. Inflorescence monoecious or dioe-
cious.

LEPTOTRICHUM, Hampe.— A genus
of Acrocarpous operculate Mosses, including
certain Didymoda and Trichostoma of au-
thors.

1 . Leptotrichum homomallum, Hinp. =
Didym. heteromallus, Hook, and Tayl.

2. L. tortile, Hmp. var. pusillum = Di-
dym. pusillus, Hook.

LEPTOTRICHUM, Corda.— A genus of
Sepedonei (Hyphomycetous Fungi).

LEPTUS, Lam. See TROMBIDIUM.

L. autumnalis (Trombidium autumnale) is
the harvest-bug.

LERNEONEMA, Edwards.— A genus of
Crustacea, of the order Siphonostoma, and
family Penelladae.

Char. Body long, slender, narrowed an-
teriorly in the form of a neck, which is ter-
minated by a swollen head, with two or
three simple, curved, horn-like appendages ;
abdomen of inconsiderable length, simple ;
oviferous tubes long and slender.

Two British species : L. spratta (PL 14.
fig. 24); entire length 2 inches; and L. en-
crasicoli. Both found upon the sprat.

BIBL. Baird, Brit. JZntomostraca, p.
339.

LEUCOBRYACE^E.— A family of oper-
culate Mosses arranged among the Acrocarpi,
but exhibiting also lateral fruit-stalks. The
leaves whitish, very fragile, composed of two
kinds of cells : 1. parenchymatous, columnar,
thick, empty cells, connected in several
layers, perforated; 2. intercellular duct-like
cells, interposed in a single curved row be-
tween those cells, 3-4-angled, filled with
chlorophyll-granules. 1-2 ductose cells,
situated in the middle of the leaf, prolonged
out from the curved row. Peduncle rigid,
very hygrometric, purple. Capsule oliva-
ceous, brown, or at length purple. Peri-
stome coloured in a similar manner, firm.
There is only one British genus :

LEUCOBRYUM. Calyptra dimidiate,

hood-shaped, exceeding the capsule, straw-
coloured. Capsule unequal, often strumose,
plaited in drying, often lateral by innova-
tion, terminal or distinctly lateral. Teeth
of the peristome sixteen, bifid, dicranoid,
densely trabeculate, purple. Intercellular
duct-like cells square ; one situated in the
middle of the leaf, mostly triangular. Leaves
without nerves. Inflorescence monoecious
or dioecious.

1. Leucobryum vulgar e, Hampe = Dicra-
num glaucum, Hedw.

The foliage of this plant is remarkable for
its pale colour, like that of the genus Sphag-
num, and the peculiar structure of the
cellular tissue renders it interesting.

BIBL. Mohl, Vermischt. Schrift. p. 310.

LEUCODON, Schwajgr.— A genus of
Mosses. See Neckera.

LEUCOPHRYINA.— A family of Infu-
soria.

Char. Body depressed, oval or oblong,
densely covered with cilia arranged in regular
rows ; no mouth.

It comprises Spathidium hyalinum, D.
(Leucophrys spathula, E.), Leucophrys, D.
(not Ehr.), and Opalina, in which Dujardin
says that the existence of a mouth appears
to be indicated by an oblique fissure.

BIBL. Dujardin, In/us, p. 458.

LEUCOPHRYS, Mull.— A genus of In-
fusoria, of the family Enchelia.

Char. Body covered with cilia, mouth
without teeth, obliquely truncated, and with
a kind of lip.

The cilia are arranged in rows upon the
body, and form a ring around the mouth.

Ehrenberg describes eight species; they
are found in salt and fresh water, both sweet
and putrescent.

L. patula (PI. 24. fig. 38, a dorsal, b ven-
tral surface). Body ovato-campanulate, hya-
line or white, turgid ; mouth large, patulous.
Aquatic and marine. Length 1-288 to 1-96".
The alimentary canal, with the sacculi, ac-
cording to Ehrenberg's view, is represented
in fig. 38 a.

L. spathula (Spathidium hyalinum, D.)
(PL 24. figs. 75, 76). Body lanceolate, com-
pressed, whitish, membranous, obliquely
truncated and dilated in front; aquatic;
length 1-144". Dujardin denies the exist-
ence of the anterior row of cilia (omitted in
the figures).

Dujardin constructs his genus Leucophrys
of (2) species found between the alimentary
canal and the tegumentary muscular stratum
of Lumbricus, with the characters: — Body

2 c

LIBELLULID^.

[ 386 ]

LIBER.

depressed, oval or oblong, uniformly rounded
at the two ends, and covered with long cilia
in very numerous parallel rows, and without
a mouth. The species are probably Opa-
lince.

PL 24. fig. 37 represents L. striata, D.

BIBL. Ehrenberg, In/us, p. 311 ; Dujar-
din, In/us, p. 458 ; Stein, In/us, p. 184.

LIBELLULID.E.— A family of Insects,
of the order Neuroptera.

It contains several common but beautiful
insects, some of which are popularly known
as dragon-flies and horse-stingers, although
they are harmless.

The great interest connected with them
relates to the structure of the larvae and
pupae, which live in the water, and are fur-
nished with branchiae, either internal or ex-
ternal, and situated at the end of the body.

External branchiae are seen in Agrion
(PL 28. fig. 17). They consist of three
membranous plates (PI. 28. fig. 2 g), tra-
versed by innumerable tracheae. In JEshna,
Libellula, and Calopteryx, the branchiae are
internal, the folds of the rectum being situ-
ated within that organ, which is powerfully
muscular (PI. 28. fig. 20, rectum of JEshna).

In jEshna the branchial plates are nume-
rous, semicircular, horizontal, imbricated, and
arranged alternately in six regular and sym-
metrical columns. The laminae consist of a
network of fine tracheae, communicating
with those of the body, and situated beneath
the mucous membrane, which is fringed
around them with tubular papillae containing
prolongations of the tracheae, the free mar-
gin of each lamina being marked with a
brown crescentic spot. In this larva, some
of the dorsal segments are spinous, and
ocelli are absent. The end of the abdomen
is furnished with five moveable valvular
pieces (PL 28. fig. 29), three of which are
larger than the others, and the uppermost
of which is notched at the end. These
pieces, by their contraction, expel the water
from the rectum, by which it becomes re-
newed, this simultaneously effecting the
locomotion of the animal.

The labium of^Eshna possesses a remark-
able structure, forming an elongated, some-
what spatulate, mask-like appendage, which
completely closes the mouth when unem-
ployed. It consists of a basal piece, uniting
it to the under side of the head ; an elon-
gated portion, somewhat dilated in front,
with the outer and anterior angles of which
is articulated a pair of somewhat triangular
pieces, furnished with minute blunt teeth

along the posterior and the internal margin,
and with a strong curved and pointed claw or
tooth on each side, let into and articulated
with its anterior margin (PI. 41. fig. 16).

In Libellula the six biserial rectal columns
are also present,but the papillae are absent, and
the intermediate external caudal appendage
is pointed, and not notched (PL 28. fig. 22).

In Calopteryx the rectal branchiae are
more simple, consisting of three plates, at-
tached only by the end, and resembling in
structure the external plates of Agrion. In
Calopteryx the ocelli are distinct, and the
external caudal apparatus consists of three
channeled and keeled pieces.

The spiracles of these larvae and pupae are
more or less concealed in the interspace be-
tween the proto- and mesothorax ; they are
transverse, bilabiate, and furnished with a
musculo- membranous valve.

BIBL. Dufour, Ann. des Sc. nat. 1852.
xvii. 65 ; Westwood, Introduction, fyc.

LIBER.— The term liber-cells or liber-
fibres is applied to the very long forms of
prosenchymatous cells, occurring either iso-
lated or in bundles at the outside of the
cambium-layer of Dicotyledons, and often
in the pith and the ribs of the leaves; to the
cells of similar form and character occur-
ring in the outer part of the fibro-vascular
bundles of Monocotyledons, and in the
branches of these containing no spiral struc-
tures ; also to the fibrous cells of the same
kind found in the husks of many fruits, as of
the Cocoa-nut. No exact line of demarca-
tion can be drawn between liber-cells and
wood-cells, since the shorter of the former
pass into the latter. As a rule, they are
much thickened by secondary deposits (PL
38. fig. 27), but these deposits are tougher
than those of wood-cells, and while they
have pores, these are never bordered with a
rim. Mohl has shown that ordinary liber-
cells are composed of cellulose. Liber-cells
are found not unfrequently branched, and
this in cases where they appear to be evi-
dently genuine elementary organs ; some of
the branched forms, however, are said to
originate in the manner generally attributed
to MILK-VESSELS, namely by deposition in
intercellular passages. Hence has arisen a
difference of opinion, which has arrived at a
climax in the assertion of Schacht that all
milk-vessels are liber-cells, and all originate
from ordinary cambium-cells.

The layers of thickening on the walls of
liber-cells frequently exhibit a spiral stria-
tion, especially after treatment with acids

LIBER,

[ 387 ]

LIBER

(PI. 21. figs. 2, 3, 25). This does not appear
to depend upon the primary cell-wall, and
therefore cannot be taken as a proof of the
origin of the latter out of minute elementary
fibres (see SPIRAL STRUCTURES).

The importance of liber as a material for
textile fabrics has been spoken of under FI-
BROUS SUBSTANCES, and examples cited;
figures of various kinds of liber-fibre are given
in Plate 21. A few particulars relating to the
structure and arrangement of liber may be
given here.

In Dicotyledonous stems they are usually
placed in large bundles opposite to the fibro-
vascular bundles of the wood, as in Urtica,
Viscum, Clematis, Quercus, &c. ; sometimes
in small irregular groups, as in Vinca and
Linum ; in other cases they stand in single
rows, alternating with parenchyma (Cupres-
sinece and Taxineci), while in many plants
they are irregularly scattered, as in ttkizo-
phora, Cinchona, Nerium, &c. Isolated liber-
cells occur on the pith of young shoots, and
may be readily seen in the elder, and Rhizo-
phora ; in the long woody radicles developed
from the seeds of the Rhizophoreae, isolated
branched liber-fibres (PL 39. fig. 31) occur
scattered throughout the whole mass.

In the Monocotyledons they occur asso-
ciated with short wood-cells in the fibro-
vascular bundles, but they form alone the
fibrous bundles, often intermixed with and
prolonged from the ends of these, occurring
especially in the outer part of the stem of
herbaceous Monocotyledons, such as Lilies
and Grasses, and in the fleshy cortical layer
of rhizomes, as in Sparganium, &c.

In both families they occur with the spiral
vessels and wood-cells in the ribs or veins of
leaves (as in Phormium tenax), bracts, spathes
of Palms, &c.

Liber-cells are generally drawn out very
gradually to a point at each end; sometimes
they are very long ; Schleiden states he has
seen them 5 ' or 6''. Sometimes they exhibit
expansions at particular points, as in the
Apocynaceae commonly. The branched
forms in Rhizophoreae, &c. are usually much
shorter than the simple fibres, and their
form is often very irregular (PI. 39. fig. 31).
The diameter varies a great deal in some
plants, and we should scarcely venture to
say that the microscopic appearance of a
liber-fibre would suffice for the determination
of the nature of the material of any textile
fabric, beyond the distinction of cotton (or
vegetable hair] from linen or other liber, but
reagents affect them differently. The ap-

pearance presented by many kinds of fibre
under the microscope, in the state in which
they occur in commerce and after treatment
with acids, is shown in PI. 21. figs. 2-7, 25
& 26. The figures are taken from very cha-
racteristic examples, but many modifications
occur in subordinate quantity. Flax (Linum
usitatissimum) (fig. 2) has the walls much
thickened with distinct pores ; it exhibits a
very oblique, close striation after boiling
with nitric acid. Jute, the liber of Corchorus
capsularis, has thinner walls, with constric-
tions at intervals and blunter ends (fig. 3); no
spiral streaks come out here on boiling with
nitric acid. The fibre from the Cocoa-nut husk
occurs in bundles (fig. 4) ; when isolated or
boiled with acid, the walls are found thin,
with wide open spiral streaks (slits in the
secondary layers) ; the ends are blunt (fig. 5
a, b}. The fibre of hemp (Cannabis sativa)
somewhat resembles flax, but is coarser and
becomes swollen up and brittle, readily
breaking across, when boiled with nitric
acid (fig. 6) ; no spiral streaks. The liber-
fibres from the bundles of Musa textilis
(fig. 7) are fine and tough, and not much
altered by boiling. Those of Bazhmeria nivea
(fig. 25) are coarse, rough on the outside,
swell up much and exhibit marked spiral
slits when boiled with acid, also very distinct
lamination of the thick wall (fig. 25 c).
Boehmeria Puya (fig. 26) closely resembles
the former, but the spiral striation is not
very evident, and the wall splits readily in
the longitudinal direction (fig. 26 c). The
spiral striation is well seen in fig. 30 of
PL 39, which represents the end of a liber-
fibre from Vinca minor after boiling with
nitric acid.

All our observations on liber-fibres lead us
to believe that they are true elementary
organs ; but we doubt whether the milk-ves-
sels are always liber-fibres, as asserted by
Schacht. Further research is required.

The liber bundles of bark are sometimes
set free as loose stringy fibres by the decay
of the outer parts of the bark, as in the vine,
Clematis, &c. In some plants they take a
wavy course, anastomosing laterally so as to
form connected reticulated sheaths over the
cambium; in the lime these sheets, formed year
after year, may be detached by maceration,
and form bast, the material used for matting,
&c. In the THYMEL^EACE^B (lace-bark
trees) the annual layers of liber can be de-
tached from each other, and form sheets of
fibrous tissue, sometimes firm and tough,
sometimes almost as delicate as muslin.
2c2

LICEA.

[ 388 ]

LICHENS.

BIBL. Works on Structural Botany ;
Schacht, Die Pflanzenzelle, p. 208, Berlin,
1852; Mohl, Vegetable Cell, and numerous
papers there referred to in the Botanische
Zeitung and Taylor's Scientific Memoirs.

See also under LATICIFEROUS TISSUE.

LICEA, Schrad. — A genus of Myxogastres
(Gasteromycetous Fungi), growing on damp
rotten wood, in garden frames, &c., with
the peridia of elongate form, grouped toge-
ther, of only one layer, and containing few
or no filaments among the spores. Four
species are described as British, of which L.
fragiformis, Nees, is not uncommon on wet,
very rotten wood, moss, &c. ; the groups of
peridia just before maturity somewhat re-
sembling a strawberry; afterwards brownish.

BIBL. Berk. Brit. Fl. ii. pt. 2. p. 321 ;
Ann. Nat. Hist. 2 ser. v. p. 36? ; Greville,
So. Crypt. Fl. pi. 308 ; Fries, Syst. Mycol
iii. p. 195, Summa Veg. p. 458.

LICHENS.— A class of Thallophytes or
cellular plants standing between the Algae
and the Fungi, exhibiting in the various
genera relations sometimes approaching
very closely to the one, sometimes to the
other of these two classes. Some authors
have thought fit to abolish the independent
existence of a class of Lichens, distributing
its members between the other two classes ;
while, on the other hand, Schleiden increased
the Lichens by adding to them all the theca-
sporous Fungi. De Bary has recently given
his adhesion to this on other grounds.
Here we shall consider the Lichens under
their ordinary limitation, as constituting a
class of Thallophytes distinguished from the
Algae in almost every case by the structure
of the thallus, the localization of the repro-
ductive function, and the aerial habit ; and
from the Fungi by the character of the thal-
lus, above all by the presence of globular
gonidia with green cell-contents, and in
most cases by the dry crustaceous habit, as
opposed to the fleshy consistence of the
majority of Fungi.

The Lichens are almost universally either
dry encrusting bodies, growing upon bark
of trees, stones, earth, &c., as a pulverulent,
or rough and horny, or laminated and mostly
wrinkled and curled crust ; or as horny or
leathery, foliaceous or shrubby, ragged or
bristling patches, seldom rising much from
the surface which they overgrow ; of grey,
greyish-green, brown, yellowish, or even
reddish colour, and with a dead, pulveru-
lent and opake surface. The fructifications,
in which the spores are produced, are either

little nodules (fig. 399), often with a minute
Fig. 399.

Sphaerophoron coralloides.

Thallus with apothecia.

Nat. size.

pore at the summit, or raised lines (fig. 400),
or round, shield-shaped or cup-shaped bo-

Fig. 401.

Fig. 400.

Fig. 400. Opegrapha atra. Thallus with lirellse. Nat.
size.

Fig. 401. Borrera ciliaris. Thallus with apothecia.
Nat. size.

Fig. 402. Section of thalamium. Magn. 150 diams.

dies (fig. 401) scattered over the surface of
their fronds, or borne at the summits of the
branches of the shrubby kinds. In some
species the 'fruits' are the only parts visible

LICHENS.

[ 389 ]

LICHENS.

to the naked eye, the thallus being com-
posed of very small collections of micro-
scopic elements, more or less concealed in
the matrix on which the plants grow.

In the simplest kind of Lichens, the frond
or thallus consists of microscopic branched
filaments penetrating among the superficial
layers of the cells of the bark upon which
the plants grow. These filaments present
globular cells here and there growing out
from them, filled with green matter, which
globular cells are capable of reproducing the
plant when detached ; they are called goni-
dia, and are regarded as analogous to the
buds of the Flowering plants and the cellular
gemmce of the higher Cryptogams. In the
simple forms here alluded to the gonidia are
not sufficiently numerous to give a coloured
tinge to the structure as seen by the naked
eye; in some even the filaments make no
show, while in others they form whitish
patches (Opegrapha, Verrucaria). In the
forms rather more developed we find a layer
of globular epidermal cells, with whitish
contents, closely coherent together, consti-
tuting a ' cortical layer' covering the upper
surface, to which the filamentous structure
then forms the * medullary layer/ The
crustaceous kinds overgrowing stones have
this filamentous medullary layer very solid,
and in some of them its lowest filaments are
seen growing out all round the borders, in
the direction in which the plant is extend-
ing, the upper filaments with the gonidia
and the cortical layer by degrees overgrow-
ing these lowest filaments, which in the
meantime have extended farther out. Some
of the crustaceous Lichens grow out in more
or less regular lobes at their borders, and
thence lead to the pseudo-foliaceous forms,
of which the common Parmelia parietina,
the yellow Lichen so abundant on walls, and
Borrera ciliaris, common on branches of
trees (fig. 401), may serve as examples. The
thin paper-like thallus of the former exhi-
bits four distinct regions (PI. 29. fig. 2) : —
1. on the upper face a layer of thick cells,
firmly connected together, coloured yellow
at the surface (upper cortical or epidermal
layer); 2 a layer like the preceding, but
white, forming the inferior surface of the
thallus (lower cortical or epidermal layer) ;
3. beneath the upper cortical layer lie the
gonidia ; and 4, under these lie the medul-
lary filaments forming the central substance,
at the upper part of which lie the gonidia
arising from these filaments, which are in-
terlaced and imprison air between them.

From the lower face arise laminae or fibrous
processes, like roots, serving as cramps by
which the plant attaches itself to the surface
on which it grows. In Peltigera canina there
is no inferior epidermal or cortical layer, the
filamentous medullary structure forming the
irregular veined surface, prolonged here and
there into pseudo-radical processes. In
Endocarpon and other fronds of solid tex-
ture, the medullary layer is formed of slen-
der linear cells, closely packed, with few
air-passages. The species of Cladonia ex-
hibit a structure of the thallus intermediate
between that of the foliaceous kind just re-
ferred to and the shrubby sort. In the
foliaceous expansion resting on the ground,
of C. pyxidata, for example, we detect the
upper epidermis, next the gonidial layer,
which again rests on the closely-felted
filamentous medullary substance. In the
branches of C. ranaiferina, as in a great
number of its congeners, there is no well-
defined epidermis. The branches are tubes,
vacant in the centre, formed of a cartilagi-
nous structure, in which only two zones can
be distinguished, the inner and more solid
of which is composed of almost simple, pa-
rallel, solid filaments intimately glued toge-
ther by mucous substance ; the outer zone
is formed of a felted mass of filaments, like-
wise solid, but branched and divaricated.
The solidity of these filaments arises from
the obliteration of the cell-cavity by second-
ary layers on its walls, giving the filaments
a horny texture. In the outer loose layer
are found scattered groups of gonidia. In
Stereocaulon denudatum the branches are
solid and formed exclusively of parallel fila-
ments, as is the case also with those of Ra-
malina scopulorum. In Evernia vulpina
there is a solid axis formed of parallel fila-
ments enclosed in a layer of interlaced fibres,
between which and the horny coat, which is
either solid or very obscurely cellular, goni-
dia are here and there to be observed.

The fronds of Collema are remarkable foi
their gelatinous texture, and differ greatly IE
organization from the foregoing, approach-
ing the simplicity of the Nostochacese( Algae).
The thallus of C. cheilewn consists of branched
and colourless filaments or tubes, imbedded
in an abundance of mucilage; in C.jacobece-
folium, there exist in addition very numerous
green granules, almost all arranged in long
beaded lines (PL 29. fig. 13), some being
larger than others, the whole mixed with
the continuous filaments and imbedded in
mucus. Both species have long, whitish,

LICHENS.

[ 390 ]

LICHENS.

branched, filamentous, pseudo-radical pro-
cesses.

Putting aside the gonidia or gemmule-
cells of the thallus, the reproductive organs
of the Lichens are of two kinds: — 1. the
apothecia, which, according to their forms,
receive diiferent names, and are all charac-
terized by producing the sacs (thecce) con-
taining spores; and 2, the spermagonia,
which some regard as antheridia, and which
produce extremely minute cylindrical bodies
growing at the ends of short pedicels, from
which they are ultimately detached, like the
spores of many Fungi.

The commonest form of the apothecia
is that of sessile or stalked disks or cushions,
flat, convex, or hollowed into a cup (fig. 401 );
in other cases they are linear, and these
open forms characterize the division called
Gymnocarpous Lichens, while in the Angio-
carpous genera the apothecia are closed
globular receptacles or conceptacles, analo-

fous to those of the Spharice among the
ungi, opening finally at the summit to dis-
charge the spores (fig. 399). The apothecia
are lined by a special layer of cellular tissue,
sometimes called the hypothecium, which
bears the thecce &n&ihe paraphyses (fig. 402);
the latter are filiform or clavate cells (PL 29.
figs. 6 & 12), probably abortive thecae,
among which they are intermingled; both
these and the thecae stand perpendicularly
upon the hypothecium. The thec<s (PL 29.
figs. 6 & 12) are usually ovoid or elongated
cells with thick walls, containing the spores ;
the thecae are shorter than the paraphyses
surrounding them, and the whole are usu-
ally glued firmly together by their contiguous
lateral surfaces, and the entire mass of thecae
and paraphyses is called the thalamium.

The spores present many points of difference
in different genera and species. In Verru-
caria muralis they are ellipsoid, colourless,
perfectly smooth and semi-transparent, con-
taining granular matter ; while in V. epider-
midis and atomaria they are bilocular bo-
dies, representing a pair of obovoid cells
adherent by their thick ends. In their
earlier stages of development they appear
solid ; subsequently four nuclei or oily glo-
bules are seen in them, each occupying a
spherical cavity. The membrane of the
spore then becomes thinner, and finally its
two cavities coalesce into one. When ripe,
these spores are about 1-1500" in length
and about 1-4000" broad. There are
eight in each theca, and they are sepa-
rately enveloped in a mucilaginous coat.

The spores are largest in the Angiocarpous
genus Pertusaria. Those of P. communis
are visible to the naked eye, and observed
in water soon after emission from the
thecae, they are not less than 7-1000" to
8-1000" long by 5-2000" broad. Their
simple cavity is filled with granular semi-
transparent matter, usually with oil-globules
of various sizes. The epispore is very broad,
transparent, and formed of several lamellae ;
these also are coated with mucus. The
genus Parmelia offers both simple and bilo-
cular spores. Of the former, P. parietina
gives an example, though in some cases a
transverse partition is formed, and this is
the normal state in P. stellaris (PL 29. figs.
6 & 7). In Peltigera (PL 29. fig. 11) the
spores are elongated. In Collema and other
genera, the spores are divided into four
chambers by three transverse septa.

In several species of Lecanora, Lecidea,
Urceolaria, and a great number of Angio-
carpous Lichens, a more complex form of
spore exists, longitudinal together with trans-
verse septa dividing the cavity into several
series of chambers. Those of Urceolaria
(PL 29. fig. 17) have eight or ten compart-
ments ; those of Lecanactis urceolata, The-
lotrema lepadina, Umbilicaria pustulata (PL
29. fig. 18), and other Lichens (called muri-
form spores), have a much larger number of
little cavities, each containing a distinct
nucleus.

The emission of the ripe spores takes
place in the same way as in the Pezizce,
Helvellts, Sphcerice, and many other Fungi
of the same kind. If a portion of the thallus,
moistened, is placed in a common phial, with
the apothecia turned toward one side, in about
eight or ten hours the surface of the glass
opposite each apothecium will be found co-
vered with patches of spores, easily perceptible
by their colour, these having been projected
from the apothecia with force. If placed on
a moist surface, and a slip of glass laid over
them, the latter will become covered with
them in the same way ; and Tulasne states
that they are projected to a distance of more
than half an inch from the theciferous layer,
the spores being emitted continuously for a
long time. The experiment may be tried
either in winter or summer, and has been
made with success on several common spe-
cies of Parmelia, Lecanora, Peltigera, Col-
lema, Borrera ciliaris, Verrucaria muralis,
Endocarpon hepaticum, Pertusaria, Urceo-
laria, Opegrapha, &c.

Tulasne explains the elastic discharge of

LICHENS.

[ 391 ]

LICHENS.

the spores in the following way :— If a thin
vertical section is cut from the middle of the
apothecium, and divided so as to separate
the hymenium or hypothecium (or layer sup-
porting the thecae) from the subjacent tis-
sues, and the parts thus dissected are placed in
water, the hymenium becomes greatly curved,
presenting its external surface outwards and
convex, while the other part, representing
the body or excipulum of the apothecium, is
curved with equal force, but its upper extre-
mities are directed inwards to meet one
another. Thus it seems that both the
hymenial layer and the outer wall of the
apothecium eagerly absorb water, much
more than the tissues separating them.
Consequently when an entire apothecium is
wetted, the borders tend to approach one
another, curving inwards, while the layer
bearing the thecae becomes bulged out above,
whence arises a pressure on the thecae, ulti-
mately bursting them at the summit, and
causing the expulsion of their contents.
The expulsion of the spores of the Lichens
takes place slowly, while that of some Asco-
mycetous Fungi is sudden, which may be
accounted for by the different consistence of
the surrounding structures.

Eight is generally set down as the normal
number of spores in each theca, but this is
not universal here any more than in the As-
comycetous Fungi; some species of Endo-
carpon, Parmelia, &c., have polysporous
thecae containing a considerable number,
while there are often less than eight.

Stylospores. — This name is given to cer-
tain very rare organs discovered by Tulasne
in Abrothallus and Scutula, consisting of
isolated spores borne upon shortish, simple
stalks. They are produced in conceptacles,
to which is applied the name of pycnidia.
They are closely analogous to the structures
of the same name found in some Fungi (see
STYLOSPORES).

Mr, Berkeley has described another struc-
ture in Lecidea sabuletorum, namely a kind
of basidium, or enlarged cell supporting
spores, developed from some of the para-
physes. Tulasne questions the correctness
of the observation.

Spermagonia. In addition to the preceding,
the Lichens exhibit another form of repro-
ductive organs, which are liable to be con-
founded with SphterifB and other Fungi
growing on the Lichens, or with parasitical
Lichens in similar positions. They appear
as black or brown points, usually near the
margins of the thallus (PI. 29. fig. 1), and

have been found in Borrera, Parmelia,
Sticta, Cladonia, Collema, Opegrapha, Sphee-
rophoron, Lichina, Endocarpon, &c., and
seem to be universal.

The spermagonia are closed receptacles,
resembling more or less the conceptacles of
the Hypoxyla among the Ascomycetous
Fungi. In most cases they are immersed in
the substance of the thallus (PI. 29. figs. 2
& 13), and are perceptible externally only
by a little projection, if at all ; in rare cases
they are free and borne above the thallus
(some Cladonice, Cetrariee, Gyalectce, &c.).
The ordinary form is globular, ellipsoidal or
irregularly oblong, and sometimes with a
sinuous outline. The spermagonia have
either a simple undivided cavity (PI. 29. figs.
13, 16), or multiple and divided in different
ways into a variable number either of sepa-
rate chambers or narrow cavities, all commu-
nicating with a common orifice, which is
the ostiole or pore of the apparatus. This
structure bears a close relation to that usual
in the Ascomycetous Fungi (Coniomycetous
forms, Cytispora, Septoria, &c.), and bears
testimony to the close relation between the
Lichens and Fungi. The form and dimen-
sions of the spermatophores, or peduncles of
the spermatia, vary much. . The simplest
are short, slender stalks, simple or branched,
or they are articulated branches composed
of a great number of cylindroid or globular
cells (PL 29. figs. 3 & 14) ; or the branches
are reduced to two or three elongated cells.
The spermatia are terminal on the spermato-
phores, and consist of exceedingly minute
bodies, ordinarily linear, very thin, short or
longish, straight or curved (PI. 29. figs. 3,
10, 15, 16), without appendages and motion-
less, and lie in a mucilage of extreme trans-
parency. The spermatophores and their
spermatia usually fill up the cavity of the
spermagonia, when just mature ; afterwards,
when the development is complete and the
spermatia discharged, the spermagODia are
found empty and discoloured.

The minute bodies, called spermatia, are
regarded by most of those who have observed
them as analogues of the spermatozoids pro-
duced in the antheridia of the higher Cry-
ptogams. Itzigsohn imagined that he saw a
spontaneous motion of them when lying in
water beneath the microscope, but this ap-
pears to have been an error, and the only
movement really existing has been regarded,
probably most correctly, as merely molecular,
that universal in extremely minute bodies,
living or dead, lying in a fluid.

LICHENS.

[ 392 ]

LICHENS.

The Lichens are ordinarily divided into
two orders according to the structure of
their sporanges, which are either closed at
first, bursting subsequently by a pore or an
irregular orifice, containing the thecce as a
nucleus in the interior; or they are open from
an early period, and bear the thecce on the
upper, mostly concave surface (disk).

GYM NOCARPI. One of the two orders of
Lichens, characterized by bearing open apo-
thecia, in the form of shields (scutella), cups
(scyphi), rings (annuli), or irregular cracks or
lines (lirellfB), with raised borders, &c. These
apothecia are either sessile on a flat, spreading
thallus, or raised on more or less developed
stalk-like processes of the branched and
shrubby forms. The upper open, often con-
cave surface of the apothecia, called the disk,
is clothed with thecse and paraphyses.

ANGIOCARPI. One of the two orders into
which Lichens are divided, characterized by
the closed apothecia, where the thecae and
paraphyses are collected into a nucleus
enclosed in a case called the perithecium,
bursting at the summit by a pore or an irre-
gular opening to discharge the spores. The
apothecium is more or less globular, and
either imbedded in the thallus, or distinct
and raised above it. The perithecium either
entirely encloses the nucleus or is hemisphe-
rical, clothing the upper, projecting portion.

Synopsis of the Families.

A. Gymnocarpi. Apothecia open, thala-
mium expanded.

* Thallus crustaceous.

1 . Apothecia sessile, shield-
shaped, or rarely pel-
tate, disk somewhat
waxy, with a border

formed by the thallus. . PARMELIACE^E.

2. Apothecia free, circular,

soon convex, with an in-
distinct margin. Disk
always open, in a spe-
cial excipulum LECIDINE^E.

3. Apothecium oblong, li-

near or waved, chan-
neled. Disk at first
connivent or with a veil . GR A p H I D E M .

4. Apothecia circular or

g'obose, always open,
isk pulverulent .... CALICHES.

** Thallus gelatinous when fresh.

5. Apothecia circular, thal-
lus composed of cylin-
drical and moniliform

filaments COLLEMACE^E.

.

B. Angiocarpi. Apothecia closed, open-
ing by a terminal pore and bursting
irregularly, thalamium subglobose,
included.

* Thallus crustaceous.

6. Thallus shrubby, apo-

thecia at the ends of

the branches SPH^ROPHOREJ?.

7. Thallus horizontal,
leaf-like or encrust-
ing, apothecia im-
mersed ENDOCARPE^E.

8. Thallus encrusting,
apothecia rounded,
projecting from the

thallus VERRUCARIE^B.

9. Thallus encrusting,
apothecia rounded,
with a carbonaceous
hypothecium, apo-
thecia bursting in
various ways,nucleus

mostly waxy, hard. . LIMBORIE^E.

** Thallus gelatinous or soft-cartilaginous.

10. Apothecia terminal,
on lobes of the thal-
lus LICHINE^B.

BIBL. L. R. Tulasne, Memoire pour servir
a Vhistoire organograpJiique et physiologique
des Lichens, Ann. des Sc. nat. 3 ser. xvii.
1-153 et seq. ; On the Reproduction of Li-
chens and Fungi, Ann. Nat. Hist. 2nd ser. vol.
viii. p. 114 (translated from Comptes Rendus,
March 1851) ; Korber, Grundriss der Kry-
ptogamen-kunde, Breslau, 1848, Sy sterna Li-
chenum, 1854-5 ; Fries, Lichenographia
europcea reformata, Lund. 1831 ; Schserer,
Enumeratio critica Lichenum europaorum,
Bern. 1850 ; Hedwig, Theoria generationis,
fyc. ; Acharius, Lichenographia universalis ;
Wallroth, Naturgeschichte der Flechten,
Frankfort.-u.-M. 1825; Meyer, DieEntwickl.
fyc. der Flechten (Nebenstunden meiner Be-
schdftigungen, ^c.),1828; Montagne, Aper$u
morphologique de la famille des Lichens,
Diet. univ. d'hist. nat. Paris, 1846 ; Bayr-
hoffer, Einig. ub. Lichen., Berne, 1851 ; It-
zigsohn, Botan. Zeit. viii. 393. 913. ix. 153;
Flotow, numerous papers in the 'Flora' and
Botanische Zeitung ; Leighton, British An-
giocarpous Lichens; Ray publications, 1851.

LICHINA, Ag. — A genus of Lichineae
(Lichens), allied to COLLEMA and EPHEBE
in many respects, formerly included among
the Alga? on account of their growing on the
sea-shore (near high-water mark) ; but
having the thallus of a lichen, and bearing

LICHINEjE.

LIGAMENTS.

true apothecia and spermagonia. The apo-
thecia occur at the ends of the branches of
the thallus ; in L. pygmeea the spevmagonia
occur underneath the apothecia, in L. con-
finis at the apices of the branches and often
on the apothecia. The spores appear gene-
rally to adhere to the walls of the thecae
which break up.

BIBL. Harvey, Brit. Alg. 1 ed. p. 22;
Hook. Brit. Fl. ii. pt. 1. p. 274; Tulasne,
Ann. des Sc. nat. ser. 2. p. 81 & 188. pi. 9
& 10; Greville, Alg. Brit. pi. 6.

LICHINE.E.— A family of Angiocarpous
Lichens, of remarkable habit, the species of
which were formerly regarded in their perfect
and imperfect states as Algae. The branched
thallus is of gelatinous texture, very soft
when wet, cartilaginous when dry, growing
on wet rocks, Lichnia being marine. The
fructification consists of closed apothecia
and spermagonia formed in the substance
or at the ends of the branches.

British Genera.

I. Li CHIN A. Frond cartilaginous, smooth,
dichotomous, bearing the apothecia at the
ends of the branches.

II. EPHEBE. Frond cartilaginous, hairy,
much branched, bearing the apothecia exca-
vated in the swollen branches (not terminal).

LICMOPHORA, Ag.—A genus of Diato-
maceae.

Char. Frustules in front view cuneate,
elongate, radiating in a fan-shaped manner
from a branched stipes; side view (valves)
convex, inflected at the larger end and fur-
nished with transverse striae (rows of dots).
Marine.

L. radians, K. (L. flabellata, S.) (PL 14.
fig. 3).

The species (one other British, Sm., five
in all, Kiitz.) are too doubtfully distinct to
deserve description.

BIBL. Smith, Brit. Diat. i. 85; Kiitzing,
Bacill. 123, and Sp. Alg. 113.

LIEBERKUHN. INTROD., p. xviii.

LIGAMENTS and TENDONS.— With the
exception of the elastic ligaments which are
noticed under that head, the structure of
ligaments and tendons is essentially the
same. They consist of areolar tissue, with
a small quantity of elastic tissue. The fibres
or fibrillae of the areolar tissue are very
minute, longitudinal, parallel, closely con-
nected, and pursue a straight or undulatory
course. Their union into bundles is some-
times very indistinct, and only to be shown

by drying transverse sections, and afterwards
treating them with alkalies. In other in-
stances the bundles are easily recognizable,
of a polygonal, rounded or elongated form

Fjg. 403.

Magnified 20 diameters.

Transverse section of a tendon of a calf : a, secondary,
b, tertiary bundles ; c, nuclear fibres, obliquely divided ;
d, interstitial areolar tissue.

(fig. 403), and connected by loose interstitial
areolar tissue.

The elastic tissue of tendons exists as

Fig. 404.

Magnified 60 diameters.

Transverse section of the tendon of the tibialis posticus ;
human, a. secondary bundles ; b, larger nuclear fibres ;
c, interstitial areolar tissue.

slender, nuclear fibres, sometimes forming

LIGAMENTS.

[ 394 ]

LIGAMENTS.

-J8

l!

Magnified 300 diameters.

Portion of the tendo-Achillis attached to the os calcis ; human. A, bone with
lacunae a, medullary and fat-cells b ; B, tendon with fibrillse and cartilage-cells c.

Fig. 406.

rows of narrow spindle-
shaped cells, connected
by slender processes, at
others uniform fibres,
or isolated spindle-
shaped cells. These are
placed at regular di-
stances apart between
the bundles of areolar
tissue.

When tendons are in
contact with bones,
they frequently contain
cartilage - cells, either
isolated, or arranged in
rows (fig. 405 c) ; these
sometimes undergo ossi-
fication.

The aponeuroses, fas-
ciae and tendinous
sheaths consist of the
same elements, but in
various proportions and
differently arranged ac-
cording to their func-
tions ; sometimes the
areolar fibres being pre-
dominant, the structure
agreeing with that of ten-
don ; whilst at others the
elastic tissue is greatly
developed (fig. 406).

Magnified 450 diameters.
Elastic fibres from the inner part of the fascia lata, human ; densely interwoven and forming an elastic membrane.

LIGNINE.

[ 395 ]

LIME.

Some of these tissues also contain cartilage-
cells.

Fig. 407.

Magnified 350 diameters.

Cartilage-cells from the membranous ligament sur-
rounding the poplitseus muscle, a, cell with one nucleus;
by cell with two nuclei ; c, cell containing one, d, two
secondary cells, the contents of both of which are more
consistent.

The intervertebral ligaments consist of
fibro-cartilage, surrounded by osseous tissue;
the centre is soft and containing concentric
cartilage corpuscles (fig. 106, p. 111).

BIBL. Kolliker, Mikroskop. Anatomie, i. ;
Henle, Allgem. Anat.; Bonders, Mulder's
Physiol Chem.

LIGNINE. — A modified condition of cel-
lulose is obtained from old wood-cells, and
called by this name. It differs in its re-
actions from pure cellulose, being coloured
yellow by sulphuric acid and iodine, but
after boiling in nitric acid and washing,
tincture of iodine and water give it a blue
colour. See SECONDARY DEPOSITS.

LIMBORIE^E. — A family of Angiocar-
pous or closed-fruited Lichens characterized
by rounded apothecia closed in by a carbo-
naceous special perithecium, finally bursting
in various ways, containing a somewhat
waxy nucleus, which grows hard.

Synopsis of British Genera.

I. PYRENOTHEA. Thallus crustaceous.
Apothecia round, carbonaceous, perforated
by a simple opening, protruding a globular
nucleus, which at length falls to pieces,
ultimately dehiscent, spread out, evacuated.

II. STRIGULA. Parasitic on coriaceous
perennial leaves. Thallus mostly produced
beneath the cuticle. Perithecium sub-glo-
bose, collapsing at length, opening by an
irregular fissure or minute pore. Nucleus
at first gelatinous, at length hard, becoming
black and cracking when exposed.

LIME, SALTS OF.

Carbonate of lime. This substance is well
known as forming chalk, marble, &c., and as
occurring in hard animal stmctures, as bone,
shell, &c. It is not unfrequently met with
in the form of granules as a component of
various animal secretions, as the urine, &c.
In this liquid, it sometimes, but rarely also
occurs in little spheres or disks, consisting

of groups of radiating needles. This we
first found to be the case in human urine
(PL 9. fig. 8); but it was subsequently
detected in that of herbivorous animals, as
the cow and the horse (PI. 9. fig. 7)> in which
its occurrence is common. It is also a com-
ponent of otolithes, in which it exists either
as granules or minute prisms, often with six
sides and trilateral summits. From river-
and spring-water it is usually deposited in
irregular and imperfect forms (PI. 9. fig. 6),
all of which consists of grouped needles.
Sometimes it assumes the rbombohedral
form, as in the shell of the oyster (PL 37.
fig. 1 0), and frequently in chemical solutions.
When treated with a dilute acid, after having
been thoroughly washed in a watch-glass, it
is dissolved with effervescence from the
escape of carbonic acid gas. During the
solution it first becomes more transparent,
exhibiting the internal crystalline structure,
and frequently a concentric or nuclear ap-
pearance, which finally disappears. When
derived from animal secretions, it leaves
undissolved an organic cast of the original,
provided the acid be not too strong, or its
action too long continued. If the number
and size of the minute bodies be relatively
very small in proportion to the amount
of water, on adding the acid, efferves-
cence will not occur, the water holding in
solution the carbonic acid evolved. The
presence of the lime may be tested in the
ordinary way, by the addition of oxalate of
ammonia, when the precipitate is insoluble
in acetic acid, or by adding dilute sulphuric
acid, when crystalline needles of the sulphate
of lime (PL 6. fig. 16) are formed.

The spheres or disks naturally occurring
in the urine, are closely imitated by those
formed in urine to which chloride of calcium
has been added, and which has been subse-
quently kept for some time.

Lactate of lime may be obtained by
acting upon carbonate of lime with lactic
acid. It is soluble in water and alcohol.
The microscopic crystals consist of tufts of
delicate radiating needles (PL 17. fig. 19).

Oxalate of lime. This salt exists in solu-
tion in the contents of many vegetable cells
combined with a proteine-compound ; it is
also probably a normal constituent of the
human blood in small quantity, combined
and dissolved as in vegetables.

In the cells of plants it is very frequently
deposited in a crystalline form, constituting
RAWHIDES. From human blood it has been
obtained in crystals by treating the alcoholic

LIME.

[ 396 ]

LIMNOCHARES.

extract with acetic acid. It is very commonly
met with in the crystalline form in various se-
cretions of animals, as the urine, the mucus of
the gall-bladder, that of the surface of the
pregnant uterus, the liquid of the allantois,
the contents of the Malpighian vessels, and
the so-called true renal vessels of insects,
cysts, &c.

Its most characteristic form is the square
flattened octohedron (PL 9. fig. 9) ; but it
also occurs in the form of the square prism
terminated by quadrilateral facets, fine
needles, in that of a flattened body with an
ellipsoidal outline, frequently constricted so
as to resemble a dumb-bell, or variously ex-
cavated at parts of the surface (PL 9. figs.
11 & 12). It may be obtained artificially
in most of these forms (PL 9. fig. 13), by
dissolving artificial oxalate of lime in dilute
nitric acid and evaporation; some of the
forms thus obtained resemble those of car-
bonate of lime. When obtained by mixing
oxalate of ammonia with soluble salts of
lime, as chloride of calcium, &c., the crystals
are generally peculiar (PL 9. fig. 14), although
sometimes the regular octohedra are ob-
tained.

It is insoluble in hot and cold water,
acetic acid and ammonia, but is soluble in
dilute mineral acids without effervescence.

Phosphate of lime. This salt is most fre-
quently deposited from animal liquids in
an amorphous or granular state. It may be
obtained in the crystalline form by mixing a
solution of phosphate of soda with chloride
of calcium. The crystals are mostly thin
rhombic plates (PL 6. fig. 17).

They are soluble in acetic and dilute
mineral acids without effervescence, but not
in potash or water. Some of the compound
crystals resemble those of the ammonio-
phosphate of magnesia, from which they may
be distinguished by the addition of dilute
sulphuric acid, which cause the formation of
needles of sulphate of lime.

Sulphate of lime. Well known as form-
ing gypsum, alabaster, selenite, &c. It
rarely or never occurs in the crystalline form
in animal or vegetable products. When
rapidly formed in chemical testing, the
crystals consist of minute needles or prisms
(PL 6. fig. 16); when more slowly formed,
these are larger and mixed withrhombicplates.

The crystals are but little soluble in water,
and not in acetic or the dilute mineral acids.
They are sometimes found in bottles con-
taining spirit in which marine animals have
been preserved.

Medicinal precipitated sulphur is very
commonly adulterated with sulphate of lime.
The microscope at once enables the crystals
of the salt to be recognized.

Urate of lime. See URATES.

See RAPHIDES and URINARY DEPOSITS.

BIBL. That of CHEMISTRY, ANIMAL.

LIMNIAS, Schrank.— A genus of Rota-
toria, of the family Floscularisea.

Char. Eyes (when young) two, red; ur-
ceoli or sheaths single ; rotatory organ with
two lobes. Teeth forming a row in each jaw.

L. ceratophylli (PL 34. fig. 45). Urceolus
at first whitish, subsequently becoming
brown or blackish, smooth, or in consequence
of its viscidity covered with foreign bodies.
Aquatic; length 1-24 to 1-18".

BIBL. Ehrenberg, Infus. p. 401.

LIMNOCHARES, Latr. — A genus of
Arachnida, of the order Acarina and family
Hydrachnea.

Char. Palpi small and short, with the
fifth joint small and forming a claw ; man-
dibles with the last joint subulate ; rostrum
cylindrical, elongate; eyes four, approximate;
coxae concealed beneath the skin, the ante-
rior larger than the posterior ; legs ambula-
tory.

L. aquatica (holosericea) (PL 2. fig. 27).
The only species. It differs from all other
water-spiders by its walking instead of swim-
ming.

Body very soft and often spontaneously
variable in form ; epidermis covered with
little conical granules (?) ; no hairs upon the
body, and but few upon the legs ; eyes at-
tached to a lanceolate scaly piece (d), and
surrounded by hairs; rostrum partly con-
cealed beneath the skin, the anterior ex-
serted half (b) cylindrical and accompanied
by the palps, the last joint of which is very
slender and obtuse ; by pressure the broader
base of the rostrum is made to protrude (f) ;
tarsi (c) thickened at the end, with large
claws; coxae of four posterior pairs of legs
longer than the others, which is contrary to
what occurs in Hydrachna, Atax, &c.; coxae
of the anterior two pairs of legs closely
approximate, as are also those of the two
posterior pairs (e), but the two groups are
widely separated.

The larvae have six legs, a large head-like
rostrum, with two large palps and two black
latero-anterior eyes, and fix themselves upon
or near the head of Germ lacustris; they sub-
sequently detach themselves from this insect,
fall into the water, and pass their nymph-
stage under submersed stones, the perfect

LIMNOCHLIDE.

[ 397 ]

LITHOFELLINIC ACID.

animal making its appearance at the end of
fifteen days.

BIBL. Duges, Ann. d. Sc. nat. 2 ser.
i. p. 159; Gervais, Walckenaer's Arachn.
p. 208 ; Koch, Deutschlands Crust ac., fyc.

LIMNOCHLIDE, Kiitz. See APHANI-

ZOMENON.

LINDIA, Duj.— A genus of Rotatoria, of
the family Hydatinaea, E.(Furcularina, Duj.).

Char. Body oblong, almost vermiform,
with transverse folds, rounded in front, but
no rotatory organ, cilia or eye; tail-like foot
with two conical and short segments or toes;
jaws very complicated (and imperfectly de-
scribed).

L. torulosa (PI. 34. fig. 40). Aquatic;
length 1-75".

BIBL. Dujardin, In/us, p. 653.

LINDSJEA, Dryander.— A genus of Lind-
sseese ( Polypodaeous Ferns) . Exotic (fig. 408) .

LINDS^EE^E.— A sub-tribe of Polypo-
daeous Ferns with indusiate sori.

SCHIZOLOMA. Sorus infra-marginal, li-
near, continuous. Indusium linear, elon-
gated, continuous, parallel with the margin
of the leaf, free outside. Veins anastomo-
sing in hexagonoid meshes.

DICTYOXIPHIUM. Sorus infra-marginal,
linear, continuous. Indusium linear, elon-
gated, continuous, parallel to the margin of
the leaf, free outside. Veins anastomosing,
with free venules.

LINDS^A. Sorus infra-marginal, linear,
continuous. Indusium linear, elongated,

Fig. 408.

Lindsaea.
A pinnule. Magn. 10 diams.

continuous, parallel with the margin of the
leaf,free outside. Veins dichotomous(fig.408).

LINUM, L. See FLAX.

LIOTHEUM, Nitzsch.— A genus of In-
sects, of the order Anoplura, and family
Liotheida3.

Char. Antennae clavate or capitate ; max-
illary palpi conspicuous ; mouth with strong
mandibles ; tarsi with two claws.

Antennae four-jointed; mandibles with two
teeth; maxillary palpilong,filiform,4-jointed ;
labial palpi very short, two-jointed.

The genus has been subdivided into seven
subgenera. The species are very numerous,
and are parasitic upon birds.

L. (Menopon) pallidum (PI. 28. fig. 7).
Elongate, of a pale straw colour, shining and
smooth ; head slightly sinuate on each side,
with a dark pitchy spot before each eye.
Length 1-24 to 1-16". Common upon the
domestic fowl.

BIBL. Denny, Anoplur. Monographic*,
p. 204.

L[THIC ACID. See URIC ACID.

LITHOBROCHYA, Presl.— A genus of
Pterideae (Polypodaeous Ferns). Exotic.

LITHOCYSTIS, Allm.— A genus of Co-
rallinaceae (Florideous Algae), consisting of a
single species, L. Allmanni, Hass., which
has been found as an epiphyte, forming
minute white dots upon Chrysimenia clavel-
losa. The minute dots consist of one or
more fan-shaped fronds composed of square
cells. The plant is colourless, brittle, and
effervesces in acid. The fan-shaped frond
somewhat resembles in structure imperfect
or segmental fronds of COLEOCH^ETE.

BIBL. Hass. Brit. Mar. Ala. p. 111. pi.
14 B; Phyc.Brit.pl 166.

LITHODESMIUM, Ehr.— A genus of
Diatomaceae.

Char. Frustules in side view triangular,
united so as to form a prismatic filament.
Marine.

L. undulatum (PL 13. fig. 4 a, front view,
4 b, side view). Surface without markings,
very pellucid, two of the sides undulate, the
third plane and with two marginal notches ;
angles obtuse; length of joints 1-480".

This organism requires further examina-
tion ; its Diatomaceous structure is very
obscure.

BIBL. Ehrenberg, Abhandl. d. Eerl. Akad.
1840; Kiitzing, Bacill p. 135, and Sp. Alg.
p. 133.

LITHOFELLINIC ACID.— This sub-
stance is a component of certain concretions
called bezoars, and found in the alimentary
canal of various kinds of goat in the East, as
in Persia, &c.

It is crystalline, insoluble in water, readily
so in hot alcohol, but little in aether.

The perfect crystals form six-sided prisms
with truncated ends; but when somewhat

LITHONEMA.

[ 398 ]

LIVER.

rapidly deposited from an alcoholic solution,
they are modified as represented in PL 7-
fig. 14.

BIBL. See CHEMISTRY.

LITHONEMA, Hass. See AINACTIS.

LITOSIPHON, Harv. — A genus of
Punctariaceae (Fucoid Algae), with fronds
composed of cartilaginous filiform unbranched
filaments, at first solid, afterwards tubular,
composed of several rows of cells ; epiphytic
on Chorda filum (L. pusillus) and Alaria (L.
laminarice), the former 2" to 6" inches long,
the latter 1-4 to 1-2". The sporanges occur
either solitary or aggregated, scattered on
the surface of the filaments, which in L. pu-
sillus are clothed with pellucid hairs, in L.
laminarife smooth.

BIBL. Harv. Brit. Mar. Aly.p. 43. pi. 8 D;
Thuret, Ann. des. Sc. nat. 4 ser. iii. p. 14.

LIVER.— It need scarcely be said that the
liver is the glandular organ which secretes
the bile.

On examining the surface of the liver or a
transverse section of that organ with the
naked eye, it usually presents a mottled
appearance, numerous spots of a dark or
light red colour being surrounded by a

Fig. 409.

Magnified about 3 diameters.

Portion of the liver of a pig, with divided branches of
the vena cava : the lobules are visible upon the divided
surfaces : a, large vein, no orifices of the intralobular
veins being visible ; b, branches of the same, with distinct
orifices of the intralobular veins, and the bases of the
lobules seen through their walls.

margin of a paler or darker colour. These
spots correspond to the lobules of the liver.

The lobules are rounded or polygonal and
about 1-2 to 1'" in diameter (fig. 409).

Between the lobules run branches of the
vena portae, forming the interlobular veins
(coloured red in PL 31. fig. 33); these
throughout their course send off numerous
smaller branches into the substance of the
lobules, which terminate in the capillary
plexus of the lobules.

Fig. 410.

Magnified about 4 diameters.

Section of the liver of a pig through a branch of the
vena portse, with accompanying branches of the hepatic
artery and duct. On the right are seen two branches
of the vena portse giving off the interlobular veins.

The branches of the vena portae are accom-
panied by branches of the hepatic duct and
ramifications of the hepatic artery, the whole
being surrounded by areolar tissue prolonged
from Glisson's capsule. Hence in a section
of the uninjected liver, those branches of
the vena portae and of the vena cava which
are visible to the naked eye are readily di-
stinguishable from each other, by the orifices
of the former collapsing, whilst those of the
latter are kept open by their close contact
with the lobules.

In the centre of each lobule arises a branch
of the vena cava, by the union of numerous
smaller branches (coloured yellow in PL 31.
fig. 33), which take their origin in the capil-
lary plexus of the lobule ; these central
branches form the intralobular veins.

The capillaries of the lobules form a close

LIVER.

[ 399 ]

LIVER.

Fig. 411.

Magnified 35 diameters.

Section of a portion of the liver of a rabbit, showing the entire course
of one of the intralobular veins, the roots only of the others.

and elegant plexus between the branches of
the inter- and intralobular veins, the rest of
the lobules being filled up with the secreting
epithelium (fig. 412).

Fig. 412.

outer coat of areolar tissue, the
bundles of fibres of which are
difficultly separable, and an internal
epithelial layer. The areolar coat
is most distinct in the larger
branches, being almost absent in
the terminal interlobular ducts ; it
contains numerous nuclei and
nuclear fibres. The epithelium of
the larger ducts is cylindrical, that
of the smaller of the pavement
kind. In the hepatic duct, the
outer coat contains scattered mus-
cular fibre-cells. The ducts also
contain small mucus-glands. The
secreting cells of the lobules fill
up the interspaces between the
blood-vessels, forming a network
with radiating meshes. They are
very transparent, of a rounded or
polygonal form, about 1-1000" in
diameter, containing a nucleus or not unfre-
quently two nuclei, with a number of gra-
nules, and a few small globules of fat (fig. 163,
page 190).

Fig. 413.

Magnified 350 diameters.

Secreting cells and capillaries of the liver of a pig. [The
spaces between the capillaries and the cells have been
left through error of the draughtsman.]

The branches of the biliary ducts accom-
pany those of the vena portse as far as the
interlobular spaces, where they do not enter
the lobules, but terminate in caecal ex-
tremities. The biliary ducts consist of an

Magnified 350 diameters.

Secreting cells and terminal interlpbular ducts ; human,
a, ducts ; b, cells ; c, spaces occupied by blood-vessels.

The division of the substance of the liver
into lobules is rather apparent than real,
being effected by the peculiar arrangement
of the vessels, the lobules having no true
coat or envelope. The areolar tissue which
accompanies the vena port* and its branches,
becomes less and less in quantity as the
branches become smaller, and is lost in the
interlobular spaces. It it much more abun-
dant in animals, as the pig, than in man,

LIVER.

[ 400 ]

LOPHIUM.

rendering the lobular arrangement much
more distinct.

The branches of the hepatic artery are
distributed to the portal vessels, the hepatic
ducts, Glisson's capsule with its prolonga-
tions, and the peritoneal coat. They are
often elegantly tortuous.

Among the more common morbid states
of the liver, may be mentioned that called
cirrhosis, in which the areolar tissue is ex-
cessively developed and mixed with a large
number of fibro -plastic corpuscles, produ-
cing an atrophied state of the epithelial
structure ; an increase in the amount of
fatty matter in the cells (fig. 163, page 190);
and the presence in these also of granules of
the pigment of the bile, rarely with crystals
of cholesterine and bilifulvine.

The examination of the arrangement of
the blood-vessels is best made in a liver
which has been injected with two kinds of
injection, as yellow (chromate of lead) and
red (vermilion), or red and white (carbonate
of lead) ; the yellow or white being injected
into the hepatic vein. As the injection is
being proceeded with, the surface of the
liver should be examined with a lens to
ascertain whether the intralobular veins are
well filled, and the injection has reached
the capillaries ; the red injection should
then^be thrown into the portal vein until
it is filled. The general vascular arrange-
ment is best observed in an injection in
which the capillaries themselves are not
filled, but only the smaller portal and hepatic
branches.

To examine the ducts as to their course
and termination, the portal vein should first
be previously injected. If this be not done,
the injection easily bursts through the walls
of the terminal ducts, and escapes into the
intralobular plexus; and thus the appearance
of a plexus of vessels prolonged from the
terminal ducts is produced.

The structure of the hepatic cells is easily
seen on scraping the surface of a section of
the liver, and placing the portion thus ob-
tained between two pieces of glass as usual.

The general arrangement of the secreting
cells is observed in sections made with
Valentin's knife.

In many animals, as fishes, the loading of
the cells of the liver with fat, which in man
represents the morbid state of fatty degene-
ration, is normal, and renders it a matter of
some difficulty to distinguish clearly the
outlines of the cells, which are also very
delicate.

BIBL. Kolliker, Mikroskop. Anat. ii. ;
Kiernan, Phil Trans. 1833 ; H. Jones, Phil.
Trans. 1846 and 1849; Guillot, Ann. d. Sc.
nat. 3 ser. 1848 ; Leidy, Silliman's Journ.
1848.

LOASACE^E.— A family of Dicotyledo-
nous Flowering plants, with stinging hairs
upon the epidermis. Loaza, Bartonia and
Blumenbachia are often to be obtained in
gardens.

LOMARIA, Willd.— A genus of Pteridea?,
separated by some authors from Pteris, to
which it is closely related. Also confused
with Blechnum.

LONCHITIS, Presl.— A genus of Aspic-

Fig. 414.

Lonchites pubescens.

A pinnule with sori.

Magnified 10 diameters.

nie8e(Polypodaeous Ferns). Exotic(fig. 414).
LOPHIUM, Fr.— A genus of Phacidiacei
(Ascomycetous Fungi), remarkably distin-
guished by the form of the perithecia resem-
bling a bivalve shell with the valves in situ
(figs. 415 & 416). The nucleus contained

Fig. 415. Fig. 416. Fig. 417.

Lophium mytilinum.

Fig. 415. A perithecium, seen sidewise.
Fig. 416. The same, seen endwise.
Fig. 417. A perithecium cut open.

Magn. 25 diams.

within the carbonaceous perithecium consists
of erect asci mixed with paraphyses, con-
taining minute spores, and soon falling away
into a powder. L. mytilinum, Pers. (figs.
415-7) occurs on the bark or naked wood
of fir-trees. L. elatum, Carm. also occurs
on fir- wood. These plants are known from

LOPHOCOLEA.

[ 401 ]

LUNGS.

allied genera by the remarkable form of the
perithecia.

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 280;
Fries, Syst. Myc. ii. p. 533, Summa Veg. p.
401; Greville, Sc. Crypt. Flor. pi. 177-

LOPHOCOLEA, Nees. — A genus of
Jungermannieae(Hepaticaceae), including the
J. bidentata, L. and J. heterophylla, Schrad.,
growing in moist situations, at the roots of
trees, &c.

BIBL. Hook. Brit. Jungerm. pi. 30, 31,
Brit. Flor. ii. pt. 1. p. 122.

LORICA. See CARAPACE.

LOUSE. See PEDICULUS and ANO-
PLURA.

LOXODES, Ehr.— A genus of Infusoria,
of the family Trachelina.

Char. Body covered with rows of cilia;
no teeth ; anterior and upper portion of the
body (lip) obliquely truncate, or bent towards
one side (hatchet-shaped, E.), and with a row
of large cilia. Ehrenberg describes four
species.

L. bursaria, E. (Paramecium bursaria,
Focke) (PI. 24. fig. 41). Oblong, green,
anterior end depressed and obliquely trun-
cate, posterior end rounded and turgid;
aquatic; length 1-288".

The rotation of the contents of the body
takes place in this infusorium. Repro-
duction by the formation of swarm-germs,
according to the process 2 b (p. 235), has also
been observed.

L. rostrum, E. (Pelecida rostrum, D.) (PL
24. fig. 39). White, lanceolate, anterior por-
tion bent on one side ; aquatic ; length 1-144
to 1-60".

Dujardin's genus Loxodes does not agree
with that of Ehrenberg ; but, according to
Stein, the observations upon which the dif-
ferences are founded depend upon faulty
observation.

Thus L. cucullulus, D. and L. dentatus, D.
(PL 24. fig. 40) are young states of Chilodon
cucullulus, E. ; and L. reticulatus, D. is the
same infusorium distended with alimentary
matters.

BIBL. Ehrenberg, Infus. p. 323; Dujar-
din, Infus. p. 449 ; Stein, Infus. p. 238, &c.
and the Bibl.

LOXOPHYLLUM, Duj.— A genus of
Infusoria, of the family Paramecia.

The species belong to the genera Amphi-
leptus, E. and Trachelius, E. See PARA-
MECIA.

BIBL. Dujardin, Infus. p. 487.

LOXSOMA, R. Brown.— A genus of Hy-
menophyllaceous Ferns, distinguished by the

projecting column bearing the sporangia
(figs. 419, 420).

Fig. 418. Fig. 419.

Fig. 420.

Loxsoma Cunningham!!.

Fig. 418. A pinnule with marginal sori. Magn. 5diams.
Fig. 41Q. A sorus opened. Magn. 25 diams.
Fig. 420. Columella with sporanges. Magn. 50 diams.

LUNGS. — The internal respiratory sacs
of animals.

Under this head we shall notice also the
larynx, trachea, and bronchi.

Larynx. — The cartilages of the larynx do
not all possess the same minute structure.
The thyroid, cricoid, and arytenoid cartilages
consist of true cartilage, the basis being
homogeneous, and containing disseminated
cartilage corpuscles. The walls of the cor-
puscles are usually thick. The basis often
becomes fibrous, and both corpuscles and
basis encrusted with calcareous salts, or
completely ossified. Their perichondrium is
firm, and is composed of areolar tissue, with
fine elastic fibres, vessels, and nerves.

The epiglottis (PI. 40. fig. 40), and the
appendices of the arytenoid consist of fibro-
cartilage ; and the corpuscles are frequently
more or less filled up by secondary deposit.

The mucous membrane, as also the sub-
mucous tissue of the larynx, consists of
areolar tissue with networks of fine elastic
fibres ; at the surface it becomes more ho-

2o

LUNGS.

[ 402 ]

mogeneous, but does not form a separable
basement layer or membrane. It contains
a number of small racemose glands, the ve-
sicles of which are lined with pavement-,
the ducts with cylindrical epithelium. Its
surface is covered with ciliated epithelium,
agreeing in structure with that of the trachea.

Trachea and larger bronchi. — The incom-
plete cartilaginous rings of these tubes are
surrounded and connected together by a
firm, elastic, fibrous membrane, forming
their perichondrium, which also covers the
posterior part of the tubes as a somewhat
thinner layer. The cartilage is of the true
kind. At the posterior part of the tubes is
a layer of unstriated muscular fibres, most
of which form transverse, but a few longitu-
dinal bundles. The elastic tissue of the
mucous membrane is greatly developed,
forming a distinct internal layer of princi-
pally longitudinal anastomosing fibres.

The epithelium is ciliated, and consists of
several layers.

Fig. 421.

Epithelial cells of the trachea in situ ; human. «, lon-
gitudinal elastic fibres ; b, homogeneous outer (basement)
layer of the mucous membrane ; c, deep layers of round
cells ; d, intermediate layers ; e, outer ciliated cells.

Magnified 350 diameters.

The deepest layers consist of roundish
cells with distinct rounded nuclei, those
succeeding being elongated, whilst those
next the surface are still longer, greatly
narrowed at the base, and with oval nuclei ;
these forms are most distinct in the detached
cells.

Those of the last row are covered with
vibratile cilia.

The smaller bronchi differ somewhat in
structure from the larger. Thus the carti-
lage forms angularplates distributed through-
out their circumference, while the elastic
and areolar coats become thinner, and the
transverse muscular fibres smaller and less
closely placed ; the latter probably extend as

LUNGS.
Fig. 422.

Isolated epithelial cells from the surface of the trachea;
human.

Magnified 350 diameters.

far as the air-cells. The ciliated epithelium
extends to the termination of the bronchi,
forming, however, a single layer only of cells
in the smaller ones.

The walls of the pulmonary air-cells con-
sist of two layers, a fibrous and an epithelial

Fig. 423.

Air-cells of a human lung, a, epithelium ; b, fibrous
portion, where the walls of several air-cells are confluent ;
c, thinner walls of air-cells.

Magnified 350 diams.

LUNGS.

[ 403 ]

LUNGS.

layer. The former is composed of a basis
of homogeneous areolar tissue, with nume-
rous elastic fibres, vessels, and nerves.

The elastic fibres surround the air-cells in
the form of elegant wavy bundles and sepa-
rate fibres, which anastomose and constitute
a dense network, most obvious at those parts
where several cells are in contact with each
other ; whilst in other parts the areolar ele-
ment supporting the numerous capillaries
predominates, and the elastic elements are
more sparing and slender. The epithelium
is of the pavement kind, not ciliated, con-
sisting of rounded or polygonal nucleated
cells, about 1-2000" in diameter.

The terminal bronchi do not end in sepa-
rate air-cells, but in a group of them, and
have no direct communication with each
other, but open into a common cavity, with
which the bronchus also communicates (fig.
424). These groups of air-cells form the

Fig. 424.

Fig. 425.

Two pulmonary lobules, a, a, with the air-cells, b, b,
and the terminations of the bronchi, c, c ; from an infant
newly born,

Magnified 25 diameters.

lobules of the lungs, and are separated from
each other by areolar tissue mixed with
nuclear fibres, containing in adult ani-
mals (fig. 425) black pigment in the form of
distinct or isolated granules, sometimes also
crystals. The lobules are best seen in the
lungs of young animals.

These smaller or primary lobules are ag-
gregated to form larger secondary lobules —
the lobules of descriptive anatomists, and
the outlines of which in adults are principally
mapped out by lines of pigment.

Outer surface of the lung of a cow, the air-cells of
which were injected with wax. a, a, a, air-cells ; b, b,
boundaries of the (primary) lobules.

Magnified 30 diameters.

The lobular structure of the lungs is best
shown in the lungs of foetal animals injected
from the trachea or bronchi.

The capillaries of the lungs are extremely
minute and very difficult to inject fully ; and

Fig. 426.

Capillaries of the human lung.
Magnified 60 diameters.

the finest injection is required for the pur-
pose.

In the lower vertebrate animals, the
structure of the lungs is much simpler than
in the higher. Thus in the Triton each
forms a simple tubular sac, whilst in the
frog and toad (PL 31. fig. 34) each lung
may be compared to a single lobule of a lung

2o2

LYCOGALA.

[ 404 ]

LYCOPODIACEvE.

of the Mammalia, having a cavity in the
centre, with which comparatively few large
cells extending into the periphery communi-
cate. The capillaries are also much larger,
especially in the two animals last mentioned.

The capillaries may often be well seen in
thin sections of the inflated and dried organs.
The altered structure of emphysematous
lungs may also be best shown by this me-
thod.

BIBL. Kolliker, Mikrosk. Anat. ii. ; Rai-
ney, Med. Chi. Trans, xxviii. & xxxi. ; Stan-
nius, Vergl. Anat.

LYCOGALA, Mich. — A genus of Myxo-
gastres (Gasteromycetous Fungi), consisting
of somewhat globular bodies, verrucose on

Fig. 427.

Fig. 428.

Lycopodium Gayanum.

Fig. 427. Scale of spike with axillary sporange ; side

view.
Fig. 428. The same seen from the outside.

Magnified 20 diameters.

Fig. 430.

Fig. 431.

Selaginella apoda.

Fig. 430. Scale with oosporange. Magn. 20 diams.
Fig. 431. Scale with pollen-sporange. Magn. 20 diams.

the outside, composed of a double papery
peridium, containing capillitium and spores,
growing on rotten wood, &c. L. epidendrum
varies from the size of a pea to that of a nut,
is globular when solitary, deformed when
growing in groups, and of a red colour.
L.parietinum is bluish black, and the peridia
do not exceed 1-20" in diam.

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 307,
Ann. Nat. Hist. 2 ser. v. p. 365 ; Grev. Sc.
Crypt. Fl. pi. 38 ; Fries, Syst. Mycol. iii.
79, Summ. Veg. p. 448.

LYCOPODIACE^. — This order of
Cormophytous Flowerless Plants, which
derives its name from the Lycopodia or
Club-mosses, is difficult to characterize in

Fig. 429.

Lycopodium complanatum.
One-third the nat. size.

Fig. 432.

Fig. 432. Oosporange with four large spores. Magn.

20 diams.
Fig. 433. Pollen-sporange burst, containing small

spores. Magn. 20 diams.

LYCOPODIACE.E.

[ 405 ]

LYCOPODIACE.E.

general terms. The bifurcating branched
stem, rooting at each fork by a slender
thread-like adventitious root, and the ordi-
narily small overlapping leaves, distinguish
most of the species of Lycopodium; but there
is considerable variation from this habit in
the Psilotete, especially in Isoetes, and the
nature of the fructification is the only mark
generally applicable. The Lycopodiacese
bear spores which are found in small dehis-
cent cases at the bases of the leaves (figs.
427, 430 and 431), on the upper face or im-
bedded in it, and these fertile leaves are
either scattered all along the stem, or col-
lected into spikes resembling, on a small
scale, elongated Pine-cones (figs. 429, 439).

The plants of the genus Lycopodium proper
exhibit both these conditions, but in all
these cases the spores are small and nume-
rous. In Selaginella, to which belong the
elegant creeping Club-mosses, with flattened
leafy stems (often with a metallic lustre),
now so much grown in Wardian cases (fig.
434), the capsular leaves are in spikes,
which are found forming one arm of a bifur-
cation of the stem, while the other continues
the vegetative growth ; and in these spikes
we find the capsules on the lo\nest scales
(oosporanges) producing only four spores
(figs. 430, 432), of much larger size than
those contained in large number in the other
spore-cases (pollen-sporanges] (figs. 431 , 433) .

Fig. 434.

Selaginella cernua. Half nat. size.

In both of these genera thesporanges have but
one cavity; in Tmesipteris the sporanges are
two-celled, and in Psilotum three-celled. In
Isoetes (fig. 380), where all the leaves are
seated on a tuberous stem, and most of them
fertile, the sporanges containing spores of
each kind are many-celled, and immersed
in the substance of the bases of the leaves.

The anatomical structure of the stem of
the Lycopodieae is not very complex. There
is an outer thickish rind, composed of cellu-
lar tissue, and on cutting across a stem, the
ends of isolated fibro-vascular bundles are
sometimes seen traversing this ; these iso-
lated bundles are merely a portion of those

forming a kind of cord running up the centre
of the stem, whence they have been sent off
to supply the leaves. The fibro-vascular
bundles are composed of spiral-fibrous ducts
surrounded by elongated cellular tissue (see
FIBRO-VASCULAR BUNDLEs),which in large
woody stems become lignified by secondary
deposits. The roots have also a central
fibro-vascular cord, connected with the central
cord of the stem. The structure of the
little-developed tuberous stem of Isoetes is
very different, and exhibits a remarkable
mode of growth, forming annual layers of
woody structure (see ISOETES).

The leaves are of very simple structure,

LYCOPODIACE.E.

[ 406 ]

LYCOPODIACE^E.

but their arrangement exhibits many curious
peculiarities. In PSILOTUM, one of the
simplest forms, where they are mere minute
scales on a widely bifurcated stem, they are
alternate; in some Lycopodia they are
opposite, in others whorled. When the

Fig. 435.

leaves are in whorls, they vary in number,
not only in different species, but often in the
same species in different localities, or even
in the same plant. Thus the arrangement
is often different on the main stem and on
the branches.

Fig. 436.

Fig. 437.

Lycopodium phlegmaria.

Fig. 435. Section of the stem. Magnified 50 diameters.
Fig. 436. The centre of ditto. Magnified 150 diameters.
Fig. 437. One of the isolated bundles of ditto. Magnified 200 diameters.

When the leaves are opposite, those
forming the pairs sometimes differ both in
dimensions and form ; in Lycopodium
complanatum (fig. 438), the pairs of opposite
leaves cross alternately at right angles so as
to form four rows up the stemj in two

Fig. 438. Fig

(opposite) rows the leaves are alike and
flattened laterally; of the other two rows, one
consists of leaves like the two just described,
but flattened against the stem; and the
fourth row (opposite the third) of minute,
scale-like bodies. In other cases, in Selagi-

439.

Fig. 440.

Fig. 438. Lycopodium complanatum. Young shoot.

Fig. 439. Lycopodium lucidulum. Spike of fruit. Magnified 3 diameters.

Fig. 440. Selaginella apoda. Young shoot. Magnified 2 diameters.

LYCOPODIACE^.

[ 407 ]

LYCOPODIACEJL

nella apoda for example, the corresponding
leaves of the pairs are unequal, and are so
arranged that the smaller lie in two conti-
guous vertical rows, on the front of the stem,
very much resembling the amphigastria of
Hypopterygium and some of the Junger-
mannice. In most of the Lycopodiaceae the
leaves are simple and almost sessile ; but in
Tmesipteris they have a blade developed
into two lobes, and borne on a long stalk ;
and in Psilotum the short, scale-like leaf is
also divided into two lobes and supported on
a petiole. The leaves of Isoetes are again
different, consisting of long, quill-like bodies
of a delicate structure, composed of large
cells ; these are aquatic plants with very pecu-
liar habits and characters (see ISOETES).

The reproduction of the Lycopodiaceae,
upon which much light has recently been
thrown, is very curious; it is only accurately
understood as yet, however, in the genera
Selaginella and Isoetes, in which, as above
stated, two kinds of spores are known to
exist. It is found that when both kinds of
spore are sown, the results of their germina-
tion are totally distinct. The small dust-
like spores burst their outer coat after a
time, and the delicate inner membrane,
which is protruded, likewise bursts after a
time and discharges extremely minute cel-
lules, in each of which is developed an
actively moving spiral filament (spermato-
zoid)like those of the FERNS. This breaks
out and swims about rapidly in the water
when seen beneath the microscope.

The large spore exhibits no external
change for a period varying from a few
weeks to a few months, but a section shows
that a process of cell-formation has com-
menced in its interior, which results in the
production of a kind of disk of cellular
tissue in the upper part, beneath that por-
tion of the outer spore-coat which exhibits
the three converging ridges produced by the
pressure of the four spores in the parent-sac
during their development. At this period
the spore appears to have three coats, an
outer tough, coloured coat, a second coat
lining this, and a third which lines the
second over the great cavity of the spore,
but at the upper part invests the inside of
the newly-formed disk of cellular tissue,
which thus lies between the second and
third coats. This disk of tissue is a pro-
thallium analogous to the green body deve-
loped from the free spores of the FERNS
and EQUISETACE^E. On its upper surface
are developed a number of archegones of

very simple structure. A cell of the sub-
stance of the prothallium taking on the
function of an embryo-sac developes a free
cell (embryo-cell) in its interior, and the cells
between this and the surface become modi-
fied, and part so as to leave an intercellular
canal between the contiguous angles of four
adjoining cells, leading down to the embryo-
cell, the four cells growing up from the
surface so as to form a kind of perforated
cellular papilla, something like that of the
archegone of the Ferns. At a certain stage
of this development, the outer coat of the
spore bursts at the converging ridges, and
the angular flaps resulting turn back and
expose the prothallium on the upper surface.
One (sometimes two, but as an irregularity)
of the embryo-cells is then fertilized by the
spiral filaments produced by the small spores
(pollinic spores], if these exist at the
right stage of the development in the vici-
nity. After this, the embryonal cell under-
goes multiplication, first growing down as a
cellular filament which breaks through into
the great cavity of the spore, the lower end
lying there then increasing until it acquires
the form of a cellular nodule, which breaks
out above and exhibits on its free portion
the first adventitious root and the first pair
of leaves ; the rootlet makes its way down-
wards into the soil, and the leaves are gra-
dually elevated on a thread-like stalk, and
separate, displaying two terminal buds
between them, whence the first bifurcation
of the stem proceeds.

This mode of reproduction allies the family
very closely to the double-spored Marsi-
leaceae, and separates them from the Ferns
and Equisetaceae, in which the prothallium is
formed outside the spores, from the single and
only kind which these plants possess. But
a difficulty still exists with regard to those
species of Lycopodieae in which only the
smaller kind of spore has been met with,
such as our common Lycopodium clavatum,
inundatum, &c. No one has yet been able
to make these germinate ; and it is conjec-
tured by Hofmeister that they may possibly
produce a prothallium in their interior which
may bear both archegones and antherids,
like the extra-sporous prothallium of Ferns.

The order Lycopodiaceae is divided into
two families, in accordance with the struc-
ture of the sporanges.

Families.

I. Lycopodiete. Sporanges simple, one-
celled.

LYCOPODIE.E.

[ 408 ]

LYMPHATIC GLANDS.

II. Psilotece. Sporanges compound,
many-celled.

BIBL. Spring, Monograph, des Lycopo-
diacees, Mem. Acad. Bruxell. xv. ; Miiller,
Entw. der Lycopodiaceen, Bot. Zeit. iv.
1846 (Ann. Nat. Hist. xix. p. 27, &c.) ;
Bischoff, Krypt. Gew. Niirnberg, 1828. p.
97; Hofmeister, Vergleich-. Untersuch.
Leipsic, 1851. p. Ill, &c.; Mettenius, Beitr.
zur Botanik. Heidelb. 1850. See also

LYCOPODIE^E.— A family of Lycopo-
diaceous plants, distinguished by their sim-
ple one-celled sporanges. The existing kinds
are all herbs, mostly creeping over the
ground; but some of the fossil kinds, met
with especially in the Coal-measures, were
large trees.

Genera.

I. LYCOPODIUM, Linn. Sporanges all
of one kind, containing numerous small
spores resembling pollen-grains.

II. SELAGINELLA, P. de Beauv. Spo-
ranges of two kinds, the greater part resem-
bling those of Lycopodium; one, situated
at the base of the spikes, larger, often
four-lobed, and containing only four large
spores.

LYCOPODIUM, Linn!— A genus of Ly-
copodieae : this has already been sufficiently
characterized under the head of Lycopodia-
ceae. There are more than half-a-dozen
British species, mostly alpine plants, but
L. inundatum occurs on bogs in all parts of
Britain. The species usually described as
L. Selaginoides has oosporanges and anthe-
ridial sporanges, and belongs to SELAGI-
NELLA.

BIBL. Hook. Brit. Flora-, Babington,
Man. Brit. Botany ; Francis, British Ferns
and their Allies, 5th ed. See also under
LYCOPODIACE^E.

LYGODIUM, Swartz.— A genus of Schi-
zseous Ferns, consisting of beautiful climbing
plants, with conjugate, palmate, lobed or
pinnate leaves, having the sessile sporanges

Fig. 441.

Lygodium reticulatum.
Fig. 441. Portion of a leaf, with fertile pinnules. Nat.

in double rows on the teeth of the pinnules

Fig. 443.

Lygodium reticulatum.

Fig. 442. Tooth of a pinnule with overlapping indusia.

Magn. 20 (li;iins.
Fig. 443. The same, with the indusia removed to show

the sporanges. Magn. 20 diams.

(fig. 441), each having a hood-like special
indusium (figs. 442, 443).

LYMPHATIC or CONGLOBATE
GLANDS.— The structure and functions of
these organs are not agreed upon by physio-
logists.

Each is surrounded by a capsule, consist-
ing of areolar tissue, with numerous scattered
fine elastic fibres (nuclear-fibres), and, in
animals, unstriated muscular fibres.

The substance of the glands consists of a
cortical and a medullary portion.

The cortical portion, which in the larger
glands forms a layer about 1-6 to 1-4" in
thickness, exhibits a coarsely granular ap-
pearance, visible externally through the cap-
sule. This granular appearance arises from
the presence of a large number of septa
prolonged from the capsule into the sub-
stance of the organ, and dividing it into
alveoli; they are about 1-96 to 1-36" in
diameter, and of a rounded or polygonal
form. They are more distinct in animals
than in man. The septa consist of areolar
tissue with a few fine elastic fibres, and nu-
merous delicate spindle-shaped bodies re-
sembling fibro-plastic corpuscles, often ana-
stomosing at their ends.

The contents of the alveoli are greyish-
white, pulpy, traversed by capillary blood-
vessels, and by numerous delicate fibres and
plates, composed of spindle-shaped and
stellate cells, resembling those found in the
septa, but forming a lacunar or spongy
tissue. The soft substance consists of free
nuclei and rounded cells, resembling those
found in the lymph and chyle.

The medullary portion exhibits no septa,

LYMPHATICS.

[ 409 ]

MACROBIOTUS.

but is composed of a plexus of lymphatic
vessels closely connected with the efferent
vessels, supported by areolar tissue, without
elastic fibres, and containing a number of
fat-cells.

The afferent lymphatic vessels penetrate
the capsule, pass through the septa between
the alveoli, and open into their lacuna,
which are not lined with epithelium.
From these the lymphatics of the medullary
plexus arise, to terminate in the efferent
vessel or vessels.

It is supposed by some physiologists that
most of the chyle- and lymph-corpuscles are
formed in the lymphatic glands, and from a
formative blastema poured out by the capil-
laries of the alveoli.

BIBL. Kolliker, Mikrosk. Anat. ii., and
the Bibl. therein; for the pathology, the
works of Forster and Wedl.

LYMPHATICS.— Absorbents or lymph-
vessels.

The structure of the lymphatics is much
the same as that of the veins, but in some
respects it is obscure.

In regard to that of their capillaries, little
positive is known. Lymphatics of interme-
diate and large size consist of three coats.
The internal is composed of somewhat elon-
gated epithelial cells, and an elastic reticular
layer of longitudinal fibres. The middle
coat consists of transverse muscular fibres,
with fine elastic fibres also transverse. The
outer areolar coat is composed of longitu-
dinal fibres, with a few reticular elastic
fibres, and a larger or smaller number of
oblique and longitudinal bundles of unstri-
ated muscular fibres ; the latter form a good
distinguishing character of lymphatics from
small veins.

The thoracic duct differs somewhat in
structure from the lymphatics. Outside the
epithelium are some striated layers, next to
which is an elastic reticular layer, the fibres
being longitudinal ; but the entire inner coat
is thin. The middle coat consists of an
inner very thin longitudinal layer of areolar
tissue, with fine elastic fibres, and an outer
transverse muscular layer, containing also
fine elastic fibres. The outer coat contains
longitudinal areolar tissue, with elastic fibres
and scattered anastomosing longitudinal
bundles of muscular fibres.

The valves of the lymphatics agree in
structure with those of the veins.

LYNGBYA, Ag.— A genus of Oscillato-
riaceae (Confervoid Algae), related to Calo-
thrix and Oscillatoria, distinguished from

the former by its stratified habit, from the
latter by the long flexile filaments. It con-
tains both freshwater and marine species.
Hassall seems to have made strange errors
with the plants included under Lyngbya in
his work on Freshwater Algae, for Ulothrix
and Sphceroplea belong to a totally distinct
group. L. muralis (PI. 4. fig. 10) grows in
damp places and in wrater. The specimen
from which our drawing was made exhibited
a remarkable motion, a snake-like advance
and retreat, coiling round other Confervae,
and waving also at the end like an OSCIL-
LATORIA. L. copulata, Hass. probably be-
longs to the genus. The rest of his species
belong apparently to ULOTHRIX. Harvey
describes five marine species, some of which
are of purple colour.

These plants appear to break up into
lenticular gonidia, but their reproduction,
like that of Oscillatoria, is very obscure.

BIBL. Hassall, Brit. Fr. Alg. p. 219.

pi. 59. 60. 72; Harvey, Brit. Mar. Alg. p.
~. pi. 26 E.; Kiitz. Spec. Alg. p. 279,
Tab. Phyc. i. pi. 86-90.

225. pi. 26 E. ; Kiitz. Spec. Alg. p. 27!

36-'
LYSIGONIUM. See MELOSIRA.

M.

MACROBIOTUS, Schultze.— A genus of
Arachnida, of the order Colopoda, and family
Tardigrada.

Char. Head not furnished with append-
ages ; mouth terminated by a sucker, without
palps ; skin soft, with irregular rugae.

M. Hufelandii (PI. 41. fig. 8). Body cy-
lindrical, colourless ; head rounded in front,
with minute coloured eye-spots ; sucker,
pharyngeal tube and styles well developed ;
cesophageal bulb supported by a solid frame-
work of jointed pieces; legs equal; claws
two, bifid, the point of each again bifid;
movement tolerably quick ; size 1-85 to
1-35".

The most common species; found upon
mosses growing on walls, stones, at the foot
of trees, &c.

M. Oberhauseri. Dark brown ; colour dis-
tributed unsymmetrically in spots, and form-
ing five longitudinal bands ; no eye-spots ;
claws three, one simple, terminal, and form-
ing a short filament ; the two others hooked,
the anterior one double or bifid, the posterior
simple; movement very active; length 1-100
to 1-85".

M.ursellus. Claws three, none filamentous.

M. Dujardinii. Claws two, bifid.

BIBL. Doyere, Ann. d. Sc. nat. 2nd ser.
xiv. xvii. and xviii. ; Dujardin, ibid. x.

MACROGONIDIA.

[ 410 ]

MAGNESIA.

MACROGONIDIA.— A name applied by
the Germans to the larger form of ciliated
zoospore, found in many Confervoid Algae,
associated with a form much smaller, distin-
guishedasMicROGONiDiA. SeeZoosFORES
and HYDRODICTYON (p. 332).

MACROSPORIUM, Fr.— A genus of
Dematiei (Hyphomycetous Fungi), growing
upon decaying vegetable matters, correspond-

Fig. 444.

Macrosporium bulbotrichum.
Magnified 200 diams.

ing to Septosporium, Corda, and Helmispo-
rium, Duby. Several species are British.
M. Cheiranthi, Fr., common on wallflowers
and stocks ; M. Erassicce, Berk., on cabbage-
leaves ; M. sarcinula on gourds; and M.
concinnum, on rotting decorticated willow
twigs. We have found one species among
the OIDIUM of the vine-fungus.

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 339,
Ann. Nat. Hist. i. p. 261. pi. 8. fig. 10, vi.
p. 435. pi. 12. fig. 21 ; Fries, Summa Veget.

S. 501, Syst. Mycol. iiii. p. 274; Corda,
cones Fung. i. p. 175. 176. 188.

MACROTHRIX, Baird.— A genus of En-
tomostraca, of the order Cladocera and
family Daphniadae.

Char. Five pairs of legs ; beak directed
forwards ; superior antennae of considerable
size, one jointed, and pendulous from the
beak ; inferior antennae two-branched, pos-
terior branch four-, anterior three-jointed,
and with a very long filament arising from
the end of the first joint ; a black spot at the
root of the superior antennae.

M. laticornis (PL 14. fig. 25). Shell
oval, smooth, anterior margin strongly
ciliated ; eye areolar.

Found in ponds.

M. roseus. Eye without an areola; su-
perior antennae longer and more slender
than in the above.

Fig. 445.

Probably a variety of the last. Found in
Scotland.

BIBL. Baird, Brit. Entomostr. p. 103.

MADOTHECA, Dumortier (Jungerman-
nia, L.). — A genus of
Jungermannieae (Hepa-
ticaceae), containing two
British species, one, M.
platyphylla (fig. 445),
common on walls, rocks
and trees ; the other, M.
Icevigata, found on alpine
rocks. The sporange is
borne on a short stalk,
globose, and bursts by
four convex valves, from
which the elaters are
quite free. The globose
persistent epigone is seen
in the figure inside the
two-lipped perigone.

BlBL. Endl, Gen. Madotheca platyphylla.

Plant. Suppl. i. p. 1341 ; ****&' 5 diams-
Hooker, Brit. Flora, ii. p. 125, Brit. Jun-
germann. pi. 35.40, and Supp. pi. 3; Ekart,
Synops. Jungermann. p. 52. pi. 3. fig. 24.
pi. 6. fig. 44.

MAGNESIA, SALTS OF.

Ammonio-phosphate of magnesia or triple
phosphate. This salt is frequently met with
in animal secretions which have undergone
decomposition, also in calculi. The most
common forms are prismatic, and figured in
the group a, PI. 9. fig. 1, but their varieties
are endless. Those of the above group are
frequent in decomposing urine, blood, faeces,
&c. Those in group c are occasional in
urine. Those of group d are found in the
contents of the vesiculae seminales. The
forms e and / are rare. Fig. 2 a, b repre-
sents the so-called penniform crystals, or
rather groups of crystals (prisms) occasion-
ally found in urine. Fig. 3 represents the
stellate form, occasionally found in urine ;
sometimes the minute and imperfectly
formed crystals of fig. 4 are met with in the
same liquid.

The crystals belong to the rhombic system.
The prismatic crystals were formerly con-
sidered as consisting of a neutral, and the
feathery of a bibasic salt ; but the composi-
tion of the two is the same, and the variation
in form depends upon the conditions under
which they are produced.

The prismatic forms may be prepared
artificially by allowing urine to decompose ;
or by diluting this secretion with water, and
gradually stirring in very dilute solution of

MAGNIFYING POWER.

MARATTIACE.E.

ammonia in small quantities at a time ; the
penniform crystals by adding excess of solu-
tion of ammonia to very dilute solutions of
the phosphate of ammonia and sulphate of
magnesia ; and the feathery forms by adding
excess of ammonia to urine. The prismatic
crystals form a beautiful polarizing object.

Sulphate of magnesia (Epsom salt). When
crystallized upon a slide from an aqueous
solution, the prisms of this salt mounted in
balsam, form an interesting polarizing object;
they are also analytic.

Ur ate of magnesia. See URATES.

BIBL. That of CHEMISTRY, ANIMAL, and
Phil. Mag. 1852. iii. p. 373.

MAGNIFYING POWER.— The method
of determining the magnifying power of a
microscope is given under MEASUREMENT.

MAHOGANY.— The wood of various
species of Swietenia (Nat. Ord. Cedrelaceae).
Cross sections of this well-known wood
form good objects for showing the structure
of WOOD with low power.

MAIZE. — Indian corn, Zea Mays, L. —
One of the family of Grasses producing
seeds used as corn. The seeds, or rather
caryopses, are remarkably firm, being of a
horny texture in the outer part of the sub-
stance, while the central mass is more or less
brittle and soft. The solidity of the grain
results from the outer cells of the albumen
being densely filled with starch-grains (PL
36. fig. 3), which, by pressure, assume a
parenchymatous form and cohere together
firmly. In the centre they are loosely
packed in the cells, and then are of rounded
forms (fig. 5). Figs. 1 to 4 represent suc-
cessive stages of development of the starch-
grains in the protoplasmic mass, originally
filling the cells but finally almost wholly
displaced. See STARCH.

MALACOSTOMUM, Werneck. — A
genus of Rotatoria.

The (three) species correspond to Notom-
matce without teeth, but require further exa-
mination.

BIBL. Werneck, Ber. d. Berl Akad. 1841.
p. 377.

MALPIGHIAN BODIES. See KIDNEY.

MANDIOC or MANIHOT. See CAS-
SAVA.

MANILLA HEMP.— One of the most
delicate of vegetable fibres used for textile
fabrics, yielded by the liber of the fibro-vas-
cular bundles of Musa textilis, a kind of
banana common in the Philippine Islands
(PI. 21. fig. 7). It is manufactured into
" Manilla handkerchiefs " and " Manilla

scarfs," consisting of a delicate muslin.
These are often erroneously stated to be
made of the fibre of some kind of Pine-apple.
See TEXTILE SUBSTANCES.

BIBL. Hooker's Journal of Botany, vol. i.
28. 1849.

MARANTACE^E.— A family of Monoco-
tyledonous Flowering plants, to which belong
the true West Indian arrow-root plants (see
ARROW ROOT), and the Tous-les-mois
plants, species of CANNA. These sub-
stances consist of the starch (PI. 36. figs. 18
& 25) obtained from the tuberous rhizomes
of the plants (see STARCH).

MARATTIA, Swartz.— The typical genus

Fig. 446.

Fig. 447.

Marattia.

Fig. 446. Side view of a sorus.
Fig. 447. Indusium with the sorus removed.
Magnified 12 diams.

of Marattiaceous Ferns. Exotic (figs. 446
& 447).

MARATTIACE^.— A family of Ferns,
approaching the Polypodiaceae in general
habit, but more resembling the Ophioglos-
saceae in their sporanges, which are destitute
of an annulus, and often so fused together
as to look like a multilocular sac.

Genera.

I. Angiopteris. Sporangia in two rows
near the apex of transverse veins, distinct,
forming linear sori, opening by a slit on the
outer side. No indusium.

II. Kaulfussia. Sporangia placed on the
anastomoses of the veins, radiately connate,
forming roundish sori, opening by a slit at
the apex.

III. Marattia. Sporangia in two rows
near the apex of transverse veins, connate,
forming oblong sori, gaping transversely bv
a vertical slit. Indusia connate with the
sori (figs. 446, 447).

IV. Eupotium. Sporangia as in Marattia,
but pedicellate.

V. Dancea. Sporangia in two rows, near
the transverse veins, connate into linear sori,
opening by a pore. Indusia superficial, en-
circling the sori (fig. 159. page 188).

MARCHANTIA.

[ 412 ]

MARCHANTIA.

MARCHANTIA, Micheli.— A genus of
Marchantieae(Hepaticace8e). The most com-
mon species, M. polymorpha, may be taken as
a type at once of this genus and of the family.
It is a little plant, not uncommon between
the stones of damp shady courtyards, the
borders of springs, &c., extending itself in
bright green thin lamellae of irregular lobed
outline, attached to the soil by radical hairs
arising on the lower surface. The frond
presents an upper and lower epidermis with
an intermediate parenchyma, and the lobes
are traversed by a kind of midrib. The
upper surface is marked by raised lines which
cross each other very regularly, leaving be-
tween them lozenge-shaped spaces (fig. 448),

Fig. 448.

Marchantia polymorpha.

Lobe of a frond.
Magnified 10 diameters.

in the centre of each of which occurs a
stomate, leading to an intercellular space in
the parenchyma. The stomates of Mar-
chantia are circular, and consist of sixteen
cells, arranged so as to form four rings, one
upon another, each ring being composed of
four cells; they may be best explained by
comparing them with a chimney composed of
four courses of bricks, each consisting of
four bricks laid together to enclose a square.
The parenchyma is composed of several
layers of cells, which contain much chloro-
phyll. The inferior epidermis is clothed by
radical hairs, which exhibit a remarkable
spiral marking, arising from the projection
of a spirally deposited secondary layer in the
interior of the tube.

The fronds do not readily produce spo-
ranges in shady places, but when exposed to
the light these are produced at the ends of
the ribs, at the base of the terminal notches
of the lobes. The male structures are pro-
duced on different plants from the female, but
both are borne on peculiar stalked receptacles.

The first appearance of one of these recep-
tacles is as a little green papilla, surrounded
by reddish scales, at the end of one of the
principal ribs. As it enlarges it pushes its
way through the scales, and the rib on which
it is borne elongates to form a pedicel, on
which it is raised up perpendicularly above
the surface of the frond, ultimately acquiring
the form of an expanded cap, in the male
receptacles with a sinuate margin (fig. 449),

Fig. 449.

Marchantia polymorpha.

Plant with antheridial receptacles.

Nat. size.

in the female with the border developed into
eight or nine thick cylindrical lobes (fig. 450).

Fig. 450.

Marchantia polymorpha.

Plant with fertile receptacles.

Nat. size.

The male receptacle is concave above,
with papillae consisting of the mouths of
flask-shaped cavities, in each of which is
formed an antheridium (fig. 451). These
antheridia are oval cellular bodies lodged in
the expansion of the cavity, with a long neck
projecting forward through the mouth of the
flask-shaped excavation. The cells of the
interior of the lower part of the antheridia
produce spermatozoids (PI. 32. fig. 32). The

MARCHANTIA.

Fig. 451.

[ 413 ]

MARCHANTIA.

Marchantia polymorpha.

Section through the antheridial receptacles, showing the
flask-shaped cavities containing the antheridia.

Magnified 25 diameters.

lower surface of the receptacle is clothed by
membranous processes and hairs.

The female receptacles are somewhat con-
vex above, and on the under surface of the
base of each lobe are found delicate mem-
branous processes with toothed margins.
The membranes of each two adjoining lobes
form a perichate (fig. 452) alternating with

Fig. 452.

Marchantia polymorpha.

A sporangia! receptacle seen from below.

Magnified 5 diameters.

the lobes, concealing between them the ar-
chegones, which are attached by their bases,
and have their mouths pointing downwards.
The archegones of Marchantia are flask-
shaped sacs with a long neck (figs. 329-331,
p. 320), containing in their cavity a cell (germ-
cell), which after fertilization becomes deve-
loped into an oval cellular body, the young
sporange. In the course of the development
of this, it soon fills the cavity of the arche-
gone, which then begins to grow with it,
and subsequently forms a loose sac around

it, the epigone, finally ruptured at the point,
so as to exhibit four or five teeth or valves,
which become recurved (fig. 453). Mean-
Fig. 453.

Marchantia polymorpha.

Vertical section of the same, showing sporanges in situ,

bursting to discharge the spores and elaters.

Magnified 10 diameters.

while another envelope grows up around the
epigone, appearing at first as a mere ring
surrounding it (figs. 329-331, p. 320), but
ultimately rising up so as to enclose it, re-
maining open however at the summit ; this
is the perigone. In its young stages the
sporange is a mere oval mass of polygonal
cells, but soon may be detected a distinction
between a cortical or peripheral layer and
the internal mass. The cells of the former
remain firmly united into a membrane form-
ing the wall of the sporange. These cells
grow so as to assume an elongated form,
and when mature exhibit internally a spiral-
fibrous secondary deposit (PI. 32. fig. 35),
analogous to that of the cells of the anthers
of Flowering plants. The cells of the inter-
nal mass present at an early period the ap-
pearance of a large number of filaments
radiating from the centre of the sporange to
the wall. These soon become free from each
other, and it may then be perceived that
some are of very slender diameter, and others
three or four times as thick. The slender
ones are developed at once into the long
elaters (PI. 32. fig. 36) characteristic of this
genus, containing a double spiral fibre, the
two fibres, however, coalescing into one at
the ends (fig. 37). The thicker filaments
become subdivided by cross partitions, and
break up into squarish free cells, which are
the parent-cells of the spores, four of which
are produced in each (P1.38.figs.lO-13). The
sporesof M^o/ymorp^ahavebuta single coat,
and their contents are bright yellow when
mature. When they germinate, the contents
are converted into chlorophyll, and the growth
commences by the production of a tubular
process from one side of the spore.

MARCHANTIA.

[ 414 ]

MARGARIC ACID.

It has been mentioned that M.polymorpha
does not fruit freely in the shade. Under
these circumstances it produces gemmce, con-
sisting of little, compressed, oblong masses
of cells, of green colour, capable of repro-
ducing the plant. These are found, when
mature, in elegant cup-like structures, with
toothed borders, sessile on the upper face of
the frond (figs..450, 454). The cup seems to

Fig. 454.

Marchantia polymorpha.

A collection of gemmae in their involucre.

Magnified 25 diameters.

be formed by a development of the superior
epidermis, which is raised up and finally
bursts and spreads out, laying bare the gem-
mae, produced from the internal parenchyma.
The gemmae consist at first of a single cell,
which divides so as to present an upper and
a lower (stalk) cell; the upper multiplies
until it becomes a cellular mass (fig. 455).

Fig. 455.

Marchantia polymorpha.

A vertical section of the same, with nascent gemmae.
Magnified 50 diameters.

The development of this structure presents
much analogy to that of the sori of the Ferns
with their indusia and sporanges.

The Marchantia also increase by innova-
tions, or lobes of the frond becoming de-
tached from those on which they originate.

These plants form most interesting objects

of microscopic investigation, in all parts of
their structure.

BIBL. Hook. Brit. Flor. ii. pt. 1. p. 105,
Engl. Botany, pi. 110; Mirbel, Reck. anat.
etphysiol. sur le Marchantia, Memoir es Acad.
Roy. Paris, xiii. pp. 337. 375 ; Nageli, Wur-
zel-haare du Marchantia, Linntea, xvi. 1842 ;
Henfrey, Dev. of Spores and Elaters of
Marchantia, Linn. Trans, xx. p. 103. pi. 11;
Thuret, Rech. sur les Antheridies, Ann. des
Sc. nat. 3 ser. xvi. p. 72. pi. 12. figs. 1-5.

MARCHANTIACE.E.— A tribe of Liver-
worts or Hepaticaceae, having broadish lobed
thalloid fronds, from the bifurcations of
which arise stems bearing variously arranged
sporanges containing spores mingled with
elaters, but destitute of a columella.

British Genera.

I. Marchantia. The fructiferous head of
the axis radiating. Perichaetes having from
one to six archegonia, alternating with the
rays of the fruit-head. Perigone 4-5-lobed.
Epigone persistent. Sporange bursting with
teeth, which are at length re volute.

II. Fegatella. Fructiferous head scarcely
thickened, umbonate. Perichaete absent.
Perigones tubular, obliquely split at the apex,
connate with each other and confused with
the axis. Epigone persistent. Sporange
bursting with 5 or 8 teeth, at length revo-
lute.

III. Rebouillia. Fructiferous head conical,
somewhat 5-lobed. Perichaete wanting.
Perigones bursting by a longitudinal slit,
distinct, adnate to the axis. Epigone per-
sistent. Sporange bursting irregularly at
the apex.

Nearly allied to these are several interest-
ing foreign genera, noticed under HEPATI-
CACE^, Grimaldia (figs. 336, 337), Fim-
briaria(ftgs. 338, 339), Lunularia (figs. 333-
335).

MARGARIC ACID and MARGARINE.
— The former general ingredient of the fatty
matters of both the animal and vegetable
kingdom, when crystallized from hot alcohol,
forms minute needles, either isolated or in
groups (PL 7- fig. 16 a). The crystals differ
from those of stearic acid, which form lan-
ceolate, single or aggregated plates (PL 7-
fig. 166).

Margarine crystallizes from a hot alcoholic
solution in fine needles, mostly grouped or
branched, sometimes surrounding globules
of oleine, or forming bulb-like aggregations
of needles (PL 7- fig- 15). It is sometimes

MARGINARIA.

[ 415 ]

MARSILEACE.E.

found crystallized within the cells of fatty
tissue (PI. 7. fig. 15 a).

BIBL. That of CHEMISTRY.

MARGINARIA, Bory.— A genus of Po-
ly podieae (Ferns), with the naked sori im-
bedded deeply in the backs of the veins and
venules. The sporanges are borne on long
pedicels, and are intermixed with articulated
paraphyses.

MARGINULINA, Ehr.— A genus of Fo-

RAMINIFERA (p. 270).

MARSILEA, L.— A genus of Marsileacese
(Flowerless Plants), growing in mud, by a
creeping rhizome, from which arise erect
filiform leaf-stalks, supporting a compound
four-lobed blade ; at the bases of the leaf-
stalks arise also stalked capsules, chambered
in the interior, being divided by one perpen-
dicular and many horizontal septa ; in these
chambers are found sacs (sporanges) con-
taining the spores. The spores are of two
kinds, the larger representing ovules, the
smaller pollen ; but while the former pro-
duce a single archegone in germination, like
those ofPilularia, the pollen-spores produce
numerous vesicles in their interior, which
become the parent-cells of sperinatozoids.
The capsules of Marsilea have a regular de-
hiscence when ripe, and the whole mass of
the spore-sacs is extruded on a thick gela-
tinous stalk-like process, produced from the
interior. As these plants do not occur in
this country, we do not enter very minutely
into their characters, especially as in all
essential respects they agree with PILU-

LARIA.

BIBL. See MARSILEACEJE.

MARSILEACE.E.— A family of Flower-
less plants possessing a distinct leafy stem,
composed of a small number of plants, of
minute dimensions, but of great interest in
a physiological point of view. They are all
aquatics, some growing in the mud in and
around ponds, others floating on the surface
of stagnant waters. Known perhaps only to
the botanist, they are distinguished from the
families to which their reproductive structures
ally them most closely, by the much more
perfect separation of these from the vegeta-
tive structure. They all bear distinct spore-
fruits or sporocarps, seated on a stalk arising
from the stem. These contain sporanges or
spore-sacs, differently arranged in the dif-
ferent genera, but agreeing in this respect,
that they contain spores of two kinds, ana-
logous to the two kinds of spore in Lyco-
podiacese, but differing in their mode of
development.

Pilularia globulifera is the only British
representative of this family ; a description
of its organization is given under the head
of PILULARIA. It agrees with Marsilea, a
genus occurring on the continent, in possess-
ing only one kind of sporocarp, which con-
tains spore-sacs, part of which contain ovu-
lary spores, part pollen-spores ; the principal
difference being that the sporocarps are of
more complex structure in Marsilea. Sal-
vinia, consisting of floating aquatic plants,
possesses two kinds of sporocarp, which may
be called male and female, and the same is
the case with Azolla ; the development of
the plants of the last genus, however, has
not yet been thoroughly elucidated.

The principal characteristics, in which all
these plants agree, consist in the possession
of free stalked sporocarps, quite distinct from
the leaves, and the production of two kinds
of spore, which agree in the history of de-
velopment. The small spores produce sper-
matozoids, formed in vesicles developed in
chambers into which the spores become di-
vided in germination. The large spores,
which are more highly organized than those
of LYCOPODIACE^E, produce in germination
a prothallium, somewhat like that of Lyco-
podiacese, inside the outer coat of the spore,
on which is developed a single archegonium
in Pilularia and Marsilea, several archegonia
in Salvinia. The conditions in Azolla at
this stage are unknown. The germ-cell of
the archegonium, fertilized apparently by
the spermatozoids, becomes developed in
situ into the new leafy plant, which was
thus formerly regarded as a product of the
simple germination of the spore. More de-
tailed particulars are given under the heads
of the genera. The distinctive characters of
the genera may be given as follows :

Genera.

* Stems creeping over mud, rooting ; sporo-
carps of one kind, containing spore-sacs
of each kind.

I. Pilularia. Leaves filiform. Sporocarps
globular, almost sessile, four-celled, contain-
ing the two kinds of spores in distinct sacs.

II. Marsilea. Leaves cruciately four-
lobed; lobes obcordate. Sporocarps stalked,
two-celled, the two cells divided transversely
into many smaller cells.

** Plants floating like Duckweed; sporo-
carps of two kinds.

III. Salvinia. Leaves opposite, small,
glandular, floating. Sporocarps on sub-

MASTIGOBRYUM.

[ 416 ]

MEASUREMENT.

merged, leafless branches, globular, with a
double wall and a central sporophore, some
containing racemosely-stalked sacs filled
with barren spores, others many simple
stalked sacs containing a solitary fertile
spore.

IV. Azolla. Leaves alternate, imbricated.
Sporocarps submerged, unlike externally : —
1. Stalked membranous sacs, irregularly
dehiscent, containing stalked sacs filled with
barren spores; 2. sessile, solitary or twin
cellular bodies, each consisting of a highly
developed fertile spore, approximating to the
condition of an ovule.

BIBL. Bischoff, Krypt. Gewdchse, Nurem-
berg, 1828, p. 63; Esprit Fabre, Ann. des
Sc. nat. ser. 2. vii. p. 221. pi. 12 & 13;
Nageli, Zeitschr. fur Wiss. Hot. Heft 1. p.
168, Ann. des Sc. nat. 3 ser. ix. p. 99. pi. 8 ;
Mettenius, Beitr. z. Kenntn. d. Rhizocar-
pen, Frankfort, 1846, Ueb. Azolla, Linncea,
xx. (1847), Ann. des Sc.nat. 3 ser. ix. p. Ill;
Schleiden, Grundz. d. Wiss. Bot. 3 ed. p. 104
(transl. Principles, p. 203) ; Meyen, Beitr.
z. Kenntn. der Azollen, Nova Acta, xviii. p.
507 ; Hofmeister, Vergleich. Unters. p. 103.
pi. 21 & 22; W. Griffith, on Azolla, Cal-
cutta Journal of Nat. History, July, 1844; R.
Brown, on Azolla, Flinders' Voyage, Botany,
612. pi. x.; Henfrey, Trans. Brit. Ass. 1851,
Ann. Nat. Hist. 2 ser. ix. p. 447.

MASTIGOBRYUM. See HERPETIUM.

MASTIGOCERCA, Ehr.— A genus of
Rotatoria, of the family Euchlanidota.

Char. Eye single and cervical; tail-like
foot styliform; carapace prismatic, with a
dorsal crest.

M. carinata (PL 34. fig. 46, side view).
Foot as long as the body ; aquatic ; entire
length 1-72".

BIBL. Ehrenberg, Infus. p. 460.

MASTOGONIA, Ehr.— A genus of Dia-
tomaceae.

Char. Frustules single ; valves dissimilar,
angular, mammiform, orbicular at the base,
free from umbilical processes, not cellular,
angles radiating. Fossil.

The (eight) species are interesting from
the structure of the two valves of the frus-
tules differing. Thus in one, M. crux, the
angles and rays are four in one valve, but
seven in the other ; in M. actinoptychus the
angles and rays are nine in one valve, and
thirteen in the other, and so on. Diameter
from 1-1600 to 1-360".

BIBL. Ehrenberg, Ber. d. Berl. Akad.
1844 ; Kiitzing, Sp. Alg. p. 25.

MATONIA, R. Brown.— A genus of

Cyathseous Ferns, with a curious stalked
and imbricat^ basin-like indusium (figs. 457,
458). Exotic.

Fig. 456.

Matonia pectinata.

Fig. 456. Part of a fertile pinna. Magn. 3 diams.
Fig. 457. Indusium opened at the side, showing thecse

in situ. Magn. 25 diams.
Fig. 458. The same with the thecse removed. Magn.

25 diams.

MAURANDYA.— A genus of Scrophula-
riaceae (Dicotyledonous Flowering Plants),
the testa of the seed of which is composed
of cells with spiral fibrous deposits, forming
an elegant microscopic object.

MEASUREMENT and MEASURES.—
In this article we shall consider the method
of measuring the magnifying power of a
microscope, of ascertaining the dimensions
of objects, and shall give a sketch of the
standard measures in which the dimensions
of objects are expressed.

Measurement of the magnifying power of
a microscope. — The apparent size which an
object will appear to possess under a micro-
scope will vary of course according to the
power of the object-glass and of the eye-
piece used, and the length of the body of
the microscope ; and it is a good plan to
determine the measurements once for all
in the case of the various object-glasses and
eye-pieces, keeping them written upon a
card, so that they may be readily accessible.

The apparatus requisite consists of a mi-
crometer-slide graduated into thousandths
of an inch, each tenth division being marked
by a longer line; or two separate slides,
one graduated into thousandths, the other
into hundredths of an inch ; and an ivory

MEASUREMENT.

[ 417 ]

MEASUREMENT.

scale graduated into inches, tenths, and
hundredths.

The simplest method is that by double
sight, as it is called. The micrometer slide
is placed upon the stage, the lines brought
into focus, and the image of one of the in-
terspaces, as seen upon the stage with the
open eye not used in looking through the
microscope, is measured with compasses.
By then dividing the measure of the image
of the space by the known measure of the
unmagnified space, the quotient is the re-
quired magnifying power. Thus, if the space
on the micrometer scale is equal to the
1- 100th of an inch, and the image of the
magnified spact corresponds to 5-10ths of
an inch, the space is magnified 50 times :
A-s-T^rrSO.

The same result may be obtained with the
aid of the camera lucida, by placing the
microscope horizontally, and its axis at a
distance from the table equal to the distance
between the focus of the eyepiece and the
stage ; the breadth of the image of a division
is then measured as before ; and this is the
best and most certain method.

The most important point in relation to
this subject is, that the joint of the micro-
scope shall be furnished with a stop or pin
(!NTR. p. xiii), by which the body may be
placed horizontally at once, so that all ob-
jects which are drawn under the same object-
glass and eyepiece may be magnified to the
same extent ; and this" should be determined
by the second of the above methods.

The obvious use of being acquainted with
the magnifying power of a microscope, is
that objects under examination may be
viewed by the same power as that with
which figures of them have been made, so
that the structure or appearance of the ob-
jects in the two cases may be compared.
We have elsewhere stated the importance of
expressing the magnifying power with which
figures of objects have been drawn (!NTR.
p. xxxix).

In the above estimation of the magnifying
power, one dimension only is taken into
account, viz. the breadth or diameter ; and
this is the ordinary manner in which the
magnifying power is taken ; objects are then
said to be magnified so many diameters, or
so many times linear. But objects are really
as much magnified in the other dimension,
or in their entire surface ; so that the true
expression of the amplification would be
given by multiplying that in one direction
by that in the other, or by itself, i. e. squaring

the linear magnifying power. This is called
the superficial measurement.

This proceeding, however, offers no advan-
tage, and is not in accordance with custom,
either in regard to the microscope or objects
in general. It is therefore never used except
for fraudulent purposes, to delude the un-
wary in the purchase of an instrument ; thus
supposing a microscope to magnify 40 dia-
meters, 40 X 40 = 1600 would express the
magnifying power in superficial measure.

Measurement of the size of objects. — This
is effected with the aid of a slide-micrometer
passed through two slits in the eyepiece
above the stop, and at the focus of the upper
glass of the eyepiece. The breadth of the
spaces between the lines must be such as to
give an even and minute fraction of an inch.
The value of the spaces will vary with the
power of the object-glass and eyepiece, so
that it must be determined in each case re-
spectively, and recorded. For measuring
small objects, the breadth of the spaces in
the eyepiece micrometer may be such that
twenty of them correspond to 1- 1000th of an
inch in the stage-micrometer slide, so that
the value of each division will be the
1 -20,000th part of an inch. It is seldom that
we have to measure objects so small as
this ; but the small size is of great advan-
tage, because in most cases it will happen
that the margins of the objects will coincide
exactly with some of the fines, whereby the
chance of error in computation will be
avoided. For larger objects, the spaces of
the eyepiece micrometer may be coarser.

The method of measuring scarcely requires
further explanation. Supposing, however,
that the divisions of the stage-micrometer
are equal to 1 -1000th of an inch, and those
of the eyepiece micrometer equal to
I -20,000th of an inch, i. e. twenty of them
cover one space in the former, an object
brought into focus and covering five of the
spaces of the eyepiece micrometer, will be
1 -4000th of an inch in diameter ; and so
for other dimensions. When the objects
are large, the compasses and the ivory scale
will suffice for their measurement; but
sometimes this may be conveniently done
under a low power, for the l-100ths of an
inch are not very clearly discernible to all
eyes.

In measuring objects, they must be co-
vered with thin glass, and not immersed in
too much liquid.

It is a matter of great difficulty, under
high powers, to adjust accurately the divi-

2E

MEASUREMENT.

[ 418 ]

MEASUREMENT.

sions of the eyepiece micrometer to those
of the stage-micrometer, or to the margins
of objects, by means of the rnoveable stage;
a very ingenious apparatus has been con-
trived by Mr. Jackson to overcome the diffi-
culty. It consists of a little brass frame,
in which the eyepiece micrometer slides
from side to side, the motion being commu-
nicated by the end of a screw working
against one end of the slide, and resisted at
the other by a spring; and as the magnifying
power with which the divisions of the eye-
piece micrometer are viewed is small, the
adjustment is easily and accurately effected.

Other micrometers, as the ' cobweb-micro-
meter/ are made ; but as they are very ex-
pensive and not necessary, we shall pass
them over.

Some authors express the measurement
of objects by means of a ruled scale appended
to the figures or plates of them, the scale
consisting of divisions of a stage-micrometer
of known value traced off under the same
power as the objects themselves ; or some-
times the divisions are ruled over the figures.
These methods are very objectionable, be-
cause the size of the objects cannot be ascer-
tained without measuring with compasses
and calculation, which is almost as bad as
the size being omitted altogether.

Whenever figures of objects are given, the
magnifying power with which they are drawn
should always be expressed in numbers near
the figures. Many or even most authors
omit all notice of dimensions, so that whe-
ther an object figured be as large as an ox
or as small as a mite, is known only to them-
selves and their friends; the student will
find for himself this to be the greatest diffi-
culty in identifying objects in the study of
natural history, because the visible structure
of objects varies according to the power
under which these are seen. Other writers
state the magnifying power in a note in the
substance of the book, or in some obscure
and inconvenient place.

Measures. — The measures in which the
dimensions of objects are expressed should
consist of parts of an English inch, and not
of a line. On the continent, fractions of a
millimetre, of a Paris or French line, and
of a Rhenish or Prussian line are used.
When fractions of a millimetre are adopted,
this is usually denoted by the addition of mm
to the figure or figures. In France the mil-
limetre and the Paris line are both used ; in
Germany fractions of a line are expressed ;
but whether this is the Paris line or the

Prussian line, we have never seen stated in
any of the works, although we believe the
Paris line to be generally signified.

The following data will be found useful in
reducing the foreign to the English mea-
sures : —

A millimetre = 0-0393707 English inch ;
or (roughly) rather less than l-25th of an
English inch.

A centimetre = 0-393707 Eng. inch ; or
(roughly) rather more than I -3rd Eng. inch.

A Paris line = 0-088815 Eng. inch; or
rather more than 1-llth Eng. inch, to which
vulgar fraction it is nearest.

To convert a foreign into the English
measure, the former must be multiplied by
its unit value ; thus, 0'25ram (millimetre) X
0-0393707 = 0-0098326/5 Engl. inch. But
in most cases a few decimal places only need
be observed. In this way, however, we get
a rather long sum, which may be avoided by
the use of the following Table, in which the

Table for conversion of foreign into English
measures.

Millimetres

Old Paris lines

Prussian lines

into
English inches.

into
English inches.

into
English inches.

1

2
3
4
5
6
7
8
9

•039370
•078741
•118112
•157483
•196853
•236224
•275595
•314966
•354337

•088815
•177630
•266445
•355260
•444075
•532890
•621705
•710520
799335

•085817
•171633
•25745
•343267
•429083
•51490

•600717

•686532
•77235

numbers in the first (or left-hand) column
correspond to the denominations expressed
in the uppermost (head) line of the three
broader columns, while the fractions oppo-
site these numbers denote their values in
parts of the denominations of the lowermost
(head) line. Thus, I™* = 0-039370 Eng.
inch; 3mm= 0-118112; 2 Prussian lines
=0-171633 Eng. inch, and so on. In using
this table, the decimal fraction to be con-
verted into parts of an English inch must
be broken up into its decimal parts, and
each valued separately from the table ; thus,
to convert 0-/5mm into a fraction of an
English inch —

0-7mm = 0-0275595 \ „ ^ . , , ,
0-05mm = 0-00196853 j(b^ the table)t

0-75mm = 0-02952803 Eng. inch.

MEDULLA.

[ 419 ]

MEDULLARY RAYS.

The only circumstance which requires at-
tention in the use of this table is the position
of the decimal point. Thus, in the above
measure of 0'75mm, which, when broken up,
makes 07mm and 0'05mm, if the first value
(0'7) had been 7'0, the value in Eng. inch
would have been, according to the table,
0-275595 Eng. inch ; but this is 10 times too
much, or = 7 whole millimetres ; hence the
shifting of the decimal point, and so on. To
express the mode of proceeding by rule, — the
decimal point in the fraction of an English
inch given by the table should be shifted to
the left and as many cyphers added as there
are decimal places in the foreign measure.

BIBL. That in the INTRODUCTION, p.xl;
Robertson, Edinb. Monthly Journ. 1852,
p. 95 ; Harting, ibid. p. 453.

MEDULLA OF PLANTS.— The name ap-
plied by the older authors to the pith of Dico-
tyledon (fig. 4 59 M), from a supposed analogy

Fig. 459.

Horizontal section of a yearling shoot of a Dicotyledon.
M, medulla ; RM , medullary rays ; T, medullary sheath.

Magnified 25 diameters.

with the medulla spinalis of animals . It affords
very excellent subjects for preparing sections
of regular parenchymatous tissues, as in the
elder, and in the tall annual stems of
many of the larger perennial herba-
ceous plants. It sometimes becomes
curiously chambered as it grows older,
as in the walnut and the jasmine, very
frequently, however, it decays away
after a time, leaving the centre of the
stem hollow ; this same hollow con-
dition occurs early in fistular stems,
such as those of the Umbelliferae,
from the pith being torn up by rapid
expansion of the wood. The Mono-
cotyledons do not generally possess
a definite pith ; the cellular mass, in
which the isolated FIBRO-VASCULAR
BUNDLES are imbedded, answers to
a diffused pith, or rather to the pith
and medullaryrayscollectively. It may

be seen well in sections of the flowering-stem of
lilies (fig. 460 M}. A more definite medulla
occurs in the stem (and in the leaves) of the

Fig. 460.

Horizontal section of a flowering- stem of a lily. M,
medulla ; F, fibro-vascular bundles.

Magnified 5 diameters.

rushes and sedges, where also the cells are often
of most elegant radiating forms, leaving large
air-canals between them (PL 38. fig. 18).
The pith of a Dicotyledonous stem loses
itself gradually in the terminal bud, where it
is confounded with the nascent wood and
cortical layers. In this stage its cells pos-
sess an active vitality, which, however, is
soon lost.

BIBL. General Works on Structural
Botany.

MEDULLARY RAYS.— The processes
of cellular tissue extending out from the
pith between the fibro-vascular bundles of a
Dicotyledonous stem in the first year of
growth (fig. 459 R M), together with addi-
tional interposed rays formed between
the older in each succeeding annual layer of
wood (fig. 461 1, 2, 3, 4). The tissue of
these rays generally becomes much com-
pressed during growth, but their size and

Fig. 461.

Section of a four- years' old shoot of the Cork oak. M, pith ;
1 , 2, 3, 4, medullary rays of successive years ; P. C, liber layers ;
S, cork layers.

Magnified 20 diameters.

2E2

MEDULLARY SHEATH. [ 420 ]

MELANCONIEI.

the degree of development differ much in
different cases. In radial sections of Dico-
tyledonous wood they often appear distinctly
to the naked eye, from the direction of their
cells being different from that of the woody
fibre, and therefore reflecting light dif-
ferently ; this causes the " silver grain " as
it is called of oak-panels, &c. ; in tangental
sections of the trunk, the ends of the me-
dullary rays usually appear as short, more
or less regular narrow streaks.

MEDULLARY SHEATH.— The earliest
layer of fibro-vascular tissue developed in a
Dicotyledonous stem, consists ordinarily of
spiral vessels, these forming the foundation
of the wood-bundles (fig. 459 T). As the
latter stand in a circle round the pith, their
internal vascular layers of course form col-
lectively a continuous cylindrical envelope
to the pith ; this is called the medullary
sheath. It is absent in some Dicotyledonous
stems, for example in the Orobanchaceae.

MEESIA,Hedw.— A genus of Bartramioid
Mosses; one species, M.uliginosa(=Bryum
trichodes), certainly British; another, M.
longiseta, doubtful.

MEESIACE^E.— A tribe of Bartrami-
oid Mosses, containing two genera, of which
there are but few British representatives :

I. MEESIA. Calyptra dimidiate. Peri-
stome double. External, of sixteen very
short, broad, obtuse teeth, with a median
line or fissile. Internal : a short membrane
produced into sixteen cartilaginous teeth
with a median line, or split and perforated ;
teeth often coherent with interposed, more
or less perfect, mostly irregularly coherent
appendiculiform cilia. Areolation of the
leaf of one character.

II. PALUDELLA. Calyptra dimidiate.
Peristome double, both of sixteen teeth,
resembling that of Bryum, but the inner
without cilia. Inflorescence dioecious. Areo-
lation of the leaves dimorphous, lax and
dense.

MEGALOTROCHA, Ehr.— A genus of
Rotatoria, of the family Megalotrochaea.

Char. Eyes two, red, sometimes disap-
pearing with age.

Rotatory organ two-lobed or horse-shoe
shaped ; teeth in rows.

M. albo-flavicans, E. (PL 35. fig. 1). Co-
lourless and unattached when young, yellow-
ish and grouped in radiant clusters when old ;
aquatic; length of individuals 1-36"; of the
clusters 1-6".

The ova remain some time attached to the
parent by a cord.

M. velata, Gosse.

BIBL. Ehrenberg, In/us, p. 396 ; Gosse

Ann. Nat. Hist. 1851. viii. p. 198.

MEGALO
of Rotatoria.

MEGALOTROCHAEA

i. p. iy».
, Ehr.—

A family

Char. Neither envelope nor carapace
present ; rotatory organ simple, notched or
sinuous at the margin.

Three genera :

Eyes none 1 . Cyphonautes.

Eyes present.

Eye one 2. Microcodon.

Eyes two 3. Megalotrocha.

BIBL. Ehrenberg, In/us, p. 394.

MEGAMERUS, Duges.— A genus of
Arachnida, of the order Acarina, and family
Trombidina.

Char. Palpi with a claw, long, free ; body
constricted ; coxae distant ; legs ambulatory,
femora, especially of the fourth pair, very
large, seventh joint short; larvae hexapod,
resembling the adults.

Mandibles forcipate.

Eight species. They live in damp, shady
places, and move rapidly.

T. celer (PI. 2. fig. 33 : a, labium ; b,
palp). Minute; abdomen oblong; the sides
narrowed posteriorly, covered with hairs and
with three terminal setae ; labium bifid ;
mandibles with a moveable, elongated,
pointed and curved claw.

PI. 2. fig. 33 c, mandible of M. roseus.

BIBL. Duges, Ann. d. Sc. nat. 2 ser. ii.
p. 50; Gervais, Walckenaer's Arachn. iii. 169.

MELAMPSORA. See UREDO.

MELANCONIEI.— A family of Conio-
mycetous Fungi growing beneath the epi-
dermis of leaves and bark. They are at first
little tubercles on the surface of a white
mycelium, without an orifice, subsequently
they become hollow and fleshy, and the
interior becomes coated with filaments, each
terminating in a spore. The tubercles mean-
time enlarge, raise up the epidermis, and
appear there in groups with irregular orifices
opening outwards. The conceptacles are
closely crowded, and form blackish patches
on the leaves or bark, and when mature the
spores are expelled, mixed with filaments in
a gelatinous condition, and in the form of
threads or ribands. The spores differ in shape.

The genera present forms which appear to
belong in common to Ascomycetous genera,
for example Cytispora is apparently a form
of Sphceria, &c. (See ASCOMYCETES, Co-

NIOMYCETES.)

Synopsis of British Genera.
I. MELANCONIUM. Conceptacle mem-

MELANCONIUM.

[ 421 ]

MELOPHILA.

branous, central heterogeneous column,
branching irregularly at the summit ; spores
ovate, simple.

II. STILBOSPORA. Conceptacle mem-
branous, without a central column, bursting
irregularly at the summit ; spores oblong,
transversely septate or cellular.

III. DIDYMOSPORIUM. Like the prece-
ding, but with didymous spores.

IV. CYTISPORA. Conceptacle celluloso-
multilocular, membranous, united above,
bursting by a common elongated ostiole;
spores simple, expelled in a gelatinous
riband-like mass.

V. CEUTHOSPORA. Conceptacle mem-
branous, solitary, immersed in a common
conceptacle, horny without, fleshy within ;
ostiole simple ; spores ovate, simple.

VI. NEMASPORA. Conceptacle mem-
branous, immersed in a grumous common
receptacle, encircling a heterogeneous colu-
mella, conjoined at the apex, dehiscing in a
common tube, hence with a solitary ostiole;
spores spindle-shaped, simple.

VII. CORYNEUM. Sporophores erect,
closely crowded into a disk, breaking out
upon the surface of the epidermis, bearing
spindle-shaped multiseptate spores.

VIII. BACTRIDIUM. Mycelium creeping,
branched, closely septate; spores spindle-
shaped, multiseptate, with transparent ends,
filled in the middle with grumous matter.

IX. ERIOSPORA. Stroma multicellular,
cells (conceptacles) globose, expelling by a
common pore very slender filiform spores,
originally attached in fours to sporophores.

X. CHEIROSPORA. Perithecia absent (?).
Spores simple, naked, crowded in bunches
at the apex of a simple filiform pedicel;
normally in moniliforin rows.

XL DISCELLA. Perithecium sub-simple,
sometimes obsolete or altogether deficient
above, hence excipuliform; spores elongated,
simple or uniseptate, borne on sporophores.

MELANCONIUM, Lk. — A genus of
Melanconiei (Coniomycetous Fungi), so
called from forming a kind of black rust on
branches of trees, reeds, &c. Several spe-
cies have been found in Britain. The com-
monest is M. bicolor, Nees (Didymosporium
elevatum, Br. Fl.), on twigs of birch. Fries
places also Cryptosporium vulgare here. (See
CRYPTOSPORIUM.)

BIBL. Berk. Brit. Flora, ii. pt. 2. p. 357 ;
Ann. Nat. Hist. vi. p. 438 ; Fries, Summa
Veg. p. 508.

MELASMIA, Lev. — A supposed genus
of Sphajronemei (Coniomycetous Fungi),

but apparently only a stylosporous form of
RHYTISMA. M. acerinum occurs on the
leaves of the sycamore, forming black spots,
sometimes as much as 1-2" in diameter.

BIBL. Berk. Ann. Nat. Hist. 2nd ser. v.
p. 456 ; Leveille, Ann. des Sc. nat. 3 ser. v.
p. 2/6; Fries, Summa Veget. p. 423.

MELICERTA, Schrank.— A genus of
Rotatoria, of the family Flosculariaea.

Char. Bodies each in an isolated tubular
carapace or urceolus; rotatory organ four-
lobed ; eyes two, at least when young.

M. ring ens (PL 35. fig. 3 ; fig. 4, animal
removed from the sheath ; fig. 6, jaws).
Carapace conical or cylindrical, brownish,
composed of numerous rounded or discoidal
bodies agglutinated together; body colour-
less. Aquatic; length of carapace 1-36 to

Frequentlyfound attached to water-plants,
especially Potamogeton crispus.

BIBL. Ehrenberg, In/us, p. 404; William-
son, Micr. Journ. 1852.

MELOLONTHA, Fabr. (Cock-chafer).
— A genus of Coleopterous Insects, of the
family Melolonthida3.

The structure of M. vulgaris, the common
cock-chafer, has been elaborately studied
and described.

BIBL. Suckow, Naturgeschichte des Mai-
kdfers-, Straus Durckheim, Consider. general,
s. V Anatomic comparee des Insectes ; West-
wood, Introduction, fyc.

MELOPHILA, Nitzsch (Melophagus,
Latr.). — A genus of Dipterous Insects, of
the family Hippoboscidse.

Char. Head posteriorly received in an
excavation of the thorax ; wings and halteres
absent ; last joint of the tarsus largest.

M. ovinus, the sheep-tick (PI. 28. fig. 23).
Common upon sheep. Antennae small, sunk
in an eye-like cavity of the head; eyes small,
oval, resembling two groups of ocelli ; setae
three, enclosed in two sheath-like, hairy,
unjointed organs (labial palpi), resembling
otherwise those of Pulex, and arising from
the sides of a triangular labium. Legs
robust ; tarsi with two stout serrated claws,
each having at its base a blunt process;
accompanying the claw is an elegant feathery
tarsal brush ; and on the under side of the
last tarsal joint is a bilobed pectinate organ.

BIBL. Lyonet, Reck. s. V Anatomic et les
metamorphoses, fyc. Paris, 1832 ; Gurlt, Ma-
gaz.f. d.gesammte Thierheilkunde, 1843. ix.;
Westwood, Introduction, fyc. ; Curtis, Brit.
Entom. 142; Dufour, Ann. d. Sc. nat.
1845. iii.

MELOSIRA.

[ 422 ]

MEMBRANES.

MELOSIRA, Ag. (Gallionella, Ehr.).—
A genus of Diatomacese.

Char. Frustules cylindrical, discoidal or
subsphericaJ, united into jointed filaments.

Hoops often very broad, to adapt themselves
to the breadth of the new frustules. In some
species a narrow projecting ridge or keel
encircles the valves near their ends. Valves
covered with depressions which are mostly
very minute and invisible under ordinary
illumination ; in the side view these some-
times have a radiate arrangement. In some
species the margins of the ends (side view)
of the frustules have coarse and distinct
radiating striae, their nature undetermined.

This genus has been subdivided ; by
Ehrenberg and Kiitzing into Lysigonium, in
which the keel is present ; and Gallionella
(proper), in which this is absent : again by
Thwaites into Aulacosira, in which the frus-
tules are cylindrical, surrounded transversely
by two furrows, with rounded (convex) ends,
but no line for division; Orthosira,in. which
the frustules are exactly cylindrical (with
flat ends), exhibit the transverse line of divi-
sion, and have spherical or subspherical
internal cavities ; and Melosira (proper),
in which the frustules are convex at the ends,
and have the central line for division ; inclu-
ding also the varieties in the reproduction

(DlATOMACE^S, p. 201).

British species.
* Marine.

M. nummuloides, Kg. (PI. 13. fig. 5 a ; b,
a frustule more magnified). Prepared frus-
tules colourless, a distinct keel present;
valves not striated by ordinary illumination ;
breadth 1-1500 to 1-1200".

This common species forms long, slightly
curved chains, and on account of the great
breadth of the frustules, shows well the
various stages of subdivision. The filaments
are sometimes stipitate.

M. moniliformis, Ag. (M. Borreri, Grev.).
Prepared frustules dark brown, ends rounded,
entire surface punctate (ordin. ilium.), no
striae nor keel present; breadth 1-850 to
1-500".

M. Dickiei (Orthosira Dickiei, Thw.)
(PI. 13. fig. 15 a, front view, b, side view).
Filaments short, frustules nearly colourless,
ends flat, no striae nor keel (ord. ilium.),
valves thickened, so as to render the cavity
of the frustules rounded; breadth 1-1500 to
1-1200".

The remarkable formation of sporangia in
this species (PL 6. fig. 9) is noticed under
DIATOMACESE, p. 201.

* Aquatic.

M.varians (PL 13. fig. 6, front view ; a, side
view, markings omitted). Frustules colour-
less, ends slightly convex and striated at the
margin (ord. ilium.), keel absent ; breadth
1-1500 to 1-1200". The end view of the
frustules resembles that of Cyclotella.

Formation of sporangia shown in PL 6.
fig. 8 a, b, sporangial frustule.

M. arenaria. Ends of frustules flat and
striated at the margin (ord. ilium.), the striae
appearing also in the front view ; keel
absent ; frustules broader than long ; breadth
1-660 to 1-260".

M. crenulata, Kg. (Aulacosira crenulata,
Thw. ; M. orichalcea, Ralfs) (PL 6. fig. 7 «
forming sporangia ; b, ,c, sporangial frustules).
Differs from the last in its less diameter, and
the frustules being two or three times as
long as broad ; breadth 1-1400".

See PODOSIRA.

BIBL. Kiitzing, Bacill. p. 52; and Sp. Alg.
p. 27; Ralfs, Ann. Nat. Hist. 1843. xii.
p. 346; Thwaites, ibid. 1848. i. p. 168.

MEMBRANES, UNDULATING.— These
are said to be simple membranous bands, one
margin only of which is attached, the other
being free, and exhibiting an undulatory mo-
tion. They are allied to and answer the same
purpose as cilia. They are described as occur-
ring upon the spermatozoa of salamanders
and tritons; as forming longitudinal pro-
cesses in the water-vessels of some Annelida,
as the Turbellaria; also as existing in
some Infusoria, as Trichodina, and some
Rotatoria.

Some authors have regarded them as con-
sisting of rows of cilia or a spiral fibre, and
not membranes. They are most easily exa-
mined in the spermatozoa of the triton, in
which we believe the appearance of an un-
dulating membrane arises from the existence
of a fibre coiled around the spermatozoa
(PL 41. fig. 17), and undulating throughout
its length. This opinion is based upon the
circumstance, that if the coiled fibre be de-
tached from the proper filament of a sper-
matozoon or spermatozoid, no margins of
the (lacerated) membrane can be detected,
other than that visible at first, and which
really represents the coiled fibre.

This is, however, an interesting subject
for further investigation. Siebold, who has
paid most attention to it, remarks that Try-
panosoma, Gruby, a supposed entozoon
found in the blood of frogs and fishes, is not
an independent animal, but simply an undu-
lating membrane swimming freely.

MENISCIE.E.

[ 423 ]

MESOCARPUS.

BIBL. Siebold, Sieb.u.Kolliker'sZeitschr.
Bd. 2. p. 356, and the Bibl. therein.

MENISCIEJL— A sub-tribe of Polypo-
dseous Ferns, without an indusium, contain-
ing the genus —

MENISCIUM, Schreb.— Son reniform,
seated on the backs of the transverse ve-
nules. Veins pinnate, anastomosing.

MENISPORA, Pers.— A genus of Muce-
dines (Hyphomycetous Fungi), one species
of which, M. lucida, Corda, is recorded as
British, growing on decayed wood.

BIBL. Berk, and Broome, Ann. Nat. Hist.
2 ser. vii. p. 101 ; Corda, Icones, i. pi. 4.
fig. 223.

MENTHA, L.— The genus of Labiatae
(Dicotyledonous Flowering Plants) to which
belong the Peppermint, Pennyroyal, Spear-
mint, and other mints. These owe their
aromatic properties to GLANDULAR HAIRS
upon the epidermis.

MERENCHYMA.— A name applied by
some authors to the form of vegetable cellu-
lar tissue where the cells are of circular,
ellipsoidal, or irregularly rounded outline;
ordinarily known as " lax parenchyma."

MERIDION, Leibl.— A genus of Diato-
macea3.

Char. Frustules (in front view) wedge-
shaped, united laterally so as to form seg-
ments of circles or spiral bands. Aquatic.

Frustules in side view obovate, and fur-
nished with coarse transverse striae visible
under ordinary illumination, and which ex-
tend into the front view.

Kiitzing distinguishes Meridian, in which
the frustules form a spiral (helical) band,
from Eumeridion, in which they form a con-
volute band.

Meridian circulare, Ag. (PI. 13. fig. 7;

a, front view; b, side view). Frustules in
side view simply obovate, forming a spiral
(helical) band or filament; length of frus-
tules 1-600 to 1-375".

Meridian constrictum, Kg. (PI. 12. fig. 28,
filament flattened and frustules (front view)
separated by drying ; a, convolute filament ;

b, side view). Frustules in side view con-
stricted near the broad end, attenuate to-
wards the narrow end, and attached to a
hemispherical stipes or cushion.

BIBL. Kiitzing, Bacill. p. 41, and Sp.
Alg. p. 10; Ralfs, Ann. Nat. Hist. 1843.
xii. p. 457.

MERISMOP^DIA, Meyen. See SAR-
CINA and GONIUM.

MERMIS, Duj — A genus of Entozoa.

M. nigrescens resembles Gordius, but dif-

fers from it principally in the vulva of the
female being transverse and situated near
the anterior end of the body, whilst in Gor-
dius this is placed at the posterior end.
Eggs black.

It is found in the newly dug-up damp
earth of gardens, and in the intestines of
insects.

BIBL. Dujardin, Ann. des Sc. nat. 2 se'r.
xviii. p. 129, and Hist. nat. d. Helminthes,
p. 294; Siebold, Entomolog. Zeitung, 1842.
p. 146.

MERULIUS, Hall.— A genus of Agaricini
(Hymenomycetous Fungi), distinguished by
the veiny or sinuously plicate folds of the
hymenium, these folds not being distinct
from the flesh of the pileus, and forming
angular or serrated pores. M. lacrymans
is the dry-rot fungus. The mycelium is
composed of filaments creeping in the sub-
stance of the infected wood, disorganizing
and feeding on this as it decays. The fruit
is at first white and cottony, forming an
effused pileus from 1 to 8" broad, subse-
quently ferruginous or deep orange. The
irregular folds finally discharge a watery
liquid, whence the name.

BIBL. Berk. Brit. Flora, ii. pt. 2. p. 129;
Sowerby, Fungi, pi. 113.

MESOCARPUS, Hassall (Spharocarpus,
Kiitz.). — AgenusofZygnemace8e(Confervoid
Algae), with evenly distributed cell-contents,
producing in conjugation a cross branch, in
which is formed a round spore. It often
happens that all the successive members of
a long series of cells conjugate with another
similar series, so as to produce a ladder-like
body, the "rounds" of which are formed of
the transverse processes (trabecults, Kiitz.).
The only kind of reproduction yet observed
is that by the spores formed in the transverse
branch from the conjoined contents of two
cells, but it is probable that zoospores and
encysted conditions of these occur, as in
SPIROGYRA and MOUGEOTIA. The stellate
encysted bodies found in most of the allied
plants have been seen in M. scalaris by
Thwaites. Thwaites also observed a division
of the contents of the spore into four parts,
such as occurs sometimes in (EDOGONIUM.

1. M. scalaris, Hass. (fig. 138. p. 166).
Sterile filaments 1-1800 to 1-1440" in dia-
meter, 6 times as long; sporanges oval or
round. Hass. pi. 42.

2. M. depressus, Hass. Sterile filaments
1-2880 to 1-2400", 6to8 times as long; spores
globose or elliptical. Hass. pi. 44. fig. 1.

M. intricatus, Hassall, is apparently the

MESOCENA.

[ 424 ]

METZGERTA.

same as M. scalaris ; all the other forms
may be brought under M. depressus.

BIBL. Hassall, Brit. Fr. Alg. p. 166.
pi. 41-45; Kiitzing, Sp. Alg. p. 435, Tab.
Phyc. v. (Sphcerocarpus] pi. 5-/; Thwaites,
Ann. Nat. Hist. xvii. 262.

MESOCENA, Ehr.— A genus of Diato-
maceae, according to Ehrenberg and Kiitzing.

The bodies referred to this title consist of
single siliceous rings, oval or angular frame-
works, without a centre, and mostly with
external and sometimes internal spines ari-
sing from them. They have no resemblance
in structure to the frustules of the Diato-
maceae; they are fossil (marine), and the
organic portion is unknown.

Several species are distinguished, which it
can be of no interest to describe ; the cha-
racters are founded upon the form, number
of angles and spines.

Whether they are spicula of Echinoder-
mata or not, remains to be decided. Diame-
ter from 1-750 to 1-400".

M. octogona, Ehr., PI. 19. fig. 1.

BIBL. Ehrenberg, Ber. d. Berl. Akad.
1840; Kutzing, Bacill. 139, and Sp. Alg.
p. 142.

MESOGLOIA, Ag.— A genus of Chorda-
riaceae (Fucoid Algse), with filiform, much-
branched fronds, of gelatinous character;
the axis of the filaments composed of inter-
lacing longitudinal cells, with gelatinous
interposed matter; the periphery of radia-
ting, dichotomous, coloured filaments. The
fructification consists of oosporanges and
trichosporanges ; the former are ovate sacs
(fig. 462) occurring attached to the ramuli

Fig. 462.

Mesogloia vermicularis.

Peripheral ramuli, with oosporanges and the filaments

upon which the trichosporanges arise surrounding them.

Magnified 50 diameters.

of the periphery ; the trichosporanges are

produced by ramifications of other ramuli
surrounding them (fig. 462). Both kinds
produce ciliated zoospores, which germinate.
M. vermicularis (figs. 462, 463), an olive-
Fig. 463.

Mesogloia vermicularis.

Portion of a filament.

Magnified 10 diameters.

green or yellowish frond, 6" high, is com-
mon on rocks and stones between tide-
marks. M. virescens, a smaller species, is
not uncommon.

BIBL. Harvey, Brit. Mar. Alg. p. 47.
pi. 10 B, Phyc. Brit. pi. 31 & 83; Thuret,
Ann. des Sc. not. 3 ser. xiv. p. 237. pi. 27.

METAXYA, Presl.— A genus of Cyathre-
ous Ferns. Exotic.

METEORIC PAPER. See PAPER,

METEORIC.

METOPIDIA, Ehr.— A genus of Rotato-
ria, of the family Euchlanidota.

Char. Eyes two, red, frontal ; foot forked ;
carapace depressed or prismatic; anterior
and upper part of head naked or uncinate ;
no hood. =Lepadella with two frontal eyes.

Lorica closed beneath. The characters are
doubtful. In one species, the uncination
appears (from Ehrenberg's figures) to arise
from the so-called respiratory tube, and
in another from the head being taper and
curved (M. tripterd).

M. triptera (PI. 35. fig. 7). Carapace
ovate, acutely trilateral, crested on the back.
Aquatic; length 1-288 to 1-144".

Two other species, E., to which Gosse
adds two.

BIBL. Ehrenberg, In/us, p. 477 ; Gosse,
Ann. Nat. Hist. 1851. viii. p. 201.

METZGERIA, Raddi.— A genus of Pel-
liese (Hepaticaceae), comprehending Junger-
manniafurcata, L.&ndJ.pubescens, Schrank,
growing on trunks of trees, rocks, &c. in very
moist places. The fronds of both are linear-

MICA.

[ 425 ]

MICROGONIDIA.

dichotomous, membranous, and ribbed. M.
furcata is hairy beneath, and smooth above]
M.pubescens hairy on both sides, and larger.
In addition to the sporanges, these plants
are increased by gemmae formed in patches
on the attenuated lobes of sterile fronds.

BIBL. Hook. Brit. Flor. ii. pt. 1. 131,
Brit. Jungermann. pi. 55. 56 & 73; Endli-
cher, Gen. Plant. Supp. 1. p. 1338; Hof-
meister, Vergleich. Untersuch. p. 10. pi. 4.

MICA. — This mineral substance, which is
often erroneously called talc in the shops,
was formerly used for covering mounted
objects, but is now replaced by thin glass.
It is, however, occasionally useful in apply-
ing a red heat to objects, as Diatomaceae,
&c., where it is required not to change the
position of the object. It often contains
crystalline and crystalloidal inorganic mineral
substances, as metallic oxides, &c., of in-
teresting appearance.

MICRASTERIAS, Ag.— A genus of Des-
midiacea3 (Confervoid Algae).

Char. Cell single, lenticular, deeply divided
into two lobed segments; lobes inciso-dentate
(rarely only bidentate), and generally radia-
ting.

Sporangia spherical, with stout spines (PL
10. fig. 12).

Thirteen British species (Ralfs).

M. denticulata (PL 10. fig. 11, undergoing
division ; fig. 12, sporangium). Cell cir-
cular, surface smooth ; segments five-lobed ;
lobes dichotomously divided, ultimate sub-
divisions truncato-emarginate, with rounded
angles. Length 1-113 . Common.

M. rotata (PL 10. fig. 13). Cell circular,
smooth; segments five-lobed; lobes dicho-
tomously incised, ultimate subdivisions bi-
dentate. Length 1-91". Common.

BIBL. Ralfs, Brit. Desmid. p. 68.

MIGROCLADIA, Grev.— A genus of
Ceramiaceae (Florideous Algae), containing
one rare British species, M. glandulosa,
with a dichotomously branched, filiform,
compressed frond 1 to 2" high, of a bright
rose colour. Its fructification consists of ( 1 )
roundish, sessile involucrated favellse with
spores, and (2) tetraspores (tetrahedrally
arranged) imbedded in the ramules.

BIBL. Harvey, Brit. Mar. Alg. p. 160.
pi. 22 B, Phyc. Brit. pi. 29; Grev. Alg.
Brit. t. xix.

MICROCODON, Ehr.— A _ genus of Rota-
toria, belonging to the family Megalotro-
chaea.

Char. Eye single ; no carapace ; foot sty-
liform. Jaws two, each with a single tooth.

M. Clams (PL 35. fig. 8). Body campa-
nulate, foot equalling or exceeding the body
in length. Aquatic. Length 1-288 to 1-216 .

BIBL. Ehrenberg, In/us, p. 395.

MICROCOLEU S, Desmaz. ( Chthonoblas-
tus, Kiitz.). — A genus of Oscillatoriaceae
(Confervoid Algae), with fronds forming strata
on moist ground, paths, mud, &c. These
plants may be described as bundles of Oscil-
/atona-filaments enclosed in a common
gelatinous sheath, which is simple or irregu-
larly dichotomously branched, and forms
twisted interwoven masses. The structure
of the filaments appears to be identical with
that occurring in OSCILLATORIA, described
under that head; the filaments oscillate;
the mode of origin of the enclosing sheath is
obscure, but it would appear to be formed
of the gelatinous half- dissolved outer mem-
branes of the enclosed filaments. No for-
mation of spores or gonidia has been de-
scribed. M. repens, Harv. (PL 4. fig. 9 a,
the open end of a sheath), is very common
on damp paths, &c., its sheaths are branched;
M. anguiformis, Harv., occurs on the mud of
brackish pools ; its sheaths are said to be
simple. M. gracilis, Hassall, said to be
found in similar situations, has no character
attached to it.

BIBL. Harvey, Brit. Mar. Alg. p. 227.
pi. 26 D, Phyc. Brit. pi. 249 ; Hassall, Br.
Freshw. Alg. p. 260. pi. 70; Kutz. Tab.
Phyc. i. pi. 54-58.

MICROCYSTIS, Kiitz.— A genus of Pal-
mellaceae (Confervoid Algae), but a doubtful
object, and possibly merely a resting form
of EUGLENA.

BIBL. Kiitzing, Linncea, viii. p. 342;
Spec. Alg. p. 208, Tab. Phyc. pis. 8, 9.

MICROGLENA, Ehr.— A genus of Infu-
soria, of the family Monadina, E.

Char. Tail absent; body truncated in
front, with a single flagelliform filament ; a
red eye-spot present.

Probably the spores of Algae.

M. punctifera (PL 24. fig. 43 a). Body
yellow, ovate, subconical, attenuate poste-
riorly,red eye-spot accompanied bya blackish
frontal spot (in Ehrenberg's figures, some
have one, some two red eye-spots). Aquatic;
length 1-620".

M. monadina (PL 24. fig. 43 b). Body
ovate, equally rounded at both ends, bright
green, eye-spot red and single. Aquatic;
length 1-1150 to 1-620".

BIBL. Ehrenberg, Infus. p. 25.

MICROGONIDIA. — See MACROGO-

NIDIA.

MICROHALOA.

[ 426 ]

MILK.

MICROHALOA, Kiitz.— A genus of Pal-
mellacese (Confervoid Algae). — An obscure
product. Kiitzing states that Hassall's
Sorospora virescens belongs here. There
does not seem to be any ground for separa-
ting this from PALM EL LA.

BIBL. Kiitz. Sp. Alg. p. 207, Tab. Phyc.
pis. 6, 7 ; Hassall, Brit. Fr. Alg. p. 326.
pi. 78. fig. 8 a.

MICROMEGA, Ag.— A genus of Diato-
maceae.

Char. Frustules arranged in longitudinal
rows within gelatinous tubes or surrounded
by slender curved or crisped fibres ; these
being enclosed in other gelatinous tubes,
forming filiform branched fronds; valves
resembling those of Navicula. Marine.

Kiitzing notices the occurrence of spo-
rangia or sporange-like bodies (spermatia)
filled with the frustules, within the substance
of the sheaths, and formed " from the dila-
tation of the naviculae " (frustules) ; but the
exact nature of the process is not described
nor understood. This formation of brood-
sporangia, as they might be called, would
appear to resemble that occurring in the
Desmidiacese (PI. 6. fig. 3 Ac?).

Kiitzing describes twenty-eight species,
and divides them into two sections ; in one
the filaments being slender and capillary,
in the other rigid, cartilaginous and thicker.

M.parasiticum (PI. 13. fig. 8; b, portion
of a filament magnified ; c, side view, d,
front view of frustule). Filaments slender,
wavy, tufted, cartilagino-gelatinous, yellow-
ish (sometimes brown), much branched,
capillary ; frustules crowded ; length of
frustules 1-1380".

Parasitic upon larger marine algae.

BIBL. Kiitzing, Bacill. p. 116, Sp. Alg.
p. 105.

MICROMETER. See INTRODUCTION,
p. xxiv, and MEASUREMENT.

MICROPERA, Lev.— A genus of Sphae-
ronemei (Coniomycetous Fungi), of which
one species is described as British, M. dru-
pacearum (Cenangium Cerasi, junior, Fr.,
Sphceria dubia, Pers.), growing on dead
branches of the cherry-tree. It forms
whitish tubercles which split the bark trans-
versely, composed of somewhat cylindrical
conceptacles, conjoined at the base, the
white mealy ostiole projecting; the linear
spores are yellowish and curved at the apex.

BIBL. Berk, and Broome, Ann. Nat. Hist.

2 ser. v. 380; Leveille, Ann. des Sc. nat.

3 ser. v. p. 283 ; British Flora, ii. pt. 2.
p. 211.

MICROSCOPE.— The first twenty-six
pages of the INTRODUCTION consist of
remarks upon the microscope and micro-
scopic apparatus.

MICROTHECA, Ehr.— A marine organ-
ism of doubtful nature, placed by Ehren-
berg first among the Rotatoria, and subse-
quently with the Desmidiaceae, to neither of
which does it seem to bear the least resem-
blance.

It consists of yellow, flattened, rectangular
(side view) bodies, with four equidistant
spines projecting from each end ; the colour
arises from the contents ; no transverse line
of division; entire length 1-216".

Does it consist of the ovum of some
marine animal ?

BIBL. Ehrenberg, In/us, p. 164.

MIELICHHOFERIA, Hornsch. — A
genus of Bryaceous Mosses, containing one
British species, sometimes referred to
Weissia (fig. 85, p. 100).

Mielichhoferia nitida, Hsch. = Weissia
Mielichhoferia, Schwag.

MIGNONETTE.— Reseda odorata, be-
longing to the Dicotyledonous order Rese-
daceae. Its seeds are elegant opake objects
under a low power.

MILK. — This liquid consists of a solution
of caseine and certain salts, holding in suspen-
sion minute globules of fatty matter (butter).

The fluid portion possesses no microscopic
peculiarities. The globules are very numerous,
round, and vary in size from mere molecules
to 1-3000 or 1-2000" in diameter. Each is
surrounded by a pellicle or coat of caseine,
which prevents the globules from fusing
into each other. If a portion of a drop of
milk be placed upon a slide, and fhe thin
glass cover be moved to and fro, the coat of
caseine will be ruptured, the globules of oil
will become confluent, and shreds of the
coats will be visible. If acetic acid be added,
the coats will be acted upon, and the con-
fluence also produced. The same effect
occurs naturally in sour milk; hence in this
the globules are often much larger than the
above dimensions, and irregular in form,
frequently becoming elongated and united
in twos, so as to bear some resemblance to
the young state of a fungus.

The milk first secreted after parturition,
called the colostrum, differs considerably
from the normal liquid. The fatty globules
contained in it vary greatly in size, often
being very large, and existing within isolated
or aggregated epithelial cells, some of them
resembling exudation-corpuscles.

MILK-VESSELS.

[ 427 ]

MNIACEJS.

Dr. Peddie's paper on the human milk in
relation to medical practice, is well worthy
of perusal.

BIBL. Kolliker, MikrosJc.Anat. ii.; Donne,
Cours de Microscopic-, Wagner, Handwor-
terb. d. Physiologic, art. Milch ; Peddie, Ed.
Monthly Journ. 1840, and the Bibl. of CHE-
MISTRY, Animal.

MILK- VESSELS. See LATICIFEROUS

TISSUE.

MILLON'S TEST, or TEST-LIQUID.—
This, a strongly acid (nitric and nitrous)
solution of proto- and pernitrate of mercury,
gives an indication of the presence of proteine
or allied compounds by the production of a
more or less deep rose-red colour.

The test-liquid is prepared by dissolving
metallic mercury in an equal weight of strong
nitric acid (sp.gr. 1'4). The acid is first
poured upon the metal; gas is copiously
evolved, and as soon as the evolution ceases,
a gentle heat is applied until the whole of
the metal is dissolved. After some hours,
the liquid portion is poured off from the
crystals which have formed and subsided,
and must be kept in a stoppered bottle.

In use, the substance to be tested is im-
mersed in the liquid, either in a tube or
upon a slide with a cover, and heat applied
over a small flame of a spirit-lamp until
boiling occurs. The substance then appears
of a red colour if it answers to the action of
the test.

Great attention is required to the purity
of the substance or body to be tested, other-
wise, e.g., a cell-wall might appear to be
coloured from the contents consisting of a
proteine compound, &c.

The following substances and tissues are
coloured by the reagent : albumen, caseine,
chondrine, crystalline, epidermis, feathers,
fibrine, gelatine, gluten, horn, legumine,
proteine, silk, wool.

The following, when pure, are not coloured :
cellulose, chitine, cotton, gum (arabic), linen
and starch.

BIBL. Millon, Comptes Rendus, 1849, or
Chem. Gaz. 1849. vii. p. 87-

MILNESIUM, Doyere. — A genus of
Arachnida, of the order Colopoda, and family
Tardigrada.

Char. Head with two very short palpiform
appendages at its anterior and lateral part ;
mouth terminated by a sucker surrounded
by palps ; skin soft, transversely furrowed ;
legs four pairs ; rings of the body divided
into two segments.

M. tardigradum (pi. 41. fig. 9). Mouth

surrounded by six minute unequal palps,
symmetrically arranged, diminishing in size
from the upper to the lower part; head
rounded in front when the mouth is retracted;
eye- spots tolerably large and granular; pha-
ryngeal tube much dilated, styles very small,
bulb elongated and pyriform, without an
internal framework; body transparent, at-
tenuated at both ends, especially the poste-
rior; skin pale brownish-yellow; three an-
terior pairs of legs nearly equal, the fourth
very short, resembling two tubercles, with
scarcely a trace of annuliform division;
claws four, two terminal, and in the form of
elongated filaments hooked at the end, and
each supported on a distinct tubercle ; two
inferior and internal, the anterior divided
into three strongly curved hooks, the poste-
rior into two; hooks or terminal filaments of
the fourth pair longer than those of the three
first. Movement active. Length 1-50 to 1-40".

BIBL. Doyere, Ann. des Sc. not.

MIRROR OF SCEMMERING. See
INTRODUCTION, p. xiv.

MISLETOE. See VISCUM.

MITES.— The animals usually included
under this indefinite term are species of
genera belonging to the family Acarina
among the Arachnida.

MNIACE.E.— A tribe of Mnioideaj
(Mosses), of Bryoid habit, but with firm,
rigid, and usually undulated leaves, mostly
increasing in size toward the summit of the
stem.

British Genera.

I. CINCLIDIUM. Calyptra conical, dimi-
diate, small, fugaceous. Peristome double,
the external sixteen, short and truncate;
the internal composed of a cup-like mem-
brane with sixteen folds, and sixteen fora-
mina opposite the outer teeth, open at the
summit.

II. MNIUM. Calyptra as in Cinclidium.
Peristome double ; exterior of sixteen lan-
ceolate, cuspidate teeth, trabeculate exter-
nally and with a longitudinal line, lamellar,
fleshy inside, yellowish ; interior a membrane
with keeled folds, produced into sixteen
lanceolate, broad, keeled teeth, with large
perforations, connivent like a cupola, sur-
passing the outer teeth, with 2-4 intervening
cilia.

III. GEORGIA. Calyptra mitriform,
plaited. Peristome simple, of four pyramidal
cellular teeth.

IV. TIMMIA. Calyptra dimidiate-hood-
shaped, very fugaceous. Peristome double :

MNIADELPHACE.E.

[ 428 ]

MOLECULAR MOTION.

exterior of teeth like those ofMnium, scarcely
lamellated, geniculately incurved when dry ;
interior a hyaline membrane prolonged into
numerous nodose filiform cilia, very much
appendiculated or rugulose, at first anasto-
mosing together, then free.

MNIADELPHACE^E. — A family of
Pleurocarpous Mosses, with the leaves ar-
ranged in four or more series, and composed
of parenchymatous cells, mostly equally
hexagonal and Mnioid, very smooth, pellu-
cid, destitute of a distinct primordial utricle,
the lowest decurrent on the stem at the base,
larger, spongy, lax, mostly beautifully dark-
tinged, never single, slender.

British Genus.

DALTONIA. Calyptra mitre-shaped, bell-
shaped, elegantly fringed at the base.
Peristome double (Neckeroid). External
sixteen narrow, subulate, trabeculate teeth,
reflexed when moistened ; internal : an
equal number of similar cilia, alternating
with the teeth, devoid of a basilar mem-
brane.

MNIOIDEJ3. — A family of operculate
Mosses, ordinarily of acrocarpous habit,
but sometimes pleurocarpous, with broadly
oval, spathulate, oval or lanceolate, flattish
leaves, having a very prominent, thick dor-
sal nerve. The base of the leaves composed
of somewhat parallelogrammic cells, rounded-
hexagonal or with equal walls towards the
apex, very full of chlorophyll, or with the
primordial utricle mostly very conspicuous,
or much thickened, firm, rarely papillose.
This family is divided into two tribes :

1. MNIACEJE. Leaves without appendi-
cular lamellae, not sheathing at the base.
Capsule oval, pyriform or cylindrical, with-
out an annulus.

2. POLYTRICHACE^E. Leaves mostly
sheathing at the base, the internal face
mostly lamellated ; lamellae composed of a
single layer of cells placed lengthwise on
the nerve. Capsule closed by an epiphragm,
without an annulus, mostly angular, apo-
physate, unequal.

MNIUM, Dill. — A genus of Mniaceous
Mosses, of acrocarpous and pleurocarpous
habit, including many Brya of the British
Flora. Among the commonest is M . hornum
= Bryum hornum, L.

MOCHA STONES.— The varieties of
chalcedony known under this name contain
a number of bodies which have been inter-
preted by authors to consist of plants, as
portions of Chara, Hypnum, Conferva,

Nostoc, Desmidiacea, &c. The evidence is
however very unsatisfactory.

Compare AGATE and FLINT.

BIBL. K. Miiller, Ann. Nat. Hist. 1843,
xi. p. 415.

MOHRIA, Swartz.— A genus of Schizre-
ous Ferns. Exotic (fig. 464).

Fig. 464.

Mohria thurifraga.

A pinnule with sporanges.

Magn. 25 diams.

MOINA, Baird.— A genus of Entomo-
straca, of the order Cladocera, and family
Daphniadae.

Char. Head rounded and obtuse; superior
antennae of considerable length, of one piece,
and arising from the front of the head near
the middle ; inferior antennae large, fleshy at
the base, and two-branched, one branch
three-jointed, the other four-jointed; legs
five pairs.

M. rectiroslris (PI. 14. fig. 26). Carapace
almost straight or but slightly rounded be-
hind. Aquatic.

M. brachiata or branchiata. Carapace
greatly rounded behind. Aquatic.

BIBL. Baird, Brit. Entomos. p. 100.

MOLECULAR MOTION.— When ex-
tremely minute particles of any substance
immersed in water or other liquid are exa-
mined under the microscope, they are seen
to be in a state of vivid motion. A little
gamboge or Indian ink mixed with water
will exhibit the phaenomenon distinctly
enough. The minute particles or molecules
are seen to move irregularly, to the right
and left, backwards and forwards, as if re-
pelled by each other, until the attraction of
gravitation ultimately overcomes the force
upon which their motion depends, when
they sink to the surface of the slide. This
applies to the molecules of those substances
which are heavier than water. In the case
of those which are lighter than water, or the
liquid in which they are immersed, the mole-

MOLLUSCA.

[ 429 ]

MONADINA.

cules ultimately become adherent to the
thin glass covering the slide.

This motion is in no way connected with
evaporation, for it takes place equally when
this is completely prevented, just as when it
is not. Neither light, electricity, magnetism
nor chemical reagents exert any effect upon
it. Heat is the only agent which affects it ;
this causes the motion to become more
rapid. Hence it might be attributed to the
various impulses which each particle receives
from the radiant heat emitted by those ad-
jacent. Or, as it takes place when the tem-
perature is uniform, may it not arise from
the physical repulsion of the molecules, un-
interfered with by gravitation, hence free to
move ? The effect of heat would then be
explicable, because this increases the natural
repulsion of the particles of matter, as in the
conversion of water into vapour.

Molecular motion plays a part in some
common phenomena. Thus, it prevents
turbid water from becoming rapidly clear by
repose ; by its agency also the disaggregated
particles of animal or vegetable matter are
diffused throughout the mass of the liquid.
The microscopist should become acquaint-
ed with the appearance of particles in mole-
cular motion, as it might give rise to error.
Thus particles under its influence might be
mistaken for monads; or particles moved
by cilia might be regarded as merely exhi-
biting this molecular motion.

Two circumstances appear most favour-
able for its production and continuance, in
addition to the augmentation of temperature,
viz. a very finely divided state of the matter,
and the specific gravity of the matter and
the liquid in which it is suspended being as
nearly as possible coincident.

BIBL. R. Brown, On Active Molecules,fyc.,
Add. Observ. on the same, 8vo (privately
printed}; Dujardin, Observateur au Micro-
scope-, Griffith, Med. Gaz. 1843.

MOLLUSCA. — Remarks upon certain

interesting structures occurring in the Mol-
lusca will be found under TONGUE, SHELL,
SNAILS, WATER, MYTILUS, OSTREA and
OVUM. The calcareous concretions, cry-
stals and spicula met with in the integument
or mantle of some mollusca are curious.

BIBL. Siebold, Veryleich. Anat. and the
copious BJBL. ; Vogt, Zoolog. Briefe ;
Adams, Genera of recent Mollusca ; Forbes
and Hanley, Brit. Mollusca ; Woodward on
Shells ; R. Jones, Animal Kingdom, and the
articles in the Cycl. of Anat. and Phys.

MONADINA.— A family of Infusoria,
according to Ehrenberg's system, but con-
sisting of a heterogeneous group of imper-
fectly examined bodies (see p. 347).

Char. Carapace absent ; no expansions ;
locomotive organs consisting of one or more
flagelliform filaments or cilia at the anterior
part of the body.

Ehrenberg distinguishes nine genera :

A. Tail none.

a. No lips.

a. Swimming.
a. No eye-spot.

1. Single 1. Monas.

2. Grouped 2. Uvella.

/3. Eye-spot present.

1. Single.

* Flagelliform filaments,

one or two 3. Microglena.

** Flagelliform filaments,

four or five 4. Chloraster.

*** Flagelliform filaments,

numerous 5. Phacelomonas.

2. Grouped 6. Glenomorum ,

b. Rolling 7. Doxococcus.

b. Lips present 8. Chilomonas.

B. Tail present Q.Bodo.

Dujardin's characters are (see p. 348) :
animalcules without an integument, consist-
ing of a glutinous, apparently homogeneous
substance, susceptible of becoming aggluti-
nated to other bodies and so drawn out and
altered in form, with one or more flagelli-
form filaments as locomotive organs, and
sometimes lateral or tail-like appendages.

Dujardin divides them thus :

FA-

MONADINA.

roughout its whole length

1 1

.

I arising obliquely from behind an anterior prolongation

A second filament, {jsSor" :".: "":::::::: I:::;::::::::::::::::: ::::::::::::::::

Two equal filaments terminating the curved angles of the anterior end

Four equal filaments in front, and two thicker ones behind

A second filament arising from the same spot as the flagelliform filament, but thicker,

trailing, and retracting
.A filament and vibratile cilia

1. Monas.

2. Cyclidlum.

3. Chilomonas.

4. Amphimonas.

5. Cercomonas.

6. Trepomonas.

7. Hexamita.

8. Heteromita.

9. Trichomonas.

Groups always free, revolving 10. Uvella,

Groups originally fixed at the ends of a branched polypidom or stalk 11. Anthophysa.

MONADS.

[ 430 ]

MONORMIA.

BIBL. Ehrenberg, Infus. p. 1 ; Dujardin,
Infus. p. 270.

MONADS are species of Monas, or of
other genera of the family Monadina (Infu-
soria).

MONAS, Mull.— A genus of Infusoria, of
the family Monadina.

Char. See MONADTNA.

Ehrenberg describes many species, con-
sisting mostly of the zoospores or lower
forms of Algae, and the young or swarm-
germs of Infusoria.

M. vinosd, E. Ovate, uniformly rounded at
each end, of a red-wine colour, motion slow
and tremulous. Length 1 -12,000 to 1-6000".

Found upon the sides of glass vessels, in
which decaying vegetable matter has been
kept, on the side next the light.

The characters of the genus given by Du-
jardin are :

No integument ; form rounded or oblong,
variable ; no expansions ; flagelliform fila-
ment single ; motion slightly vacillating.

Dujardin describes ten species, which
cannot be identified with those of Ehrenberg.

M. lens, D. (PI. 24. fig. 44 a). Body
rounded or discoidal and tubercular. Breadth
1-5200 to 1-1800".

One of the most common organisms in
animal and vegetable infusions. We have
found one common in animal infusions (PI.
24. fig. 44 b), perhaps the same as the
above, but it possesses usually two filaments ;
on the left side is one without filaments, but
with the body drawn out from adhesion to
the slide.

M. attenuate D. (PI. 24. fig. 44 c). Body
ovoid, narrowed at the ends, nodular, un-
equal; filament arising from the anterior
narrowed portion. Length 1-1600".

BIBL. Ehrenberg, Infus. p. 3 ; Dujardin,
Infus. p. 279.

MONILIA, Hill.— A genus of Mucedines
(Hyphomycetous Fungi). Under BRIAREA,
Corda (fig. 82. p. 99), it is stated that a di-
stinction exists between that genus and the
present, but they are really synonymous, and
the older name, that of Hill, should stand.
Another species, M. racemosa, Pers., should
be added to M. penicillata.

MONOCERCA, Bory, Ehr.— A genus of
Rotatoria, of the family Hydatinaea.

Char. Eye red, single, cervical ; foot -like
tail simply styliform.

Gosse mentions a second eye situated in
the breast of one (new) species. Ehrenberg
describes three species, to which Gosse adds
two.

M. rattus, E. (PL 35. fig. 9). Body ovate-
oblong ; forehead truncate, unarmed ; foot
styliform, as long as the body. Aquatic.
Length 1-120".

BIBL. Ehrenberg, Infus. p. 422; Gosse,
Ann. Nat. Hist. 1851. viii. p. 199.

MONOCOTYLEDONS. — One of the
classes of Angiospermous Flowering Plants,
so called from the structure of the embryo
contained in the seed, which in a large number
of cases is of microscopic dimensions, and
always requires the use of the simple micro-
scope for its dissection. Some of the fami-
lies placed under this head have usually an
acotyledonous embryo, as Orchidaceae, but
these possess the character of the class

Fig. 465.

Reduced view of a stem of a Palm, showing the perpen-
dicular and horizontal section in which the fibre-vascular
bundles F. V are seen isolated in the medullary paren-
chyma.

in all other respects. Among the most
important of their other characters is the
isolated condition of the fibro-vascular
bundles forming the woody structures (see
TISSUES, VEGETABLE). This character,
mostly very evident both in perpendicular
and horizontal sections of the stems, is illus-
trated by figs. 460 & 465.

MONOLABIS, Ehr.-— A genus of Rota-
toria, of the family Philodinaea.

Char. Eyes two, frontal, tail-like foot
with two toes ; horns absent.

Two species.

M. gracilis (PI. 35. fig. 10). Body slender,
no cervical process nor respiratory tube ;
teeth two in each jaw. Aquatic. Length
1-240 to 1-144".

BIBL. Ehrenberg, Infus. p. 497.

MONORMIA, Berkeley.— A genus of
Nostochaceae (Confervoid Algae), distin-

MONOSTROMA.

[ 431 ]

MOSSES.

guished by its definite, linear, convoluted
frond, enclosing a single moniliform filament.
It might readily be mistaken for a Nostoc
if superficially observed, but its convoluted
frond is devoid of the common membranous
pellicle. The only known British species is
Monormia intricata, Berk.

This plant occurs in gelatinous masses,
each about as large as a walnut and of a red-
dish-brown colour, floating in slightly
brackish ditches. When the spermatic cells
are quite mature, the definite outline of the
linear frond is almost lost, and there is
little to distinguish the plant from Trichor-
mus, except the peculiar convolutions of
the moniliform filament; the frond then also
assumes a greenish tint.

BIB L. Berkeley ( Gleanings of Brit. Algce,
t. 18) ; Ralfs, Ann. Nat. Hist. ser. 2. vol. v.
pi. 8. fig. 1 ; Harvey, Phyc. Britann. t. 256 ;
Hassall, Brit. Fr. Alga, t. 75. fig. 11.
Nostoc intricatum, Meneghini; Anabaina
intricata, Kiitzing, Tabula Phycologicce,
vol. i. t. 94. fig. 1.

MONOSTROMA, Thuret.— A genus of
Ulvaceae (Confervoid Algae), of which M.
bullosa (Ulva bullosa, Roth.) is the type,
distinguished from Ulva by consisting only
of a single layer of cells, and these being
roundish (mostly grouped in fours), im-
bedded in an apparently homogeneous gela-
tinous membrane (PI. 5. fig. 1 a). This
plant is reproduced by zoospores formed
from the cell-contents, and discharged by
bursting of the cell- wall (fig. 1 b, c). They
have four cilia.

BIBL. Thuret, Ann. des Sc. nat. 3 ser.
xiv. p. 225. pi. 21. figs. 1-4; Note sur les
Ulvacees, Mem. de la Soc. Scient. de Cher-
bourg, ii. p. 1 (1854).

MONOSTYLA, Ehr.— A genus of Rota-
toria, of the family Euchlanidota.

Char. Eye single, cervical; tail-like foot
simply styliform ; carapace depressed.

Four species, three Ehrenberg, and one
other, Gosse.

M. quadridentata (PL 35. fig. 11). Cara-
pace yellowish, fore-part of head deeply
cleft into four horns. Aquatic. Length
1-120".

BIBL. Ehrenberg, In/us, p. 459 ; Gosse,
Ann. Nat. Hist. 1851. viii. p. 200.

MONOTOSPORA, Corda.— A genus of
Sepedonei (Hyphomycetous Fungi), of which
one species has been found in England,
growing on dead bark of the yew. M. mega-
lospora, Berk, and Br. Filaments erect,
simple, straight, nearly equal, articulated.

Spores terminal, obovate, even, '0014 to
•00133" long. Fries regards this genus with
doubt.

BIBL. Berk, and Broome, Ann. Nat. Hist.
2 ser. xiii. p. 462. pi. 15. fig. 11; Fries,
Summa Veget. 497.

MONURA, Ehr.— A genus of Rotatoria,
of the family Euchlanidota.

Char. Eyes two, frontal; foot simply
styliform. Carapace somewhat compressed
and open beneath.

Two species.

M. dulcis (PL 35. fig. 12). Carapace
ovate, obliquely truncate and acute behind ;
eyes distant. Aquatic. Length of carapace
1-280".

BIBL. Ehrenberg, Infus. p. 474.

MORELS.— Species of Morchella, Dill.
(Ascomycetous Fungi), having a pileiform
receptacle, with a ribbed and lacunose hy-
menium on the upper side, bearing asci.

MORPHIA. See ALKALOIDS, p. 25.

MORPHO, Fabr. — A genus of Exotic
Lepidopterous Insects.

M. Menelaus. The scales from the wings
of this beautiful insect are sometimes used
as TEST-OBJECTS.

MOSSES, MUSCACE.E.— This order of
flowerless plants is distinguished from the
Hepaticaceae by the vegetative structure, or
by the sporange. In one group alone (Hy-
popterygiece) is the stem clothed with leaves,
accompanied by amphigastria (stipule-like
leaflets), in the manner of the foliaceous Hepa-
ticaceae (fig. 359, p. 337); and here the sporange
is a stalked urn-shaped body, with a deciduous
lid, and like those of the Mosses generally;
and this Jungermannia-like leafy stem is
erect, and not procumbent, as in Junger-
mannia itself. In all other Mosses the leaves
clothing the stem are arranged in a spiral
order around the stem, so as to give the
vegetative structure a very characteristic
aspect.

The stem of the Mosses is a slender,
thread-like or wiry structure, wholly com-
posed of cellular tissue, without vessels, but
the external layer has an epidermoid cha-
racter, while the central portion is composed
of elongated cells. In one section of the
Mosses this stem terminates in a sporange,
and these are called Acrocarpous Mosses ; in
others the sporanges spring from lateral
branches, and the terminal bud of the stem
elongates the stem year after year; these
latter are called Pleurocarpous Mosses.

The leaves are of simple structure, usu-
ally composed of a single layer of cells, the

MOSSES.

[ 432 ]

MOSSES.

forms of which are used as characters by
systematic Muscologists. They are either

466.

all alike in a leaf, and filled
with chlorophyll, and in these
cases may be either paren-
chymatous (PL 38. fig. 19) or
prosenchymatous (PI. 38. fig.
20), or several rows running
up the centre are more elon-
gated than the rest, and give
the appearance of a mid-nerve.
In other cases two sorts of
cells occur arranged in a pe-
culiar way ; some, smaller,
containing chlorophyll, form a
kind of network, the meshes
of which are occupied by large
uncoloured cells (see SPHAG-
NUM and LEUCOBRYUM).

The leaves often differ on
different parts of the stem,
and we hence have radical, MaSn- 50 diams>
cauline, and perichcetial or involucral leaves,
the last ordinarily forming a kind of rosette,
in the midst of which the reproductive or-
gans are produced. SCHISTOSTEGA exhibits
two forms of stem, with two kinds of folia-
ceous structure ; the stems which terminate
in a sporange have leaves only at the upper
part, and these arranged in eight rows stand-
ing crosswise on the stem, like ordinary
leaves ; the barren stems have two rows of
leaflets arranged in one plane on the stem,
like the leaflets of a compound leaf (such as
that of the Acacias) of Flowering plants.
The stem-leaves of many genera exhibit

Fig. 467. Fig. 468.

Leaf.

Barbula chloronotus.
Fig. 467. Leaf with cellular filaments at the tip. Magn.

30 diams.
Fig. 468. Leaf with cellular filaments crowded on the

midrib, with an arm-like prolongation.

Magn. 20 diams.

wing-like structures, hair-like appendages,
or peculiar forms of curvature (figs. 255-50,
FISSIDENS); others, like certain Barbulce
(figs. 467-470), have collections of cellu-
lar filaments on the upper side.

Fig. 469.

Fig. 470.

Barbula chloronotus.

Fig. 469. Cross-section of 467. Magn. 50 diams.
Fig. 470. Cross-section of 468. Magn. 50 diams.

The outer leaves surrounding the repro-
ductive organs are called perichcetial, and
sometimes they form the only envelopes;
sometimes, however, a few small leaves, dif-
fering very much from the above, form the
immediate envelopes of the archegones, and
these perigonial leaves, forming the peri-
gone, are developed afterthe reproductive or-
gans themselves (as is the case also with the
perigone of the Hepaticacere). The perigo-
nial leaves either overlap and cover in the
reproductive organs, or they are keeled at
the base and turned back above, so as to
expose the organs of reproduction (POLY-
TRICHUM).

The young reproductive organs consist of
antheridia and archegonia or pistillidia, which
are found either together (fig. 471) in the

Fig. 471.

Fig. 472.

Bryum nutans.

Fig. 471. Inflorescence of antheridia and archegonia.

Magn. 25 diams.
Fig. 472. Spermatozoids from antheridia. Magn. 600

diams. (The cilia omitted.)

same perigone, or on different parts, or on
different individuals of the same species. To
these structures the term inflorescence is
applied. The antherids occur either with
the archegones in one perigone (fig. 471) or
in the axils of the upper leaves of the stem,
which terminates in a perigone containing
archegones ; or they have a special perigone

MOSSES. [ 433 ]

(fig. 473), either on the same plant, or on a
Fig. 473.

Mnium arcticum.

Antheridial inflorescence.

Magn. 25 diams.

different one from that which bears the
archegones. The antherids are globular,
oval (fig. 471), or elongate membranous sacs
composed of cellular tissue, filled with mi-
nute cellules, which escape by the bursting
of the apex of the sac ; and these cellules
exhibit a fibre coiled in their interior, which
circulates rapidly, even before the expulsion
from the antherid, and after a time breaks
out of its cellule (fig. 472, and PI. 32. fig. 33),
and moves rapidly round in the water under
the microscope (see ANTHERIDIA). The
antherids are generally accompanied by cel-
lular filaments which have received the name
of paraphyses ; no physiological office is
attributed to these, but the antherids are
regarded as male organs.

The archegone of the Mosses (figs. 32, 33,
p. 60, 471), like that of the Hepaticacea3
(excepting Anthoceros), is a flask-shaped
cellular case, the epigone containing an em-
bryonal cell at the bottom of its cavity. This
embryonal cell becomes gradually developed
by cell-division into a conical body elevated
on a stalk, which at length tears away the
walls of the flask- shaped epigone by a cir-
cular fissure, and carries the upper part up-
wards as a hood, while the lower part re-
mains as a kind of collar round the base of
the stalk (figs.474,476); the latter is termed
the vaginule (fig. 477) ; the cap-like portion
carried upwards on the sporange is called
the calyptra (figs. 474-476). The sporange,
elevated more or less by the development of
its stalk (seta or peduncle], is gradually con-
verted by internal changes into a hollow urn-
like case, usually with a stalk-like column
(CoLUMELLA)runningupitscentre(figs. 50,
p. 72, 479), the space between the central
column and the side walls becoming filled
with free spores, which are minute cells with
a double coat, the outer of which exhibits
elegant markings (see SPORES). In some
cases this hollow case does not burst natu-
rally, but the spores escape by its decay

MOSSES.
Fig. 474. Fig. 475.

Fig. 476.

Fig. 477.

Fig. 474. Coscinodon pulvinatus. Capsule enclosed in
the calyptra, with the vaginule below.
Magn. 10 diams.

Fig. 475. Orthotrichum Hutchinsii. Capsule covered by
the calyptra, with vaginule below. Magn.
10 diams.

Fig. 476. Ditto. Calyptra. Magn. 25 diams.

Fig. 477. O. stramineum. Vaginule. Magn. 25 diams.

(ASTOMUM, fig. 50). In the ANDR^EE^E
(fig. 11, p. 33) the sporange bursts by four
vertical slits, so as to be divided into four
valves, like the Jungermannieae, and there is
no column in the sporange here, but the valves
do not separate at their summits, and the
character of the leafy stem at once distin-
guishes these Mosses from those Hepaticaceae.
The ordinary course, however, in the Mosses
is the formation of a horizontal slit near the
top of the sporange, so that the upper part
falls off like a lid (operculum, fig. 483).

The sporange of the Mosses exhibits a
very complex anatomical structure, which

2 F

MOSSES.

[ 4S4 ]

MOSSES.

we have not space to enter into very mi-
nutely here ; it will suffice to state that the
lower part next the peduncle is sometimes
enlarged into a thickened mass, called the

Fig. 478.

Fig. 479.

Fig. 478. Tayloria serrate. Dimidiate calyptra.
Magn. 25 diams.

Fig. 479. F. hygrometrica. Section of young capsule,
showing the columella. Magn. 50 diams.

apophysis ; sometimes the peduncle is very
long, sometimes very short (Phascum, fig.
482), so that the sporange is hidden in the
perichaete; finally, the mouth may either

Fig. 480.

Fig. 481.

Fig. 480. Coscinodon pulvinatus. Fragment of peri-
stome. Magn. 100 diams.

Fig. 481. Barbula flavipes. Fragment of peristome.
Magn. 100 diams.

exhibit a smooth edge (fig. 483), or a single
(figs.480,481) or double (figs. 487, 488) fringe
of very variously constructed teeth, which are

of great service in discriminating the genera.
When the mouth of the sporange is naked,

Fig. 482.

Fig. 483.

Fig. 482. Phascum serratum. Sessile sporange en-
closed by few leaves. Magn. 15 diams.

Fig. 483. Pottia truncate. Operculum separating
from the sporange. Magn. 10 diams.

the Mosses are called gymnostomous, when
furnished with only a single row of teeth
aploperistomous, when with a double row
diploperistomous. When a double peristome
exists, the outer consists of teeth, the inner
of processes or cilia (fig. 487) or of both
(Brywri). The teeth sometimes arise di-
rectly from the mouth of the sporange,

Fig. 484.

Cinclidium arcticum.

Part of double peristome, the inner processes united
into a plaited membrane in the centre.

Magnified 100 diameters.

sometimes are seated on a basal membrane,
sometimes connected together irrregularly
(FuN A RI A, fig. 263, p. 279), or by regular bars
(GUEMBELIA, fig. 205, p. 299), or the whole
of the inner circle may be conjoined entirely

MOSSES.

C 435 ]

MOSSES.

(BUXBAUMIA, fig. 97, p. 104) or at the tips
(fig. 484) into a membrane, or by a number
of cross-bars into an open trellis (fig. 488).
The rows of teeth are continuations of the
inner layers of tissue of the sporange (fig.
485), the outer wall of the sporange is,
as it were,, continued by the operculum,
but ordinarily these do not separate directly
from each other when the lid falls off, since
one or several layers of elastic cells forming
a ring (annulus, fig. 486) round the mouth,
split out from between the sporange and its
lid, and cause the latter to fall off.

Allusion has been made to the sexual
import of the antherids and archegones, and
attention must be directed to the peculiar
phenomena exhibited in the reproduction
of the Mosses. The embryo-cell of the
archegone appears to be fertilized by the
spiral filaments produced by the antherids ;
the result here is not the production of a
simple plant, but of a sporange or fruit
which produces a number of spores, each of
which may grow up into a new plant.

Fig. 485.

Fig. 486.

Fig. 487.

Fig. 485. Racomitrium fasciculate. Section of margin
of sporange, with a tooth of the peristome. Magn. 100
diams.

Fig. 486. Bryum csespititium. Annulus. Magn. 100
diams.

Fig. 487. Orthotrichum diaphanum. Portion of double
peristome, the outer composed of teeth, the inner of
cilia. Magn. 50 diams.

The Mosses exhibit a variety of forms of
vegetative multiplication. The lower part
of the stem often sends out horizontal
branches, which root and produce buds

(fig. 489), from which arise new leafy stems,
and in this way patches of moss frequently
increase to a great size. They also produce
confervoid filaments, which exhibit tuberous
thickenings, a form of #erawwe (figs. 492, 493),
which may be detached from each other like
bulbels, so as to propagate the plants with-
out any sexual reproductive organs.

Gemmce or minute cellular tubercles,
capable of development into new plants, are
likewise met with, in other situations, as
in the axils of leaves, on the surface, the
margins (fig. 494), or at the tips (figs. 490,
491) of the leaves or the stems (fig. 495);
these are formed of only a few cells at the
time when they fall off, and illustrate well the
independence of the individual cells forming

Fig. 488.

Neckera antipyretica.

Double peristome, the inner composed of teeth united
by cross bars, forming a trellis.

Magnified 100 diameters.
Fig. 489.

Polytrichum undulatum.

Creeping filaments with innovations.

Magnified 5 diameters.

the organs of these plants, where, under
peculiar circumstances, a single cell of the
tissue may be developed so as to lay the
foundation of a new plant.

2r2

MOSSES.

[ 436 ]

MOSSES.

In the following arrangement of the
Mosses we follow C. Miiller, the ' Bryologia
Britannica* having appeared too late for us
to adopt its classification. The order Mus-
caceae is first divided into two sub-orders
according to the habit of growth :

Fig. 490.

Fig. 491..

Orthotrichum phyllanthum.

Leaves with gemmae at the tips.

Magnified 25 diameters.

1. ACROCARPI. Mosses with the fruit-
stalk terminating the stem.

Fig. 492.

2. PLEUROCARPI. Mosses with the
fruit-stalk produced only from lateral buds.

Synopsis of the Families.
ACROCARPI.

* Schistocarpi. Capsule without a lid
(operculum), opening by longitudinal
fissures.

I. ANDR^BACE^;. Capsule splitting into
four valves.

** Cleistocarpi. Capsule without a lid,
bursting open irregularly.

II. BRUCHIACE.E. Cells of the leaf
(areolation) parenchymatous, looser at the
base, not papillose, dense.

III. PHASCACE^E. Areolation of the
leaf parenchymatous, dense, filled with chlo-
rophyll, more or less papillose.

IV. EPHEMERE.E. Areolation of the
leaf parenchymatous, everywhere lax, not
papillose.

* Stegocarpi.
A. Acrocarpi.

Capsule bursting by a lid.

Fruit terminal, or lateral
by subsequent budding at the sides.

I. Distichophylla. Leaves arranged in
two straight rows.

Fig. 494.

Fig. 495.

Hedwigia ciliata.

Creeping filaments with tuber-like gemmae.
Fig. 492, magnified 50 diameters. Fig. 493, 20 diameters.

Fig. 494. Orthotrichum Lyellii. Leaves with
marginal gemmae. Magnified 50 diams.

Fig. 495. Aulocomnium undulatum. Gemmae
in the place of the capsule, Magn. 20 diams.

MOSSES.

[ 437 ]

MOUGEOTIA.

a. Leaves regularly vertical.

V. SCHISTOSTEGE.E.

b. Leaves regularly subvertical.

VI. DREPANOPHYLLE.E.

c. Leaves horizontal.

VII. DISTICHIACE^E. Areolation of the
leaves parenchymatous, minute ; leaves
without appendicular laminae.

VIII. FISSIDENTE^. Areolation of the
leaves parenchymatous ; leaves produced
into appendicular laminae at the back and
point.

II. Polystichophylla. Leaves arranged
in three or more straight or alterna-
ting rows.

a. Leaves exhibiting narrow, green cells, forming a
reticulation between larger diaphanous cells.

IX. LEUCOBRYACE^E. Leaves composed
of several layers of columnar, empty, paren-
chymatous cells; the 'intercellular' green
cells three- to four-angled, interposed be-
tween the empty cells in a single curved row.

X. SPHAGNACE^:. Leaves composed of
a single stratum of empty prosenchymatous
cells ; intercellular green cells interposed
between all the empty cells.

b. Leaves without ' intercellular ' cells.

a. Leaves not papillose.

1 . Loosely areolated.

XI. FUNARIOIDEJE. Areolation of the
leaf parenchymatous, lax, containing much
chlorophyll.

XII. DISCELIACEJS. Areolation of the
leaves rhomboid-prosenchymatous, destitute
of chlorophyll, empty, fuscescent.

XIII. BuxBAUMiACE^E. Areolation of
the leaf hexagonal or polygonal, very minute,
dark-coloured, destitute of chlorophyll.

2. Densely areolated. •

XIV. MNIOIDE.E. Areolation of the
leaf in parallelograms at the base, roundly
hexagonally-parenchymatous towards the
apex ; very full of chlorophyll or more fre-
quently thickened (very rarely papillose).

XV. BRYACE^:. Areolation of the leaf
prosenchymatous, ordinarily rhomboidal,
abounding with chlorophyll.

XVI. DiCRANACE,E. Cells of the leaf
prosenchymatous, very often intermixed with
parenchymatous cells (rarely scabrously pa-
pillose), alar basilar cells ordinarily crowded
and ventricose, or flat and much more
loosely reticulated than the upper cells.

XVII. LEPTOTRICHACE.E. Cells of the
leaf rhombic at the base, rectangular or both

mixed further up, smooth, without proper
alar cells.

b. Leaves papillose,

XVIII. BARTRAMIOIDE^B. Cells of the
leaves parenchymatous, square, ordinarily
nodulose or scabrous with papillae at the
transversal sides, never opake.

XIX. POTTIOIDE.E. Cells of the leaves
parenchymatous, square, ordinarily covered
on all sides with papillae above the base, but
smooth and pellucid at the base.

XX. DiPHYSciACEjE. Leaves of two
kinds: the cauline with the cells densely
hexagonally parenchymatous, abounding
with chlorophyll, the perichaetial leaves with
the cells destitute of chlorophyll and more
loosely reticulated.

PLEUROCARPI.

1 . Distichophylla. Leaves arranged in
two opposite rows.

XXI. PHYLLOGONIACE.E.

2. Tristichophylla. Leaves arranged in
four rows, appearing like three, erect,

of two forms.

XXII. HYPOPTERYGIACE.E. Cells of
the leaf everywhere prosenchymatous, equal.

3. Polystichophylla. Leaves arranged
in four or more rows.

XXIII. MNIADELPHACE.E. Cells of the
leaf parenchymatous, Mnioid.

XXIV. HYPNOIDE.E. Cells of the leaf
prosenchymatous, rhombic or rounded.

BIBL. Hooker, Taylor and Wilson, Bryo-
logia Britannica ; Bruch and Schimper,
Bryologia Europ&a ; Hedwig, Theoria gene-
rationis; Bridel, Bryologia universa', Miiller,
Synopsis Muscorum frondosorum ; Dillenius,
Historia Muscorum ; Lanzius-Beninga, Nova
Acta, xxii. p. 555 ; Hofmeister, Vergleich.
Untersuch. Leipsic, 1837; Valentine, Lin-
nean Transactions, xviii. p. 499.

MOTH, CLOTHES. See TINEA.

MOTHER-CELL, or PARENT-CELL, is
the term commonly applied to the cell in
the interior of which a new generation of
cells is developed.

MOTHER-OF-PEARL. See SHELL.

MOUGEOTIA.— A genus of Zygnemaceae
(Confervoid Algae), distinguished by the con-
jugation of the filaments taking place with-
out the formation of transverse processes,
the conjugating filaments being geniculately
bent. There is still obscurity as to the
mode of reproduction of the plants of this
genus. According to Vaucher, a spore is

MOULDS.

[ 438 ]

MOUTH.

formed in one of the conjugating cells, with-
out transfer of contents, and this, germina-
ting in situ, breaks out from the parent-cell.
This account is probably correct as far as it
goes, but does not explain fully the develop-
ment of the spores. Hassall says the plants
are reproduced by zoospores ; this has been
confirmed by Kiitzing, who, together with
Itzigsohn, has observed the formation of
small rounded resting-spores in the joints,
which underwent segmentation and deve-
loped a number of smaller cells, the ultimate
fate of which was not observed. All this tends
to prove that the reproduction agrees with
that of Spirogyra, where we have — 1. large
conjugation-spores, sometimes germinating
in situ, producing in some cases new fila-
ments, in others zoospores ; 2. zoospores
produced immediately from the contents;
and 3. what appeared to be encysted forms
of these (see SPIROGYRA).

The only satisfactorily established British
species of this genus seems to be M. genu-
flexa, Ag. (fig. 139. p. 166). The cells are
about 1-720" in diameter in large specimens
(M. major, Hass.), and about three or four
times as long ; in smaller specimens (M. ge-
nuflexa, Hass., M. gracilis, Kiitz.) the dia-
meter is about 1-1200", the length of the
cells five or six times greater. The contents
of the cells, like those of MESOCARPUS, are
mostly evenly distributed.

Mesocarpus notabilis, Hass. (Sirogonium
notabile, Kiitz.) is an obscure plant, perhaps
referable to this genus.

BIBL. Vaucher, Conferees d'eau douce,
p. 79. pi. 8; Hassall, Brit. Fr. Alg. p. 171.
pi. 40 ; Kutzing, Sp. Alg. p. 43, Tab. Phyc.
v. pi. 1-3, and 36 ; Itzigsohn, Bot. Zeit. xi.
p. 681 (1853).

MOULDS and MILDEWS. — :These
names are generally applied indifferently to
a multitude of Hyphomycetous, Physomy-
cetous and Coniomycetous Fungi, but some
of the more common ones are especially
distinguished. Thus ordinary 'blue mould'
of cheese, &c. is ASPERGILLUS glaucus -,
another still more common blue or green
mould is PENICILLIUM glaucum ; various
species of OIDIUM and ERYSIPHE are known
as the mildews of the Hop, Vine, Rose, &c.
The mildew of wheat is PUCCINI A gra-
minis.

MOUNTING. See PRESERVATION.
MOUSE, HAIR OF (PI. 1. fig. 3; PL 22.
figs. 27, 28). See HAIR OF ANIMALS and
TEST-OBJECTS.

MOUTH.— The mucous membrane of the

mouth, which becomes continuous with the
skin at the lips, is furnished with very nume-
rous conical or filamentous papillae resem-
bling those of the skin, sometimes simple,
at others branched, and a number of mucous
glands.

Its epithelium is of the pavement kind,
consisting of several layers of delicate cells ;
these are roundish in the deeper, flattened
and polygonal in the superficial layers.

Fig. 496.

Epithelial cells of the mucous membrane of the human
mouth, a, large, b, smaller cells ; c, one with two nuclei.

Magnified 350 diameters. •

The glands, distinguished according to
their situation, as the labial, the buccal, and
the palatine glands, are rounded, about 1-36
to 1-6" in size, and open by short excretory
ducts into the mouth. They consist of
glandular lobules enveloped in areolar tissue
with elastic fibres, the whole being sur-
rounded by a firmer portion or capsule, and
a branched duct. The lobules are composed
of a number of convoluted canals or lobular
ducts, with simple or compound caeca or
glandular vesicles, each consisting of a base-
ment membrane, and a single layer of angu-
lar epithelial cells. The latter separate very
readily, and then the caeca appear filled
with a granular mass.

MOUTH.

[ 439 ]

MUCEDINES.

The ducts of the lobules have a coat of j form of exudation corpuscles, and this view

.499.

^**^?_^

Human racemose mucous gland from the floor of the
cavity of the mouth, a, areolar coat ; b, excretory duct ;
c, glandular cseca ; d, lobular ducts.

Magnified 50 diameters.

areolar tissue, with networks of fine elastic
Fig. 498.

Diagram of two lobular ducts of a mucous gland, a, common duct ; b,
lobular branch ; c, glandular vesicles in situ ; d, the same separated, and
the ducts unfolded.

Magnified 100 diameters.

fibres, and a single layer of cylindrical, epi-
thelial cells.

The mucous liquid of the mouth contains,
in addition to detached epithelial cells,
very transparent corpuscles, about 1-2000
to 1-1500" in diameter, consisting of a deli-
cate cell-wall, a nucleus, with a number of
minute moving molecules. We have figured
these among the TEST-OBJECTS (PL 1.
fig. 5). They are called mucous or salivary
corpuscles. Kolliker regards them as a

Two glandular vesicles of a human racemose mucous
gland, a, basement membrane ; b, epithelium, side
view ; c, the same in surface view.

Magnified 300 diameters.

is probably correct, for they may occur in the
secretion of any mucous surface, and have no
special connexion with the salivary glands :
we have found them in myriads in the urine.
The secretion of the mouth generally con-
tains also very slender filaments of a fungus
(LEPTOTHRIX), with species of Monas, E.
and of Vibrio.

BIBL. Kolliker, Mikr. Anat. ii.
MUCEDINES.— A family of Hyphomy-
cetous Fungi, forming moulds and mildews
upon living or decaying animal or vegetable
substances, and contributing to their de-
composition, characterized by a flocculent
mycelium bearing erect, continuous or
septate, simple or branched, tubular,
pellucid filaments, terminating
in single spores or strings of
spores, which soon separate
from each other, and lie among
the filaments of the mycelium.
This tribe includes a number
of the most interesting of the
microscopic fungi, noted for
their destructive influence upon
organic bodies which they at-
tack. The species of Botrytis,
Oidium, &c. spread with won-
derful rapidity as mildews over
the herbaceous parts of vege-
tables and moist vegetable sub-
stances generally; in the former
situations their spores enter the
stomata, their mycelia ramifying among the
subjacent cells, and carrying decomposition
and decay into all the soft structures. They
are most abundantly developed in a close,
damp atmosphere. Themyceliaofotherkinds,
as of PENICILLIUM, growing in liquids con-
taining organic matter, or upon decaying
vegetable substances, produce remarkable
chemical decompositions, causing a fermen-
tation of the medium in which they exist.
Sec PENICILLIUM and FERMENTATION.

MUCEDINES.

[ 440 ]

MUCEDINES.

Synopsis of British and nearly allied Conti-
nental Genera.

A. Fertile filaments (pedicels) simple or
branched, terminating in single spores or
a very short row.

t Spores simple.

I. BOTRYTIS. Pedicels erect, septate,
branched ; branches and branchlets septate ;
spores solitary, on the tips of the branchlets.

II. VERTICILLIUM. Pedicels erect, sep-
tate, with whorled branches terminating in
a solitary spore, or a short row of spores.

III. ACREMONIUM. Pedicels creeping,
septate, armed with subulate branches bear-
ing spores.

IV. OIDIUM. Pedicels simple, short,
erect, clavate, septate, bearing usually one,
sometimes two more or less oval spores.

V. FUSIDIUM. Pedicels? Spores elon-
gate, fusiform.

VI. MENISPORA. Pedicels erect, septate,
bearing fusiform or cylindrical spores, at first
joined in bundles.

VII. SCEPTROMYCES. Pedicels erect,
geniculate, verticillately branched ; branches
short, racemose; sporesin grape-like bunches.

** Spores septate.

VIII. BRACHYCLADIUM. Pedicels
branched above, septate, moniliform; branches
and branchlets forming a sporiferous capitu-
lum ; spores transversely septate.

IX. PAPULASPORA. Pedicels erect,
short, articulate, simple or slightly branched,
each terminating in an oblong two- or four-
partite spore.

X. TRICHOTHECIUM. Pedicels inter-
woven in tufts, the central erect, fertile;
spores acrogenous, didymous, free, com-
monly loosely heaped together.

XI. CEPHALOTHECIUM. Pedicels sim-
ple, continuous, bearing a terminal head of
didymous spores.

B. Erect filaments (pedicels) terminating
in strings of spores.

* Spores simple.

XII. PENICILLIUM. Pedicels erect, sep-
tate, penicillately branched above ; branches
and branchlets septate; strings of spores
attached to the tips of the branches.

XIII. ASPERGILLUS. Pedicels conti-
nuous, erect, simple filaments, inflated into
a little head at the summit ; strings of spores
crowded upon the head.

XIV. SPOROTRICHUM. Pedicels erect,
simple, or slightly branched, septate and
articulate, articulations remote, inflated ;
spores simple, usually found collected in
heaps among the filaments.

XV. RHODOCEPHALUS. Pedicels erect,
continuous, not septate, divided at the sum-
mit into simple branchlets forming a capitu-
lum; strings of spores attached singly to
the tips of the branchlets.

XVI. GONATORHODUM. Pedicels erect,
septate, nodulose, with minute sporomor-
phous branchlets crowded in whorls, septate,
affixed to the nodules, bearing chains of
spores at the apex.

XVII. MONILIA. Pedicels erect, sep-
tate, crowded at the summit with chain-
like branches composed of strings of spores
soon falling apart.

** Spores septate.

XVIII. DACTYLIUM. Pedicels erect,
septate, unbranched; strings of spores at-
tached in a bunch to the apex ; spores sep-
tate.

XIX. DENDRYPHIUM. Pedicels erect,
septate, branched above ; strings of septate
spores attached singly or in pairs to the
apices of the branches.

C. Fertile filaments (pedicels), inflated at the
tips or at various points in their length,
with projecting points or warts on the
inflations bearing

* Simple spores.

XX. RHINOTRICHUM. Pedicels erect,
septate, sometimes sparingly branched, the
apices clavate, bearing scattered points sup-
porting simple spores.

XXI. STACHYLIDIUM. Pedicels erect,
articulated, whorled-branched above ; branch-
lets geniculate and articulate; spores sub-
pedicellate, accumulated in little capituli-
form heads inserted at the tips of the
branches.

XXII. GONATOBOTRYS. Pedicels erect,
septate, nodulose; nodules distant, warty;
warts spirally arranged, and bearing con-
globated solitary spores.

XXIII. ACMOSPORIUM. Pedicels erect,
septate, branched above; branches and
branchlets forming a cyme, thickened at the
apex, and furnished with globular capitules
covered all over with points ; spores simple,
attached on the points of the capitules.

XXIV. HAPLOTRICHUM. Pedicels erect,
septate, terminating above in a continuous,

MUCEDINES.

[ 441 ]

MUCOR.

simple, solitary, sporiferous head; spores
simple.

XXV. ACTINOCLADIUM. Pedicels erect,
septate, umbellately branched at the sum-
mit ; spores simple, accumulated at the tips
of the branches.

XXVI. BOTRYOSPORIUM. Pedicels erect,
septate, with short needle-shaped branchlets
above ; branches spirally placed, articularly
joined to papillae, bearing at the tips five
sporiferous points, and quaternate or quinate
heads of spores, resembling an elongated
and dense raceme ; spores heaped together
regularly in globules.

** Spores septate.

XXVII. ARTHROBOTRYS. Pedicels sim-
ple, septate, nodular; nodules glomerulife-
rous, warty ; warts spirally arranged, sus-
taining spores at first solitary, afterwards
crowded into glomerules. Spores didymous.

D. Fertile filaments conjoined into a com-
pound pedicel.

XXVIII. STYSANUS. Pedicel compound,
fibrous or fleshy-cellular, erect, thickened
at the summit, bearing a hemispherical or
cylindrical warty capitulum ; spores in sim-
ple strings attached singly to the sides of
the capitulum (to the tips of the fibres com-
posing the pedicel).

XXIX. COREMIUM. Pedicel compound,
erect, composed of a number of parallel
conjoined branching filaments, forming a
penicillate head at the summit; filaments
septate, the fertile verticillately branched,
mixed with sterile simple ones.

[Excluded genera : — Briarea •=. Monilia ;
Clonostachys = Botrytis (vera) ; Polyactis
= Botrytis (vulgaris) ; Peronospora = Bo-
trytis ; Cladobotryum = Dactylium.~\

MUCOR, Micheli. — A genus of Mucorini
(Physomycetous Fungi), forming the com-
mon moulds of paste, decaying fruits or
other vegetable matters. The general cha-
racter is that of an interwoven mass of hori-
zontal branched filaments, sending down
little root-like ramules and pushing up erect
fertile filaments (not septate), which branch
at the base in a stoloniferous manner, and
thus form loosely grouped tufts. At the
summit of the erect filaments, a globular
vesicle is formed, which soon becomes cut
off by a septum. Its contents become divided
by segmentation in a large number of spores,
and the septum at the base becomes mean-
while pushed up or protruded into the centre

of the vesicle so as to form a kind of " core,"
called the columella. After a time the vesicle
(peridiole) bursts and discharges its spores;
the pressure of the turgid columella appa-
rently hastens the bursting. The dehiscence
takes place either by a circular slit just above
the base of the columella, leaving this alone,
surroundedby a narrowragged collar(-Mwcor),

Fig. 500.

Fig. 501.

Mucor Mucedo.
(Ascophora-form.)

Fig. 500. Nat. size, growing on a leaf.

Fig. 501. Single fertile filaments, with the columella
collapsed, and fallen like a cap over the end. Magn. 50
diams.

or the peridiole bursts above and disappears
by solution, and columella collapses upon
the pedicel (Ascophora, fig. 501). The mem-
brane of the peridiole of M. Mucedo (and
perhaps of other species) is clothed with
minute spines. The erect filament is some-
times simple, sometimes branched. It ap-
pears likely that the columella may become
converted into a second peridiole, by being
shut off by a septum which is converted into
a new columella.

It has been imagined that ACHLYA is
only an aquatic form of Mucor, and this
seems not improbable ; however, the experi-
ments we have made on this point have
hitherto given negative results.

The species of Mucor described by authors
are pretty numerous, but we think consider-
able allowance for variation should always
be made in this genus. RHIZOPUS, Ehr.=
Mucor, when distinctly stoloniferous. It

MUCOR.

[ 442 ]

MUCORINI.

seems very doubtful whether HYDROPHORA
should be separated from Mucor.
* Fertile filaments simple.

1. M. mucedo, L. (figs. 500, 501). My-
celium byssoid, peridiole and spores globose,
at first white, ultimately blackish. (This
includes Ascophora Mucedo, Tode). Ex-
tremely common. Sowerby, Fungi, pi. 3/8.
fig. 6 ; Greville (Ascophora), Sc. Crypt. Fl.
pi. 269.

2. M. caninus, Pers. Mycelium byssoid,
peridiole globose, ultimately yellow or ferru-
ginous ; spore globose or elliptic. Very
common on excrement of dogs and cats in
wet weather. Grev. -Sc. Crypt. Fl. pi. 305.

3. M. fusiger, Lk. Mycelium byssoid.
Peridiole globose, ultimately black; spores
spindle-shaped. On decaying fungi.

4. M . clavatus, Lk. " Mycelium byssoid.
Clavate apices of the fertile filaments simply
penetrating the globose peridiole; spores
globose, at first white, then brown, at length
black." On rotten pears. (Possibly only a
state of M . Mucedo or the following.)

5. M. amethysteus. Mycelium thick,
white, closely interwoven. Peridiole at first
white, then pale yellow, then crystalline and
pure violet, finally violet -black or brownish ;
" spore globose, filled with globose spori-
dioles(?)." Fertile filament 1-40" high. On
rotten pears with the foregoing.

6. M. delicatulus, Berk. Mycelium form-
ing a thin velvety stratum. Very minute,
fertile filaments short, peridioles globose,
pale yellow; spores globose. On rotting
gourds.

7. M. succosus, Berk. Mycelium forming
small, pulvinate, yellow, spongy masses.
Peridiole very minute, globose, yellow, at
length olive ; columella minute. On dead
shoots of Aucuba. Berk. Ann. Nat. Hist.
vi. pi. 12. fig. 15.

** Fertile filaments branched.

8. M. ramosus, Bull. Mycelium woolly.
Fertile filaments racemose. Peridioles glo-
bose, yellow, then bluish-grey or reddish-
brown. On rotting fungi. Bulliard, pi. 480.
fig. 3.

9. M. subtilissimus, Berk. Mycelium
creeping, filaments exceedingly slender.
Fertile filaments branched, the short patent
branches each terminating in a globose
peridiole; spores oblong, elliptical. A mildew
of onions. Berk. Hort. Journal, iii. p. 97-
figs. 1-5.

BIBL. Berk. Brit. Flora, ii. pt. 2. p. 332,
Ann. Nat. Hist. vi. p. 433, Hort. Journal,

iii. p. 91 ; Fries, Summa Veg. p. 487, Syst.
Myc. iii. p. 318; Fresenius,Be^r. z. Mycologie,
1 heft. p. 4 (1850).

MUCORINI.— A family of microscopic
Physomycetous Fungi, constituting the
moulds, &c. common on moist decaying
vegetable and animal substances, consisting
of a filamentous mycelium, forming flocks
and clouds in or on decaying matters,
bearing vesicles (on erect pedicels or sessile)
filled with minute sporules, discharged by
the rupture of the vesicles (peridioles) . These
plants correspond among the thecasporous
Fungi to the Mucedines among the acrospo-
rous or free-spored orders. The peridiole
consists of the terminal cell of an erect
filament, enlarged (like the head on a pin)
into a globular vesicle. At first the cavity of
this vesicle communicates with that of the
pedicel, but a septum is soon formed; in
some genera this septum is flat, in others
projecting into the interior of the peridiole
like the " punt " of a bottle, forming a hemi-
spherical or cylindrical columella. While this
columella rises in the peridiole, the latter
becomes filled with spores, forming thus a
polysporous sporange, and it bursts to let
them escape.

The manner of bursting of the sporange
and the form of the central column vary
much, and afford generic characters. " The-
lactis" presents a remarkable peculiarity;
each filament terminates in a sporange con-
taining a great number of spores, while at its
base it gives origin to whorls of branches,
the terminal cells of which remain sterile.

Sizygites is stated by Ehrenberg to exhibit
a phenomenon of conjugation of its branches,
like that of the Zygneinaceae among the
Algae. (See SIZYGITES.)

Some remarkable observations have been
published lately by Be Bary, tending to show
that the genus Eurotium only represents
certain conditions of Aspergillus. (See EU-
ROTIUM.)

Synopsis of British and allied Continental
Genera.

I. PHYCOMYCES. Peridiole pear-shaped,
separated from the apex of the erect pedicel
by an even joint ; opening by an umbilicus.
Spores oblong, very large. Filaments caes-
pitose, tubular, continuous and shining.

II. HYDROPHORA. Peridiole subglobose,
membranous, dehiscent, at first crystalline,
aqueous, then turbid and at length indurated,
persistent. Columella absent; spores simple,
conglobated.

MUCOUS CORPUSCLES.

[ 443 ]

MUSCA.

III. MUCOR. Peridiole subglobose, se-
parating like a cap (leaving an annular
fragment attached) from the erect, simple,
continuous pedicel, or bursting irregu-
larly ; columella cylindrical or ovate, spores
simple.

IV. EUROTIUM. Peridiole membranous,
sessile, at length bursting irregularly; spores
globose, very small, gelatinous, diffluent in
water ; filaments of the mycelium radiating
from the base of the peridiole.

V. ^EGERITA. Peridiole spherical, very
fugacious; sporidia soon scattered like white
meal over the gruraous receptacle.

VI. PILOBOLUS. Peridiole globular,
separating Hke a cap from the short stalk
composed of a single cell, attached on an
unicellular ramified mycelium; columella
conical; spores very numerous, free in the
peridiole.

VII. SIZYGITES. Filaments erect, sim-
ple, very much branched above, branches
and branchlets di- or tri-chotomous, fertile
branches forcipate, bearing pairs of opposite
internal, clavate branches, which subsequently
coalesce.

Excluded genera. Ascophora == Mucor ;
Thelactis = Mucor ? ; Rhizopus = Mucor ;
Acrostalagmus = Botrytis.

MUCOUS CORPUSCLES. SeeMouTH.

MUCOUS MEMBRANES.— Those in-
ternal canals and cavities of the body which
open externally, as the alimentary canal,
bladder, &c., are bounded by what may be
regarded as internal prolongations of the
skin, called mucous membranes.

They consist of four layers : — 1, an inner-
most, or epithelial layer, corresponding to
the cutaneous epidermis ; 2, a subjacent
structureless basement membrane, which is
not always separable and demonstrable ;
next comes 3, a layer of variable thickness,
consisting of areolar and elastic tissue, well
supplied with blood-vessels and nerves, often
containing numerous small glands, frequently
furnished with conical or filiform processes,
termed papillae or villi, and sometimes tra-
versed by muscular fibres. These three
layers form the proper mucous membrane j
and are supported by 4, an outermost
submucous layer or coat, composed of the
same elements as the last, but much more
lax in structure, and frequently containing
fatty tissue.

The mucous membranes are usually very
vascular, and injected preparations of them
are very beautiful, and to some extent cha-
racteristic.

The size and form of the epithelial cells
are to a certain extent also characteristic,
especially those of the uppermost layer ; and
a knowledge of the peculiar structure in
individual cases, is of use in determining the
source of morbid mucous products mixed
with epithelial cells.

See the special articles.

MUCUS. — Natural mucus contains no
essential morphological elements. As ordi-
narily met with, it often, however, exhibits
some epithelial cells, mucous corpuscles and
numerous granules; and the peculiar mucous
matter has a striated or fibrous appearance,
mostly produced artificially. The abnormal
elements are principally those of inflammation .

BIBL. See CHEMISTRY, ANIMAL.

MUD. — The organisms found in mud are
very numerous; they consist principally of
Diatomaceae and other minute Algae. The
surface of mud is often covered with yellow-
ish or greenish layers, composed almost
entirely of these organisms. The most beau-
tiful and most numerous forms of Diatoma-
ceae are found in the mud of sea-water, or
that of tidal rivers. On exposing a bottle of
mud and water to the light, they will rise
to the surface of the mud, some adhering to
the side of the bottle next the light, and can
then be easily separated. The surface of
freshwater mud frequently appears of a
blood-red colour, from the presence of Tu-
bifex rivulorum.

MUREXIDE. See AMMONIA, PURPU-

RATE OF, p. 29.

MURIATE OF AMMONIA. See AM-
MONIA, HYDROCHLORATE OF, p. 28.

MUSA, Tournef.— A genus of Musaceae
(Monocotyledonous Flowering Plants), com-
prising the Bananas and Plantains. The
fibro-vascular bundles of Musa afford ex-
amples of spiral vessels with numerous
spiral fibres (see SPIRAL-FIBROUS STRUC-
TURES). Musa textilis affords the fibre
called Manilla hemp (see PI. 21. fig. /). See
TEXTILE SUBSTANCES.

MUSCA, Linn. — A genus of Dipterous
Insects, of the family Muscidae.

It would be of little use to detail the cha-
racters of this genus, as they vary so much
according to different authors. Among the
well-known species (all of which have been
formed into new genera), we may mention :

Musca domestica, L., common house-fly.
Third joint of antennae thrice the length of
the second; style plumose, eyes reddish-
brown, front of head white, the rest black ;
thorax blackish-gray with four longitudinal

MUSCACEJE,

[ 444 ]

MUSCLE.

black bands, abdomen blackish-brown above,
with blackish elongated spots, pale yellow-
ish-brown beneath.

M. carnaria, L. (Sarcopliaga, Meigen),
the flesh-fly. Antennae feathery ; head
golden-yellow in front, eyes reddish ; thorax
gray with black longitudinal lines, abdomen
black, with four square white spots on each
segment, all the body strewed with black
hairs. Viviparous, 1-2" long.

M. Ctesar, L. (Lttc*7ia,Donov.). No spots,
abdomen green, with a metallic lustre.

M. vomitoria, L. ( Calliphora, Donov.), blue-
bottle or blow-fly. Head yellowish, golden
or white, eyes brown ; thorax black ; abdo-
men shining blue with black stripes and
long black hairs.

The larvae are known as gentles. The
ova or larvae are deposited upon animal or
vegetable substances, mostly in a state of
decay, upon which they live.

Several parts of the species of Musca are
of general microscopic interest : — as the
proboscis (PI. 26. fig. 29) with its two fleshy
lobes (c), kept expanded by a beautiful and
elastic framework of modified tracheae ; the
setae or lancets (b], which are modified
maxillae, sometimes rudimentary, with their
palpi (a) at the base ; the remarkable an-
tennae (PI. 26. fig. 20) ; the elegant tarsus
(PI. 27. fig. 7 «), with its terminal spine,
pulvilli (figs. 7, 8 & 9) and claws ; and the
rudimentary wings (halteres, INSECTS, p.
358).

Musca pumilionis (Chlorops, Meig.) de-
posits its eggs in the young wheat-grain,
which is consumed and destroyed by the larvae.

Many other members of allied families of
Diptera, commonly known also as flies, are
of microscopic interest, on account of their
oral setae or lancet-like organs.

BIBL. Westwood, Introduction, fyc.; Mac-
quart, Hist. nat. d. Ins. Dipt.; Meigen,
Syst. Beschr. d. bek. eur. zweiflug. Insect. ;
Keller, Gesch. d. gemein. Stubenfliege ;

MUSCACE.E. See MOSSES.

MUSCLE. — Muscular tissue forms the
greater portion of the flesh of animals.

It occurs in two principal forms ; one of
which is termed organic, unstriated, or un-
striped muscle ; the other, voluntary, striated
or striped muscle.

Unstriated muscle. — This consists of more
or less elongated, somewhat spindle-shaped,
narrow fibres (p. 62, fig. 34), having the
import of cells, and hence often called fibre-
cells. They are, however, solid. Each
contains an elongated nucleus, brought to

light by the addition of acetic acid, but ex-
hibiting no nucleolus. The fibres are of
variable length, from about 1-580 to 1-250",
and 1-5000 to 1-3500" in diameter. They
sometimes exist singly in the midst of areolar
tissue; at others they are united into rounded
or flattened bundles, and surrounded by an
imperfect kind of sarcolemma, composed of
areolar tissue with elastic fibres.

They occur most abundantly in the hollow
viscera ; as the stomach, the intestines, the
bladder and the uterus ; but they also exist
in other situations, as the spleen, trachea
and bronchi, the dartos, the arteries, veins,
and lymphatics, the prostate gland, fallopian
tubes, urethra, villi of the small intestines,
the skin, iris, &c.

Fig. 502.

Unstriated muscular fibres from the oesophagus of a
pig, after treatment with diluted nitric acid.

Magnified 10 diameters.

Striated muscle. —The structure of striated
is more complex than that of unstriated
muscular tissue. It consists of a num-
ber of very slender fibres, called fibrillae,
connected into bundles, termed primitive
bundles or fasciculi, each of which is en-
closed in a sheath or sarcolemma. The pri-
mitive bundles are again united into second-
ary and tertiary bundles, the whole being
bound together by a connected mass of
areolar and elastic tissue surrounding each
of them, and forming the perimysium. This
arrangement is best seen in a transverse sec-
tion (fig. 503).

The primitive bun dies are from about 1-1000
to 1-200" in diameter, and of a rounded or po-
lygonal form (fig. 504). Their surfaces are
marked by a number of transverse striae,
which forms the most characteristic appear-
ance of the tissue. They also exhibit irre-
gular longitudinal striae, which are the indi-

MUSCLE.
Fig. 503.

[ 445

Transverse section of a portion of the sterno-cleido-
mastpideus. a, outer perimysium ; b, inner perimysium ;
c, primitive and secondary muscular bundles.
Magnified 50 diameters.

Fig. 504.

Transverse section of the muscular fibres or primitive
bundles of the human gastrocnemius : a, sarcolemma
and interstitial areolar tissue ; b, section of fibrillse and
intermediate substance.

Magnified 350 diameters.

cations of the component fibrillse (PI. 17.
fig. 35).

The sheath or sarcolemma, when separated
from the muscular substance by treatment
with water, acetic acid, and alkalies, in which
it is insoluble, forms a structureless, trans-
parent and smooth membrane. It is perhaps
most easily seen in the muscle of fishes by
simple dissection (PI. 41. fig. 18). On its
inner side are numerous spindle-shaped or
lenticular nuclei (fig. 505).

The ultimate or primitive fibrillse in man
are about 1-20,000'' in diameter, and each
exhibits numerous regularly alternating light
and dark portions (PI. 17. fig. 36/); the
relative positions of the two may, however,
be made to change by altering the focus.
The ends of the fibrillse are distinguishable
in transverse sections of the primitive bun-

MTTSCLE.
Fig. 505.

Portion of a primitive bundle treated with acetic acid.
a, sarcolemma ; b, single nucleus ; c, twin nuclei sur-
rounded by granules of fat.

Magnified 450 diams,

dies, and their lateral margins are perfectly
straight.

Different views have been taken of the
structure of the fibrillae, and, in fact, of the
general structure of muscle. Thus the ulti-
mate fibrillge have been described as monili-
form or beaded (PI. 17. fig. 36 c); this ap-
pearance, however, arises from an optical
illusion, connected either with imperfection
in the object-glasses used, viewing the object
in too much liquid, or the use of too low an
object-glass, and too high an eye-piece.

It often happens, especially when muscle
has been kept in spirit, that it separates
transversely into a number of flat disks (fig.
506) ; hence it has been viewed as consisting

Fig. 506.

A, a primitive bundle, magnified 350 diameters, partly
separated into disks, side view. B, the same, rather
more magnified, end view.

MUSCLE.

[ 446 ]

MUSCLE.

of these disks. Again, as under certain con-
ditions it separates longitudinally into fibrillae
and transversely into disks, it has been sup-
posed to consist of * primitive particles ' or
' sarcous elements' united end to end as well
as laterally. We admit the existence of the
primitive fibrillae as original components of
muscle, although there can be little doubt
that the fibrillae are not homogeneous, and
of uniform constitution either chemical or
physical. On carefully examining them at
different foci, it is seen that those portions
of isolated fibrils which appear dark when
the margins of the fibrils are best in focus,
are more highly refractive than the interme-
diate portions, as shown by the greater lu-
minosity they acquire on altering the focus
of the object-glass ; and that this focal effect
does not arise from a lenticular form of the
parts, is evident from the straight condition
of the margins of the fibrils. Hence these
more highly refractive parts probably con-
stitute the proper muscular substance, con-
nected in the direction of their length by a
different kind of substance, which becomes
brittle under the action of spirit, whilst the
former does not so ; for the line of separa-
tion into the disks occurs through the less
highly refractive portions. And that these
compound fibrils naturally exist is shown by
their being distinguishable in a primitive
bundle without the use of reagents, or even
of mechanical means.

It has also been supposed that the ulti-
mate fibrils are composed of cells arranged
end to end, and the appearance represented
in PI. 17. fig. 36 a, which is sometimes met
with, might countenance this notion. But
whenever it is seen, there is imperfect defi-
nition, from the presence of too much liquid,
or some other cause ; for we have never ob-
served it when the object was properly ar-
ranged and examined.

There are other appearances exhibited by
the fibrillae which cannot at present be satis-
factorily explained. Thus, sometimes each
more highly refractive portion is divided by
a dark line, indicating less refraction at that
part (PI. 17. fig. 36 d, taken at the elevated
focus); at others the same part appears
bounded at each end by a transverse dark
line (fig. 36 b], or both parts are traversed
mesially by a transverse dark line. In some
instances we have noticed a very delicate
constriction, which would account for these
appearances, but the indication of this we
have failed to discover.

The dark portions of the various fibrillae

of the primitive bundles being opposite to
each other, gives rise to the coarser dark
striae seen under a low power. But it often
happens that by pressure or manipulation
this natural relation is destroyed, the direc-
tion of the striae altered, and sometimes
those of one bundle are made to alternate
with those of the next. Hence arises an
appearance of transverse or spiral fibres (PL
I/, fig. 35), but none such really exist in
muscle.

The proper substance of muscle consists
chemically of a proteine compound called
syntonine, resembling fibrine in several of
its properties, but differing from it in the
greater action of dilute muriatic acid, &c.
By pressing muscle, a liquid is obtained
containing some peculiar organic substances.
This liquid probably exists between the
fibrillae.

The unstriated and the striated muscular
fibres have the same chemical composition.

In regard to the development of muscle,
in its earliest stage it consists of nucleated
cells ; these become fusiform, arranged in
rows, and uniting by their ends, form fibres.
The proper muscular substance is then
formed within them, as a secondary deposit,
from the inner surface of the cells towards
the centre, until the whole is solidified.

The muscles are very vascular. The
smaller branches of the vessels mostly run
parallel to the primitive bundles in the peri-
mysium, and anastomose by transverse or
oblique branches.

They are also well supplied with nerves ;
these mostly terminate in a plexus of looped
branches (fig. 507).

Muscle undergoes important changes in
disease. Wounds are filled up with areolar
or tendinous tissue. In atrophy and fatty
degeneration, the bundles become smaller,
softer, more readily broken up, the trans-
verse striae and fibrillae indistinct, or appa-
rently absent, and contain yellowish or brown
pigment-granules, with more or less nume-
rous globules of fat (PL 30. fig. 14 a), and
sometimes a large number of nuclei or small
cells.

The interfascicular areolar tissue is also
sometimes increased in amount, and fatty
tissue developed in it. Sometimes the mus-
cular substance is partially absorbed, and
the sarcolemma contracting, gives the bun-
dles a moniliform appearance (PL 30. fig.
14 b}. In tetanus, the fibres become vari-
cose and often ruptured, and the striae closer.

The muscular tissue of the lower Verte-

MUSCLE.

Fig. 507.

[ 447 ]

MYRIAPODA.

Termination of the branches of a nerve in a portion of
the omohyoideus muscle, treated with caustic soda.
a, meshes of the terminal plexus ; b, loops ; c, muscular
fibres.

Magnified 350 diameters.

brata, and some of the Invertebrata, agrees
essentially in structure with that of man ;
but the sarcolemma is often much thicker,
the fibrillse larger, and the nuclei contained
within the substance of the bundles, and
sometimes arranged in regular linear series.
The margins of the bundles are also some-
times uneven, and rounded at regular inter-
vals (PI. 17- fig. 35), giving the appearance
of their being surrounded by fibres.

In many of the lower members of the In-
vertebrata, although the substance of the
body is voluntarily contractile, no trace of
bundles or fibres can be detected.

To obtain the separate fibrillae of striated
muscle, the tissue should be macerated for
about two hours in alcohol. This removes
any fatty matter, and renders the fibrillae
more easily separable, by dissection with
mounted needles. The fibrillae are very
minute, as we have stated; hence a very
small portion of the tissue only should be
taken for examination. That of fishes (the
cod or the skate) or of reptiles (the frog) is
the best for the purpose.

The unstriated muscular fibres are best
seen in muscle which has been treated with

diluted nitric or muriatic acid (1 part acid to
4 water). This renders them more opaque,
and often curiously tortuous or spiral (fig.
502).

BIBL. Kolliker, Mikrosk. Anat. ii. and
the Bibl. ; Henle, Allgem. Anat. ; Bowman,
Todd's Cycl. iii. art. Muscle, and Phil.
Trans. 1840—41 ; Donders, Mulder's
Physiolog. Chem.-, and the Bibl. of CHE-
MISTRY, ANIMAL.

MUSHROOMS. See AGARICUS.

MUSSEL. — The species of Mollusca
commonly known as mussels are of interest
to the microscopist, on account of their ali-
mentary canal containing Diatomaceae ; the
same probably applies also to other marine
and aquatic Mollusca, as well as other ani-
mals living upon these minute Algae.

If it be required to obtain the valves only,
the entire animal may be dissolved in hot
nitric acid, and the residue washed as usual
in preparing the Diatomaceae.

The gills of the common marine mussel
(Mytilus edulis) are well adapted for the
examination of the cilia and ciliary motion.

Mussels also frequently contain the
* nurses' and larvae (Cercarice) of Distoma
and other Trematoda (Entozoa).

One of the Acarina, Hydrachna (?) con-
charum (or Limnochares (?) anodontce), is
found in the pallial cavity or beneath the outer
lamella of the branchial plates of the Naia-
deae (Unio, &c.).

BIBL. Dickie, Ann. Nat. Hist. 1848. i.
p. 322 ; Vogt, Ann. des So. nat. 3 ser. xii. ;
and the Bibl. of MOLLUSCA.

MYCOTHAMNION, Kiitz. — One of
Kiitzing's genera of Leptomiteous Algae,
composed of obscure byssoid productions
growing in foul water. Probably the mycelia
of fungi.

MYOBIA, Heyd. See ACARINA, p. 4.

MYRIAPODA.— An order of Insects.

Char. Wings absent; legs numerous;
thorax not separated from the abdomen.

These animals are commonly known as
centipedes or millipedes.

The body is usually long, cylindrical
or flattened, and consisting of numerous
rings or joints. The head distinct, and the
jointed legs arranged on each side of the
body throughout its length. A few of them
are broad, short, and flattened, somewhat
resembling wood-lice. The head is furnished
with a pair of antennae. Behind these are
laterally placed the eyes, which in some are
absent ; they consist of mostly a group of
ocelli.

MYRIOCEPHALUM.

[ 448 J

MYRIOTRICHIA.

The structure of the trophi varies in the
different genera. The labrum is small, and
usually consolidated with the cephalic plate.
The mandibles (PL 28. figs. 25, 26 6) are often
large and powerful, somewhat resembling
those of the spiders, and, like them, traversed
by a canal, through which the duct of a
poison-gland passes. The maxillae are
smaller, softer, and furnished with two palpi.
The labium (PL 28. fig. 26 c) is often deeply
cleft, its anterior and inner margin elegantly
toothed, and to it are attached the labial
palpi (fig. 26 c). In some the labial palpi
and mandibles are absent, the labium form-
ing a kind of sheath or suctorial rostrum.

One or two pairs of legs, with a single
claw, are attached to each joint of the body.

The internal structure resembles that of
other insects.

The sexes are separate. The embryo, on
escaping from the ovum, has but few legs,
sometimes three pairs, at others none, the
number being augmented each time the
skin is cast ; the same applies to the ocelli.

The Myriapoda live in dark places, be-
neath the bark of trees, under dead leaves,
stones, &c.

They form very interesting objects when
properly prepared and mounted. The small
ones, when slightly compressed between
two glasses, dried in that position, subse-
quently macerated in oil of turpentine, and
mounted in balsam, become very transpa-
rent, and show the structure beautifully ;
the nervous ganglia and cords are often very
distinctly seen in these specimens without
dissection. The abdomen of the longer
specimens should be slit up with fine scis-
sors, and the viscera removed ; the integu-
ment being gently compressed, and dried as
above.

BIBL. Newport, Linn. Trans, xix. ; id.
Phil. Trans. 1841 ; Gervais, Ann. des Sc.
nat. 2 ser. vii. ; Leach, Linn. Trans, xi. ;
R. Jones, Todd's Cycl. Anat. and Phys. iii.

MYRIOCEPHALUM, De Not. See
CHEIROSPORA.

MYRIONEMA, Grev.— A genus of Myri-
onemaceae (Fucoid Algae), consisting of mi-
nute epiphytic plants, forming patches of
short, erect, simple, jointed filaments, spring-
ing from a thin expanded layer of decum-
bent cohering filaments. They are described
as bearing oblong 'spores,' but these are
probably oosporanges producing zoospores;
and it is probable that they are accompanied
by trichosporanges, as in Elachistea.

1 . M. strangulans, Grev. Patches convex,

confluent ; erect filaments clavate ; ' spores
on the decumbent filaments. Forming dark
brown dot-like spots on Ulvce, or little rings
round Enteromorpha. Grev. Sc. Crypt. Flor
pi. 300.

2. M. Leclancherii, Chauv. Patches or-
bicular; erect filaments cylindrical; 'spores
on the decumbent filaments. Forming
patches 1-12 to 1-4" in diameter (at first like
a Coleochcete) on decaying fronds of Rhody-
menia and Ulva. Harv. Phyc. Brit. pi. 41 A,

3. M. punctiforme, Lyngb. Patches glo-
bose; filaments tapering to the base ; 'spores'
fixed to the erect filaments near their bases ;
' spores > very narrow. Forming minute
patches on Ceramia, Chylocladia. Harv.
I. c. pl.41B.

4. M. clavatum, Carm. An obscure spe-
cies. Hook. Brit. Fl. ii. pt. 1. p. 391.

BIBL. Op. cit. sup. ; Harvey, Brit. Mar.
Ala. p. 51. pi. 10 E.

MYRIONEMACE^.— A family of Fu-
coideae. Olive-coloured sea-weeds, with a
tuber-shaped or crustaceous spreading frond,
sometimes minute and parasitical. Ovoid
oosporanges and filamentous trichosporanges
attached to the superficial filaments, and
concealed among them.

Synopsis of the British Genera.

I. LEATHESIA. Frond tuber-shaped.

II. RALFSIA. Frond crustaceous.

III. ELACHISTEA. Frond parasitical,
consisting of a tubercular base bearing pen-
cilled erect filaments.

IV. MYRIONEMA. Frond parasitical,
forming a flat base bearing cushion-like tufts
of decumbent filaments,

MYRIOTRICHIA, Harv.— A genus ol
Ectocarpaceae (Fucoid Algae), consisting oi
minute epiphytic plants, forming tufts oi
capillary filaments on larger Algae. The
filaments are simple jointed tubes, set all
over with minute, simple, spore-like ramules.
which again are clothed with very slender,
long, articulated filaments. The fructifica-
tion consists of oval oosporanges on the side
of the main axis, producing zoospores ; pro-
bably also trichosporanges exist.

1. M. claviformis, Hook. Main filament
with quadrifarious ramules, increasing in
length upwards. Fronds 1-2" long, forming
tufts on Chorda lomentaria. Harv. Phyc.
Brit. pi. 101.

2. M. Jiliformis, Harv. Main filaments
very long, often flexuous, set at irregular
intervals with oblong clusters of minute pa •
pilliform ramules. Frond 1" or more long.

MYROTHECIUM.

[ 449 ]

MYXOGASTRES.

On Chorda lomentaria and Asperococcus
echinatus. Harv. Phyc. Brit. pi. 156.

BIBL. L. c. sup. ; Harv. Brit. Mar. Alg.
p. 63. pi. 9 D, Hook. Journ. Bot. i. p. 300.
t. 138.

MYROTHECIUM, Tode.—A genus of
Onygenei(?) (Ascomycetous Fungi).

M. roridum, Tode, a somewhat obscure
plant, with a peridium formed of slender
filaments, evanescent in the centre, and con-
taining a gelatinous mass of cylindrical
sporidia (?); grows on rotting plants, dried
fungi, &c.

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 323;
Fries, Summa Veg. p. 448.

MYXOGASTRES.— A family of minute
Gasteromycetous Fungi, of curious and in-
teresting structure, characterized by their
development from a mucilaginous matrix,
out of which arise sac-like dehiscent pe-
ridia, emitting a very remarkable, often
reticulated, filamentous structure, bearing
the spores.

The Myxogastres grow upon bark of trees,
or decayed wood, or on leaves (especially
under certain atmospheric conditions), or on
the ground, and consist in infancy of a dif-
fluent mucilage of varied form and colour.
In proportion as this acquires consistence,
there is formed a crust common to the
whole mass, divided within into chambers, or a
number of individuals appear separate from it
and associated on a common thallus. In the
first case a single peridium is formed, which
may be regarded as a common peridium if
we consider the inner cells as partial peridia
soldered together, while in the second case
each individual has its own peridium. This
peridium, sessile or stalked, is composed of
one or more membranous, papery or crusta-
ceous coats; in some cases where there are two
coats, the outer is crustaceous and persistent,
or it is extremely thin and membranous, and
breaks up into deciduous scales. The mode
of dehiscence varies. Sometimes an irregular
opening is formed at the summit, as in Phy-
sarum ; sometimes the peridium opens like
a little box, as in Craterium ; sometimes the
upper half falls off, leaving a cup-shaped
base, as in Arcyria ; or the membrane may
be very delicate, and break up entirely into
little scales, which fall off and leave the
capillitium with its spores naked, as in Ste-
monitis. The capillitium or sporiferous
structure is formed of filaments, simple or
branched, free and loose, or anastomosing so
as to form a network ; in Trichia they have
spiral markings, and resemble the elaters of

Hepaticse (PL 32. fig. 39). The filaments are
often elastic, and when the peridium bursts
they rise from the bottom of it, forming a
coloured, erect or drooping plume (Arcyria).
In many species there is a stalk (columella
or stylidium) in the centre of the capillitium.
The spores appear to be produced upon
these filaments by growing out from them in
the manner of basidiospores. They are
formed in vast numbers, and lie when com-
plete on the branches and in the interstices
of the capillitium.

Synopsis of British Genera.

* TRICHIACEI. Primary mucilage con-
joining several distinct peridia. Fila-
ments of the capillitium free, entwined,
elastic, or almost absent.

1. LIC^EA. Peridium subpersistent, mem-
branous, bursting irregularly. Spores in
heaps, with scarcely any filaments.

2. PERICH^ENA. Peridium persistent,
membranous, bursting by a circumscissile
slit. Filaments few, free.

3. TRICHIA. Peridium simple, persist-
ent, bursting irregularly at the summit.
Filaments densely interwoven, elastic.

4. ARCYRIA. Peridium simple, membra-
nous, splitting all round at the base, the
upper part very fugacious. Filaments densely
interwoven, elastic.

** STEMONITEI. Primary mucilage con-
necting several distinct peridia. Fila-
ments conjoined into a network, adnate
or innate.

5. CRIBRARIA. Peridium simple, mem-
branous, the upper part falling off. The
filaments adherent in the interior, at length
expanding into a free network above.

6. DICTYDIUM. Peridium simple, sub-
globose, very delicately membranous, burst-
ing indeterminately, leaving the filaments
(innate) forming a cage-like, latticed capilli-
tium.

7. STEMONITIS. Peridium simple, glo-
bose or cylindrical, delicately membranous,
finally evanescent. Filaments forming a
determinate capillitium, attached to a bristle-
like central columella, and forming a network
around it.

8. DIACHEA. Peridium simple, ovate-
oblong, membranous, detached in fragments,
leaving a radiately reticulate capillitium,
with a floccose-grumous, pulverulent axis.

9. ENERTHENEMA. Peridium simple,
globose, membranous, at length evanescent,
laying bare a conical columella with a cap at

2 G

MYXORMIA.

[ 450 ]

NACCARIA,

the summit, bearing underneath ascending
entwined filaments.

*** PHYSAREI. Primary mucilage spread-
ing widely , passing into many peridia.
Filaments adnate, straight, vague.
Spores Hack.

10. CRATERIUM. Peridium simple, va-
ried, papery, persistent, closed by a lid,
which finally falls off. Capillitium some-
what chambered, formed of crowded fila-
ments, at length erect.

11. PHYSARUM. Peridium simple, va-
riable, naked, membranous, bursting irregu-
larly. Capillitium floccose ; filaments at
first joined into a net or forked.

12. DIDYMIUM. Peridium double; the
outer bark-like, breaking up into little fur-
furaceous scales or mealy down, the inner
membranous, bursting irregularly ; filaments
vague, adnate to the peridium.

13. DIDERMA. Peridium double; outer
crust-like, distinct, brittle, dehiscent, the
inner very delicately membranous, evanes-
cent ; filaments vague, adnate to the base.

**** ^ETHALINEI. Primary mucilage pro-
ducing one peridium.

14. SPUMARIA. Peridium indeterminate,
crustaceous, divided into cells by regular
ascending folds, and finally falling away.
No internal filaments.

15. ^ETHALIUM. Peridium indetermi-
nate, fragile, falling away, covered with a
floccose bark externally, cellular internally
by means of filaments conjoined into mem-
branous layers.

16. RETICULARIA. Peridium indetermi-
nate, simple, naked, fugacious, bursting irre-
gularly, laying bare branched, reticulated
adnate filaments.

17. LYCOGALA. Peridium determinate,
composed of a double membrane, membra-
nous, somewhat warty, persistent, bursting
at the summit. Filaments adnate on all
sides of the peridium.

BIBL. See under the heads of these
genera ; also, for the development of Myxo-
gastres, Schmitz, Mycologische Beobach-
tungen ; Linncea, xvi. 188.

MYXORMIA, Berk, and Br.— A genus of
Phragmotrichacei(?) (Coniomycetous Fungi),
containing one species, M. atroviridis, form-
ing minute cup-like bodies, on dead leaves
of grass. It is allied to Excipula, but dif-
fers in its concatenate spores being con-
nected by a slender thread, which frequently
breaks off with them ; spores very gelati-

BIBL. Berk, and Br. Ann. Nat. Hist. 2
ser. v. p. 457. pi. 2. fig. 9.

MYXOTRICHUM, Kze. — A genus of
Dematiei (Hyphomycetous Fungi), growing
on rotten wood, paper, &c. Three species
are described as British : M . ccesium, Fr. ;
M. chartarum, Kze.; and M. defiescum, Berk.
They form little tufts or downy balls, send-
ing off radiating branched filaments. The
spores are described as occurring collected
in masses'about the base of the threads (?).

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 335 ;
Ann. Nat. Hist. i. p. 260. pi. 8. fig. 9; Fries,
Summa Veg. p. 502, Syst. Myc. iii. p. 348.

N.

NACCARIA, Endl.— A genus of Crypto-
nemiaceae (Florideous Algae), containing one
rare British species, N. Wigghii, usually
thrown up from deep water. Its rose-co-
loured frond is 6 to 12" high, and consists of
a branched filiform expansion, the central
axis being about as thick as a crow-quill,
the branchlets quadrifariously alternate and
clothed with ramules about 1-12" long. The
cells of the main axis and branches of the
frond are large and empty in the centre,
small and closely packed at the circumfe-
rence; the ramules are composed of jointed
dichotomous filaments having a whorled
arrangement, surrounded by gelatinous mat-
ter. The difference between the character
of the axes and the ramules is shown in the

Fig. 508.

Naccaria Wigghii.

Fragment of a branch with a fertile ramule.
Magnified 10 diameters.

figure (fig. 508). The spores are borne on
branches of the filaments of the ramules,

NAIDINA.

[ 451 ]

NAILS.

the fertile ramules being swollen in the
middle.

BIBL. Harvey, Brit. Mar. Alg. p. 152.
pi. 20 D, Phyc. Brit. pi. 38; Greville, Alg.
Brit. pi. 16.

NAIDINA.— A family of Ammlata, of the
order Setigera.

Char. Body worm-like, distinctly seg-
mented, without suckers or soft leg-like
appendages ; segments furnished with par-
tially retractile bristles or setae, excepting
the three or four first ; head distinct from
the body.

Animals aquatic, living among aquatic
plants, or burrowing in mud. Sexes di-
stinct ; propagation by ova and by sponta-
neous transverse division. The bristles are
moved by muscles, and answer the purpose
of legs. They are situated on the upper or
under surface of the body, mostly in rows.

Nais, Mull. Four anterior segments with-
out upper bristles.

2V. Scotica, Johnst. Body cylindrical,
ends obtuse, the anterior smooth and cylin-
drical, the portion behind it provided with a
double row of thin tufts of prickles, some of
them composed of several bristles, shorter
than the diameter of the body ; mouth and
anus terminal ; no proboscis. Length 1".

IV. serpentina (Serpentina quadristriata).
Body cylindrical, not flattened in front;
head snake-like, with a produced lower lip ;
eyes two, upper bristles subulate, lower
forked or uncinate. Length about 1£".

The lower bristles have a globular swel-
ling below the middle ; segments eighty to
ninety; head with four dark transverse
bands.

N. proboscidea (Stylaria lacustris). Body
cylindrical, flattened in front; first four
segments divided by a stricture from the
body, the first, or head, being prolonged
into a filiform proboscis; eyes two; upper
bristles simple, lower forked. Length about
1-2".

Found on the roots of aquatic plants.
Middle segments nearly twice as broad as
long, regularly decreasing backwards ; upper
bristles twice as long as the width of the
body, the lower uncinate, with an incisure
about the middle.

Chatogaster, Baer. All the segments
without upper bristles.

C. vermicularis. Body cylindrical, trun-
cate in front ; eyes none ; mouth terminal ;
setae bifid. Length about 1".

Found amongst Lemna, in ditches, and in
the respiratory chamber of the Lymneidae.

We may append a notice of a very com-
mon setigerous Annelidan, which is perhaps
Tubifex rivulorum ; if so, it has been incor-
rectly described, and we cannot identify it.

Body annular, but not divided into seg-
ments, although an appearance of this is
given by the existence of numerous trans-
verse muscular septa, which suspend the
alimentary canal. Head separated by a
slight constriction, somewhat narrower than
the body, and triangular (when viewed from
above), the apex forwards ; eyes none ; body
furnished with two kinds of bristles, mostly
in tolerably equidistant groups, and these
in four rows, but their arrangement is
not constant ; two upper or dorsal rows of
seta3 longest towards the head, rather longer
than the width of body, consisting usually
of three to five long setaceous, and two
short bifid bristles, the two ventral groups
with three short bifid bristles ; towards the
posterior end of the body the bristles become
shorter, the setaceous ones absent, and near
the end the groups are represented each by
one short bifid bristle. Blood red. Poste-
rior end of body rounded ; anus terminal.

This animal lives in mud, and when un-
disturbed, protrudes about one-third of the
anterior part of the body from the mud into
the supernatant water, where it exercises a
constant undulatory and to-and-fro motion.
When in numbers, they give the surface of
the mud a blood-red appearance, and if dis-
turbed, instantly retract entirely into the
mud. They sometimes crawl upon water-
plants, Confervae, &c. Their length is very
variable; from 1-5 to 3-4", or even more.

They are transparent, and show well the
alimentary canal, with its peristaltic actions,
and the cilia lining it; the blood-vessels
and their movements, with the loops bathed
in the chylaqueous liquid, and the coiled
water- (respiratory or renal) vessels with
their cilia.

BIBL. Schmidt, Mutter's Archiv, 1846.
p. 406 ; Duges, Ann. d. Sc. nat. 2 ser. xv.
p. 319 ; Johnston, Catal. of British Non-
parasitical Worms.

NAILS. — These organs, which consist of
modified epidermic formations, are imbedded
posteriorly and laterally in depressions, or
are covered at these parts by a fold of the
skin. The posterior depression (fig. 509 d)
is much deeper than the lateral depressions
(fig. 510 c).

The nail itself consists of the root (fig.
509 I), the body (A;), and the free end (TO).
The root extends over that part of the matrix
2c2

NAILS.

Longitudinal section through the middle of the nail and its matrix, a, matrix and cutis of the back and point
of the finger ; b, rete mucosum of the point of the finger; c, that of the nail ; d, that of the bottom of the root-fold;
e, the same of the back of the finger; /, epidermis of the point of the finger; g, its origin beneath the margin
of the nail ; h, epidermis of the back of the finger ; i, its termination at the upper surface of the root of the nail ;
k body, / root, TO free end of the proper nail.

Magnified 8 diameters.

Transverse section of the nail and its matrix, a, matrix with its ridges (black) ; b, cutis of the lateral fold ; c, rete
mucosum of the same ; d, rete mucosum of the nail with its ridges (white) ; e, epidermic layer of cutaneous fold ;
/, proper substance of the nail, with short teeth on its under surface.

Magnified 8 diameters.

furnished with the ridges, and is either en-
tirely lodged in the posterior depression of
the cutis, or the crescentic portion of it is
exposed. The body of the nail is uncovered
except at the sides, which are overlapped by
the lateral folds of the skin.

The portion of the cutis (fig. 510 a) to which
the under surface of the nail, except that of
the anterior free portion, is attached, — the
matrix or bed, — is covered with ridges (fig.

510 a), extending from the posterior part
or root of the nail to the convex margin of
the white crescentic portion called the lu-
nule, where they become larger and higher,
forming plates which run to the end of the
matrix. The margins of the ridges and
plates are covered with short papillae. The
anterior portion of the matrix of the nail is
very vascular.

The under surface of the root and body
of the nail is covered with depressions and
ridges to adapt itself to those of the matrix.

Two layers are distinguishable in the
nails; an under soft layer (figs. 509 d, 510 c,

511 B), corresponding to and directly conti-
nuous with the rete mucosum of the skin,

and the upper horny layer forming the true
nail (figs. 510/, 509 *," 511 C). The lower
surface of the latter is furnished with small
ridges (fig. 511 c), which occupy correspond-
ing furrows in the mucous layer.

In minute structure the soft layer resem-
bles that of the cutaneous rete, except in
the deeper layers of cells being elongated
and arranged perpendicularly (fig. 511 b).

The horny portion, or proper nail, con-
sists of epidermic cells, flattened and aggre-
gated into plates or laminae (fig. 511 C). In
the natural state, these cells are undistin-
guishable, except at the root and the under
surface, where the nail is in contact with
the mucous layer; the remainder merely
exhibiting shorter or longer dark lines, re-
presenting the flattened nuclei, or indicating
the existence of the laminae. But if a sec-
tion of nail be treated with solution of caustic
potash or soda, the nucleated cells swell up,
and resume their natural form and appear-
ance.

The cutaneous epidermis (fig. 510 e) ex-
tends for a certain distance into the lateral
and posterior depressions of the skin, covers

NAILS. '

[ 453 ]

NAVICULA.

the anterior portion of the root, the poste-
rior part of the body, and the lateral mar-
gins of the nails, terminating in a fine layer,

Fig. 511.

Transverse section of the body of the nail. A, cutis of
the matrix. B, rete mucosum of the nail. C, epidermis
of the same, or proper nail, a, plates of the matrix ;
b, plates of the rete mucosum of the nail ; c, ridges of
the proper substance of the nail ; d, deeper perpendicular
cells of the rete mucosum of the nail ; e, upper flattened
cells of the same ; /, nuclei of the cells of the proper
nail.

Magnified 250 diameters.

Laminae of a nail after boiling with solution of cau-
stic soda or potash. A, side view. B, surface view,
a, cell-membranes ; b, nuclei seen from above ; c, the
same in side view.

Magnified 350 diameters.

which is, however, nowhere directly conti-
nuous with the substance of the nail.

BIBL. Kolliker, Mikrosk. Anat. ii. and
the Bibl. therein.

NAIS, Mull. See NAIDINA.

NARCOTINE. See ALKALOIDS, p. 25.

NASSULA, Ehr.— A genus of Infusoria,
of the family Trachelina.

Char. Body covered with cilia arranged
in longitudinal rows ; mouth surrounded by
a cone of rod-like teeth ; no proboscis nor
ear-like processes.

The gastric sacculi of these animals fre-
quently contain a violet-coloured liquid, de-
rived from the solution of partly digested
Oscillatorice.

N. elegans (PL 24. fig. 45; 6, teeth).
Body cylindrical or ovate, somewhat nar-
rowed in front, very obtuse at the ends;
white or greenish. Aquatic; length 1-144
to 1-120".

N. aurea (PL 24. fig. 46). Body ovate-
oblong, subcylindrical, golden-yellow, very
obtuse at the ends. Aquatic; length 1-1 20".

2V. ornata. Brownish green.

It is questionable how far this genus is
different from Chilodon.

BIBL. Ehrenberg, Infus. p. 338 ; Stein,
In/us, p. 248.

NAUNEMA, Ehr. — A genus of Diatoma-
cese, no longer retained.

BIBL. Ehrenberg, Infus. 233 ; Kiitzing,
Bacill. and Sp. Alg.

NAVICULA, Bory.— A genus of Diato-
maceae.

Char. Frustules single, free; valves ob-
long, lanceolate or elliptical, sometimes with
the ends narrowed and produced, rarely
constricted in the middle, furnished with a
longitudinal line or keel, and a nodule in
the middle and at each end; surface of
valves covered with depressions or dots ar-
ranged in transverse or slightly radiating
rows, producing an appearance of lines,
although both dots and lines are often invi-
sible by ordinary illumination.

The valves are usually symmetrical, and
the keel median, but in two species the keel
is sigmoid and the valves inequilateral.
Sometimes the keel is double. There is
mostly a little space between the rows of
dots (PL 11. fig. 8), so that these readily
exhibit transverse lines or stria3 by unilateral
oblique light ; but sometimes they are pretty
uniformly distributed, as in many of the
species belonging to the first section of Gy-
rosigma.

The species or forms are very numerous.

NEBALIA.

[ 454 ]

NEMASPORA.

Kiitzing describes 170, some of them, how-
ever, belonging to Pinnularia, Gyrosigma,
and other genera. Smith describes thirty-
six British species. They may all have been
derived from a frustule of a Schizonema or
Colletonema which had escaped from its ge-
latinous envelope !

The formation of sporangial frustules has
been noticed by us in Navicula amphirhyn-
chus, and they are contained in a siliceous
sporangial sheath or case. The process is
sufficiently illustrated by the figures (PI. 41.
figs. 19-24) ; fig. 19, side view of the parent
frustule ; fig. 20, front view of conjugating
frustules, with young sporangial sheath;
fig. 21, empty mature sheath; fig. 22, crushed
empty sheath and parent frustules in situ ;
fig. 23, sheath, one parent-frustule and spo-
rangial frustule in front view ; fig. 24, spo-
rangial frustule in side view.

IV. cuspidata (PI. 11. fig. 6, side view;
fig. 7? front view ; a, hoop). Valves lanceo-
late, somewhat rhomboid, acuminate ; aqua-
tic; length 1-350 to 1-200". Valves slightly
iridescent, no striae by ord. ilium.

IV. didyma (PI. 11. fig. 9). Valves elliptic-
oblong, slightly constricted in the middle ;
marine; length 1-600 to 1-300". Ends
sometimes broadly rounded, and the con-
striction very deep.

N. rhomboides. Valves rhomboid-lanceo-
late ; colourless and not striated by ordin.
ilium.; aquatic; length 1-350". Striae 85
in 1-1000" (Sm.).

Ar. amphirhynchus (PI. 41 . fig. 19, side
view ; fig. 22, front view of conjugating frus-
tules). Valves linear, or nearly so, suddenly
contracted near the produced and obtuse
ends; aquatic; length 1-500 to 1-250".

BIBL. Smith, Brit. Diatom, i. 46 ; Kiit-
zing, Bacill. p. 91, and Sp. Alg. p. 69.

NEBALIA, Leach. — A genus of Entomo-
straca, of the order Phyllopoda, and family
Aspidephora.

Char. Antennas two pairs, large and rami-
form ; eyes two, stalked ; legs twelve pairs,
eight branchial and four natatory ; carapace
large, enclosing head, thorax, and part of
abdomen.

N. Upes (PI. 14. fig. 28). Marine; body
yellowish ; length 3-8".

BIBL. Baird, Brit. Entomostr. p. 36.
NECKERA, Hedwig.— A genus of Hy-
pnoid Mosses.

Elegant little perennial plants, growing
on trunks of trees and shady rocks, having
stems pinnately branched, bearing compla-
nate leaves arranged in eight rows.

IV. complanata, Ilu\m.=.Hypnum compla-
natum, Hedw.

IV. crispa, Dill., found in mountainous
districts, is a large moss, with stems 4 or 6"
long or more, growing horizontally from a
creeping rhizome.

NECTRIA, Fries.— A genus of Sphseriacei
(Ascomycetous Fungi), distinguished from
true Sphcerice by the free, membranous, flac-
cid, brightly-coloured perithecia, the pale pa-
pilla, and the gelatinous pale nucleus expelled
in the form of a drop or of white flocks ;
the asci contain eight pellucid spores. The
imperfect forms of these plants are described
as distinct genera. Thus Tubercularia vul-
garis, common on bark of dying or dead
trunks, and on dead twigs of birch especially,
ripens into IV. cinnabarina ; this we have ob-
served, and it is probable that other Coniomy-
cetous forms will require to be reduced in
like manner. Nectria includes the following
Sphesrice of the British Flora : cinnabarina,
coccinea, ochracea, aurantia, rosella, citrina,
Peziza, sanguinea, episphceria, &c., and se-
veral new species are described by Messrs.
Berkeley and Broome.

BIBL. Fries, Summa Veg. p. 387; Berk,
and Broome, Ann. Nat. Hist. 2 ser. xiii. p.
467.

NEMALEON, Targioni. — A genus of
Cryptonemiaceae (Florideous Algae), contain-
ing two British species, one, IV. multifidum,
not uncommon on shells and stones near
low-water mark. Its frond consists of a
somewhat cartilaginous, simple or once or
twice dichotomous cord, 3 to 6" high and
1 to 2'" in diameter, of a dull purple colour.
The cord consists of a dense axis formed of
interlaced longitudinal filaments, clothed
with horizontal, dichotomously- branched
filaments, moniliform and coloured towards
the circumference of the cord. The fruit
consists of — l.favellidia, consisting of glo-
bular masses of " spores" attached singly to
the filaments of the periphery (MM. Derbes
and Solier say that the single cells arising
from the filaments each discharge one spore
from the interior, so that they are spore-
sacs) ; and 2, of collections of antheridia,
consisting of minute hyaline cells seated on
the peripheral filaments, exactly correspond-
ing to the spore-sacs, but discharging sper-
matozoids.

BIBL. Harv. Br. Mar. Alg. p. 153. pi. 21
B, Phyc. Brit. pi. 36 ; Derbes and Solier,
Ann. des Sc. nat.^ 3 ser. xiv. p. 274. pi. 35 ;
Thuret, ibid. 4 ser. iii. p. 21 .

NEMASPORA, Fries.— A genus of Me-

NEMATHECIA.

[ 455 ]

NEPHROMA.

lanconiei (Coniomycetous Fungi), the spe-
cies of which present two forms, one bearing
minute conidia (Nemaspord), the other
spores (Libertella, Desmaz.), and which pro-
bably also wall be found to exhibit an asci-
ferous form. N. crocea, Pers. is common
on beech-trees, N. Rosce on roses and lilacs.
They are at first minute gelatinous masses
of conidia,, coherent into a nucleus under the
epidermis, devoid of a perithecium ; the
spores finally exude as a gelatinous tendril ;
the spores are curved and of an orange-
colour.

BIBL. Berk. Brit. Fl. ii. pt. 2. p. 355 ;
Fries, Summa Veg. p. 413; Desmaz. Ann.
des Sc. nat. 1 ser. xix. p. 269. pi. 6. figs.
3-6.

NEMATHECIA.— Wart-like collections
of vertical filaments found on the surface of
the fronds of the Cryptonemiacese (FLO-
RIDE.E).

NEOTTIOSPORA, Desmaz.— A genus of
Sphseronemei (Coniomycetous Fungi), re-
markable from the fusiform spores being
furnished with three or four terminal threads.
N.Caricum grows upon dead leaves of sedges,
bursting from beneath the epidermis by a
circular black orifice, from which an orange-
coloured (sometimes olive-coloured) gelati-
nous mass of spores escapes in the form of
a cirrhus. Diameter of conceptacles about
1-80".

BIBL. Desmazieres, Ann. des Sc. nat.
2 ser. xix. p. 346 ; Berk. & Broome, Ann.
Nat. Hist. 2 ser. xiii. p. 3/9.

NEPA, Linn. — A genus of Hemipterous
insects.

N. cinerea, the common water-scorpion,
is of a dirty brown colour, the body broad
and flat, with two long terminal respiratory
tubes, the anterior pair of legs stout and
greatly elbowed, the posterior formed for
crawling and not swimming.

PL 26. fig. 26 represents the trophi. The
labium (i) is three-jointed, with two small
lobes between the second and third joints ;
the four setae (mandibles and maxillae) are
furnished with teeth, directed towards the
free end (and not as shown in the figure) ;
the lingua or tongue (*) is trifid at the apex.

The lateral trachea? are dilated opposite
the thorax to form two internal respiratory
sacs. The eggs are oval, and surmounted
by seven reflexed filaments.

BIBL. Westwood, Introduction, &c.; Du-
four, Reck. s. 1. Hemipteres.

NEPENTHES, L.— A genus of Nepen-
thacea3 (Dicotyledonous Plants), in which

the spiral vessels have four parallel fibres
(see SPIRAL-FIBROUS STRUCTURES).

NEPIIROCYTIUM, Nageli.— A genus of
Unicellular Algre, perhaps merely decom-
posing spores of Spirogyra.

BIBL. Nageli, Einzellig. Algen. p. 79.
pi. 3. fig. 2.

NEPHRODIE^.— A subtribe of Poly-
podaeous Ferns, with a cordate or reniform
indusium.

I. NEPHRODIUM. Sori reniform. Indu-
sium cordate, deeply two-lobed at the base.
Veins pinnate.

II. FADYENIA. Sori reniform. Indu-
sium cordate, deeply two-lobed at the base.
Veins anastomosing, with free venules.

NEPHRODIUM, Schott.— A genus of
Nephrodieaa (Polypodaeous Ferns); some of
the species are often placed in a distinct
genus, as Lastrcea, and these made part of
the old genus Aspidium. Several species are
indigenous.

Fig. 513.

Nephrodium.

A pinnule with indusiate son.
Magnified 5 diameters.

NEPHROMA, Ag.— A genus of Parme-
Iiacea3 (Gymnocarpous Lichens). N. resu-
pinata, Sch. occurs on trees and mossy
rocks in subalpine districts. This genus
differs from Peltigera in the situation of
the kidney-shaped apothecia.

BIBL. Hook. Brit. Flor. ii. pt. 1. p. 220,
Eng. Bot. pi. 305.

NERIUM.

J

NERVES.

NERIUM. See STOMATA and LIBER,
p. 387.

NERVES and NERVOUS CENTRES.
— The nervous system is usually regarded
as consisting of two parts : the nerves, which
are divided into the cerebro-spinal and the
sympathetic; and the nervous centres, re-
presented by the brain and spinal chord,
with which must also be placed the ganglia.
These parts are composed essentially of
either nerve-tubes, nerve-cells, or of both
these elements.

The nerve-tubes or primitive nerve-fibres
are most numerous in the white portion of
the nervous centres and in the nerves. They
are slender, soft, cylindrical filaments, vary-
ing in diameter from 1-20,000 to 1-1100".
When quite recent, they are transparent and
apparently homogeneous (fig. 514, 1), but

Fig. 514.

Nerve- fibres. 1 . From nerves of the dog and rabbit,
in the natural state : a, fine, b, moderate, c, large fibre.
2. From a frog, after the addition of serum: a, drop
forced out by pressure ; b, part of the axial fibre contained
in it. 3. From the human spinal marrow, treated with
serum : a, sheath ; b, white substance with a double out-
line; c, axial fibre. 4. Fibre with double outline, from
the human fourth ventricle : a, axial fibre. 5. Two iso-
lated axial fibres, with a portion of the white substance
adherent to the right-hand one.

Magnified 350 diameters.

they really consist of three distinct parts, —

an enveloping membrane or sheath, a tena-
cious liquid, and a soft but elastic internal
fibre.

The sheath of the nerve-tubes is a very
delicate, structureless and transparent mem-
brane (fig. 515, la, 2, 3 a, 4 a) ; it is not
demonstrable in the smallest fibres, although
probably always present.

Fig. 515.

Nerve-tubes. 1. From a frog, after boiling with acetic
acid and alcohol : a, sheath ; b, axial band ; c, crystals of
fat. 2. Isolated sheath of a frog's nerve boiled with soda.

3. From the human fourth ventricle, after treatment with
soda : a, sheath ; b, white substance exuding in drops :
the axial band has been removed in the preparation.

4. Human, treated with soda : a, sheath ; b, white sub-
stance ; the axial band not visible.

Magnified 350 diameters.

Within the sheath is a hollow cylinder or
tube (%s. 514, 3 b, 515, 3, 4 b), called the
white substance of Schwann. It is homo-
geneous and tenacious in perfectly fresh
nerves, but soon after death becomes coagu-
lated, sometimes externally only, giving a
double outline to the walls of the nerve-
tubes (fig. 5 14, 2, 3, 4), or becoming granular
externally, and remaining liquid internally.
It is also easily altered by pressure, some-
times escaping in globules or masses of va-
rious form, from the ends or the broken
sides of the tubes, at others accumulating at
intervals in various parts of the tubes, giving
them an elegant varicose appearance (fig.
516).

The third structure exists within the last,
in the form of a rounded or flattened, pale,
elastic band or fibre, occupying the axis of
the tube, and called the axial band (figs. 514,
2 b, 3 c, 4 a, 5 ; 515, 1 a).

These three structures of nerve are some-
what difficult of demonstration. The outer
sheath may sometimes be shown by pressing

NERVES.

[ 457 ]

NERVES.

the nerve-tube, which forces out the white
substance. Boiling the nerves in absolute

Fig. 516.

Human nerve-tubes, showing tubes of various sizes ;
some with a single, others with a double outline ; some
varicose, others with the white substance in a granular
state.

Magnified 350 diameters.

alcohol, with the subsequent addition of
caustic alkali, or in acetic acid, when cry-
stals of fat separate from the white substance
(fig. 515, 1), will answer the same purpose.
Treatment with strong nitric acid, and after-
wards with potash, causes the white sub-
stance to exude, and the axial fibre being
dissolved, the yellow sheath is left empty
and very distinct. Solution of "corrosive
sublimate has also been recommended. The
axial band is best seen in nerves treated
with strong acetic acid, cold absolute alcohol,
aether, chromic acid, &c.

Chemically the sheath and axial band
consist of a proteine compound, and the
white substance of a mixture or compound
of fat with a proteine substance.

Inthecerebro-spinal nerves, the nerve-tubes
are aggregated into bundles, and surrounded
by an envelope of areolar tissue, called the
neurilemma, in which blood-vessels ramify,
thus corresponding with the arrangement of
the primitive fibrillae of muscle. Sometimes,
towards the terminations of the nerves, the
neurilemma appears as a homogeneous
membrane with elongated nuclei.

The nerves rarely branch; they usually
terminate in loops.

In the gray, sympathetic, or ganglionic
nerves, the fibres of which are sometimes

called gelatinous fibres, the nerve-tubes are
smaller and paler than those of most of the
cerebro-spinal nerves, and scattered through
a more copious areolar sheath or neurilemma
of mostly longitudinal fibres (Remak's fibres),
containing numerous elongated nuclei (fig.
517).

From the human sympathetic. A. Portion of a gray
fibre treated with acetic acid : a, fine nerve-tubes ; b, nu-
clei of Remak's fibres. B, Three ganglion- globules, one
with a pale process.

Magnified 350 diameters.

Nerve- cells, nerve-corpuscles, or ganglion-
globules are nucleated cells, most numerous
in the cineritious or dark portions of the
nervous centres, and in the ganglia, but
sometimes met with in the trunks and termi-
nal expansions of nerves, as the retina, &c.
They are furnished with a delicate outer
coat or membrane (fig. 518, la); this is
easily seen in the cells of the ganglia, but
with difficulty in those of the central organs.

They are rounded, elongate, pyriform, or
angular (fig. 518). Some of them are sim-
ple, others furnished with one, two, or more
simple or branched processes, by which they
are connected with nerve-tubes ; hence they
are described respectively as uni-, bi-, or
multipolar. Their contents are a soft, tena-
cious, and elastic mass (fig. 518, 3), consist-
ing of a clear, homogeneous, proteine basis,
and a number of larger and smaller granules,
as well as a nucleus. In size they are very
variable, from 1-5000 to 1-500". The granules
are sometimes colourless, at others yellow,
brown or black ; and occasionally these are
aggregated to form a mass.

Intermingled with the cells in the cineri-
tious matter of the nervous centres, is a
finely granular pale substance, resembling
that within the cells, also aggregations of
free nuclei.

The ganglia consist of nerve-tubes either
separate or united into bundles, intermingled

NERVES

NERVES.

Nerve-cells and fibres from the auditory nerve. 1, Nerve-cell with the origin of a fibre, from the anastomosis
between the facial and auditory nerve in the meatus auditorius externus of the ox : a, cell-membrane ; b, contents ;
f, pigment ; d, nucleus ; e, prolongation of the sheath upon the nerve- tube ; /, nerve- tube. 2. Two nerve-cells with
tubes from the auditory nerve of the ox : a, sheath with nuclei; b, cell-membrane ; c, nucleus ; d, origin of tube, with
intents of a nerve-cell, with a nucleus and two nucleoli.

nucleated sheath. 3. Separate cor

Fig. 519.

Magnified 350 diameters.

Cells from the central gray nucleus of the human spinal
marrow.

Magnified 350 diameters,

with nerve-cells, from which some of the
nerve-tubes arise. The tubes and cells are
imbedded in or supported by a stroma of

areolar tissue, sometimes homogeneous, at
others more or less distinctly fibrous, form-
ing an apparent sheath to the ganglia, and
ending in numerous septa ; rarely but
occasionally forming a distinct envelope to
the individual cells; sometimes it consists
of elongated, triangular, or spindle-shaped
nucleated cells, — in short, corresponding to
areolar tissue in various stages of develop-
ment.

The nerves are developed from the ele-
mentary embryonic cells, which at first ap-
pear rounded, or slightly elongated, and
somewhat flattened. In their further growth
they either retain the primitive shape (fig.
522), or send out persistent lateral processes,
so forming nerve-cells or ganglion-globules;
or the processes of adjacent cells unite into
nucleated fibres, much resembling those of
the sympathetic system, in which the white
substance and axial fibre of the nerve-tubes
are formed as secondary deposits (fig. 523).

In atrophy and degeneration of the ner-
vous elements, the nerve-cells become loaded
with fat and pigment, and the walls of the
nerve-tubes thinner, brittle, and the white
substance more or less replaced by granules
of fat.

BIBL. Kolliker, Mik. Anat. 2; Todd,
CycL Anat. and Phys, iii.; Paget, Brit, and
For. Med. Rev. 1842. xiv.

NERVES.

[ 459 ]
Fig. 520.

NERVES.

Large cells from the gray cortical layer of the human cerebellum. Magnified 350 diameters

Fig. 521. Fig. 522.

Fig. 521. Sixth thoracic sympathetic ganglion of the left side of a rabbit, seen from behind, after treatment with
soda. T. 2, trunk of sympathetic ; R.c, communicating branches, each bifurcating; Spl. splanchnic branch; S, gan-
glial branch, with large and small branches probably going to vessels ; g, ganglion-globules and ganglial fibres.
Magnified 40 diameters.

Fig. 522. 1. Ganglion-globules from a spinal ganglion of a four-months' human foetus, a, nucleus in the pale process
of the cell. 2. Nerve-tubes in development, from a two-months' human foetus. 3. Cells from the cineritious
cerebral substance of the same fcetus.

Fig. 523. l.Two nerve-fibres from the ischiatic nerve of a four-months' foetus. 2. Nerve-tubes from a newly-born
rabbit ; «, sheath ; A, nucleus ; c, white substance. 3. Nerve-fibre from the tail of a tadpole : a, b, c, as above ; at d
the fibre has still the embryonic character.

NEW ZEALAND FLAX. [ 460 ]

NIDULARIACEI.

NEW ZEALAND FLAX. See PHOR-
MIUM and TEXTILE SUBSTANCES.

NICOTHOE, Aud. & Edw.— A genus of
Crustacea, of the order Siphonostoma, and
family Ergasilidse.

N. astaci (PL 14. fig. 36, fern.) is found
upon the gills of the lobster.

The sides of the body are extended into
two remarkable lobes, containing the ovaries
(a) and the intestinal canal.

BIBL. Baird, Brit. Entom. p. 300; Van
Beneden, Ann. des Sc. not. 3 ser. xiii.

NIDULARIACEI.— A small family of
Gasteromycetous Fungi, including the Ni-
dularini or bird's-nest-like Fungi, and the
Carpoboli which contain only one concep-
tacle. They are small and inconspicuous
Fungi, growing on the ground among de-
caying sticks, dung, &c., bearing upon the
flocculent mycelium yellow or dull-coloured
fruits or receptacles (fig. 524). The external

Fig. 524.

Fig. 525.

Cyathus vernicosus.

Fig. 524. A ripe receptacle. Nat. size.
Fig. 525. The same, opened vertically.

part of the receptacle consists of a more or
less globular or ovate peridium, which bursts
when mature, in the Carpoboli by a lid or
by more or less regular slits, in the Nidu-
larini by an orifice which enlarges so that
the mouth becomes turned out as a spread-
ing lip around a cup-shaped cavity (fig. 524).
The Carpoboli, containing only one concep-
tacle, project this out with elasticity when
ripe. The Nidularini contain many concep-
tacles lying like eggs in a nest (figs. 524, 525),
in Cyathus and Crucibulum (fig. 526), at-

Fig. 526.

Crucibulum vulgare.

A conceptacle detached from the ^receptacle.
Magnified 12 diameters.

tached by a funiculus. The structure of the
conceptacles is alike in all. The envelope
of each is triple (fig. 527), and they form a

Fig. 527.

Cyathus vernicosus.

A nearly ripe receptacle, cut open vertically, showing
the two halves filled with conceptacles.

Magnified 3 diameters.

cavity lined by delicate filaments which con-
verge towards the centre, where their extre-
mities are expanded into basidia crowned
by four spores (fig. 528), which are cylindri-

Fig. 528.

Cyathus striatus.

Basidia and spores from the fertile layer of a conceptacle.
Magnified 250 diameters.

Fig. 529. Fig. 530.

Fig. 531.

Cyathus striatus.

Fig. 529. Vertical section of a young receptacle. Magn.

10 diams.

Fig. 530. Another, more advanced. Magn. 10 diams.
Fig. 531. Another, still more advanced. Magn. 5 diams.

cal and almost sessile. The filaments being
of very unequal length, the basidia are inter-

NIPHOBOLUS.

[ 461 ]

NITZSCHIA.

mingled with them in the cavity of the con-
ceptacle, not forming a definitely marked
layer.

Synopsis of British Genera.

* CARPOBOLI. Peridium containing only one
conceptacle.

1. ATRACTO BOLUS. Peridium simple,
cup- shaped, sessile, closed at first by an
umbonate lid. Conceptacle spindle-shaped,
simple, indehiscent, projected when ripe
from the bottom of the peridium.

2. THELEBOLUS. Peridium simple, ses-
sile, roundish, urceolate-inflated ; mouth
entire. Conceptacle globose, papilliform,
protruded from the mouth.

3. SPH^EROBOLUS. Peridium double,
each layer bursting in a stellate manner, the
internal membrane at length turned inside
out, and elastically projecting the globular
conceptacle.

** NIDULARINI. Peridium with many
conceptacles.

4. CRUCIBULUM. Peridium at first glo-
bose-capitate, afterwards crucible-shaped,
open at the mouth, exposing numerous disk-
shaped smooth conceptacles, each with a glo-
bular process on the under side prolonged
into a long slender thread-like funiculus.

5. CYATHUS. Peridium at first obovate
or fusiform, sessile or stalked, closed by a
veil, afterwards widely open at the mouth,
exposing ten to eighteen disk-shaped, thick,
fleshy or horny conceptacles, umbilicate be-
neath and attached to the walls of the peri-
dium by a compound peduncle.

6. NIDULARIA. Peridium sessile, sub-
globose, finally open (without evident veil).
Conceptacles numerous, disk-shaped, nest-
ling in copious gelatinous mucus, destitute
of a funiculus.

BIBL. Tulasne, L.-R. and C., Recherches
sur les Nidulariees, Ann. des Sc. nat. 3 ser.
i. 41 ; Schmitz, MycologischeBeobachtungen,
Linncea, xvi. 141.

NIPHOBOLUS, Kaulf.— A genus of Po-
lypodieae (Ferns), with elegantly articulated
veins and numerous naked sori at the tips of
free branchlets.

NITELLA. See CHARA.

NITOPHYLLUM, Greville.— A genus of
Delesseriaceae (Florideous Algae), containing
about half-a-dozen British species, only two
of which are commonly met with. Their
fronds are membranaceous, of reticulated
(parenchymatous) structure, mostly rosy red,

without ribs, or with irregular ribs towards
the base. The membranously expanded
frond ofN.punctatum, 4 to 12" high, is either
regularly dichotomously divided or parted
into two or three principal lobes, which have
a border of dichotomous wedge-shaped lobes.
N. lacerum has the frond 2 to 10" high,
much dichotomously divided and marked
with flexuous veins, the segments mostly
linear, waved or fringed at the margins.
The fructification consists of spores, tetra-
spores, and spermatozoids. 1. The spores
are contained in coccidia, sessile on the
frond, the spores arising from tufted
filaments; 2. the tetraspores form distinct
scattered spots on the frond; 3. the an-
theridia are minute cellules standing per-
pendicularly on the surface of the frond,
collected into patches, only distinguishable
by the help of the microscope.

BIBL. Harvey, Brit. Mar. Alg. p. 116.
pi. 15 B, Phyc. Brit. pis. 202, 203, 247,
&c.; Greville, Alg. Brit. pi. 12; Thuret,
Ann. des Sc. nat. 4 ser. iii. p. 22.

NITRATE OF POTASH. See POTASH,

NITRATE OF.

NITRIC ACID,or Aquafortis, is usefulas a
reagent (!NTR. p.xxxix, 6),andfor separating
the organic matter of the Diatomaceae from
the siliceous valves (p. 202), &c.

NITZSCHrA, Denny. (Liotheum). — A
genus of Anoplura.

N. Burmeisteri is the louse of the common
swift (Cypselus opus).

BIBL. Denny, Anopl. Monogr. p. 230.

NITZSCHIA.— A genus of Annulata.

BIBL. Johnston, Non-parasitic Worms,
1855.

NITZSCHIA, Hass.— A genus of Diato-
maceae, the name of which must be cancelled.

Char. Frustules free, depressed, usually
elongate, straight, arched, or sigmoid, with
a longitudinal, not median, external keel (?),
and one or more longitudinal rows of puncta;
suture in front view of frustules not median.

The valves have no nodules ; we have not
been able to satisfy ourselves of the presence
of the external keel ; upon the portions of
the valves forming the middle of the side
view of the frustules, is one or two longitu-
dinal rows of slightly elongate dots or puncta
(PI. 13. fig. 10 d), often visible under ordi-
nary ilium. ; surface of valves covered with
smaller dots, mostly opposite (not quincun-
cial) (fig. lOrf), invisible under ordin. ilium.

The frustules and valves are either linear,
lanceolate, or of intermediate forms, some-
times constricted or beaked.

NOCTILUCA.

[ 462 ]

NOSTOC.

Smith describes twenty -three species,
mostly removed from other genera in the
systems of Ehrenberg and Kiitzing.

N. sigmoidea (PL 13. fig. 9; a, side view;

b, front view). Frustules (front view) linear,
sigmoid, or arched, truncate, side view
straight or nearly so, attenuate, acute ; aqua-
tic; common; length 1-75".

N. lanceolata (PL 13. fig. 10; a, front
view of frustule ; b, front view of single valve;

c, side view of frustule). Frustules (front
view) straight, lanceolate, ends prolonged,
somewhat obtuse ; side view narrowly linear-
lanceolate, ends acute; marine; length
1-150".

Fig. 10 a is too broad ; the form of the
frustules is best represented by 10 b ; 10 d
exhibits the two kinds of markings as seen
with the stops, &c.

N. longissima (N. birostrata, Sin.) (PL 13.
fig. 11 ; a, side view; b, front view). Frus-
tules straight, narrowly linear-lanceolate,
ends produced into linear beaks, longer than
the intermediate portion; marine; length
1-70".

N. acicularis (PL 13. fig. 13, right-hand
frustule). Frustules linear-lanceolate, some-
times sigmoid, ends beaked and straight;
aquatic, and brackish water; length 1-300".

N. reversa (PL 13. fig. 12). Differs from
the last in having the ends bent at an angle
in opposite directions.

N. gracilis (N. tania (?), Sm.) (PL 13.
fig. 13, left hand). Linear or slightly lan-
ceolate, with two spiral markings; ends
somewhat suddenly produced ; brackish
water; length 1-250".

The spiral bands probably arise from the
frustules being twisted, and correspond to
the sutures; they are most distinct after
a red heat.

BIBL. Smith, Brit. Diat. p. 37 ; Hassall,
Freshwater Algce, p. 435.

NOCTILUCA, Suriray.— A genus of ma-
rine animals, the systematic position and
structure of which is doubtful.

N. miliaris is spherical or nearly so, with
a tentacle-like, transversely striated, and
curved process arising from it, and by means
of which it propels itself through the water.
The part to which the process is attached is
plicate and depressed, so as to render the
body somewhat bilobed; it has no carapace.
The body has been described as of gelatinous
consistence, and as surrounded by a smooth
or wrinkled membrane ; again, as consisting
of an air-bag. Its diameter has been esti-
mated at 1-1000", and as lying between

1-50 to 1-30", the latter of which is probably
correct.

It is phosphorescent, rendering the sea
luminous by night.

BIBL. Suriray, Lesson's Acalephae ; Qua-
trefages, Ann. des Sc. nat. 3 ser. xiv.; Gosse,
Naturalist's Rambles, <^c. ; Krohn, Wieg-
mann'sArchiv, 1852 ; Huxley, Micr.Journ.
1855 ; Brightwell, Ann. Nat. Hist. 1850. vi.;
Pring, Phil. Mag. 1849.

NOSTOC, Vaucher.— The typical genus
of the Nostochaceac, distinguished from the
allied genera by the definitely formed hard-
ened pellicle or rind enclosing the fronds,
which are composed of a gelatinous sub-
stance (fig. 532), in which are imbedded

Fig. 532.

Nostoc commune.
Nat. size.

numerous more or less beaded filaments
(fig. 533). The filaments are composed of

Fig. 533.

Nostoc cseruleum.
Filaments. Magnified 200 diameters.

rows of cells (PL 4. fig. 7), .which increase
the length by repeated transverse subdivi-
sion ; here and there appear larger cells (a,
c) which appear brighter than the rest ; these
seem to be what Kiitzing calls the spermatia
or spermatic cells, but they more resemble
the vesicular cells of the allied genera. The
filaments break up after a time into short
fragments, which by cell-division produce
new filaments. Thuret has observed this
process in N. verrucosum ; he states that the
pellicle of the frond bursts, allowing the
gelatinous mass to escape, and the filaments
to spread abroad in the water; these are

NOSTOC.

[ 463 ]

NOSTOC.

Fig. 534.

verrucosum.

Filaments mul-

seen, by the aid of the microscope, to consist
of short, straightish pieces, which, as first
observed by Vaucher, are endowed with the
power of moving slowly along in the direc-
tion of their length ; after a time they cease
to move, and a new gelatinous
envelope is formed around
each piece, like a transparent
sheath. They soon become
enlarged considerably, and
then divide in the direction of
the length of the filament, to
form two new ones (fig. 534).
This process is repeated se-
veral times, and the mass of
new filaments becomes con-
fused, until the development
of a greater quantity of the
gelatinous matter, when they
become more distinct. The
same process was observed
in another species, which ap-
peared to be N. commune i
and Thuret considers it likely division
that this mode of reproduction Magn.soodiams.
extends to the other species.
We find that the gelatinous fronds break up
when kept in water, and the colourless cells
become green. Nothing is known of the
import of the enlarged, brighter cells.

The resemblance of the Nostocs to the
species of Collema (Lichens) has attracted
much attention, and some authors even as-
sert that they are only different forms of the
same plants. We do not place much reliance
on the statements of Itzigsohn, but the me-
moir of Sachs on this subject is deserving of
attention.

The gelatinous fronds of the British spe-
cies of this genus are found on damp ground,
wet rocks, mosses, &c., and free or attached
to stones in fresh water.

* Frond globose or subglobose.

1. Nostoc minutissimum, Kiitzing. Frond
globose, from 1-30 to 1-4'" ; filaments equal,
deep ajruginous green, densely entangled ;
periderm growing brown. Kiitzing, Tab.
Phyc. vol. ii. pi. 1. fig. 1. Kiitzing doubt-
fully refers to the terrestrial form of this,
Hassall's N. muscorum (Br. Fr. Algce, pi. 74.
fig. 4), which grows on calcareous rocks, and
among the mosses covering them.

2. N. lichenoides, Vaucher. Fronds from
the size of a mustard-seed to that of a pea,
aggregated and heaped together ; filaments
equal, loosely entangled, aeruginous or oliva-
ceous ; periderm pellucid, colourless, firm.

£. vesicarium ; larger, soft, with a fuscous

distinct periderm, mucous within, sometimes
hollow. Kiitzing, Tab. Phyc. vol. ii. pi. 2.
iv. N. vesicarium, Hassall, Br. Fr. Algce,
p. 290. Road-side near Perth.

3. N. sphcericum, Vaucher. Frond the
size of a pea, firm, blackish aeruginous or
somewhat olive-coloured, soft within ; fila-
ments pale green, loosely entangled; peri-
derm firm, colourless or fuscescent, sub-
opaque. Vaucher, Hist, des Conferees, xvi.
fig. 2 ; Kiitzing, Tab. Phyc. vol. ii. pi. 3. ii.;
Hassall, Br. Fr. Alga, pi. 76. fig. 5. On
stones in mountain rivulets. Meneghini
states, that when dried and again moistened,
it emits a pleasant odour like violets. Has-
sall thinks it probably an immature form of
N.foliaceum.

4. N. cceruleum, Lyngbye. Frond from
the size of a pea to that of a sloe (rarely
larger), very soft and slimy, pale aeruginous
blue ; filaments unequal, loosely entwined,
joints oblong-elliptical ; periderm colourless,
pellucid, soft. Lyngbye, Hydrophytol. t. 68;
Kiitzing, Tab. Phyc. vol. ii. pi. 3. iv. ; Has-
sall, Br. Fr. Algce, pi. 74. fig. 1; 75. fig. 10;
76. fig. 11. Attached to mosses in flowing
water or very moist places.

5. IV. pruniforme, Agardh. Frond the
size of a large round plum, deep aeruginous
green, very soft and watery within ; filaments
unequal, bright aeruginous green, loosely
entangled, joints subdepressed, dimidiate ;
periderm leathery, crystalline. Berkeley,
Gleanings, t. 19. 2; Kiitzing, Tab. Phyc.
vol. ii. pi. 4. iv. ; Hassall, Br. Fr. Algae,
pi. 76. 3-4 ; Lyngbye, Hydroph. t. 68 A.
Fronds unattached, in freshwater pools or
rivulets.

** Frond foliaceous, irregular, or vesicular.

6. N.foliaceum, Agardh. Frond terres-
trial, membranous, erect, plaited, olive-green;
filaments slender, copious. Hassall, Br. Fr.
Algce, pi. 76. fig. 2. On clayey ground con-
stantly moistened by oozing water.

7. N. commune, Vaucher (fig. 532 & PI. 4.
fig.7). Frond terrestrial, gelatinous, subcoria-
ceous, olivaceous or obscurely green, irregu-
larly plaited; filaments nearly equal, flexuose,
colourless or green, loosely entangled, the
joints loosely conjoined, distant in one place,
geminate in others, subspherical, depressed,
marked with a central opaque spot ; peri-
derm hyaline, growing brown. Vaucher,
Hist, des Cow/, t. 16. fig. 1 ; Kiitzing, Tab.
Phyc. vol. ii. pi. 6. i.; Hassall, Br. Fr. Algce,
pi. 74. 2. Tremella terrestris, Dillwyn, Br.
Conferva, t. 10. fig. 14. Gravelly soils,

NOSTOCHACE.E.

[ 464 ]

NOSTOCHACE^E.

garden walks, rocks, barren pastures, &c. ;
very common in autumn and winter.

8. IV. verrucosum, Vaucher. Frond blad-
der-shaped, softly -leathery, fuscous-green ;
filaments spiral, densely entangled, joints
globose ; periderm gelatinous, soft, green or
dirty brown. Vaucher, Hist, des Conf. t.
16. fig. 3 ; Kiitzing, Tab. Phyc. vol. xi. pi.
9. fig. 2 ; Thuret, Ann. des Sc. nat. ser. 3.
vol. ii. pi. 9. figs. 1-4 ; Hassall, Br. Fr. Alg.
pi. 75. fig. 1. On stones in streams.

9. N. variegatum, Moore. Frond terres-
trial, expanded, gelatinous, livid, variable in
shape; filaments rather distant ; joints oval
and variable in size. Hassall, Br. Fr. Algae,
pi. 74. fig. 3. On a moist bank in Ireland.
A doubtful plant, perhaps referable to a
different genus of the Nostochaceae.

BIBL. The works above quoted; Itzig-
sohn, Bot.Zeit. xii. p. 521. 1854; Sachs,
Bot. Zeit. xiii. p. 1 (1855).

NOSTOCHACE.E.— A family of Confer-
voideae. A tribe of Algae, composed of plants
forming gelatinous strata or definitely formed
gelatinous balls or masses, either on damp
ground, or floating at the bottom of water ;
consisting of minute, unbranched, usually
moniliform, microscopic filaments, tranquil
or oscillating, imbedded in a mass of muci-
laginous or sometimes firmish substance
(the amorphous matrix is produced by the
fusion of the special gelatinous sheaths of
the individual filaments) ; filaments finally
breaking up. Cells of the filaments of three
kinds : — 1. ordinary cells ; 2. vesicular cells,
usually large and without granular matter,
frequently with erect hairs ; 3. sporangia or
spermatic cells, produced by the enlarge-
ment of the ordinary cells, globular, elliptical
or cylindrical. [Some of the genera are de-
scribed as without sheaths ; but this is very
doubtful, and probably depends on imperfect
observation.]

Synopsis of British Genera.

I. APHANIZOMENON. Filaments un-
branched, cylindrical, oscillating, with evi-
dent sheaths, cohering laterally into flat plu-
mose lamellae, expanding in the middle into
usually single, distinct spermatic cells, of
unequal length, vesicular cells absent (?).
Floating on stagnant pools.

II. Tr ICHORMUS. Filaments moniliform,
motionless, entangled in an indefinite mu-
cous mass, without evident sheaths; the
joints of cells filled with contents (hologo-
nimic), here and there expanding into (inter-
stitial) globular spermatic cells, which are

separated from the vesicular cells by ordi-
nary cells.

III. SPH^ROZYGA. Filaments mostly
moniliform, motionless, involved in an amor-
phous mucous matrix; the cells hologonimic,
here and there expanding into elliptical
spermatic cells, in groups of two or more,
connected by a vesicular cell ; sheaths (ap-
parently) none.

IV. CYLINDROSPERMUM. Filaments
jointed, composed of hologonimic cells, and
involved in a common mucous matrix, social,
straight or curved, sometimes oscillating;
spermatic cells cylindrical, rounded at both
ends, granular, interposed between the ordi-
nary cells and terminal vesicular cells.

V. SPERM o si RA. Filaments articulated,
cylindrical, oscillarioid, motionless, with an
evident sheath ; ordinary cells discoid, at
length swelling into concatenate moniliform
spermatia, separated by ordinary cells from
the vesicular cells, which are interstitial,
single or two together.

VI. DOLICHOSPERMUM. Filaments sim-
ple, generally moniliform, without evident
sheaths, aggregated into a gelatinous stra-
tum ; spermatic cells interstitial, elongated,
separated by the ordinary joints from the
vesicular cells.

VII. CONIOPHYTUM. Filaments simple,
without evident sheaths, rarely spiral, curled
and interwoven into a minute, distinct frond;
vesicular cells interstitial, spermatic cells
formed sometimes of the cells next the vesi-
cular cells, sometimes from those distant
from them.

VIII. MONORMIA. Frond or phycoma
definite, gelatinous, elongated, linear, spirally
curled and convoluted, enclosing a single,
continuous moniliform filament; vesicular
cells interstitial; spermatic cells developed
from joints most distant from the vesicular
cells.

IX. NOSTOC. Phycoma or general mass
of the plant enclosed by a periderm formed
by the condensation of the surface, determi-
nate, globose or spread out, of variable form,
gelatinous or mucous, coriaceous, soft or
hard, elastic, slimy, containing moniliform,
simple, curved and entangled filaments,
composed of hologonimic cells, imbedded
in a continuous amorphous gelatinous ma-
trix, spermatic cells globose, interstitial,
larger than the ordinary joints of the fila-
ments.

Exotic genus. TRICHODESMIUM. Fila-
ments straight, short, unbranched, without
evident sheaths, in simple separate bundles,

NOTEUS.

[ 465 ]

NUCLEUS.

involved in a matrix of mucus, social, swim-
ming in masses. Marine.

[Our knowledge of these plants is very
unsatisfactory. Kiitzing enumerates a vast
number of species, which would be probably
reduced to a comparatively small number if
the history of development were known.
We cannot see any distinctive character in
his genus HormosipJion ; the filaments of
Nostoc have proper sheaths when first deve-
loped. The nature and functions of the so-
called spermatic and vesicular cells require
further elucidation.]

BIBL. Ralfs, on Nostochinece, Annals of
Nat. Hist. 2 ser. vol. v. 321. pis. 8 & 9;
Kiitzing, Tabula Phycologicce, B. i. p. 91-
100. Bd. ii. pi. 1-15 ; Thuret, on Nostoc
verrucosum, Ann. des Sc. not. 2 ser. t. ii. ;
Meneghini, Monographic, Nostochinearum
italicarum, Mem. Turin Acad. ser. 2. v. 1843;
Allman, Micr. Journal) 1855.

NOTEUS, Ehr.— A genus of Rotatoria,
of the family Brachionaea.

Char. Eyes absent; foot forked (= eye-
less Brachionus).

N. quadricornis (PI. 35. fig. 13). Cara-
pace suborbicular, depressed, scabrous, areo-
late, with four spines in front, and two be-
hind; aquatic; length 1-120 to 1-70".
BIBL. Ehrenberg, In/us, p. 502.
NOTODELPHYS, Allm.— A genus of
Entomostraca, of the order Copepoda.

N. ascidicola (PI. 14. fig. 22) resembles
Cyclops in general appearance. The external
ovary is a single organ, lying across the back
of the abdomen ; eye single. Marine.

BIBL. Allman, Ann. Nat. Hist. xx. p. 1 ;
Baird, Brit. Entom. p. 237.

NOTOMMATA, Ehr.— A genus of Rota-
toria, of the family Hydatinaea.

Char. Free ; eye single, cervical ; tail-like
foot with two toes ; rotatory organ simply
ciliated.

In some the rotatory organ is extended
laterally in an ear- or arm -like form.

Ehrenberg describes twenty-three species,
some of which are parasitic, N. petromyzon
and parasita living within Volvox globator,
and IV. Werneckii within the vesicles of
Vaucheria ; and divides them into the sub-
genera : Labidodon, jaws each with a single
tooth; Ctenodon, jaws each with several
teeth.

Many of the species are large and well
adapted for the study of the internal struc-
ture.

M. centrura (PI. 35. figs. 14 ; 15, jaws and
teeth). Body attenuate at each end, foot

small and hard ; cephalic auricles short ; no
lateral setae ; aquatic ; length 1-36".

BIBL. Ehrenberg, In/us, p. 424 ; Duiar-
din, In/us, p. 646.

NOTONECTA, L.— A genus of aquatic
Hemipterous insects.

N. glauca is common in pools. Its setae
or lancets, and natatorial hind-legs form in-
teresting microscopic objects.

Fig. 535.

Notonecta glauca.
Magnified 3 diameters.

NUCLEUS and NUCLEOLUS OF
PLANTS. — The term nucleus is applied in
botany to two very different things ; first to
the central body of the young ovules of
Flowering plants, and secondly to a peculiar
structure met with in the interior of cells.
The first will be described under the head of
OVULE; the cell-nucleus and nucleolus,
mentioned in the article CELL (Vegetable],
will be discussed here.

Few parts of the minute organization of
plants are more obscure than the structure
and function of nuclei ; some authors regard
them as of the highest physiological import-
ance, others consider their import altogether
unknown. The nucleus may be observed
most easily in the parenchymatous cells of
the herbaceous structures and flowers of
Monocotyledons (PI. 36. fig. 28 6), or in the
young cells of the hairs of Flowering plants
generally (PI. 38. figs. 8, 9 6), or in the em-
bryo-sacs of unfertilized ovules (PI. 38. figs.
4-6) ; in such cases the characters are well
defined and unmistakeable. It consists of a
lenticular body formed of more or less gra-
nular substance, apparently not diverse from
the PROTOPLASM, with one or more well-
or ill-defined bright points or cavities (nu-
cleoli) in the interior. Wherever it appears
throughout the higher plants, it seems to
possess the same characters. Nageli indeed
declares that it is a vesicle ; but we believe
this to be an error, that real nuclei are ordi-
narily solid, although bodies akin to them,
2 H

NUCLEUS.

[ 466 ]

NUCLEUS.

really hollow, do occasionally occur in the
cell-contents. Nageli, who has investigated
the subject of nuclei very extensively, states
that they exist in every class of plants, and
that in those cases where he failed to find
them, there was a probability of their being
concealed in the cell-contents. The nuclei
of certain plants exhibit very remarkable
peculiarities, especially in SPIBOGYRA and
ZYGNEMA.

Ordinarily, nuclei are found attached to
the side of cells, being intimately connected
with the PRIMORDIAL UTRICLE, or, when-
ever this is partially absorbed, forming the
centre of the radiating protoplasmic filaments
this leaves behind (PL 38. fig. 9) ; some-
times, however, the nucleus is suspended in
the cavity of the cell by filamentous pro-
cesses of protoplasm; in all such cases it
forms a kind of centre for the circulation of
the protoplasm, where this exhibits move-
ment (ROTATION), and it is itself carried
about to a certain extent by the currents.

The nucleoli (PL 38. fig. 8 ») of these
larger nuclei are apparently usually solid
granules of a transparent substance, but
sometimes they appear more like minute
cavities.

The nuclei and nucleoli of the lower plants
are exceedingly obscure ; in a great many
cases the so-called nuclei are little different
from the nucleoli of the larger forms, occu-
pying to the entire cell-contents the same
relation as the nucleoli to large nuclei, for
example, in the spores of Lichens (PL 29.
fig. 7)j Fungi, &c. Indeed, from our own
observations we are led to believe that the
term nucleus is very loosely applied in the
lower plants, to irregular granular structures
which do not represent the nuclei of the
Flowering plants, and we doubt the wide
diffusion claimed for them by Nageli. In
the lower Confervoid Algae the nucleus (or
nucleolus) appears to be represented by the
entire cell-contents (PL 3), in which one or
more well-defined granules often occur, re-
presenting nucleoli ; in certain stages, how-
ever, a larger granule is met with, coloured
-by chlorophyll, which some regard as a
nucleus ; this disappears totally at particular
epochs, and is replaced by starch-granules
or oil-globules. The bright coloured point,
or * eye-spot,' seen very generally in the ZOO-
SPORES both of Confervoids and Fucoids,
may represent a nucleolus.

Nuclei originate in two ways. The sim-
plest mode is found where they precede free
cell-formation, as in the development of the

germinal vesicles in the embryo-sacs of
Flowering plants. Here the nuclei appear
first as globular or lenticular masses, which
become gradually defined in the substance
of a collection of protoplasm accumulated
at the upper end of the cell (PL 38. figs. 1-4).
This is a spontaneous isolation of a portion
of the protoplasm to become the foundation
of a new cell. We may compare this with
the segmentation of the entire mass of con-
tents of the cells of Confervse in the forma-
tion of Zoo SPORES, which may perhaps be
regarded as at first free nuclei. In cells
multiplying by division, a division of exist -
ing nuclei has been observed to take place
in certain cases, as in the hairs of Trades-
cantia (PL 38. figs. 8 & 9), but in other
similar cases of division no nuclei are ob-
served (PL 38. figs. 10 & 11). In the case
of Tradescantia, the oval parent-nucleus
fills up the end of the growing cell, so that
the division of the nucleus is almost syno-
nymous with the division of the primordial
utricle. But in this case, as in the develop-
ment of cells from free nuclei, as indicated
of the germinal vesicles, the cell-membrane
in expanding draws away from the nucleus,
which remains adherent to or suspended in
connexion with a layer of protoplasm lining
the cell-wall and forming its primordial
utricle. In SPIROGYRA and Zygnema, a
division of the free suspended nucleus pre-
cedes the division of the large primordial
utricle.

Mohl describes a division of nuclei as oc-
curring in Anthoceros, and most authors
who have written on the development of
pollen and spores lay great stress on the
influence of the nuclei, which they describe;
and it is curious that in our own researches
we have failed to trace the dependence of
the development of the new cells upon nuclei
(PL 38. figs. 10-13).

The import of nuclei in vegetable cells is
certainly still a problem. Some believe
they are the universal agents of production
of new cells, others that they are not the
agents of this in any case, but, when present,
may be divided with the cells. Others
imagine that they are merely the original
" mould" of protoplasm on which the cellu-
lose membrane of the nascent-cell is depo-
sited, and which is left unaltered when this
expands (the phenomena in Spirogyra are
opposed to this). Some of those who deny
their influence in cell-development believe
them to be the vital centres of the cells in
which they exist.

NULLIPORES.

[ 467 ]

(ECISTES.

They are best seen in very young cells in
all cases ; in nascent tissues they almost or
quite fill the cavity of the young cells. As
the cells grow older, their history differs in
different cases. Sometimes they persist
until the decay of the organ in which they
exist. This happens very generally in the
cells of the flowers, stems, &c. of Monoco-
tyledons; not unfrequently, in stems and
leaves they become converted into starch or
chlorophyll-granules. In other cases they
have a more definite purpose, for in the
vesicles in which are formed the SPERMA-
TOZOIDS of Ferns, Mosses, Hepaticae,
Characeae, &c., these structures appear to
be produced by a metamorphosis of the
nuclei.

In examining supposed nuclei of plants,
especially those of lower cellular organization,
tincture of iodine should always be applied,
to distinguish starch-granules, &c. from true
nuclei, which are always coloured deep yel-
low or brownish by that reagent, besides
being coagulated, contracted and thereby ren-
dered more distinct.

The nuclei of plants require much more
investigation.

BIBL. R. Brown, on Orchidacete, Phil.
Mag. Dec. 1831 ; Schleiden, Phytogenesis,
Miiller's Archiv, 1838, transl. in Sc. Memoirs,
ii. p. 281, Grundzuge, 3 ed. (Principles, p.
568); Nageli, Zeitschr. fur Wiss. Bot.
(transl. in Ray Soc. Vols. 1845 & 1849) ;
Mohl, Pflanzen-zelle (Vegetable Cell), pp.
36 & 51 ; Hofmeister, Entsteh. d. Embryo,
Leipsic, 1849. p. 7 ; Al. Braun, Verjungung
(Ray Soc. Vol. 1853. p. 175).

NULLIPORES. See CORALLINACEJS.

NYMPILEACE.E. See HAIRS (p. 313).

O.

OAT, Avena sativa (Nat. Order Grami-
naceae, Flowering Plants). — The form of the
starch-corpuscles of the oat is very unlike
that of the other common corn plants, con-
sisting of numerous small polygonal grains
grouped together in roundish or oval masses
(PI. 36. fig. 10). See STARCH.

OCHLOCILETE, Thwaites.— A genus of
Chaetophoraceae (Confervoid Algae), consist-
ing of minute plants growing epiphytically
on leaves of grasses, &c. O. hystrix occurs
both in brackish and freshwater ditches.
The minute, dot-like, discoid frond is formed
of radiating branched filaments composed of
cells, each bearing a very long tubular fila-

ment on its back. Fructification unknown.
We suspect this plant is closely connected
with the lax forms of COLEOCH^ETE.

BIBL. Harvey, Brit. Mar. Ala. p. 211.
pi. 25 E, Phyc. Brit. pi. 226.

ODONTELLA, Ag.— This genus of Dia-
tomaceae is united with BIDDULPHIA, Bid-
dulphia (Odontella) aurita undergoing spon-
taneous division, PL 14. fig. 9.

ODONTHALIA, Lyngb.— A genus of
Rhodomelaceae (Florideous Algae) containing
one British species, O. dentata, which has
an irregularly bipinnatifid frond, 3 to 12"
long, the main axis and lobes being about
1-4" wide throughout; the colour is deep
wine-red, darker when dried. The frond
bears marginal, stalked, ostiolate, ovate ce-
ramidia with spores; lanceolate stichidia,
in which are contained two rows of ternate
tetraspores ; and antheridia.

BIBL. Harv. Brit. Alg. p. 77. pi. 11 A,
Phyc. Brit. pi. 34 ; Greville, Alg. Br. pi. 13;
Kiitzing, Phyc. generalis, p. 448.

ODONTIDIUM, Kg.— A genus of Dia-
tomaceae.

Char. Frustules quadrangular, united to
form an elongated biconvex filament ; linear
in front view ; side view (valves) with trans-
verse striae (visible under ordinary ilium.).
Aquatic and marine.

Differs from Denticula in the elongated
filament, which sometimes, however, con-
sists of only three or four frustules !

Kiitzing describes fifteen species, two
doubtful.

O. turgidulum (PI. 13. fig. 14 ; a, front
view; b, side view). Valves lanceolate, ob-
tusish ; striae on each valve six. Aquatic ;
length of frustules 1-1720 to 1-570".

BIBL. Kiitzing, Bacill. p. 44, Sp. Alg.
p. 12.

ODONTODISCUS, Ehr.-A genus of
Diatomacese.

Char. Frustules single, lenticular ; valves
circular, alike, without nodules or apertures,
not areolar (under ordin. ilium.), but covered
with puncta either arranged in radiating
rows, or in excentrically curved lines, and
with erect marginal teeth.

The puncta are surely the ordinary de-
pressions imperfectly examined.

Three species. Fossil and in guano.
Diameter from 1-860 to 1-240".

BIBL. Ehrenberg, Ber. d. Berl. Akad.
1844. p. 73 ; Kiitzing, Sp. Alg. p. 129.

(ECISTES, Ehr. — A genus of Rotatoria,
of the family (Ecistina.

Char. Single ; rotatory organ single, with
2n2

(ECISTINA.

[ 468 ]

(EDOGONIUM.

an entire margin; body attached to the bot-
tom of a fixed cylindrical carapace; eyes
two, frontal, red, disappearing in advanced
age.

O. crystallinus (PL 35. fig. 16). Carapace
hyaline, viscid, covered with foreign bodies ;
aquatic; entire length 1-36".

Jaws each with three teeth.

BIBL. Ehrenberg, In/us, p. 392.

(ECISTINA, Ehr.— A family of Rotatoria.

Char. Animals single or aggregate, at-
tached to the bottom of a gelatinous cara-
pace; rotatory organ single, with an entire
margin.

A distinct carapace for each animal l.CEcistes.

Carapaces aggregated into a sphere Z.Conochilus.

BIBL. Ehrenberg, Infus. p. 391.

CEDEMIUM, Fr.— A genus of Dematiei
(Hyphomycetous Fungi). (E. atrum, Corda,
consists of dense tufts of brown erect fibres,
scarcely branched, and without true septa.
The roundish "spores" are sessile upon the
sides of the erect filaments.

BIBL. Corda, Sturm's DeutschL FL 6.
pi. 9 ; Fries, Sy sterna Myc. 344 ; Berkeley
and Broome, Ann. Nat. Hist. 2 ser. vi. p. 466.

(EDIPODIUM, Schwagr.— A genus of
Splachnaceae (Acrocarpous, operculated
Mosses), sometimes included under Gymno-
stomum. CEdipodium Griffithianum, Schwag.,
the only species, is remarkable for the pecu-
liarly thickened fruit-stalk, whence the name
of the genus is derived.

CEDOGONIUM,Link.(Pro^r«,Leclerc,
Vesiculifera, Hass). — A genus of Conferva-
cese (Confervoid Algae), which, from their
peculiar mode of growth and reproduction,
ought perhaps to form a distinct family.
Some of the CEdogonia are among the com-
monest and most abundant of freshwater
Algae, occurring in every pond, ditch, or
stream, and quickly making their appearance
in tanks, aquaria, &c. They may generally
be recognized at a glance by the dense and
uniform green protoplasm, sometimes filling
the cells, sometimes (after dividing) leaving
half of the cell colourless and devoid of
chlorophyll ; above all, by the annular striae
occurring at the ends of many of the cells
(PL 5. fig. 7 b, h}. The cells have each a
large parietal nucleus (fig. 7 a). The large
round interstitial sporangial cell (fig. 7 ff) is
also a very distinctive character. The zoo-
spores also are peculiar, consisting of the
entire contents of a cell, therefore very large,
and are crowned by a wreath of cilia (PL 5.
fig. 7 c). The filaments are attached, when
young, to stones, plants, &c., by root-like

processes. These plants, on many grounds,
deserve a somewhat close examination. The
filaments are composed of rows of cylindrical
cells, which multiply interstitially in a very
curious manner. When a cell divides, the
division of the primordial utricle first takes
place (this division must be looked for in
cells densely filled with contents), and two
new cells are formed within the parent. At
the same time an annular deposit of cellulose
occurs around the upper part of the parent-
cell. Next the wall of the parent-cell breaks,
by a circumscissile dehiscence, just below
the cellulose ring. The new cells elongate
and remove the margins of the circular slit
from each other, the upper piece of the
parent-cell wall being pushed up as a kind
of cap on the uppermost of the new cells.
This is pushed up further and further by the
elongation of the lower cell, until the upper
end of the latter comes above the line of
dehiscence, The annular deposit of gela-
tinous cellulose has meanwhile become
stretched or developed over the space left
by the separation of the halves of the parent
membrane, forming an outer coat to the new
cell. After the growth of the lowrer cell is
finished, the upper one begins to elongate,
until it attains equal length ; it remains poor
in protoplasm and chlorophyll while grow-
ing, but becomes densely filled when it has
attained its full dimensions. The margins or
broken ends of the parent-cell wall form the
annular striae seen on the filaments (PL 5.
fig. 7 b, g, h) ; at first there is only one at
the top of any given cell, but the next dehis-
cence takes place just below this, giving
rise to a second, and so on, until many suc-
cessive rings are produced at one spot.

The zoospores or ciliated gonidia (fig. 7 c)
are formed from the entire contents of a
cell, and exhibit a large round nucleus ; they
escape by a circumscissile dehiscence of the
wall of the parent-cell (b) ; the filament,
however, does not generally become quite
brokeninto two; theportions remain attached
by a strip of the side-wall forming a kind of
hinge. The zoospores are large, somewhat
ovate in form, with a transparent region at
one end, whence the numerous cilia arise.
When expelled, they move for a time, and
then come to rest, attaching themselves to
foreign objects by the ciliated end, acquiring
a membrane, sending out root-like processes
below (e), and elongating and expanding
above into a longish pear-shaped body.
Sometimes the zoospores do not completely
extricate themselves from the parent-cell,

(EDOGONIUM.

[ 469 ]

OIDIUM.

and then germinate in this way in situ, the
root-like processes remaining engaged in the
parent-cell. Very often they attach them-
selves upon the parent filament to germinate.
The next stage after germination presents
two different classes of phenomena ; in the
one the young plant elongates gradually
into a jointed filament by extension and
cell-division; in the other the contents of
the unicellular or bicellular germinating
plant become converted into minute globular
bodies, which are discharged by an orifice
formed at the summit of the filament by a
circumscissile dehiscence of the cell-mem-
brane (PL 5. fig. 7 /, t). The after-history
of these globular bodies is not certainly
known; the function of spermatic bodies
has recently been attributed to them. We
have seen bodies of similar appearance pro-
duced in the ordinary cells of decaying fila-
ments (fig. 7 A).

The (Edogonia likewise produce large
resting-spores (fig. 7 ff), which are formed
from the entire contents of the upper of the
two cells, developed as above described. It
is stated by Pringsheim that a slight rupture
of the parent-cell wall takes place at the
side during the development of the spore ;
from the small orifice thus formed a portion
of the nascent spore bulges out, afterwards
becoming retracted; and this author believes
that the bulging portion of the spore-mass
becomes fertilized through the agency of the
little globular bodies above alluded to as
produced by some of the germinating zoo-
spores. Ultimately the spore, while increa-
sing in size, retracts itself from the walls of
its parent-cell, and lies free in the cavity,
presenting a double coat, the outer of which
is thick and tough ; its contents acquire a
red colour as it ripens. The parent-cell of
the spore mostly acquires a globular or ellip-
tical form, appearing like a kind of nodule
on the filament ; and the ripe spore, of glo-
bular, elliptical, or depressed spherical form,
is mostly of greater diameter than the ordi-
nary cells. The ripe spore escapes by the
decomposition or dehiscence of the parent-
cell ; the history of its germination does not
appear to have been traced.

The systematic arrangement of the (Edo-
gonia is at present in a very confused condi-
tion. Hassall and Kiitzing have enumerated
a number of species which rest on very in-
sufficient grounds, for the length of the
joints appears variable. The synonymy of
the more distinct forms is also perplexed.
We are compelled to content ourselves with

selecting a limited number of species, which
present tolerably satisfactory characters.

1. GE. vesicatum, Link. Filaments 1-2500
to 1-3000" in diameter, joints two to four
times as long as broad ; spore-cells globose,
swollen. [This appears to include (E. Rothii,
Candollii, and ochroleucum.']

2. (E. tumidulum, Kg. Filaments 1-1400
to 1-1800" in diameter, joints two to six
times as long ; spore-cells oval, swollen.

3. (E. grande, Kg. Filaments 1-700 to
1-900" in diameter, joints one to four times
as long ; spore-cells elliptical, swollen. [Pro-
bably includes (E. giganteum, Ktz. and Vesi-
culifera lacustris, Hass.]

4. CE. Landsborouahii, Hass. Filaments
1-500 to 1-700" in diameter, two to four
times as long; spore-cells roundish-oval,
swollen.

5. (E.capillaceum,K%. Filaments 1-1 200"
long, one and a half to two times as long ;
spore-cells elliptic-globose, slightly swollen.
[Vesiculifera virescens, Hass.]

6. (E. crispa, Vauch. (PI. 5. fig. 7 a).
Filaments 1-700 to 1-900" in diameter,
equally or twice as long ; spore-cells slightly
swollen, spores squarish. Filaments curled.
Apparently Vesiculifera princeps, Hass.,
Conferva capillaris, Ag., Tiresias crispa,
Bory, &c. It seems to us also that Thuret's
(E. vesicatum (Ann. des Sc. not. 3 ser. xiv.
pi. 19) belongs here.

BIBL. Link, Hor. physic, berolin. (1820);
Kiitzing, Sp. Alg. p. 364, Tab. Phyc. Bd.iii.
pi. 33, &c.; Hassall, Br. Fr. Ala. p. 195;
Thuret, Ann. d. Sc. nat. 3 ser. xiv. p. 226;
Pringsheim, Monatsber. Berl. AJcad. 1855,
Ban und Bildung der Pflanzenzelle, Berlin,
p. 33, 1854.

OIDIUM, Link (Acrosporium and Sporo-
trichum, Greville, Torula, Corda). — A sup-
posed genus of Mucedines (Hyphomycetous
Fungi), but very probably consisting merely
of imperfect conditions of plants of more
complex nature. The Oidia have recently
attracted great attention on account of the
extraordinary development of the form called
Oidium Tuckeri on the vines of Europe and
the Atlantic islands. This, however, like
O. leucoconium and others, appears to be
only the conidiferous mycelium of an ERY-
SIPHE or some allied plant; the particulars
of its history are given more at length under
VINE FUNGUS. Oidium lactis seems also
referable to Torula, or to the mycelium of
PENICILLIUM. O. abortifaciens, Lk. is an
imperfect state of CLAVICEPS; O. albi-
cans, C. Robin, the fungus of APHTHA, is

OIL.

[ 470 ]

ONYGENEI.

probably referable to some other genus when
mature, as Achorion should perhaps also
be included under Puccinia. The objects
described as Oidia consist of delicate hori-
zontal filaments, creeping over leaves, fruits
or decaying vegetable and animal substances
(0. lactis at the edges of sour milk, 0. albi-
cans in the mouth of the human subject),
forming an interlaced fleecy coat, the hori-
zontal filaments giving origin to numerous
erect (usually short), articulated pedicels,
the uppermost cells of which (or several of
the uppermost) become expanded into oval
bodies (conidia) which become disarticulated,
and falling upon the matrix, germinate and
produce new filaments (PL 20. figs. 8, 9).

Oidium leucoconium, Tuckeri, erysiphoides
are white; 0. aureum, fulvum,fructigenum,
and others subsequently become coloured.

As we do not regard them as independent
organisms, it seems unnecessary to give the
characters of the supposed species.

BIBL. Berk. Hook. Brit. Fl. ii. pt. 2. p.
349; Ann. Nat. Hist. i. p. 263, vi. p. 438,

2 ser. vii. p. 178, xiii. p. 463; Fries, Summa
Veg.494; Fresenius, Beitr.z.Mycologie,T:Left
i. p. 23, ii. p. 76 ; Leveille, Ann. d. Sc. nat.

3 ser. xv. p. 109 ; Grev. Sc. Crypt. Fl. pi.
73 ; Ch. Robin, Vegetaux Parasites, 2nd ed.
p. 488; and the Bibl. of VINE FUNGUS.

OIL. — Oils of various kinds are most
abundantly produced by a very large number
of plants, and occur to some extent in almost
all. For the microscopist, it is convenient
to divide them into essential and fixed oils.
The former are special secretions, and occur
in the cells of the GLANDS and GLANDULAR
HAIRS of the epidermis of those parts of
plants exposed to the air and light. Fixed
oils are found principally in the cells of
tissues still physiologically active in the nu-
trition of the plants, and they appear in
many cases to have a close relation with and
to form substitutes for starch. Thus fixed
oils occur stored up in the cells of the peri-
sperms or of the cotyledons of certain seeds
in which little or no starch is produced, as
in the Papaveracece, Crucifera, Linum, the
almond, nut, &c. Oil may occur also in
the pulp of fruits, as in the olive.

SPORES of Cryptogamic plants and POL-
LEN-grains are remarkable for the oil they
exhibit in their mature condition. It ap-
pears to serve as an indifferent or inert form
of assimilated nutriment.

Oil occurs in the cavity of cells in the
form of minute drops, which may be distin-
guished mostly, by the experienced micro-

scopist, by simple inspection ; but it is often
desirable to prove the nature of the globules,
which may be done by removing them with
aether, or, in the case of pollen, by viewing
them in spirit of turpentine or oil of lemons.
Potash does not act readily upon oil-globules
in the cells of plants.

In certain cases it is convenient to view
objects in oil instead of water, in order to
render them more transparent ; for this pur-
pose oil of lemon is conveniently employed.

OMPHALOPELTA, Ehr.— A genus of
fossil Diatomaceae.

Char. Agrees with Actinoptychus, but the
upper part of the margin of the valves has a
few opposite erect spines.

Four species. Fossil and marine.

BIBL. Ehrenberg, Ber. d. Berl. Akad.

1844. p. 263; Kiitzing, Sp. Ala. p. 132.
ONCOSPHENIA, Ehr.— A genus of Dia-
tomaceae.

Char. Frustules single, cuneate in front
view ; valves equal, uncinate at the apices ;
neither vittae nor nodules present.

0. carpathica. Valves cuneate, laxly stri-
ated (ord. ilium.), one end turgid, rounded,
and straight, the other attenuate and unci-
nate; aquatic; diameter 1-790".

BIBL. Ehrenberg, Ber. d. Berl. Akad.

1845. p. 72; Kiitzing, Sp. Alg. p. 11.
ONION, Allium Cepa (Flowering Plants,

Nat. Ord. Liliaceae). — The young bulb of the
onion offers a very good and cheap subject
for the investigation of the development of
spiral vessels, to those who do not object to
its odour ; other bulbs will do equally well.
In the cells of the base of the bulb occur
very elegant groups of prismatic crystals
(see RAPHIDES).

ONOCLEA, Linn.— A genus of Cystopte-
rideae (Polypoda3ous Ferns). Indusium very
thin, membranous and reticulated. The fer-
tile pinnae are usually so rolled up as to look
like little berries seated on a spike, filled
with sporangia. Exotic.

ONYGENEI.— A family of Ascomycetous
Fungi, containing a few inconspicuous plants
growing upon the feathers of dead birds, or
upon cast-off horse-shoes. The flocculent
spreading mycelium usually produces on its
surface little white stalk-like bodies crowned
by a globular perithecium. At first erect and
thick, these supports become more slender
as they elongate, and seem to bend under
the weight of the light perithecium (fig. 536).
In some species the perithecium is sessile.
The perithecium is filled with branching
filaments, arising from the walls of its inter-

ONYGENEL

[ 471 ]

OPALINA.

nal cavity, interlacing together and bearing
at their free extremities globular cells (asci)
containing the spores (figs. 538. 540). At

Fig. 536.

Fig. 537.

Onygenei corvini.

Fig. 536. Plants on a feather. Nat. size.

Fig. 537. Single plant with the perithecium dehiscing.

Magn. 10 diams.
Fig. 538. Portion of the sporiferous layer, with asci.

Magn. 350 diams.

Fig. 539. Asci detached. Magn. 700 diams.
Fig. 540. Spores. Magn. 700 diams.

the epoch of maturity the perithecium, ori-
ginally closed, bursts circularly towards the
base, the upper part becoming detached un-
der the form of a more or less regular cap
(fig. 537), exposing the spores set free by a
solution of the filaments.

British Genus.

O N Y G E N A . Perithecium capitate, at length
slit round the base, and falling off as an im-
perforate cap. Asci borne at the free ends
of filaments forming an entangled mass in
the perithecium, finally free and pulvera-
ceous.

BIBL. Berk. Brit. Flora, ii. pt. 2. p. 322,
Ann. Nat. Hist. vi. p. 432, 2nd ser. vii. p.
184 ; Tulasne, Ann. des Sc. nat. 3 ser. i. p.
367- pi. 17; Greville, Sc. Crypt. Fl. pi. 343.

OOLITE.— The substance of oolitic rocks
consists principally of carbonate of lime,
sometimes crystallized, at others granular,
and usually abounding in organic remains,
as shells, &c. It consists of two parts, one
of which forms the matrix, is mostly colour-
less, often crystalline, and exhibits a number
of rounded or oval cavities, each of which
contains a nodule, or mass of a correspond-
ing form. These nodules give the stone
somewhat the appearance of the roe of a fish,
hence oolite is sometimes called roe-stone.
The nodules possess rather a granular than
a crystalline structure. They are sometimes
coloured, hollow, and often exhibit concen-
tric rings like those of calculi, and indicative
of the successive deposition of layers. Some
kinds of oolite contain grains of sand im-
bedded in the matrix between the nodules.

Polished sections of oolite form interest-
ing objects; and where the nodules are co-
loured and the matrix colourless, as in oolite
from Bristol, in which the former are red,
the beauty of the appearance is increased.

BIBL. Works on geology (see the Bibl.
of CHALK).

OOMYCES, Berk, and Br.— A genus of
Sphaeriacei (Ascomycetous Fungi), founded
on a minute plant growing upon the leaves
of grasses. 0. carneo-albus (Spharia car-
neo-alba, Libert.) has pale, flesh-coloured,
tough receptacles 1-18 high, marked with
the ostioles of 3-7 perithecia closely packed
within it, bearing resemblance to the eggs of
some insects.

BIBL. Berk. & Broome, Ann. Nat. Hist.
2 ser. vii. p. 185.

OOSPORANGES.— The name applied
by Thuret to the organs (called ' spores' by
most authors) producing the larger kinds of
zoospores, in those tribes of Algae where
zoospores of two sizes occur (see fig. 462,
p. 424). These organs are usually ovate, or
of some analogous form ; those containing
the smaller zoospores are usually filiform,
and are distinguished as trichosporanges.
The term is also applied, together with
oophoridium, to the sporanges containing
the larger spores in SELAGINELLA and
ISOETES.

OPALINA, Purk. and Val.— The animals
comprised under this title were formerly re-
garded as Infusoria, among which they were
placed, but later researches tend to show
that they are imperfectly developed forms
or intermediate stages of animals probably
higher than the Infusoria. They are micro-
scopic, oval or oblong, colourless, covered

OPEGRAPHA.

[ 472 ]

OPHRYDINA.

with vibratile cilia arranged in regular rows;
they contain a so-called nucleus, and exhibit
contractile vesicles, hut they do not admit
colouring matters, nor have they a mouth.
In one form, an adhesive suctorial disk has
been observed, and in another a hook-appa-
ratus, probably serving the same end. They
are parasitic within the bodies and usually
the intestinal canal of earth-worms, frogs,
Planarice, Naides, beneath the gill-plates of
Gammarus> &c.

0. (Bursaria, E.) ranarum, P. & V., is
figured in PI. 24. fig. 47.

Dujardin places some of them in his genus
Leucophrys.

BIBL. Purkinje and Valentin, De phen.
mot. vibr.; Schutze, Beit. z. Naturg. d. Tur-
bett.; Stein, Infus. p. 178, &c.

OPEGRAPHA, Ach.— A genus of Gra-
phideae (Gymnocarpous Lichens), growing
on bark of trees, stones, &c. Besides their
linear lirella, the fronds bear spermaaonia, in
O. varia and 0. calcarea, forming black spots
on the surface, communicating with little
unilocular cavities lined with short, linear
sterigmata bearing numerous spermatia.
Mr. Leighton enumerates fourteen species
and numerous varieties in his recent mono-
graph.

BIBL. Brit.Flor.ii. pt. 1. p. 147; Leigh-
ton, Ann. Nat. Hist. 2ndser. xiii.; Tulasne,
Ann. des Sc. nat. 3 ser. xvii. p. 207.

OPERCULARIA, Goldfuss.— A genus of
Infusoria, of the family Vorticellina.

According to Ehrenberg's description,
Opercularia resembles Epistylis in being
furnished with a rigid (not contractile),
branched stalk, but differs in the presence
of two kinds of bodies, larger and smaller,
attached to the branches, the former being
usually situated in the axils. Stein regards
the larger bodies as belonging to individuals
of an older generation, which attach them-
selves to the branches as to other foreign
bodies, and there secrete a new polypidom.
This author would distinguish Opercularia
by the circular anterior margin or rim (peri-
stome) of the body not being thickened and
everted, by no cilia arising from it, and by
the presence of a kind of lower lip, formed
of a delicate everted fold.

Adapted to the peristome in both genera
is a conical plug-like retractile body, fringed
with cilia, and flat or convex at the end.

O. articulata, E. Found adherent to Hy-
drophilus piceus and Dytiscus marginalia.
PI. 25. fig. 25, Acineta-stage (INFUSO-
RIA).

0. berberina, St. Found upon Noterus
crassicornis, a water-beetle.

BIBL. Ehrenberg, Infus. p. 286 ; Stein,
Infus. passim.

OPHIDOMONAS,Ehr.— A generic name
applied to slender, filiform, spiral (helical),
vibrio-like bodies, of a brown or red colour,
withobtuse ends, and actively moving through
the water by means of an anterior flagelliform
filament. Ehrenberg places them among
the Infusoria, in the family Cryptomonadina,
and admits two species, characterized by the
difference in colour. One was found in
fresh, the other in brackish water. Length
about 1-570", breadth 1-9000". In some
the spire forms only half a turn, in others
two and a half turns.

Probably an Alga. Is it the young state
of Spirulina ?

BIBL. Ehrenberg, Infus. p. 43, and Ber.
d. Berl. Akad. 1840.

OPHIOGLOSSACE^E. — A family of
Ferns, distinguished from all others by the
characters both of the vegetative and repro-
ductive structures. The fronds are always
divided into two parts, one foliaceous and
sterile, and the other fertile, neither being
ever rolled up in the form of a cross. The
sporanges are destitute of any trace of an
annulus, and always split very regularly to
discharge the spores.

Synopsis of Genera.

1. OPHIOGLOSSUM. Sporanges dehiscing
transversely, connate on an undivided disti-
chous spike.

II. BOTRYCHIUM. Sporanges dehiscing
transversely, arranged on a distichous, se-
cond, bi-, tri-pinnate spike.

III. HELMINTHOSTACHYS. Sporanges
dehiscing externally, vertically from the base
to the middle, collected in whorls, with
crest-like appendages and stalked, arranged
distichously on an elongated spike.

OPHIOGLOSSUM, Linn.— The typical
genus of Ophioglossaceous Ferns, repre-
sented by the Adder's-tongue Fern, Ophio-
glossum vulgatum.

OPHRYDINA, Ehr.— A family of Infu-
soria, corresponding to Vorticellina with a
carapace (p. 348).

Animals grouped in a gelatinous mass 1. Ophrydium.

(Body attached to the bottom 1 „ „,. ..
Animals] of the carapace by a stalk J
single | Body not f Carapace stalked . . 3. Cothurnia.

L stalked \Carapacesessile .. 4. Vaginicola.

BIBL. Ehrenberg, Infus. p. 291.

OPHRYDIUM.

[ 473 ]

ORTHOTRICHACE.E.

OPHRYDIUM, Ehr.— A genus of Infu-
soria, of the family Ophrydina.

Char. Consists of a colourless, gelatinous,
rounded mass, either adherent or free, con-
taining numerous greenish Vorticella-like
animals imbedded and somewhat radiately
arranged within it. Aquatic. Length of
extended bodies 1-100 ; size of entire
mass from that of a pea to that of the fist,
and even more.

O. versatile (PL 24. fig. 49, portion near
the surface; fig. 48, portion expanded by
pressure; fig. 50, separate animal). The
gelatinous mass or envelope has been de-
scribed as consisting of separate portions or
cells, and again as forming a homogeneous
whole. It somewhat resembles and has been
mistaken for frog's spawn. The bodies of
the animals, when extended, are spindle-
shaped, when contracted, oval, or nearly
spherical ; they have a row or ring of cilia
at the anterior margin of the peristome, also
a lid with a fringe of cilia, as in Opercularia,
&c. The body exhibits annular constrictions
and longitudinal folds, and contains scat-
tered chlorophyll-granules, and a long, nar-
row, tortuous nucleus. A distinct narrow
elongated oesophagus is present. Ehrenberg
remarks, that at first the individual bodies
are united in the centre by filaments, which
subsequently disappear. The animals un-
dergo the encysting process, and assume an
Acineta-form. When they leave the jelly,
a posterior ring of cilia is formed, as in Vor-
ticella, and the animals swim with the tail first.

This organism bears some resemblance to
Coccochloris among the Palmellacese, yet it
appears decidedly animal.

BIBL. Ehrenberg, In/us, p. 292 ; Stein,
In/us., passim.

OPHRYOCERCINA, Ehr.— A family of
Infusoria.

It contains the single genus Trachelocerca,
E., which corresponds to Lachrymaria with
a tail. Dujardin unites these two genera,
so that the former becomes unnecessary. If
the family be retained, it should be called
TRACHELOCERCINA.

OPHRYOGLENA, Ehr.— A genus of In-
fusoria, of the family Colpodea.

Char. Body ciliated all over ; a frontal
eye-spot present ; cilia arranged in longitu-
dinal rows.

Three species. Stein remarks, that on
treating these animals with acetic acid, the
cilia became converted into a dense network
of curved and geniculate hairs, some as long
as the body.

0. atra (PI. 24. fig. 53). Body ovate, com-
pressed, black, acute posteriorly; eye-spot
black, marginal; cilia whitish. Aquatic;
length 1-180".

O. acuminata, brown; eye-spot red;
O.flavicans, yellowish; eye- spot red. Both
aquatic.

Dujardin places this genus in his family
Bursarina.

BIBL. Ehrenberg, In/us, p. 360; Stein,
In/us, p. 240; Dujardin, In/us, p. 506.

ORBICULIN A, Lam.— A genus of Fora-
minifera.

0. numismatis (PI. 18. fig. 11-15). Found
in sea-sand.

BIBL. That of FORAMINIFERA.

ORIBATA, Latr.— This genus has been
subdivided, and now constitutes the family
Oribatea. The position of three species is,
however, doubtful, viz. Acarus conferva,
Schr., living in fresh water, and creeping
upon Confervae, &c.; Oribata demersa,T)u].,
aquatic, with a cervical eye, and found upon
Hypnum inundatum ; and Oribata marina, a
marine species.

We have found one species doubtfully re-
ferable to the above, agreeing with the cha-
racters of the Oribatea (p. 58) : body brown,
tarsi with a single claw, and no caruncle.
The individuals were creeping upon broken
stems of Ceratophyllum.

BIBL. Gervais, Walckenaer's Apt. iii.
p. 251 ; Schrank, Ins. Austria, p. 511; Du-
jardin, L'Institut, 1842. p. 316; Koch,
Deutschl. Crustac. &c.; Duges, Ann. des Sc.
nat. 2 ser. ii. p. 46.

ORTHODONTIUM, Schwagr.— A genus
of Bryaceous Mosses, included under Bryum
by some authors.

Orthodontium gracile, Schwagr. = Bryum
(Pohlia) gracile, Wils.

BIBL. Wilson, Bryologia Britann. p. 218.

ORTHOSIRA, Thw. See MELOSIRA.

ORTHOTRICH ACE.E.— A tribe of Pot-
tioid Mosses including several British genera.

a. Papilla distinct, tuberculate, rarely obso-
lete-, peristome mostly pale, rarely orange-
coloured.

1. ZYGODON. Calyptra dimidiate. Peri-
stome wanting, simple (external or internal)
or double ; external of thirty-two simple, Or-
thotrichoid,twin or bigeminate-conglutinate,
flat, pale, regular, rather fleshy teeth, formed
of a single row of cells, spreading or reflexed
on drying, and appressed to the capsule as
in Orthotrichum ; internal : eight to sixteen
linear, hyaline, more or less connivent, hori-

ORTHOTRICHUM.

[ 474 ]

OSCILLATORIA.

zontal cilia, or resembling the outer teeth.
Capsule pyriform, grooved, more rarely gla-
brous, without an annulus.

II. ORTHOTRICHUM, Hedw. Calyptra
campanulate, plaited. Peristome absent,
simple or double. External of thirty-two
geminate (sixteen) (fig. 487- p. 435), or bi-
geminate (eight) (fig. 542) teeth, more rarely
of sixteen entire, undivided teeth, granular,
fleshy, or brittle, mostly pale, rarely orange-
coloured, erect, afterwards reflexed, arising
below the mouth of the capsule. Internal :
eight or sixteen cilia, simple, hyaline, or
(rarely) resembling the teeth. Vaginule
ochraceous. Inflorescence monoecious or
dioecious. Capsule without an annulus,
more or less pyriform, grooved, rarely gla-
brous; operculum capitate, conical.

b. Papilla mostly obsolete, rarely distinct,,
peristome always coloured, purple, red or
orange.

III. GLYPHOMITRIUM. Calyptra cam-
panulate, large, totally enclosing the capsule,
deeply laciniate, plaited. Peristome com-
posed of sixteen short, lanceolate, densely
trabeculate, entire teeth, with a central line,
approximated in pairs, incurved, arising be-
low the orifice, orange-coloured, smooth
(fig. 287, p. 293). Inflorescence monoecious.

IV. BRACHYSTELIUM. Calyptra as in
the preceding, altogether or almost entirely
covering the capsule, mitre-shaped, with long
and repeated laciniations, slightly plaited.
Peristome like that of Trichostomum, the
teeth being split more or less down to the
base, into two arms. Inflorescence monoe-
cious.

V. GUEMBELTA. Calyptra dimidiate, other-
wise like the following (figs. 293-295, p.
299).

VI. GRIMMIA. Calyptra mitre-shaped,
laciniate, scarcely exceeding the operculum,
and smooth, or else shorter. Peristome
simple, teeth sixteen, lanceolate, with a me-
dian line, trabeculate, often however fissile,
hence very polymorphous, more or less split,
as far as the middle, into two or four teeth,
or into two arms down to the base (fig. 292,
p. 299).

ORTHOTRICHUM, Hedwig.— A genus
of Orthotrichaceae (Pottioid Mosses), grow-
ing in round tufts, fertile at the summit, on
trees and stones, never on the earth. There
are numerous British species, which are re-
markable for the apophyses (sometimes
having stomata) and for the varied character
of the outer peristome, the thirty-two teeth

of which are variously conjoined, so as to
appear as thirty-two, sixteen, or eight. The
calyptra is mostly covered with hair-like
processes (fig. 476, p. 433).

Fig. 541.

Fig. 542.

Fig. 541. Orthotrichum pulchellum. Magn. ISdiams.
Fig. 542. Orthotrichum pollens. Fragment of peri-
stome. Magn. 50 diams.

BIBL. Wilson, EryologiaErit. p. 185;
Hooker, Brit. Fl. ii. pt. 1. p. 57.

OSCILLATORIA, Vauch.— A genus of
Oscillatoriaceae (Confervoid Algae), distin-
guished from the allied forms by the simple,
rigid, elastic filaments, forming a stratum in
a common gelatinous matrix. The filaments
are enclosed singly in tubular cellulose
sheaths, open at the ends, from which the
fragments emerge when they are broken
across (PL 4. fig. 8). The young filaments
or growing extremities are continuous and
scarcely striated, but by degrees transverse
striae appear, sometimes very close together,
sometimes distant, which striae indicate a
constriction and final fission in the substance
of the filament, which, when old, readily
breaks at these places. The internal struc-
ture of the filament is obscure ; it would
seem to be composed wholly of protoplasmic
substance, the joints not possessing special
cellulose coats, but the substance of the
filament, although apparently solid, seems
sometimes less dense internally, since we
have noticed a kind of hour-glass contraction
intermediate between the striae after the ac-
tion of thick syrup (by endosmose) and after
desiccation. The curious rounding-off of
the separated ends of dividing filaments (PI.
4. fig. 8, right-hand figures) seems to depend
on some power of expansion of an outer
thicker layer of the substance of the fila-
ment. The motion of the filaments has

OSCILLATORIA.

[ 475 ]

OSCILLATORIACE^.

been described under OSCILLATORIACEJE.
The filaments ultimately break up at the
strise into distinct joints, which may be re-
garded as gonidia. No formation of spores
has been observed. A remarkable and un-
explained appearance is occasionally observed
at the growing ends of the filaments ; they
appear crowned by a wreath of cilia, but
these processes are rigid ; no motion of them
has ever been seen.

Kutzing has multiplied the species beyond
all reason, and separated some without good
grounds under the name of Phormidium.
We follow Harvey in the enumeration of the
commoner British species; but this genus,
like its allies, requires a thorough study of
recent specimens. They occur on damp
ground, on stones, on mud, in fresh water,
running or stagnant in springs and in brack-
ish water ; a few are truly marine. In the
following characters the colour of the strata
is given as seen by the naked eye, that of
the filaments as seen under the microscope.

* In fresh water, or on damp earth, &c.
a. Stratum teruginous or blue-green.

1. O. limosa, Ag. Stratum dark green,
glossy, with long rays; filaments green,
1-3300 to 1-3600" in diameter; articulations
shorter than the diameter. At the bottom
of ditches and pools.

2. 0. tennis, Ag. Stratum dark green,
thin, with short rays ; filaments pale
green, 1-4200" in diameter; articulations
equalling or half the diameter. In muddy
ditches, &c. ; at first on the bottom, finally
floating to the top.

3. O. muscorum, Ag. Stratum dark seru-
ginous-green, 3 or 4" in extent, growing over
mosses in rapid streams; filaments 'thickish,'
pale blue-green.

4. O. turfosa, Carm. Stratum pale ver-
digris-green, glaucous, I or H' in diameter,
resting on an ochraceous substratum; fila-
ments hyaline, 'very slender/ On floating
sods in turf-pits.

5. O. decorticans, Grev. Stratum smooth,
glaucous-green, membranous, peeling off in
flakes ; filaments pale bluish - green, * very
slender.' Damp walls, pumps, &c. ; com-
mon.

b. Stratum dull green, inclining to purple,
black, or brown.

6. O. nigra, Vauch. Stratum blackish-
green (bluish-black when dry), with long
radii ; filaments pale bluish -green, 1-2800 to
1-3000" in diameter; joints equalling or a

ittle shorter than the diameter. Ditches
and ponds. Common.

7. 0. autumnalis, Ag. (PI. 4. fig. 8). Stra-
tum purplish or greenish-black; filaments
pale dirty bluish-green, 1-4000 to 1-5000" in
iiameter ; joints shorter than the diameter.
Damp ground, walls, &c. Common.

8. 0. contexta, Carm. Stratum glossy
black, spreading three feet or more, appear-
ing satiny and striated to the naked eye;
filaments pale green, 1-3000" in diameter ;
articulations largish. On mud ; apparently
common.

O. ochracea, Grev. is probably the same
as Leptothrix ochracea.

** Marine, or in brackish water.

9. 0. littoralis, Carm. Stratum bright
seruginous - green ; filaments deep green,
* thicker than in 0. nigra;' joints one-third
the diameter. Pools on the sea-shore.

Other species are described, but without
dimensions, so that they are obscure with-
out the aid of figures. See also SYMPLOCA.
BIBL. Harvey, Brit. Alg. 1st ed. p. 161,
Br.Mar.Alg.v.228,Phyc.Brit. pis. 105,251;
Hassall, Br. Fr. Alg. p. 244. pi. 70-72;
Kutzing, Sp. Alg. p. 237, Tab. Phyc. Bd. i.
pis. 38-44.

OSCILLATORIACEJS. — A family of
Confervoid Algae, containing organisms of
considerable diversity and not very well cha-
racterized at present, owing to the obscurity
of the reproduction. The genus Oscillatoria,
with its nearest allies, is composed of cylin-
drical filaments of protoplasmic substance,
invested by a continuous cellulose sheath or
tubular cell-membrane. The internal (solid?)
filament gradually becomes transversely
striated as it increases in age, and subse-
quently readily breaks across at the trans-
verse lines, and the fragments readily escape
from the sheaths, since no cross-walls of
cellulose are produced (PI. 4. fig. 8). These
kinds exhibit clearly the remarkable motion
from which the family takes its name. They
are mostly found upon damp ground, form-
ing wide and irregular strata; Rivularia and
the allied genera have the joints of the fila-
ments more distinct, and the filaments are
coherent into definite fronds, on which they
stand erect or radiate from a centre (PI. 4.
figs. 13. 16). The sheaths become compli-
cated in many of these, from the internal
multiplication and the persistence of the
cellulose sheaths of several generations one
within another (see PETALONEM A), often ge-
latinously swollen up and sometimes decom-

OSCILLATORIACE^.

[ 476 ]

OSCILLATORIACE.E.

posed into spiral fibrous structures (PI. 4. fig.
15; see SPIRAL STRUCTURES). Some of the
remaining forms, included here for the pre-
sent, differ considerably from the above, and
are imperfectly understood. Vibrio (PL 3.
figs. 18-21) consists of moniliform filaments
without an apparent sheath. Spirulina (PL
3. fig. 15) has the (solid?) filaments curled
spirally, and in the strange plant Didymo-
helix (PL 1. fig. 10) two spiral filaments oc-
curred twined together. These last minute
forms generally occur imbedded in a gelati-
nous stratum, but their relation to this is
not yet clearly ascertained.

The structure of the Oscillatoriaceae,
judging from Oscillatoria, Microcoleus, and
Lyngbya, differs importantly from that of
all other Confervoids. The filaments are
not composed of rows of cells, but, in the
earliest condition, of a cylindrical thread of
protoplasm, coloured greyish, green, brown,
or purple in different cases. The ends of
growing filaments are narrower and devoid
of striae, and have no perceptible cellulose
sheath ; when a little older, cross striae ap-
pear, consisting of double rows of granules
or dots, and the tubular cellulose coat is
evident ; finally, the striae become distinct
lines (see PL 4. figs. 8-22). In this stage,
external violence will cause the filament to
break across at the striae, and the fragments
then slide along inside the cellulose sheath,
the broken ends always assuming a rounded
form like that of the free extremities (PL 4.
fig. 8 b}. When these fragments slide quite
out of the sheaths, the latter appear as con-
tinuous tubes (PL 4. fig. 8 a), seldom with
any cross markings opposite the striae of the
internal mass. InLyngbya the division seems
to take place in a peculiar manner, accom-
panied by an interstitial growth comparable
to that of ZYGNEMA. In a well-developed
filament, every eighth stria is strongest, the
intermediate fourths rather lighter, every
second one between them paler still, and the
intermediates of these only just marked;
while in Oscillatoria the striae seem to be
gradually less definite towards the growing
apex of a filament. The filaments appear
solid as ordinarily viewed ; but the endos-
mose resulting from placing them in syrup
or gum-water causes them to contract be-
tween the striae, or to break up into lenticular
disks. The ultimate fate of all the filaments
seems to be a separation into disks or glo-
bular gonidia, by breaking across at the
striae.

In Microcoleus (PL 4. fig. 9) and many

Rivularieae there would appear to be a trans-
verse multiplication like that occurring oc-
casionally in NOSTOC, as the filaments are
found lying side by side in gelatinously de-
composed outer (parent) sheaths. The fila-
ments of the Rivularieae are seated on a
large basal cell (PL 4. figs. 13. 16. 18), the
nature of which is not understood.

The remarkable spontaneous motion of
many Oscillatoriaceae presents a considerable
variety of conditions. In Oscillatoria and
Microcoleus the ends of the filaments emerge
from their sheaths, the young extremities
being apparently devoid of this coat ; their
ends wave backwards and forwards, some-
what as the fore-part of the bodies of cer-
tain caterpillars are waved when they stand
on their pro-legs with the head reared up.
The filaments also emerge from the tubes
and break up, and the fragments then exhi-
bit an oscillating movement like that of a
balance, together with an advance in a lon-
gitudinal direction. Lyngbya (PL 4. fig. 10)
does not appear to oscillate, at all events
when in long filaments; but it presents a
curling snake-like or worm-like movement.
Vibrio, Spirulina, and other forms, exhibit
only a tremulous oscillation ; the same ap-
pears to be the case with Bacterium, These
last organisms were included by Ehrenberg
among the Infusoria, but there is every rea-
son to regard them as vegetables. Leptothrix
and the allied genera are very imperfectly
known, and are only included here from the
absence of indications of closer affinities else-
where; very likely they are mycelial fila-
ments of Fungi.

All these plants occur on damp ground,
rocks or stones, and among Mosses and
other Confervae on rocks, stones, &c., in
fresh and salt water, and are allied in some
respects to the NOSTOCHACE^E, but the
articulations of the filaments of the latter
are all perfect cells with a complete cellulose
wall, multiplying by division in the same
way as the Confervaceae.

Synopsis of British Genera.

A. Oscillatorieee. Filaments transversely
striated or moniliform, sometimes spi-
rally curled ; sheathed, or in the minute
forms, without evident sheaths; exhi-
biting spontaneous oscillating, creeping,
or serpentine motion. Increased by
transverse division.

I. BACTERIUM (PL 3. fig. 17). Filaments
extremely small, short, wand-shaped, or

OSCILLATORIACE^.

[ 477 ]

OSCILLATORIACE.E.

longish-oval, with two to four cross striae,
exhibiting a vibratory motion. No sheaths
evident.

II. VIBRIO (PI. 3. figs. 18-20). Filaments
extremely slender, moniliform, with an ac-
tive serpentine motion. No sheath evident.

III. SPIRULINA (PL 3. figs. 15. 22. 23).
Filaments very slender, continuous or moni-
liform, curled into a long spiral or screw-like
form ; oscillating ; no sheaths evident, but
often a common investing jelly.

IV. DIDYMOHELIX (PL 1. fig. 10). Fila-
ments very slender, continuous, curled spi-
rally and twisted together in pairs. Motion?.
No evident sheaths, but a common investing
jelly.

V. OSCILLATORIA (for this and the re-
maining genera see PL 4). Filaments con-
tinuous, transversely striated, readily break-
ing across, with a proper cellulose sheath,
oscillating ; collected in strata and imbedded
in a common gelatinous matrix.

VI. MICROCOLEUS. Filaments as in
Oscillatoria, but collected in bundles in a
common gelatinous tubular sheath, which is
dichotomously branched; filaments oscil-
lating.

VII. SYMPLOCA. Filaments as in Oscil-
latoria, but erect and tufted, coherent at
their bases, bristling above.

B. Lyngbyea. Filaments motionless (?), oscil-
larioid, enclosed in a very distinct sheath,
tufted, or forming strata, with or without
an enveloping jelly.

VIII. DASYGL^EA. Filaments unbranched,
sheathed; older sheaths broad, coalescent
outside into an amorphous gelatinous stra-
tum.

IX. LYNGBYA. Filaments elongated,
distinctly articulated, unbranched, with di-
stinct convoluted cellulose tube, but without
a gelatinous matrix ; (motion creeping?) arti-
culations very close.

X. LEIBLEINIA. Filaments short, erect,
tufted, unbranched, with distinct cellulose
coat, free, without an investing jelly.

C. Scytonemece. Filaments distinctly arti-
culated, simple or branched, motionless,
with distinct articulations and large in-
terstitial (propagative ?) cells; sheaths
at length softened and swollen, but with-
out a common gelatinous matrix.

XI. SCYTONEMA. Filaments caespitose,
or more rarely fasciculate, with a double
(lamellar) gelatinous sheath, (mostly) closed

at the apex ; branches continuous by lateral
growing out of the primary filaments, with
a knee-like base.

XII. ARTHRONEMA. Filaments distinctly
articulated, simple, in short lengths, over-
lapping at their ends within the gelatinous
sheath.

XIII. PETALONEMA. Filaments branched,
with the outer sheaths of the single joints
expanded upwards and outwards into fun-
nel-shaped bodies, each partly overlapping
its successor, forming a common obliquely
lamellated and transversely barred gelatinous
cylinder.

XIV. CALOTHRIX. Filaments very closely
articulated, tufted, with branches in apposi-
tion for some distance, here and there co-
hering laterally. Sheaths firm, often dark-
coloured.

XV. TOLYPOTHRIX. Filaments free,
radiantly or fastigiately branched, most di-
stinctly articulated at the bases of the
branches ; branches continuously excurrent,
not in apposition ; sheaths thin, hyaline.

XVI. SIROSIPHON. Filaments single,
double or triple, within a distinct common
sheath, very distinctly articulated; branched
by lateral budding, the branches divergent.

XVII. SCHIZOTHRIX. Filaments branched
by division ; sheaths lamellated, thick, rigid,
curled, thickened below, finally longitudinally
divided.

XVIII. SYMPHYOSIPHON. Filaments
erect or ascending, enclosed in lamellated,
hard sheaths, concreted laterally at their
bases, involved in jelly.

D. Rivulariea. Filaments distinctly arti-
culated, with an enlarged basal cell,
mostly attenuated above, connected into
definite or indefinite fronds ; motionless.

XIX. SCHIZOSIPHON. Basal cells glo-
bose, filaments simple, distinctly articulated,
mostly attenuated to wards the apex, sheathed,
sheaths connate into groups, hard, dark-
coloured, open and expanded above, and
overlapping so as to form a succession of
pchrea3 which have the free borders slit up
into filaments or fringes ; also displaying a
spiral-fibrous structure in dissolution.

XX. PHYSACTIS. Filaments whip-
shaped, torulose at the base, sheathed,
sheaths simple, gelatinous ; collected into a
globose and solid, or subsequently a bullose-
vesicular frond; in the globose fronds the
filaments radiate from the centre; in the
vesicular fronds from the internal (lower)
surface of the gelatinous matrix.

OSMUNDA.

[ 478 ]

OVARY.

XXI. AINACTIS. Filaments branched,
articulated, with thin sheaths, collected into
a solid, pulvinate frond, which is concen-
trically zoned by the dichotomous branching
of the filaments. Sheaths more or less soli-
dified by carbonate of lime ; sometimes ex-
hibiting a spiral structure in dissolution.

XXII. RIVULARIA. Filaments with an
oval basal cell succeeded by one of cylindric-
al form (manubrium), the remainder short,
attenuated in diameter upwards (whip-
shaped). Sheaths sometimes saccate below,
open (not fringed) above ; forming a slippery
gelatinous frond.

XXIII. EUACTIS. Filaments whip-
shaped, with repeated ochreate sheaths,
forming fronds in which they radiate, and,
by superposition of successive generations,
form concentric layers. The ochreate sheaths
are cartilaginous, lamellated, firmly united
laterally, dilated upwards (funnel-shaped),
decomposed into a fringe at the open edge.

XXIV. INOMERIA. Filaments whip-
shaped, vertical, parallel, with obscure
sheaths, everywhere decomposed into very
slender filaments; forming crustaceous fronds,
becoming stony.

E. Leptothricece. Doubtful Oscillatoriacese.

XXV. LEPTOTHRIX. Filaments very
slender, neither branched, articulated, con-
creted, nor sheathed.

XXVI. HYPHEOTHRIX. Filaments un-
branched, inarticulate, sheathed, interwoven
into a more or less compact stratum.

XXVII. SYMPLOCA. Filaments un-
branched, inarticulate, sheathed, concreted
into branches, conjoined at their bases;
sheath a simple hyaline membrane.

Excluded Genera.

Stigonema, Ag. See EPHEBE. — Arthro-
siphon,Ktz.=Petalonema. — Chthonoblastus,
Ktz. = Microcoleus. — Hassallia, Berk. =
Sirosiphon. — Lithonema}l^.Si&s.=Amactis. —
Phormidium, Ktz . = Oscillatoria. — Sympky-
othrix, Ktz. = Oscillatoria. — Spirochceta,
Ehr. = Spirulina. — Spirillum, ~Ehr.=Spiru-
lina, and also SPERMATOZOIDS of Mosses
and Characeae. — Spirodiscus, Ehr. ?

BIBL. See the genera, especially OSCIL-
LATORIA and RIVULARIA, and SPIRAL

STRUCTURES.

OSMUNDA, Linn. — A genus of Osmun-
deaeous Ferns, represented in Britain by
Osmunda regalis (figs. 226, 227, p. 260), the
' Royal or Flowering Fern,' as it is termed,

a large and handsome plant, found in damp
situations ; riot common.

OSMUNDE^E.— A tribe of Polypodea-
ceous Ferns, characterized by the broad im-
perfect annulus on the back of the sporanges.

Synopsis of Genera.

I. OSMUNDA. Sporangia borne on meta-
morphosed pinnules.

II. TODEA. Sporangia placed on un-
changed pinnules.

OTOGLENA, Ehr.— A genus of Rotato-
ria, of the family Hydatinsea.

Char. Eyes three ; one sessile and cervi-
cal, the two others stalked and frontal.

Neither jaws nor teeth present.

O. papillosa. Body campanulate, turgid,
rough with papillae ; aquatic ; length 1-96".

BIBL. Ehrenberg. Infus. p. 453.

OVA, OF ANIMALS. — The germs secreted
by the ovaries. When extruded from the
body, they are generally termed eggs(EGGs).
See OVUM.

OVARY. — The organ in which the ova or
germs of the future offspring are formed
and temporarily contained.

The ovary consists of an outer fibrous
coat, and a parenchyma or stroma.

The outer coat, or tunica albuginea, is
firm, white, and intimately connected with
the subjacent stroma; it consists of inter-
lacing bundles of areolar tissue, with but
few fibres of elastic tissue.

The stroma (fig. 543 e) is composed of
nucleated areolar tissue, in which the fibrillae
are mostly indistinct, and in it are imbedded
the Graafian vesicles or follicles (fig. 543 a).

Transverse section of a human ovary at the fifth month
of pregnancy, a, Graafian vesicle of the under, b, of the
upper surface ; c, peritoneal layer continued from the
broad ligament of the uterus to the ovary, and becoming
fused with d, the tunica albuginea ; in the centre are two
old corpora lutea ; e, stroma of the ovary.

The vesicles vary greatly in number and
size ; the largest are generally nearest the

OVULE.

[ 479 ]

OVULE.

surface, and project more or less, so as to
give it a nodular aspect. They are round
closed sacs (fig. 544). Each possesses two

Fig. 544.

Graafian vesicle of the pig. «, outer, b, inner layer of
the fibrous coat ; c, membrana granulosa ; d, liquid con-
tained in the vesicle ; e, proligerous disk ; /, ovum with
the zona pellucida, yolk and germinal vesicle.

Magnified 10 diameters.

coats; the outer is a fibrous and vascular
layer, connected with the stroma by some-
what lax areolar tissue, and which some
physiologists consider as consisting of two
layers. It is composed of imperfectly deve-
loped nucleated areolar tissue, with nume-
rous, somewhat spindle-shaped, formative
cells. Lining this is a basement-membrane,
which is most distinct in the young vesicles;
and within this again is a layer of epithelial
cells, constituting the membrana granulosa
(fig. 644 c). Next the surface of the ovary,
this is thickened and projects inwards, form-
ing the proligerous or granular disk, e. Its
component cells form several rows; they
are roundish -polygonal, about 1-3000" in
diameter, with comparatively large nuclei,
and frequently contain granules of fat. The
ovum is imbedded in this proligerous disk, e.

The cavity of the Graafian vesicle contains
a liquid resembling the serum of the blood ;
and in it are found granules, nuclei, and
cells, arising from the disintegration of the
membrana granulosa.

When the vesicle bursts or is opened, the
ovum escapes surrounded by the cells of the
proligerous disk and the adjacent part of
the epithelium.

In those animals in which the amount of
stroma present is small in proportion to the
size of the vesicles, the ovaries have a race-
mose appearance.

In many of the lower animals, the ovaries
are tubular, the ova lying closely packed
within them.

BIBL. Kolliker, Mikr. Anat. ii.; Siebold,
Vergleich. Anat.

OVULE or OVULUM.— The name ap-

plied to the rudiment of the seed of Flower-
ing Plants, produced in the ovary or germen
during the development of the flower, fer-
tilized by the pollen-grains when complete,
and afterwards converted into a SEED by the
development of the EMBRYO and other
secondary structures during the conversion
of the ovary into the fruit. For the general
conditions of the ovules in ovaries, reference
must be made to botanical works. The
ovules make their appearance upon the
placenta as cellular papillae rising up from
its surface, and at first are simple ; this first
development, the main feature of the organ,
is called the nucleus (figs. 645-547). In

Fig. 545.

Fig. 546.

Fig. 547.

End

--P

Atropous ovules.

Fig. 545. Young ovule of Chelidonium. n, nucleus ;
ch, chalaza.

Fig. 546. Young ovule of misletoe, consisting of a
nucleus only.

Fig. 547. Young ovule of walnut, consisting of a
nucleus, N, with a single coat, S; End, the endo-
stome or micropyle.

Fig. 548. Young ovule of Polygonum. F, funiculus ;
P, primine (of Mirbel) ; S, secundine ; Ex, ezostome ;
End, endostome.

Magnified 40 diameters.

rare cases this remains naked, but in most
instances one or two coats are produced,
arising as circular folds near the base, and
gradually growing up over the nucleus (fig.
547), leaving only a small passage at the
apex, leading down to the point of the
nucleus. When two coats are formed (fig.
548), the inner appears first, the outer ori-
ginates later and grows up over the inner,
and it is generally thicker and more deve-
loped. The inner is called the secundine by
Mirbel, the outer the primine (figs. 548, 549.
552 S, P). The German writers reverse these
names, resting on the true order of develop-

OVULE.

[ 480 ]

OVULE.

ment. Some term them the integumentum
internum and externum. The inner is the
tegmen, the outer the testa of R. Brown.
The passage at the apex, leading to the
nucleus, is called the micropyle ; sometimes
the orifice in the outer coat is distinguished
from that in the inner coat, and they are
termed respectively exostome and endostome
(fig. 552). While the nucleus and coats are
becoming perfected, one of the cells situated
near the apex of the nucleus takes on a pecu-
liar character, becoming more developed than
the rest, and often causing the absorption of
part (or sometimes the whole) of the tissue
of the nucleus ; it appears at length as a
large sac occupying the centre of the ovule ;
this is the embryo-sac (fig. 549). The base

Fig. 549.

Sections of atropous ovule of Polygonum.

P, primine ; S, secundine ; N, nucleus ; SE, em-
bryo-sac ; V. e, PI, nascent embryo.

Magnified 20 diameters.

of the ovule is pushed up from the surface of
the placenta during its development so as to
appear at length supported on a stalk of vari-
able length, this is termed ihefuniculus (figs.
548 F, 552/) ; the point of attachment of
this stalk to the body of the ovule (marked by
a scar when the ripe seed separates) is called
the hilum. That region of the interior where
the lower parts of the coats are confluent

551.

Section of campylitropous ovule of the wallflower.
C, chalaza ; N, nucleus ; S, inner coat ; P, outer coat.

Magnified 20 diameters.

with the base of the nucleus, is called the
chalaza (fig. 551 C).

The form of ovules is much affected by
excessive development of its constituent parts
in special directions before the fertilization.
If all parts grow equally, the complete ovule
is erect on the placenta, with its hilum and
also the chalaza turned towards the latter,
and its micropyle at the opposite free end ;
such an ovule is technically termed atropous
or orthotropous (figs. 546-550). Very fre-

Fig. 553.

Fig. 554.

Magnified 40 diameters.

Fig. 555. Fig. 556,

Magnified 20 diameters.

Amphitropous ovule of Mallow in different stages.
Fig. 556. Section.

quently an excessive growth takes place at
one side of the coats of the ovule, so that
the chalaza is carried up and directed away
from the placenta, the micropyle being at
the same time turned down towards the
latter ; but as the growth is in the coats of
the ovule, the hilum remains at the base,
near where the micropyle arrives ; such an
ovule is termed anatropous (fig. 120, p. 131).
The hilum is then connected with the chalaza
by a ridge (a kind of adherent funiculus)
called the raphe. In other cases the form
becomes altered by the point of the ovule
turning down, and the entire structure beco-

OVULE.

[ 481 ]

OVULE.

ming folded or bent upon itself, without
disturbance of the relative positions of the
hilum and chalaza, while micropyle is brought
down, as in the anatropous ovule, to the
vicinity of the hilum. This form is termed
campylitropous (fig. 55 1) . Other conditions
occur less frequently, among which is the
amphitropous form (figs. 555 & 556).

During these developments the embryo-
sac also undergoes various changes. Some-
times, as in the Orchidaceae, it expands so
as to obliterate all the tissue of the nucleus,
and appears like a simple sac enclosed by
the coats ; in the Scrophulariaceae and other
orders it produces peculiar lobes or pouches
at various points ; in the Santalacese it grows
out from the summit of the nucleus, as a
free, naked, tubular process, &c.

Up to this point the differences in ovules
are such as may be termed secondary, but a
primary distinction now comes into view,
connected also with a difference in the
external conditions, affording grounds for
the division of the Flowering Plants into two
great classes. In the Coniferae and Cyca-
dacese the ovules are developed upon open
carpels, and consequently the micropyle may
receive the pollen-grains immediately, when
expelled from the anthers. Plants exhibiting
this condition are termed GYMNOSPERMS,
or naked-seeded. In the Dicotyledons and
Monocotyledons the carpels are always closed
up into cases or ovaries, surmounted by a
stigma, sessile or elevated upon a style, and
the pollen, falling upon the stigma, produces
there its pollen-tubes, which pass down
through what is called the conducting tissue
of the style and upper part of the ovary, on
to the placentas, where they make their way
to the micropyles of the ovules. Plants ex-
hibiting these conditions are distinguished
as ANGIOSPERMS or covered seeded.

The next phenomena which characterize
the development of the ovules of the Angio-
sperms may be briefly given as follows. The
formation of the embryo-sac has already
been described. Shortly before the opening
of the flower, in most cases this sac is more
or less densely filled with granular proto-
plasm, in which a variable number of nuclei
may be seen (PL 38. figs. 1-7). About the
time when the pollen-grains are discharged
from the anthers, a number of minute free
cells may be discovered in the embryo-sac,
usually three, more rarely one, of these being
crowded into the upper end of the embryo-
sac and constituting what are called the
germinal vesicles (PL 38. fig. 4). Others,

which often occur in the embryo-sac, are
generally collected near the bottom of the
embryo-sac ; they are apparently character-
istic of particular families only; in some
plants they are very large, as in the Crocus.
About this time the embryo-sac often exhi-
bits asymmetrical growth, forming pouches
or processes, sometimes at the summit,
sometimes at the base.

When the pollen -grains fall upon the
stigma, they produce their pollen-tubes (See
POLLEN), which pass down through the
conducting tissue, and enter the micropyles
of the ovules. When they reach the apex
of the embryo-sac, they either stop, often
swelling a little, or they pass down a short
way over its side (PL 38. fig. 5). Not un-
frequently two pollen-tubes are found
engaged in the micropyle of the same ovule.
It is not absolutely known whether the
cavities of the pollen-tube and the embryo-
sac become actually continuous by absorption
of the walls at the point of attachment ; it
is generally believed not, but we have recently
had occasion to feel some doubt on this
point. Soon after the pollen-tube has
reached the point of the embryo-sac, one
(rarely two, giving rise to POLYEMBRYONY)
of the germinal vesicles becomes richer in
protoplasm, and usually changes from a sphe-
rical to an oval form, a transverse septum
soon dividing it into two. Most frequently
the elongation continues, with a successive
formation of septa, until the nascent embryo
appears as a rounded or oval cellule sus-
pended at the base of a simple confervoid
filament (suspensor) ; in other cases the for-
mation of the first transverse septum is
followed by the expansion into two globular
cellules connected by a narrow neck, the
upper, almost devoid of contents, constitu-
ting the suspensor (Potamogeton, Zanni-
chellia) ; in Orchis, the upper of the first
two cells grows upwards and outwards, as a
blind septate confervoid filament, through and
beyond the micropyle of the ovule. In Tro-
pcsolum and Zea, the suspensor becomes more
complex, by formation of perpendicular septa.
In all cases the end-cell (embryonal vesicle],
at the point of the suspensor, which always
appears densely filled with protoplasm,
ultimately enlarges, and by segmentation is
converted into the embryo (PL 38. fig. 6).

During the early development of the
embryo, the embryo-sac is often found more
or less densely filled with free cells formed
from its protoplasm (endosperm-cells). These
are generally absorbed and disappear during

2i

OVULE.

[ 482 ]

OVULE.

the growth of the embryo, this ultimately
filling the embryo-sac. In the Nymphse-
acese, however, these cells remain, forming
an inner ENDOSPERM or ALBUMEN, in
addition to that formed from the body of the
nucleus. In other cases (those of exalbumi-
nous seeds) the embryo not only displaces
these internal endosperm-cells, but in the
course of its growth causes the absorption
of the tissue of the nucleus, and ultimately
constitutes the entire seed, enclosed only by
the true integuments. The remaining cha-
racters are given under ALBUMEN and EM-
BRYO. We must not omit to notice the
views entertained by Schleiden with regard
to the origin of the embryo. This author
believes that the embryonal vesicle is the
swollen and subsequently detached end of
the pollen-tube, which enters the embryo-sac,
and progressing to a variable distance, there
itself constitutes the suspensor. Only one
author, Schacht, perseveres with Schleiden
in maintaining this view. Tulasne, however,
is in doubt whether the germinal vesicles
exist before the pollen-tube enters the micro-
pyle. We have certainly seen them before,
but entertain great doubt whether they
possess a cellulose coat before impregnation.
Recent observations on the ovule ofSantalum
album lead us to imagine that they receive
the influence of the pollen while in the state
of nucleated protoplasmic corpuscles, analo-
gous to the unimpregnated spores of Fucus.
In the Gymnospermous Flowering Plants
(Coniferse, "&c.), the ovule, consisting of a
cellular nucleus and a single coat, is placed
upon an open carpel, and its widely-open
micropyle receives the pollen-grain directly.
At the period of impregnation, the embryo-
sac is a cavity deeply seated in the tissue of
the nucleus ; it is formed by the coalescence
and expansion of several cells (in the Yew
there are often at first three embryo-sacs).
In the embryo-sac a number of free nuclei
soon appear, and numerous free (endosperm-)
cells are formed. In many of the Abietineae
this goes on until the spring following the
impregnation. Ultimately the embryo-sac
is found to have increased to more than
twenty times its original size, with the endo-
sperm-cells applied in layers over the inside
of its walls, increasing in number until the
cavity is filled up. Then a certain number
of cells (from three to eight in different
genera), situated near the micropyle end,
but each in the layer next but one to the
wall of the embryo-sac, — become enlarged,
and the cells intervening between these en-

larged ones (secondary embryo-sacs) and
the wall of the original embryo-sac, become
divided by two perpendicular septa standing
at right angles into four cells. A central
intercellular passage then appears at the
contiguous angles of these four cells. These
new bodies, which closely resemble the
archegonia of the LYCOPODIACE^E, were
called corpuscula by Mr. Brown, who dis-
covered them.

Free cells are next formed in the secondary
embryo-sacs of the corpuscula, several at
the upper, one at the lower end. The pol-
len-tubes now advance, breaking down the
tissue of the nucleus, until their points reach
the corpuscula, and one then makes its way
down the intercellular canal of each, to reach
its secondary embryo-sac; the free cell at
the base of this (germinal vesicle) then be-
comes divided into four collateral cells, these
multiply again, and subsequently the cellular
body (proembryo) so formed, breaks through
the base of the secondary embryo-sac, and
grows down in the substance of the lower
part of the nucleus, which is now in a state
of semi-solution. The proembryo then se-
parates into four cords (corresponding to its
four primary cells), and these filaments (sus-
pensors) terminate in rounded cells, which
divide into four, each of which is an em-
bryonal vesicle ; so that there are now four
times as many rudimentary embryos as there
are corpuscula. Out of all these, only one
ultimately remains and becomes perfectly
developed ; the rest are absorbed during the
ripening of the seed. In the latter, the per-
fect embryo is found lying in a mass of albu-
men formed of the nucleus, but its radicle,
developed at the point of junction of the
suspensor, never becomes very clearly defined
at its extremity, but remains organically
continuous with the albumen. It should be
stated that Schleiden. and Schacht affirm
here also that the proembryos are really
formed from the extremities of the pollen-
tubes which enter into the archegonia.

Other points relating to the development
of ovules will be found under POLYEM-
BRYONY, SEEDS, and CELL-FORMATION.

The methods of investigating the develop-
ment of ovules are simple in their nature
but rather difficult in practice. The ordi-
nary plan is to place an ovule between the
thumb and fore-finger of the left hand, and
with a very sharp razor cut it into two un-
equal pieces, in the direction of the axis.
The larger of the two being then laid on its
flat side on the finger (by the aid of a mounted

OVUM.

[ 483 ]

OVUM.

needle), another slice is made so as to leave
a section preserving all the central part of
the ovule. This adheres either to the finger
or the razor, and a drop of water should be
placed on it to free it ; then it may be trans-
ferred to a slide with a very fine camel's-
hair pencil. Examined under a low power
(a half-inch), it will be probably found to
require further dissection, with exceedingly
fine needles, under a simple lens ; sometimes
mere pressure is of service. For the minute
details, the quarter and eighth object-glasses
will require to be applied. We have found
ovules which have been kept in spirit easier
to dissect ; when fresh, the cell-membranes
are excessively delicate. It need scarcely be
added, that ovules require to be examined
in all stages in order to understand their
developmental characters; and the student
must not be disheartened by the failure of a
large proportion of his sections to afford
satisfactory observations.

BIBL. Works on Physiological Botany;
Amici, Ann. des Sc. nat. 3 ser. vii. p. 193;
Mohl, ibid. ix. p. 24; Miiller, ibid. p. 33
(abstracted from the Botanische Zeitung,
1847); Hofmeister, DieEnstehung des Em-
bryo, Leipsic,1849 (abstr. iuAnn. des Sc. nat.
3 ser. xi. 375), Vergleich. Untersuch. Leipsic,
1841, Flora, 1851. p. 450, 1855. p. 257;
Tulasne, Etudes, fyc., Ann. Nat. Hist. 2 ser.
i. p. 49, ix. p. 442, Ann, des Sc. nat. 3 ser.
xii. p. 21 ; Henfrey, Linnean Trans, xxi. p.
7; Schleiden, Enstek. d. Eichens, Nova
Acta, xix. p. 29, Grilndzuae, 3rd ed. Bd. ii.
p. 339 ; Schacht, Entwick. des Pflanzenemb.
Verh. Nederlandsch. K. Inst. 1850 (abstr.
Ann. des Sc. nat. 3 ser. xv. p. 80), Beitr. z.
Anat. u. Phys. Berlin, 1854, Flora, 1855.
p. 145; Criiger, Bot. Zeit. iv. p. 57 (1851);
Mohl, Botan. Zeit. xiii. p. 385 (1855).

OVUM, OF ANIMALS. — Several points
in regard to the structure of the ovum, and
the nature of the changes which it under-
goes at different periods of its development,
are in doubt and obscurity.

The first perceptible trace of the ovum
existing within the ovary is formed by a
very minute granule or globule, not sur-
rounded by a cell- wall. This gradually en-
larges, and when it has attained a certain
size, being still very minute, a smaller sphe-
rical globule forms in its interior. The mi-
nute internal globule is the germinal spot,
and the external globule is the so-called ger-
minal vesicle.

It appears, however, that in some cases
the germinal spot is formed first and the

germinal vesicle subsequently. When these
have still further grown, a cell- wall separated
by a slight interspace forms around the ger-
minal vesicle, and this interspace contains a
transparent liquid. Minute granules then
arise in the liquid, which becomes inspissated,
and subsequently a number of globules of
sarcode become perceptible in it. This mass
forms the yolk. When this unimpregnated
ovum has attained considerable development,
it is found to consist of the following parts :
an outer structureless coat, sometimes of
considerable thickness, and then appearing
under the microscope as a white ring (fig.
55 7«), the zona pellucida or chorion ; within

Fig. 557.

Human ovum from a Graafian vesicle of moderate size,
a, vitelline membrane or zona pellucida ; b, outer boun-
dary of the yolk and inner boundary of the zona ; c, ger-
minal vesicle with the germinal spot,

Magnified 250 diameters.

this the vitellus or yolk, consisting of a more
or less inspissated medium, and containing
granules and globules of sarcode, or con-
densed yolk-substance (b); the germinal ve-
sicle (c), and the germinal spot. The glo-
bules are sometimes transparent or slightly
granular, at others they contain one or seve-
ral vacuoles ; they are known as the yolk-
cells or globules, and are frequently aggre-
gated into little groups. The yolk, as it ap-
proaches maturity, frequently becomes co-
loured ; it is usually whitish or pale yellow
in the mammalia, reptiles, and fishes; bright
yellow or reddish in many birds ; and green,
blue, violet, or red in the invertebrata.

According to the cell-theory, viewing the
ovum as a simple cell, the germinal spot re-
presents the nucleolus, the germinal vesicle
the nucleus, the zoiia pellucida the cell- wall,
and the yolk the cell-contents.

At a subsequent period the yolk becomes
surrounded by a distinct, delicate, structure-
less cell-membrane, lying within the chorion,
and forming the vitelline membrane.

The ovum of man and the mammalia dif-
fers from that of the lower animals in its re-
markably small size, which depends upon
the extremely small quantity of yolk entering
into its composition. The mature ovum of
2i2

OVUM.

[ 484 ]

OXYRRHIS.

man and mammalia averages about 1-150
to 1-200" in diameter, being rarely 1-100".
Another peculiarity consists in their ova, in-
stead of being in immediate contact by means
of their chorion or outer envelope, with the
stroma of the ovary, or being loose within
the cavity of the latter, as in other animals,
are enclosed in distinct larger cells, — the
Graafian vesicles.

When the ovum of the mammalia leaves
the ovary, a portion of the proligerous disk
is seen to be adherent to it. In other ani-
mals new layers are secreted upon the out-
side of the ova by the oviduct or ovary, as
in the eggs of birds, insects, &c.

On the escape of the ovum from the ovary,
the phenomena which ensue vary according
to whether the ovum has been impregnated
or not. In both cases the germinal vesicle
and spot disappear; an interspace, filled
with albuminous liquid, occurs between the
yolk and the zona pellucida ; the ovum be-
comes covered with cilia, and undergoes a
regular motion of rotation, and certain move-
ments and changes in form of the yolk-sub-
stance, which forms Amceba-like processes,
have been noticed. In the unimpregnated
ovum, decay and decomposition subsequently
take place.

The essential part of the process of im-
pregnation is the perforation of the vitelline
membrane by the spermatozoa, and their
entrance into the yolk, in which they subse-
quently dissolve.

In the impregnated ovum, the germinal
vesicle soon disappears, the chorion becomes
thinner, the ovum grows, and the yolk begins
to undergo the process of segmentation ;
but just before this process commences, one
or two globules separate from the substance
of the yolk, being apparently pressed out of
it, and occupy the interspace between the
yolk and the chorion ; these globules subse-
quently dissolve in the liquid.

The process of segmentation has been de-
scribed under CELLS (p. 115); but according
to another account, it takes place thus : — at
first a notch or slight indentation appears on
some part of the surface of the yolk ; this
becomes deeper and deeper, so as to encircle
the yolk with an annular depression. Soon
after the commencement of this, a clear spot
appears in the centre of each circumscribed
portion of the yolk. The depression be-
coming deeper, the yolk is divided into two
distinct portions. The process is continued
in the case of each of these in exactly the
same manner, and in that of the segments

arising from their subdivision also, each
simultaneously acquiring a clear spot, until
the yolk appears entirely composed of innu-
merable small bodies, having the appearance
of nucleated cells. Finally, these become
very minute, and the yolk acquires much
the appearance it had before impregnation.
Cells then form in the yolk, as in an ordi-
nary blastema, from without inwards, and
from the spot originally occupied by the
germinal vesicle as a centre, and from these
the tissues of the embryo are formed.

According to this description, which is
most probably correct, the segmentation is
not a process of cell-division or endogenous
cell-formation, and the nuclear spots would
correspond to portions of the yolk-substance
from which the granules and globules of
sarcode were absent.

In unimpregnated ova, segmentation takes
place to a certain extent, but irregularly and
incompletely.

In the impregnated ova of some animals,
as in some of the Batrachia, most fishes and
Cephalopods, the segmentation is only par-
tial, a portion of the yolk remaining as at first.
The study of ova and their changes is very
difficult. The most favourable objects for
the purpose exist perhaps in those of the
aquatic Mollusca ; the ova of insects, as the
large species of Musca, of species of Pulex,
&c., are also easily accessible. Some import-
ant results have been obtained with the ova
of the frog (frog's spawn).

BIBL. Kolliker, Mikr.Anat.ii.', Al. Thom-
son, Cycl. Anat. fyc., art. Ovum ; Vogt, Phy-
siol. Brief e ; Keber, De sperm, intr. in ovula;
Bischoif, Widerlegung des v. Keber behaupt.
Eindringens d. Sperm, in das Ei; id. Be-
st'dtigung d. von Newport behaupt. Eindring.
8fc.y and numerous other memoirs; New-
port, Phil. Trans. 1851 and 1853 ; Siebold,
Vergleich.Anat.', Wagner, Elements of Phy-
siology, by Willis ; V. Beneden, Ann. d. Sc.
Nat. 3 ser. xiii.

OXALATES. See the bases.
OXYGONIUM, Presl.— A genus of Di-
plasieae (Polypodaeous Ferns). Exotic.

OXYRRHIS, Duj.— A genus of Infusoria,
belonging to the family of Thecamonadina.
Char. Body ovoid-oblong, rugose, ob-
liquely notched in front and prolonged into
a point ; several flagelliform filaments arising
laterally from the bottom of the notch.

O. marina (PL 24. fig. 54). Body colour-
less, subcylindrical, rounded behind; marine;
length 1-500".

BIBL. Dujardin, Infus. p. 34/.

OXYTRICHA.

[ 485 ] PACINIAN CORPUSCLES.

OXYTRICHA, Bory, Ehr.— A genus
of Infusoria, of the family Oxytrichina.

Char. Neither styles, hooks, nor horns
present. Ehrenberg describes eight species;
some are marine, others aquatic.

O. pellionella, E. (PI. 24. fig. 52). Body
whitish, smooth, slightly depressed, equally
rounded at the ends, often somewhat broader
in the middle ; head not distinct ; mouth
ciliated ; tail with bristles. Aquatic ; length
1-720 to 1-280".

0. ffibba, E. (PI. 24. fig. 53). Body white,
lanceolate, obtuse at each end, ventricose in
the middle ; ventral surface flat, with a dou-
ble row of seta3; mouth large, rounded.
Aquatic; length 1-240".

Dujardin places his genus Oxytricha among
the Keronia, with the characters : body soft,
flexible, oval or oblong, more or less de-
pressed, with cirrhi or larger non-vibratile
cilia in the form of bristles or styles, but
without horns ; and describes nine species,
mostly not corresponding to those of Ehren-

ic whole requires revision.

BIBL. Ehrenberg, Infus. p. 363; Dujar-
din, In/us, p. 416.

OXYTRICHINA, Ehr.— A family of In-
fusoria.

Char. Carapace absent; alimentary ori-
fices two, neither terminal ; body furnished
with vibratile cilia and bristles, non-vibratile
styles or hooks.

Body depressed ; locomotive organs prin-
cipally situated upon the under surface.
Propagation by longitudinal and transverse
division, and by the periodical formation of
egg-like granules.

The five genera are thus distinguished :

Cilia and bristles present, but no styles nor hooks.

No anterior horns Oxytricha.

Anterior horns present Ceratidium.

Cilia present, with styles or hooks, or both.

Hooks present, but no styles Kerona.

Styles present, no hooks Urostyla.

Both styles and hooks present Stylonichia.

BIBL. Ehrenberg, Infus. p. 362.

OXYURIS, Rud. See ASCARIS.

OYSTER (Ostrea).—A genus of Lamelli-
branchiate Mollusca.

The gills of O. edulis, the common oyster,
show the ciliary movement ; but it is not so
easily seen in this as in the marine mussel.

The shells of the fry or ' embryo-oysters '
exhibit the black cross and an imperfect set
of coloured rings with polarized light.

P.

PACHNOCYBE, Berk.— A genus of Stil -
bacei (Hyphomycetous Fungi), somewhat
confused at present withDor«£omyces,Corda,
and Periconia, Nees. These plants have an
erect filiform stem, composed of conjoined
filaments, capitulate above, the head being
pruinose (not flocculent), with crowded sim-
ple spores. The pedicels are mostly brownish
or blackish, the spores light-coloured ; the
entire plants from 1-24 to 1-6" high. Seve-
ral species occur on rotten wood, stems, &c.

BIBL. Berk. Hook. Brit. Flor. ii. pt. 2.
p. 333, Ann. Nat. Hist. 2 ser. v. p. 465;
Fries, Summa Veg. p. 467.

PACHYGNATHUS, Duges.— A genus of
Arachnida, of the order Acarina, and family
Trombidina.

Char. Palpi conical, last joint scarcely
forming a claw ; mandibles stout, chelate ;
body entire, narrowed in front; coxae distant;
legs gressorial, sixth joint very long, seventh
very short; anterior legs longest and stoutest.

P. velutinus (PI. 2. fig. 34), the only spe-
cies. Found in autumn, under damp stones.
The hairs covering the body are short, flat,
and curved, giving it a velvety aspect. Body
inflated, narrowed in front, the narrowed
portion with two projecting brownish eyes.
The insertions of the legs are in two groups,
not far distant from each other nor from the
median line ; second pair of legs shortest ;
in all the sixth joint is very long, the seventh
very short and narrow (6), as in Tetranychus,
Megamerus, and Raphignathus ; claws two,
large ; rostrum projecting ; palpi (a) short,
about twice the length of the labium ; man-
dibles chelate or like a lobster's claw, very
large and stout at the base. Movement
slow.

BIBL. Duges, Ann. d. Sc. nat. 2nd ser.
ii. p. 54 ; Gervais, Walckenaer's Apter. iii.
p. 171.

PACINIAN CORPUSCLES. — These
curious organs are found as terminations of
the spinal nerves in the skin and subcuta-
neous tissue of the palm of the hand, the
sole of the foot, the fingers and toes, in the
sympathetic semilunar ganglia, the mesen-
tery, &c.

They are elliptical or pear-shaped, whitish,
about 1-25 to l-6th in diameter. Each con-
sists of from twenty to sixty concentric
layers of areolar tissue (fig. 558), the inter-
spaces between the outer being considerable,
those between the inner being small, and

PADINA.

[ 486 ]

PADINA.

filled with a clear serous liquid, contained in
largest quantity in the central cavity of the

Fig. 558.

A human Pacinian corpuscle, a, stalk ; b, nerve-fibre |
within it ; c, outer, d, inner layers of the sheath ; e, pale
nerve-fibre in the central cavity ; /, its branches and ter-
mination.

Magnified 350 diameters.

innermost layers. Each is also furnished
with a stalk, containing a slender branch of
a nerve, which passes from the stalk into
the central space, in the upper part of which
it terminates frequently in two or three
branches, each with a free granular tubercle.
The nerve-fibre contains no white substance.

BIBL. Kolliker, Mikrosk. Anat. ii., and
the Bibl. therein.

PADINA, Adanson. — A genus of Dictyo-
lacese (Fucoid Algse), containing one species,
P. Pavonia (fig. 559), found rarely in sum-
mer and autumn on the south coast of Eng-

land. The fan-shaped or reniform fronds
grow in tufts, and are 2 to 5" high, sometimes
entire, sometimes cleft (fig. 559). They are

Fig. 559.

Fadina Pavonia.
Frond, one-third natural size.

marked with concentric zones. The sub-
stance is parenchymatous, the number of
layers of cells diminishing with the thickness
and solidity from the base to the edges.
The back of the frond is covered by a layer
of cells much smaller than the rest, forming
a kind of epidermis, which ultimately ac-
quires a thickish cuticular layer. The grow-
ing edge of the frond is rolled backwards
(circinate) and fringed. The fructification
occurs in linear concentric sori, on the co-
loured zones of the frond. The pear-shaped
spore-sacs (fig. 560) originate from cells of

Fig. 560.

Vertical section of a frond at a concentric zone, made
in a radial direction, cutting through the sorus of spore-
sacs and a line of hairs. The indusial layer of cuticle has
been omitted by the artist.

Magnified 50 diameters.

the epidermal layer, which take on special
development, and in the course of their
growth push up and finally burst through
the loosened cuticular layer which originally
clothed them, so that the latter form a kind
of indusium like that of the Ferns. The
spore-sacs produce each four spores, which
separate after their escape from the sac.
The zones of the sori alternate with zones
composed of tufts of jointed hairs placed in

PALMELLA.

[ 487 ]

PALMELLACEJE.

corresponding lines (fig. 560). Thuret states
that he has never found antheridia hitherto,
and he believes that Agardh mistook the
hairs or paranemata for them.

BIBL. Harvey, Brit. Mar. Alg. p. 37.
pi. 6 C, Phyc. Brit. pi. 91 ; Greville, Alg.
Brit. pi. 10; Agardh, Sp. Alg. i. p. 112;
Nageli, Neuer. Algensyst. p. 180. pi. 5;
Thuret, Ann. des Sc. nat. 4 ser. iii. p. 12;
Kiitz. Phyc. generalis, pi. 22; Al. Braun,
Rejuvenescence, fyc. (Ray Soc. Vol. 1853),
p. 79.

PALMELLA, Lyngbye. — A genus of Pal-
mellaceae (Confervoid Algae), of which the
best-known example is the common P. cru-
enta (PL 3. fig. 3 a). This plant, very com-
mon on damp walls in shaded places, appears
at first in the form of rosy gelatinous patches;
these spread and become confluent until the
mass extends sometimes over a great extent
of surface, as a tough, gelatinous, irregular
mass, of the colour and general appearance
of coagulated venous blood; when dried up in
this state, it forms a horny, somewhat crumb-
ling stratum; if placed in water, portions
float to the top in pellucid rosy masses of
jelly. In its natural habitats its colour
and general appearance become disguised
when old by the admixture of Oscillatoriece,
and other Confervoid growths.

When placed under the microscope, the
frond appears to be composed of a colourless
homogeneous jelly, in which are imbedded
globular cells, single or in pairs (from divi-
sion), of a beautiful rose-colour (fig. 3 a, b} ;
by the application of reagents, these may
be shown to possess a proper membranous
coat (c). The contents of the cells appear
uniformly granular (b, c), and it would ap-
pear that, besides increasing by division,
the cells also burst and discharge their con-
tents, since patches of minute granules occur
imbedded in the jelly (lower figs, of b}, pro-
bably destined to grow up into the ordinary
cells. No zoospores, nor the remarkable
phenomena generally that occur in Proto-
coccus, have yet been observed in this, which
appears to be a very distinct genus. The
jelly of full-grown fronds (which appears to
be derived from the gelatinous softening of
the coats of the parent-cells of the successive
generations of cells) is often over-grown and
traversed by minute filamentous structures,
which at first sight seem to belong to it ; but
on the application of a high power are found
to consist of a very minute Nostochaceous
plant, apparently the Anabaina subtilissima
of Kiitzing, or Vibrio Bacillus, Ehr. (PL 3.

fig. 21), which we find to occur commonly
among the Palmellaceous Algae.

P. cruenta has received an extraordinary
number of generic names : Tremella, Byssus,
Thelephora, Sarcoderma, Phytoconis, Por-
phyridium, Globulina, Coccochloris, and
Chaos (I).

From the examination of specimens of the
true " red snow," brought home by Captain
Parry (for which we are indebted to Mr.
Brown), we incline to regard this as a Pal-
mella, distinct generically from the Proto-
coccus or Hcematococcus pluvialis of the
German writers, with which it is commonly
associated. Our specimens consist of a tough,
colourless gelatinous substance, containing
globular cells differing only in size (PL 3. fig.

3 d) from those of Palmella cruenta ; and in
the jelly occur also abundance of the minute
granules or cellules, which are the discharged
contents of the larger cells. The red cells
of the red-snow plant turn green when ex-
posed to light, if kept moist. More par-
ticulars are given on this subject under RED
SNOW and RUBEFACTION OF WATER, and
PROTOCOCCUS.

Other species of Palmella are described,
but most of them are too imperfectly known
to allow of definite characters being given ;
P. rosea is perhaps a good species. The
forms with a definite frond formerly placed
here, P. protuberans, botryoides, &c., will
be found under COCCOCHLORIS.

BIBL. Eng. Botany (as Tremella cruenta),
pi. 1800; Greville, Sc. Crypt. Alg. pi. 205 ;
Meneghini, Monogr. Nostoc. (Trans. Turin
Acad. ser. 2. v.), pi. 6 ; Hassall, Brit. Fr.
Alg. pi. 80; Nageli, Einzell. Alg. p. 66. pi.

4 D (as Porphyridium), p. 71. pi. 4 H;
Kiitz. Sp. Alg. p. 211. See also under RED
SNOW.

PALMELLACE^.— A family of Coufer-
void Algae, consisting of gelatinous or pul-
verulent crusts, growing on damp surfaces,
in fresh water or in the sea ; composed of
globular or elliptical cells, either more or
less adherent together into a definite or in-
definite pseudo-membrane orfrond, or loosely
aggregated within a definitely or indefinitely
formed gelatinous matrix, or loosely coherent
in the form of a pulverulent crust. Some
authors have imagined that the cells of Coc-
cochloris or Palmella are attached to fila-
ments included in the gelatinous frond : this
is an error (see PALMELLA). Yellowish or
bluish-green, or red, often varying from green
to red, and vice versa, during the course of
development. Increased by cell-division

PALMELLACE.E.

[ 488 ]

PALMBLLACE2E.

into two or four, and by ciliated zoospores.
Many exhibit three forms, — 1. active; 2.
quietly vegetating by subdivision ; 3. resting
form, with a tough membrane.

Synopsis of British and some allied Conti-
nental Genera.

I. CHLOROCOCCUM, Ag. Frond pulveru-
lent, scarcely existing, consisting of a dryish
stratum; cells with a simple coat, loosely
coherent, with little amorphous gelatinous
matter.

II. PROTOCOCCUS, Ag. Frond a slimy
stratum composed of cells irregularly cohe-
rent, with little mucus. Dissolving in water
into free cells, dividing into two and four
ciliated zoospores.

III. PALMELLA, Lyngb. Frond a tough
amorphous jelly ; cells with a simple indi-
stinct coat, imbedded in abundant gelatinous
matter, containing numerous very minute
granules.

IV. UROCOCCUS, Hass. Frond gelatinous,
cells with a single coat imbedded in the ends
of striated mucous tubes, which constitute
the gelatinous mass of the frond.

V. GLQEOCAPSA, Kiitz. Frond very mi-
nute, gelatinous, composed of cells enclosed
in wide gelatinous coats, these again en-
closed in fours in a gelatinous mother-cell,
the latter again encased in like manner, and
so on, the older coats gradually becoming
indistinct and mucous.

VI. MERISMOP^EDIA, Meyen. Frond
very minute, flat, squarish, floating, com-
posed of cells coherent in fours and sixteens
into a gelatinous plate (see SARCINA).

VII. COCCOCHLORIS, Sprengel. Frond
gelatinous, globose, composed of minute
cells imbedded, scattered, or agglomerated
in a continuous gelatinous substance.

VIII. HORMOSPORA, Breb. Frond a ge-
latinous, simple or branched tube, broad,
soft and transparent, containing a single
row of cells approximated in twos or fours.

IX. HYDRURUS, Ag. Frond filiform,
attached, slippery, simple or branched, com-
posed of tough gelatinous material, contain-
ing longitudinal rows of cells.

X. TETRASPORA, Link. Frond more or
less definite, foliaceous, gelatinous, contain-
ing imbedded cells, arranged in distant groups
of four, or occasionally of two.

XI. BOTRYDINA, Breb. Frond very mi-
nute, subglobose, consisting of a vesicle with
the wall composed of a single layer of pa-
renchymatous cells, containing free cells in
the interior, finally discharged.

XII. SCHIZOCHLAMYS, A. Br. Stratum
gelatinous, composed of aggregated distinct
cells, the contents of which divide into two
or four portions, and escape by the regular
fission of the cell-membrane into two or four
segmental fragments.

XIII. APIOCYSTIS, Nag. Frond very
minute, bladder-shaped, attached, enclosing
cells (gonidia) arranged in fours upon the
wall, subsequently breaking out and swarm-
ing.

XIV. PALMODICTYON, Ktz. Frond ge-
latinous, filiform, branched; branches reti-
cularly divided and anastomosing, composed
of large vesicular cells containing minute
coloured cells, the minute cells escaping as
zoospores.

Doubtful organism.

SARCINA, Goodsir. Fronds (?) flat, ex-
tremely minute, squarish, tough, formed of
coherent squarish cells, combined in quater-
nate groups to the number of eight, sixteen
or sixty-four. Found floating free in the
liquid of the human stomach, &c.

Excluded genera (doubtful).

Htematococcus, Ag. = Protococcus.

Polycoccus, Kiitz. = Protococcus.

Exococcus, Nageli = ?

Sorospora, Hass. = Glceocapsa or Proto-
coccus.

Characium, Al. Braun = apparently the
germinating gonidium of an (Edogonium,
producing zoospores.

Microcystis, Kg. Probably a resting form
of Euglena.

Anacystis, Kg. Do.

Caelocystis, Kg. Do.

Polycystis, Kg. Do.

Botryococcus, Kg. Do.

Botryocystis, Kg. = Form of Volvox ?

Cylindrocystis, Breb. =Palmoglcea, Kiitz.

Microhaloa, Kg. = Protococcus and Pal-
mella.

Trichodictyon, Kg. = ?

Trichocystis, Kg. = Actinophryst

Palmophyllum, Kg. = Prasiola ?

Gomphosphceria. Kg.=young ColeocJKete!

Palmodictylon, Nag. = germinating spores
of a moss ?

Chroococcus, Nag. = Protococcus.

Aphanocapsa, Nag. = Palmella.

Calosphcerium, Nag. = Coccochloris.

Synechococcus, Nag. = Protococcus.

Glceothece, Nag. = Palmoglcea ?

Aphanothece, Nag. = Palmella ?

Pleurococcus, Menegh. = Protococcus.

PALMODACTYLON.

[ 489 ]

PAPER.

Gloeocystis, Nag. = Glaeocapsa.

Porphyridium, Nag. = Palmella cruenta.

Dictyosphcerium, Nag. = Palmella ?

Stichococcus, Nag. = Protococcus.

Nephrocytium, Nag. = decomposing spores
of Spirogyra ?

Cystococcus, Nag. = Protococcus.

Dactylococcus, Nag. = Protococcus.

Ophiocytium, Nag. = ?

Chlamidomonas, Ehr. = Protococcus.

Chlamidococcus, Al. Br. = Protococcus.

GlcBococcus, A. Br. = Coccochloris!

Chytridium, A. Br,= probably a form ana-
logous to Characium, A. Br. (». sup.).

PALMODACTYLON, Ktz. — Perhaps
germinating spores of a Moss.

PALMODICTYON, Ktz. — A genus of
Palmellaceae (Confervoid Algae), described
as possessing a frond which appears like a
delicate network to the naked eye, of gelati-
nous texture, and consisting of anastomosing
branches, each composed (in P. viride) of a
single or double row of large vesicular cells,
1-600 to 1-960" in diam. These contain a
pair of elliptical green cellules, 1-3000" in
diameter, which ultimately escape as active
zoospores. This genus appears nearly re-
lated to HYDRURUS and TETRASPORA.

P. rufescens, Ktz., doubtfully referred
here, is larger ; it occurs near Aberdeen.

BIBL. Kiitzing, Sp. Ala. p. 234, Tab.
Phyc. Bd. i. pi. 31.

PALMOGLGEA, Kiitz. (Cylindrocystis,
Menegh.). See COCCOCHLORIS.

PALMOPHYLLUM, Ktz. — Perhaps a
Prasiola.

PALUDELLA, Ehr.— A genus of Meesia-
cese, having only one representative, which
occurs in Britain, P. squarrosa =. Bryum
squarrosum, L.

PALUDICELLA, Gervais.— A genus of
Polypi, of the order Bryozoa, and family
Paludicellaida3.

Char. Polypidom fixed, filamentous, dif-
fusely and irregularly branched, coriaceous,
consisting of a single row of club-shaped
cells arranged end to end ; apertures unila-
teral, tubular, placed near the broad end of
each cell; tentacular disk circular, with a
single row of free tentacles.

P. articulata. The only species ; olive-
green ; polypes ascidian. Aquatic ; diameter
of filaments about 1-30 to 1-20".

BIBL. Johnston, Brit. Zooph. p. 405;
Allman, Ann. Nat. Hist. xiii. 331, and Proc.
Irish Acad. 1843.

PANDORINA, Bory.— A genus of Vol-
vocineae (Confervoid Algae), the individuals

of which consist of a globular hyaline vesicle
enclosing a mulberry-like assemblage of
green ciliated bodies, whose cilia project
through the enveloping membrane, and
effect a slow rotatory motion. The green
bodies resemble those of Volvox and Gonium,
and the solitary active forms of Protococcus.
Ehrenberg says they have but one cilium ;
this seems doubtful, and it is very possible
that these objects are forms of Volvox.

P. Morum is 1-120" in diameter, its green
corpuscles 1-1150". (See VOLVOX.)

BIBL. Ehrenberg, In/us, p. 53; Dujardin,
In/us, p. 317.

PANOPHRYS, Duj.— A term proposed
to designate certain Bursarice, E., in which
the row of larger cilia leading to the mouth,
characteristic of Bursaria, D., is absent.

Dujardin's specific names are new, al-
though the species are old !

P.farcta, D. = Bursaria vernalis, B. leu-
cos, and B. flava of Ehrenberg.

P. chrysalis (PI. 24. fig. 55). Marine.

BIBL. Dujardin, In/us, p. 491.

PANTOTRICHUM, Ehr.— A genus of
Infusoria, of the family Cyclidina.

Char. Body turgid, covered with vibratile
cilia. Aquatic.

P. lagenula, E. (PL 24. fig. 58). Body
ovate, equally rounded at each end, yellow-
ish ; tegument produced anteriorly in the
form of a neck or truncate rostrum ; length
1-1080 to 1-580".

P. volvox, E. Probably a young Para-
mecium (Dujardin).

P. enchelys, E. = Enchelys nodulosa, D.

BIBL. Ehrenberg, In/us, p. 247; Dujar-
din, Infus. p. 388.

PAPER. — Only a few general observations
can be made under this head. Ordinary
paper, as is well known, is generally manu-
factured from rags of linen or cotton fabrics,
so that it consists of a kind of felt of the
fibres of cotton or flax ; but other substances,
such as straw, for instance, are now coming
into use, from the growing scarcity of rags.
The manipulation to which the material is
subjected, together with the effect of fre-
quent washing in the case of rags, affects
the characters of the fibres to some extent,
and the cellulose is in some cases already
brought into that state in which iodine co-
lours it blue. The addition of sulphuric acid
and iodine always colours the fibres of paper
blue ; and care must be taken on this account
to avoid errors from the accidental presence
of them, when blotting-paper is used to ab-
sorb these reagents when applied to objects

PAPER, METEORIC.

[ 490 ]

PARAMECIUM.

on a slide. The determination of the nature
of the filaments of which a paper is com-
posed, by the aid of the microscope, would
require a very thorough knowledge of the
characters of vegetable fibres, and we should
imagine could scarcely be very decisive in
most cases, except so far as distinguishing
between classes of substances, as between
parenchymatous and filamentous or fibrous
substances, &c.

Rice-paper, as it is termed, is a totally
different material, consisting of thin layers,
cut by a peculiar operation, of the pith of
Aralia papyri/era, a Chinese Araliaceous
tree; this consists of parenchymatous cel-
lulose tissue.

Papyrus, consisting of pressed superposed
laminse of the pith of Papyrus plant (Pa-
pyrus antiquorum, a kind of Sedge), exhibits
the lax parenchymatous structure character-
istic of similar tissues, such as the pith of
Rushes, &c.

PAPER,METEORTC,andAEROPHYTES.

The structure and origin of these substances
are the same as that of the so-called natural
flannel (FLANNEL). They were formerly
regarded as of meteoric origin. They have
been observed in some instances to fall from
the air, having been wafted perhaps many
miles from their place of formation by whirl-
winds and hurricanes.

BIBL. Ehrenberg, Abhandl. d. Berl.Akad.
1838.

PAPULASPORA, Preuss.— A genus of
Mucedines (Hyphomycetous Fungi) consist-
ing of a decumbent articular mycelium,
sending up erect pedicels, bearing a collec-
tion of oblong erect spores, which spores are
bi- or quadrilocular.

P. sepedonioides has been found on rice-
paste.

BIBL. Berk, and Broome, Ann. Nat. Hist.
ser. 2. xiii. p. 462.

PAPYRUS.— The pith of the stems of the
Papyrus antiquorum (modern papyrus from
P. syriacus], cut into slices, which are laid
upon one another and pressed so as to form
a compact stratum. Sections display the
parenchymatous tissue more or less deformed
by pressure.

PARAMECIA or PARAMECINA, Duj.
— A family of Infusoria.

Char. Body soft, flexible ; form variable,
usually oblong and more or less depressed ;
with a lax reticulate integument, through
which numerous vibratile cilia pass in regular
rows ; mouth present.

The organisms included in this family
belong to the Ophrycercina, Enchelia, Tra-
chelina, and Colpodea of Ehrenberg.

Dujardin distinguishes the genera thus :

Mouth indistinct
or doubtful

Mouth lateral

("Body round, prolonged in the form of a neck, with an appearance of a mouth at
I the end 1.

LBody oval-oblong, depressed, with a broad lateral orifice, from which a bundle of
filaments issues 2.

fwith a lip-like flip longitudinal, vibratile ; body oval, depressed, broader behind. 3.

appendage \ lip inferior, projecting ; body ovoid, sinuous or reniform 4.

< oblong, compressed, with a longitudinal oblique

bodv never ! fold 6<

i h la \ fusiform, greatly elongate and narrowed in front 6.

without an
appendage

c
globular by contraction \ teeth absent 10.

Mouth terminal ; body ovoid or oblong, becoming globular by con- / mouth with teeth 11.

traction. I teeth absent 12.

Lacrymaria.

Pleuronema.

Glaucoma.
Colpoda.

Paramecium.

Amphileptus.

Chilodon.

Loxophyllum.

Nassula.

Panophrys,

Prorodon.
Holophrya.

BIBL. Dujardin, Infus. p. 463.

PARAMECIUM, Hill, Ehr.— A genus of
Infusoria, of the family Colpodea.

Char. Body covered with cilia ; no eye-
spot ; a papilliform tongue-like process
present.

Ehrenberg describes eight species, two
being doubtful.

P. aurelia (PI. 24. figs. 56 and 57). Body
cylindrical, ovate-oblong, rounded or obtuse
at the ends, with an oblique longitudinal
fold extending to the mouth. Aquatic;
length 1-120 to 1-100".

This common infusorium shows well the
curious star-shaped contractile vesicles. Eh-
renberg notices in it the periodical occur-
rence of small black crystalline particles at
the anterior end. The depressions on the
surface of the integument (PI. 25. fig. 1) are
distinctly seen in the dried animal.

P. chrysalis, E. (Pleuronema crassa, D.)
(PI. 25. fig. 37, undergoing division). Body
oblong, cylindrical, oral cilia very long.
Aquatic; length 1-240".

P. Kolpoda, E.=the adult stage of Kolpoda
cucullus, E.

PARAPHYSES.

[ 491 ]

PARASITES.

P. compressum, ~&.=.Playiotoma lumbrici,
D.

P. milium, E.=Enchelys nodulosa or tri-
quetra, D.

Dujardin places this genus with the family
Paramecina.

BIBL. Ehrenberg, In/us, p. 349; Dujardin,
Infus. p. 481 ; Stein, Inf us., passim.

PARAPHYSES. — The name applied to
more or less delicate-jointed, hair-like fila-
ments which occur in small numbers around
and between the antheridia and archegonia
of Mosses and Hepaticaceae (fig. 25. p. 48,
fig. 331, p. 320). The same term is applied
to simple tubular, more or less clavate cells,
occurring in large numbers among the spore-
sacs (asci and theca] of the Ascomycetous
Fungi and the Lichens (fig. 40. p. 66, fig.
402. p. 388, PL 29. figs. 6, 12).

PARASITES. -Under this head are to be
included a number of animals and plants
infesting other animals and plants, nourished
at the expense of their structures or juices.
Of the animal parasites, the chief portion
belong to the class CRUSTACEA, order Si-
PHOSTOMA, class ARACHNIDA, family ACA-
RINA ; the class Insecta, orders ANOPLURA
and STREPSIPTERA; and the class EN-
TOZOA.

The Plants parasitic on animals chiefly
belong to the class of Fungi, and they are
tolerably numerous, but many of the forms
which have been described and named are
certainly not distinct plants. They will be
most conveniently enumerated under the
heads of classes of animals infested.

1. Man and Mammalia.

On the Skin. — ACHORION Schoenleinii and
PUCCINIA favus (the former probably an
earlier stage of the latter), on the hair and
in the follicles, in Favus. — TRICHOPHYTON
tonsurans, on the hair in Plica polonica
and Favus ; this appears to be a Torula-
like growth, probably not a mature plant.
Tr. ? sporuloides, C. Rob., occurs in Plica,
and Tr.? ulcerina, C. Rob., in the pus
of ulcers. — Microsporon Audouinii occurs in
the hair-follicles in Porrigo decalvans ; M.
mentagrophytes, on the beard, &c. ; M.
furfur, on the skin of the chest, &c., in
Pityriasis versicolor. — The occurrence of
Mucor Mucedo on the skin, and of an Asper-
gillus in the external conduit of the ear,
must be regarded as accidental.

On the mucous surfaces or in cavities. —
SARCINA ventriculi in the stomach, &c.,
Torula cerevisice (?), ditto. Various species

of LEPTOMITUS, which must be regarded as
imperfect mycelial growths, found in almost
all the cavities of the body. Oidium albicans,
Ch. R., the fungus of " Aphtha," probably a
peculiar condition of PENICILLIUM; Lep-
tothrix buccalis, a filamentous growth con-
stant in the tartar of the teeth, probably
some allied mycelium.

2. Birds.

Various species of ASPERGILLUS have
been found in the lungs and air-sacs ; their
introduction would appear to be accidental.
In the eggs of the common fowl, DACTY-
LIUM oogenum occurs not unfrequently,
sometimes on the membrane of the yolk,
sometimes on the outer membrane, just
beneath the shell. — SPOROTRICHUM brun-
neum, Schenk, in the white of eggs, convert-
ing it into a brownish gelatinous mass.

3. Reptiles and Fishes.

On the skin of Tritons, as of Fishes,
ACHLYA is frequently extremely developed;
other obscure forms are also enumerated by
Ch. Robin. The same author describes the
PSOROSPERMIA of J. Muller, as Algae allied
to the Diatomaceae, but they appear to be
pseudo-naviculae of GREGARIN.E.

4. Insects

are subject to the invasion of various para-
sitic fungi, among the most remarkable of
which is the Muscardine of the Silk-worm,
BOTRYTIS bassiana, which sometimes occa-
sions enormous loss to the silk-cultivators.
This fungus grows in or upon any part of
the silk- worm, Bombyx mori, in its larva,
chrysalis and imago forms. It is not fully
developed until after the death of the insect,
but if the spores penetrate the body of a
living specimen and this is placed in a damp
and confined atmosphere, the germination
takes place, and a development of the fungus
ensues which destroys the tissues and organs,
finally causing death. It has been developed
on many other Lepidoptera which have been
inoculated with it, and even the larvae of
certain Coleoptera take it. It is very
common to find flies in autumn infested
with a fungus, a kind of muscardine of flies ;
this belongs to the genus SPORENDONEMA ;
its mycelial filaments ramify in the interior
of the body, and emerge at the articulations
of the segments of the abdomen to bear fruit,
killing the fly. A number of so- called genera
of Fungi and Algae have been described by
Robin and Leidy as occurring in the intes-

PARASITES.

[ 492 ]

PARMELIACE/E.

tines, &c. of insects ; these appear to us to
be imperfect organisms (see ECCRINA, EN-

TEROBRYUS, ARTHROMITUS, LEPTO-

THRIX, CLADOPHYTUM). — Several species
of Sphceria infest the larvae of insects, the
mycelium ^destroy ing them and gradually
completely displacing the internal organs,
while the skin retains its shape and dries ;
the fruit subsequently breaks out from the
anterior or posterior extremity (see SPHCE-
RIA). The species of ISARIA, sometimes
described as parasites, appear to grow upon
dead insects.

5. The microscopic parasites of Plants
are very numerous, belonging all to the class
of Fungi. Much confusion exists in many
works between the true parasites and mere
epiphytes, and it is sometimes very difficult
to draw any line of demarcation. Among
the undoubted parasites are all the genera
and species of the family UREDINEI,
together with a large portion of the other
genera of Coniomycetes, and the Ascomyce-
tous forms to which they mostly belong.
Among the Hyphomycetes may especially be
cited the genus BOTRYTIS, B. infestans
being the potato-fungus. FUSISPORIUM,
"OioiUM," &c., form destructive mildews,
and among the PHYSOMYCETES, the ERY-
SIPHES, and especially their mycelia (com-
monly forming spurious Oidia), are well-
known pests. Further particulars are given
under POTATO-FUNGUS, VINE-FUNGUS
and BLIGHT.

BIBL. Ch. Rob. Hist. nat. des Vegetaux
Parasites, 2nd ed. Paris, 1853 ; Baeren-
sprung, Ann. Nat. Hist. xii. ; Siebold, Wag-
ner's Handwort. d. Phys. ; Hannover, Mill-
ler's Archiv, 1842, Bennett, Ed. Phil. Trans.
xv.

[We omitted GAMASUS, Latr.,in its proper
place. It designates a genus of parasitic
Arachnida, of the order Acarina, and family
Gamasea.

Char. Last joint of palpi smallest; labium
trifid ; mandibles cheliform, denticulate ;
body entire, with two dorsal plates; anterior
legs generally longest.

The species are mostly parasitic upon
insects ; some are found running upon the
ground ; others exist upon the higher
animals.

A. coleoptratorum (PI. 2. fig. 26). Found
upon dung-beetles ( Geotrupes), &c. Anterior
coxae attached at a little distance from those
of the second pair ; tarsi (fig. 26 a) termi-
nated by two claws and an elegant pulvillus ;

palpi of moderate length, with a moveable
seta like that of Dermanyssus; labium broad,
terminated by a median point and two lateral
hooks.

G. marginatus. Found upon the human
brain ! also upon a fly.

BIBL. Duges, Ann. d. Sc. nat. 2nd ser.
ii. p. 24 : Gervais, Walckenaer's Apteres,
iii. 215 ; Koch, Deutschl. Crustac. Mvriap.
4-c.]

PARASITIC FUNGI. See PARASITES.

PARENCHYMA. See TISSUES, VEGE-
TABLE.

PARKERIA, Hooker.— The typical genus
of Parkerieaeous Ferns. Aquatic ; exotic.

PARKERIE^.— A tribe of Exotic Poly-
podiaceous Ferns, consisting of aquatic
forms, in which the sporanges are not
gathered in sori, and with a habit very dif-
ferent from the majority of Ferns.

Genera.

I. CERATOPTERIS. Sporangia surrounded
by a broad, complete, articulated annulus,
placed upon longitudinal veins. Spores
globose, trifariously streaked.

II. PARKERIA. Sporangia with an almost
obsolete basilar annulus, placed on longitu-
dinal veins. Spores three-sided, concen-
trically streaked.

PARMELIA, Ach. — An extensive genus
of Parmeliaceae (Gymnocarpous Lichens),
characterized by their spreading, lobed, foli-
aceous thallus, with orbicular apothecia fixed
by a central point beneath, growing upon
trees, palings, rocks, stones, walls, &c.
About thirty British species exist ; P. parie-
tina, the yellow wall-lichen, is one of the
commonest plants of this family, and fur-
nishes a ready means of observing the struc-
ture both of the apothecia and the sperma-
gonia (PL 29. figs. 1-3).

BIBL. Hook. Brit. Fl. ii. pt. 1 . p. 202 ;
Engl. Bot. pi. 194, &c. ; Schaerer, Enum.
Crit. Lich. Europ. Berne, 1850. p. 33 ;
Tulasne, Ann. des Sc. nat. 3 ser. xvii. pp.
66, 137.

PARMELIACE^.— A family of Gymno-
carpous or open-fruited Lichens, bearing
sessile shields, the borders of which are
formed by the surface of the thallus.

Synopsis of British Genera.

I. USNEA. Thallus somewhat crusta-
ceous, rounded, branched, generally pendu-
lous, with a central thread. Apothecia cir-
cular, terminal or processes of the thallus,
peltate, nearly of the same colour, mostly

PARMELIACE/E.

[ 493 ]

PEDIASTRUM.

without a raised border, but ciliated at the
margins.

II. EVERNIA. Thallus somewhat crus-
taceous, branched and laciniated, angled or
compressed, cottony within. Apothecia cir-
cular, shield-shaped, sessile, with the disk
concave, coloured, and an inflexed border
formed by the thallus.

III. ALECTORIA. Thallus cartilaginous,
somewhat thready, branched, prostrate or
pendulous, somewhat fistulose and cottony
within. Apothecia circular, thick, sessile,
plane or convex, more or less bordered,
entirely formed of the thallus, and of the
same colour.

IV. CORNICULARIA. Thallus cartilagi-
nous, branched, subcylindrical, nearly solid
and cottony within. Apothecia circular,
terminal, obliquely peltate, entirely formed
of the substance of the thallus, at length
convex, more or less bordered and often
toothed.

V. RAMALINA. Thallus cartilaginous,
generally branched and laciniated, somewhat
shrubby, generally bearing powdery warts,
cottony and compact within. Apothecia cir-
cular, shield-shaped, stalked and peltate, flat,
bordered, entirely formed of the substance
of the thallus, and mostly of the same colour.

"VI. ROCCELLA. Thallus cartilaginous,
leathery, rounded or flat, branched or laci-
niated. Apothecia circular, adnate to the
thallus, the disk coloured, plano-convex,
with a border, at length thickened and ele-
vated, formed of the thallus, and covering a
black powder concealed within the substance
of the thallus.

VII. CETRARIA. Thallus foliaceous,
cartilagineo - membranous, ascending or
spreading, lobed and laciniated, smooth and
naked on both sides. Apothecia circular,
obliquely adnate to the margin of the
thallus, the lower portion being free (from
the thallus) ; disk coloured, plano-concave,
with an inflexed border formed of the
thallus.

VIII. NEPHROMA. Thallus foliaceous,
leathery or membranous, spreading, lobed,
naked or hairy beneath. Apothecia circular
or reniform, adnate on the underside of the
lobules of the thallus, with a border formed
by the latter.

IX. PELTIGERA. Thallus foliaceous,
leathery or membranous, spreading, lobed,
with woolly veins beneath. Apothecia some-
what circular, adnate on the upper side of
the lobules of the thallus, and having a
border formed by this.

X. STICTA. Thallus foliaceous, leathery-
cartilaginous, spreading, lobed, free and
downy beneath, with little cavities or hollow
spots, often containing a powdery substance.
Apothecia beneath formed of the thallus, to
which they are appressed and fixed by a
central point, the disk coloured, flat, sur-
rounded by an elevated border formed of the
thallus.

XI. PARMELIA. Thallus foliaceous, mem-
branous or leathery, spreading, lobed and
stellated or laciniated, more or less fibrous
beneath. Apothecia circular, formed by the
thallus, fixed by a central point, disk con-
cave, coloured with an inflexed margin from
the thallus.

XII. BORRERA. Thallus cartilaginous,
branched and laciniated, the segments free,
generally grooved beneath, the margins fre-
quently ciliated. Apothecia circular, peltate,
formed of the thallus, the disk coloured and
surrounded by an inflexed margin derived
from the thallus.

XIII. LECANORA. Thallus crustaceous,
spreading, flat, adnate and uniform. Apo-
thecia circular, thick, sessile and adnate ;
disk plano-convex, the border thickish,
formed of the crust, and of the same colour.

BIBL. See the genera.

PASTE, EELS IN. See ANGUILLULA.

PEARLS.— These well-known bodies are
formed as secretions from the mantle of
bivalve mollusks ; the best being obtained
from the Ceylon pearl-oyster or mussel
(Avicula margaritifera}. They occur natu-
rally from the irritation produced by particles
of sand accidentally confined between the
mantle and the shell; and they are produced
artificially by wounding the mantle with
pieces of iron-wire, &c. Their structure
agrees with that of the shell of the animal in
which they are formed. Sometimes they
consist entirely of nacre or pearly matter,
arranged in close concentric layers ; at
others, the interior exhibits the prismatic
structure of shell.

When acted upon by a dilute mineral acid,
the lime-salt is removed from the organic
cast of the original, which is left.

See SHELL.

PEDIASTRUM, Meyen.— A genus of
Desmidiaceae (Confervoid Algae).

Char. Cells aggregated into a usually
circular, minute disk or flattened star, and
generally arranged either in a single or in
two or more concentric series; marginal
cells bipartite on the outside.

Ralfs describes eleven British species.

PEDICELLARLE.

[ 494 J

FELLIES.

Interstices of the cells usually hyaline, but in
one species (P. selenaum) these are greenish.

P. Boryanum (PL 10. fig. 48). Cells ar-
ranged in one or more circles around one or
two central ones; marginal cells gradually
tapering into two long subulate points ;
notch narrow. Diameter of outer cells
1-2730 to 1-2220".

P. granulatum (PL 10. fig. 49). Cells six,
granular or punctate on the surface ; lobes
of marginal cells tapering. Diameter of
outer cells 1-1850".

The method of reproduction is noticed
under DESMIDIACE.E, p. 196.

BIBL. Ralfs, Brit. Desmid. p. 180; Cas-
pary, Bot. Zeit. viii. p. 786, 1850; Al. Braun,
Rejuvenescence, fyc., Ray Soc. Vol. 1853,
passim, pis. 3 & 4.

PEDICELLARLE. See ECHINODER-

MATA, p. 219.

PL 37. fig. 3 represents a pedicellaria from
the common star-fish : the stalk is not
figured.

The bird's-head processes of the polypes
(POLYPI) are probably analogous organs.

PEDICULUS, L.— A genus of Ano-
plurous Insects, of the family Pediculidae.

Char. Legs all scansorial or prehensile;
thorax large, not constricted from the abdo-
men; abdomen with seven segments; an-
tennae five-jointed; mouth with a fleshy
rostrum.

The species are human lice.

Rostrum retractile, concealed beneath the
head, forming a soft tubular sheath dilated
at the end, where it is furnished with a
double row of hooks, and containing a horny
tube formed of four setae.

P. capitis. Ashy-white, thorax elongate,
quadrate, abdomen ovate, laterally lobed,
segments blackish at the margin. Length
of male, 1-16"; of female, 1-8 .

P. vestimenti, body or clothes' louse (PL
28. fig. 3). Dirty white, elongato -ovate ;
head much produced ; thorax contracted in
front; abdomen with the segments indistinctly
indicated. Length about 1-8".

P. tabescentium, distemper-louse. Pale
yellow ; head rounded ; antennae long ;
thorax large and quadrate ; abdomen large,
the segments intimately united.

Doubtfully British.

BIBL. Denny, Anoplur. Monogr.

PELARGONIUM. See POLLEN, RA-
PHIDES, and HAIRS.

PELECIDA, Duj.— A genus of Infusoria,
of the family of Trichodina.

Char. Body flexible, contractile, oblong,

compressed, rounded behind, recurved like a
hatchet in front, ciliated all over, and fur-
nished with a mouth, which is either visible,
or shown to exist by the presence in the in-
terior of various objects swallowed by the
animals.

P. rostrum (PL 24. fig. 39) = Loxodes
rostrum, E., differs from the Paramecina, D,,
by the absence of a contractile integument.

BIBL. Dujardin, Infus. p. 403.

PELLIA.— A genus of Pelliese (frondose
Hepaticaceae). P. epiphylla (fig. 561) is not
uncommon in damp shady places, by springs
and wells, where it grows rapidly. Its pedi-
cels are silvery-white, and the capsules pale
brown, and when the valves are fully ex-
panded, the elaters form an elegant tuft in
the middle. The form of the frond varies
somewhat according to the degree of moist-
ure of the habitat.

BIBL. Hooker, Brit. Jung. pi. 47, Brit.
Flora, ii. pt. 1. p. 130; Endlicher, Gen.
Plant. Supp. i. No. 472-5; Ekart, Syn.
Jung. p. 63. pi. 7 & 13.

Fig. 561.

Pellia epiphylla.
Magnified 2 diameters.

PELLIESE. — A tribe of Liverworts or
Hepaticae, nearly allied to the Jungerman-
nieae in the character of the fructification,
but having a lobed thalloid frond, traversed
by a mid-nerve, from which the fruit-stalks
arise.

British Genera.

I. BLYTIA. Fructification emerging from
the end of the rib below the apex of the
frond, at length dorsal. Perichaete 4-5-

FELLIES.

[ 495 ]

PENICILLIUM.

parted; lobes torn. Perigone herbaceous,
tubular, the mouth denticulated. Arche-
gones eight to twenty. Epigone persistent,
torn at the summit. Sporange 4-valved.
Antheridia dorsal, placed on the rib, covered
by dentate incumbent leaflets.

II. FOSSOMBRONIA. Fructification emer-
ging from the end of the rib below the apex
of the frond, at length dorsal. Perichsete
obconic-bell-shaped, the mouth crenate or
dentate. Perigone wanting. Archegones
few. Epigone persistent, torn at the sum-
mit. Sporange circumscissile. Antheridia
dorsal, situated on the rib, naked.

III. METZGERIA. Fructification emer-
ging from the ventral side of the midrib of
the frond. Perichaete ventricose, at length
bipartite. Perigone none. Archegones few.
Epigone persistent, torn at the summit.
Sporange four-valved. Antheridia ventral,
placed on the rib, covered by incumbent,
dentate leaflets.

IV. ANEURA. Fructification emerging
from the ventral side, near the margin of
the frond. Perichaete short, lobed or torn.
Perigone wanting. Archegones few. Epi-
gone persistent, torn at the summit. Spo-
range four-valved. Antheridia immersed in
the back of special lobes of the frond.

V. PELLIA. Fructification emerging from
the dorsal side of the frond. Perichaete
short, somewhat cup-shaped, the mouth
lacero-dentate. Perigone wanting. Arche-
gones several. Epigone membranous, ac-
companied by a few sterile archegones, at
first, at the lower part. Sporange four-
valved. Antherids immersed in the surface
of the frond.

VI. BLASIA. Fructification at first im-
mersed in the rib of the frond, then emer-
ging from the apex. Perichsete and peri-
gone wanting. Epigone membranous, with
few sterile archegones, at first, scattered to-
ward the lowest part. Sporange four-valved.
Antherids immersed in the rib of the thallus,
more prominent below, and covered by
little dentate scales.

VII. TARGIONIA. Fructification sessile,
inferior, solitary and terminal to the frond.
Perichaete two-valved, splitting vertically.
Perigone wanting. Epigone delicate, per-
sistent, investing the sporange until matu-
rity, sometimes evanescent above. Spo-
range bursting by an irregular slit, or into
fragments. Antherids immersed in the rib
of the frond below, covered by papillae.

BIBL. See the genera, and HEPATI-
CACE.E.

PELOPS, Koch (Acarina}.— Is consoli-
dated with GALUMNA.

PELTIDEA, Ach.— A genus of Parme-
liaceae (Gymnocarpous Lichens), charac-
terized by a foliaceous, usually leathery thal-
lus, with woolly veins beneath; the sub-
orbicular, shield-like apothecia arising on
the upper sides of the lobules.

P. canina, a large Lichen, is extremely
common on the ground among moss in
woods. Two or three nearly allied species
are separated from this by most authors,
but with questionable propriety. Three or
four others are subalpine.

BIBL. Hook. Brit. Flora, ii. pt. 1. p. 218,
Eng. Bot. 2229.

PELTIGERA, Hoffm. = Species of PEL-
TIDEA and STICTA.

PENICILLIUM, Link.— A genus of Mu-
cedines (Hyphomycetous Fungi), of which
the species P. glaucum is at once one of the
most frequent and the most puzzling plants of
the class. This fungus is the commonest of
the constituents of the greenish or bluish
mould formed on decaying vegetable sub-
stances of all kinds, especially on semifluid
or liquid matters. On the surface of liquids
it forms a kind of dense pasty crust, slimy
on the lower surface, and coloured and pul-
verulent (bearing spores) above. When the
upper fertile layer is examined under the
microscope, it is found to consist of pedicels
terminating in a repeatedly but "shortly bi-
furcated pencil, each ultimate branch of
which bears a moniliform row of spores
(the ramification of the pedicels is not di-
stinctly represented in fig. 562, but the ap-
Fig. 562.

Penicillium.

A fertile plume with pencils of spores.
Magnified 200 diameters.

pearance of the spores is characteristic).
The mode of attachment of the spores is

PENICILLIUM.

[ 496 ]

PERACANTHA.

shown in figs. 15 and 16 of PI. 20. The
mycelium consists of interwoven articulated
filaments, most extensively ramified. The
spores appear whitish, yellowish, greenish,
or bluish, according to age : under the mi-
croscope, they appear opake when mature.

So far there is little difficulty about the
history of these plants, and if the spores of
the above form are sown on a glass slide,
kept moist with an organic liquid, they will
germinate and ramify, and under favourable
circumstances bear thin penicillate tufts of
spores at points which emerge from the
nutrient liquid. But this same fructification
of P. glaucum presents itself invariably
under certain circumstances associated with
the vinegar-plant and the yeast-plant, toward
the close of the ordinary development of
these fungi. In common with most obser-
vers, we find that the exhaustion of the sac-
charine matrix of the vinegar-plant is fol-
lowed in all cases by the appearance of
crusts of Penicillium-moulA on the upper
surface, whence it would appear that the
vinegar-plant was only the mycelium of
Penicillium. It was asserted, moreover,
many years ago, by Turpin, that P. glaucum
is the last term of the growth both of the
true yeast-plant, Torula Cerevisice, and of
the milk-yeast, Oidium lactis. We have
found the gelatinous crusts of the vinegar-
plant to contain structures which represent
Torula and Oidium, and to grow like them ;
and we have also observed, in repeated expe-
riments, that beer allowed to stand until
sour, at first appears clothed with a whitish
mealy collection of minute vesicles, repre-
senting the ultimate stage of Torula, and
subsequently this gradually gave place to
gelatinous matter, which at length covered
the whole surface with a tough film, and
fruited as Penicillium glaucum. Hence it
would appear that the yeast-fungus also is
merely a vegetative form of Penicillium
developed under peculiar conditions. More
is said on this point under VINEGAR-PLANT
and YEAST.

Several species are enumerated, and we
have given under the separate head of
COREMIUM a form which is now regarded
as merely a confluent growth of Penicillium,
producing a compound pedicel.

1. P. glaucum, Grev. Mycelial filaments
form a crust-like web, spores green or bluish.
Greville, Sc. Crypt. Fl. pi. 58. fig. 1. P.
crust aceum, Fries. Extremely common.

2. P. candidum, Lk. Mycelial filaments
woven together, spores white. (Distinct ?)

3. P. sparsum, Grev. Mycelium lax,
spores white. -Sc. Crypt. Fl. pi. 58. fig. 2.
Perhaps not different from the last.

^ . P. fasciculatum, Sommer. Mycelium
scarcely developed, filaments all fertile,
trifid at the apex, spores glaucescent.

5. P. subtile, Berk. Extremely minute,
mycelium creeping, fertile filaments erect,
simple or ternate ; chains of spores few,
spores broadly elliptical. Ann. Nat. Hist.
vi. pi. 14. fig. 25.

6. P. roseum, Lk. Mycelium effused ;
fertile filaments slightly branched, spores
rose-colour.

BIBL. Berk. Hook. Brit. FL ii. pt. 2.
p. 344 ; Ann. Nat. Hist. i. p. 262, vi. p. 437,
ser. vii. p. 102; Greville, loc. cit.; Fries,
Syst. Myc. iii. 407, Summa Vegetabilium,
p. 489. See also under YEAST and VI-
NEGAR-PLANT.

PENIUM, Brelj.— A genus of Desmidi-
acese.

Char. Cells single, entire, elongated,
straight, and slightly or not at all constricted
in the middle.

Sporangia round or quadrangular, smooth,
not spinous.

At each end of the cells is a rounded
space containing moving molecules.

Eight British species (Ralfs).

P. Erebissonii (PI. 10. fig. 36). Cells
smooth, cylindrical, ends rounded, transverse
median band inconspicuous. Length 1-640
to 1-400".

Common. Sporangium at first quadrate,
but finally orbicular ; conjugating cells per-
sistent, or remaining permanently attached
to the sporangium.

P. margaritactum (PI. 10. fig. 37. empty
cell). Cells cylindrical or fusiform, with
rounded-truncate ends, and covered with
pearly granules in longitudinal rows. Length
1-160".

BIBL. Ralfs, Brit. Desmid. p. 148.

PENTASTERIAS, Ehr. (Desmidiacese).
— The two British species are referred to
Staurastrum.

PERACANTHA, Baird.— A genus of En-
tomostraca, of the order Cladocera and family
Lynceidae.

Char. Side view of shell oval, the lower
and posterior portion with an acute projec-
tion directed backwards and upwards, and,
as well as the upper extremity of the anterior
margin, beset with strong hooked spines ;
beak sharp, curved downwards.

P. truncata (PI. 14. fig. 31). Superior
antenna; conical ; inferior short, the anterior

PERANEMA.

[ 497 ]

PERIDINIUM.

branch with five setae, one from first, one
from second, and three from last joint ; pos-
terior branch with three setae from the last
joint only; intestine convoluted, with one
turn and a half; ova two. Aquatic.

BIBL. Baird, Brit. Entom. p. 136.

PERANEMA, Duj .—A genus of Infusoria,
of the family Euglenia.

Char. Form variable, sometimes nearly
globular, at others inflated posteriorly and
narrowed in front, where it becomes pro-
longed into a long flagelliform filament;
movement slow, uniform, forwards.

P. globulosa (PL 24. fig. 59). Body almost
globular, more or less drawn out anteriorly,
with oblique wrinkles on the surface ;
aquatic; length 1-1400".

BIBL. Dujardin, Infus. p. 353.

PERICH^NA, Fr.— A genus of Tricho-
gastres (Gasteromycetous Fungi), consisting
of little rounded membranous sacs of brown-
ish or yellowish colour, generally splitting
all round (transversely), and discharging
yellow spores and (few) free and elastic
filaments. The commonest, P. populina,
yellowish, and about as large as a mustard
seed, occurs on fallen poplar trees ; two
others occur in fir-plantations.

BIBL. Berkeley, Hook. Brit. Fl. ii. pt. 2.
p. 321; Fries, Syst. Myc. p. 190, Summa
Veget. p. 459; Greville, Sc. Crypt. Fl. p. 252.

PERICONIA, Tode.— A genus of Stil-
bacei (Hyphomycetous Fungi), apparently

nearly related to PACHNOCYBE, but with
the stem fistular, and the capitulum vesicular.
P. alaucocephala, Corda, has been found on
rotten linen.

BIBL. Fries, Summa Veg. p. 168; Berk,
and Broome, Ann. Nat. Hist. 2 ser. v. p. 165.

PERIDERM. See BARK.

PERIDERMIUM, Lk.— A genus of Cas-
omacei (Coniomycetous Fungi), distin-
guished from JEciDiuM by the sac-like
perithecium bursting irregularly, as if by a
circumscissile dehiscence. The type of this
genus is P. (jEcid.} Pini, found on the
leaves and bark of Scotch Firs. The spores
are covered with very numerous small
tubercles. See UREDINEI.

BIBL. Berk. Brit. Flora, ii. pt. 2. p. 374;
Grev. Scot. Crypt. Fl. pi. 7 ; Tulasne, Ann.
des Sc. nat. 4 ser. ii. p. 176. pi. 10; De Bary,
Brandpihe, Berlin, 1853. p. 72.

PERIDIN^A, Ehr.— A family of Infu-
soria.

Char. Body furnished with a membranous
carapace, from which a long flagelliform
filament issues, and which has one or more
furrows occupied by vibratile cilia, or exhi-
bits setae or minute spines upon the sur-
face.

These Infusoria live either in the sea, or
in stagnant fresh water ; never being found
in infusions or decomposing water.

Five genera :

Carapace with rigid setae or points, but no transverse f Eye-spot present 1 . Chtetoglena.

furrow nor longitudinal crest I Eye-spot absent 2. Chcetotyphla.

Carapace smooth or rough, and with a transverse ciliated f Eye-spot present 3. Glenodinium.

furrow, but no crest \ Eye-spot absent 4. Peridinium.

Carapace with an incomplete longitudinal crest 5. Dinophysis.

Dujardin appends the genera Chatoglena
and Cheetotyphla to his genus Trachelomonas
as uncertain, and arranges the genera Gle-
nodinium and Peridinium as stated under
the latter head.

BIBL. Ehrenberg, Infus. p. 249; Dujardin,
Infus. p. 371.

PERIDINIUM, Ehr.— A genus of Infu-
soria, of the family Peridinaea.

Char. Those of Glenodinium with the
absence of the red (eye-) spot.

A flagelliform filament is present as well
as the cilia. Some species have horn-like
processes.

Eleven species; two (fossil) doubtful.
Some of them are phosphorescent.

P. cinctum (PL 24. fig. 9). Green ; not
phosphoresent; carapace subglobose, smooth,

subtrilobed; no horns. Aquatic; length
1-580".

P. fuscum (PL 24. fig. 11). Brown; not
luminous ; carapace ovate, slightly com-
pressed, smooth, acute in front, rounded
behind ; no horns. Aquatic ; length 1-430
to 1-290".

P. tripos (PL 24. fig. 12). Yellowish ;
splendidly phosphorescent ; carapace urceo-
late, broadly concave, smooth, with three
horns, two very long, frontal and recurved,
the third posterior and straight. Marine ;
length 1-140".

P. uberrimum, Allman. Cilia distributed
over the whole surface. Length 1-1000 to

i-socr.

Dujardin unites those species of the genera
Glenodinium and Peridinium which have no

2K

PERIOLA.

[ 498 ]

PERTUSARIA.

horns, to form the single genus Peridinium,
placing those with horns in a genus Cera-
tium.

BIBL. Ehrenberg, Infus. p. 252 ; Dujardin,
Infus. p. 374 ; Allman, Micr. Journ. iii. 24.

PERIOLA, Fries. P. tomentosa, Fr.,
described as a Sclerotioid Fungus, is an
obscure, irregular, fleshy body, with a white
villous surface, found growing on potatoes.
It is probably the early form of some unas-
certained species of fungus.

PERIPTERA, Ehr.— A genus of Diato-
maceae.

Char. Frustules single, compressed; valves
circular, dissimilar, one being simply turgid,
the other winged or furnished with horns ;
horns sometimes branched and attached to
the extreme margin. Fossil.

Valves not areolar nor punctate under
ordinary illumination.

Four species. America and Bermuda.

BIBL. Ehrenberg, Ber. d. Berl. Akad.
1844. p. 263; Kiitzing, Sp. Alg. p. 25.

PERISPORACEL— A family of Ascomy-
cetous Fungi, mostly epiphytic and of small
size, characterized by producing floccose
common receptacles (mostly) radiating from
a point, forming patches upon leaves, &c.,
in the centre of which are developed some-
what globular perithecia, of obscure cellular
structure, persistent, bursting at the summit,
filled densely with subgelatinous, scarcely
diffluent gelatine; sporidia produced in asci,
subsequently often effused, simple, free, and
mixed with the gelatine in the centre of the
perithecium. The mycelia of these plants,
bearing conidial structures, have been de-
scribed as distinct fungi, for example those
of Erysiphe, as Oidia, &c. See ERYSIPHE.

Synopsis of British Genera.

I. LASIOBOTRYS. Perithecium fleshy-
horny, globular, naked, collapsing at the
summit.

II. ERYSIPHE. Perithecium membranous,
closed at first, afterwards open, supported
on a persistent radiating mycelium, formed
of continuous filaments, bifid at their ends.
Asci four or eight, paraphyses none ; spores
continuous, ovate.

III. PERTSPORIUM. Common receptacle
floccose. Perithecium superficial, at length
bursting irregularly. Asci club-shaped, not
mixed with paraphyses. Spores simple,
ovate.

IV. CH.ETOMIUM. Common receptacle
floccose. Perithecium superficial, finally
open at the mouth, clothed externally with

opake hairs. Asci clavate, mixed with para-
physes. Spores simple, ovate.

V. ASCOTRICHA. Perithecium thin, at
length bursting, clothed with dark, subpel-
lucid, even, obscurely-jointed hairs. Spores
simple, contained in linear asci. Superficial,
at length free or resting on the investing
thallus, black.

PERISPORIUM, Fr.— A genus of Peri-
sporacei (Ascomycetous Fungi), consisting
of minute, globular, free, punctiform sacs,
with fleshy or waxy walls, seated on an obscure
thallus, growing on leaves or stalks j finally

Fig. 563.

Fig. 564.

Perisporium disseminatum.

Magnified

Fig. 564. An ascus detached. Magnified 300 diams.

Fig. 563. A perithecium in vertical section
100 diameters.

bursting and collapsing. The spores are
produced in large numbers in swollen clavate
asci (figs. 563, 564), which are accompanied
by paraphyses.

BIBL. Fries, Summa Veg. p. 404, Syst.
Myc. iii. p. 248 ; Berk. Ann. Nat. Hist. vi.
p. 432.

PERITHECIUM.— The name applied to
the special envelope, mostly of different
structure from the rest of the thallus or the
receptacle, enclosing the " nucleus " of the
Angiocarpous Lichens and the Pyrenomyce-
tous Fungi.

PERITONEUM. See SEROUS MEM-
BRANES.

PERONOSPORA, Ung. See BOTRYTIS.

PERTUSARIA, D.C.— A genus of En-
docarpeae (Angiocarpous Lichens), having an
adnate, uniform thallus, spreading over bark,
rocks, &c., and bearing wart-like apothecia,
finally exhibiting a depressed pore in their
centre, leading to the one or several cells
containing the theca?. P. communis is very
common on trees.

BIBL. Hook. Brit. Flor. ii. pt. 1. p. 164 ;
Engl. Botany, pi. 677 ; Leighton, Brit.
Angioc. Lichens, p. 26. pis. 9-11.

PETALONEMA.

[ 499 ]

PEZIZA.

PETALONEMA, Berk. (Arthrosiphon,
Kiitz.). — A genus of Oscillatoriaceae(Confer-
void Algae), presenting a very remarkable
mode of growth . The filaments are branched
and cylindrical, with a very evident terete,
gelatinous, duplicate sheath (PI. 4. fig. 21).
The inner is thin and follows the filament,
the outer presents oblique striae indicating
the interposition of lengths of the outer
sheaths, one inside another, like a series of
nested funnels or conical cups. This appear-
ance is produced by the bursting and expan-
sion of each length of the sheath at the apex
alone, to make room for the growth of the
new cells of the filament formed at the apex.
This structure is analogous to that occurring
in UROCOCCUS, when each parent-cell mem-
brane bursts at one side only to allow the
new one to emerge, thus at length forming
a jointed pedicel. The edges of the " fun-
nels " of Petalonema sometimes become de-
composed into curled filamentous processes.

The filament of P. alatum is green and
striated, about 1 -3000" in diameter, the inner
sheath is yellowish, the outer colourless and
1-400" in diameter. It forms a brownish
stratum on rocks and stones.

BIBL. Berkeley, Gleanings, p. 23. pi. 7 ;
Greville, Sc. Crypt. Fl. pi. 222; Hassall,
Brit. Fr. Alg. p. 237. pi. 68. fig. 6; Kiitzing,
Spec. Alg. p. 311, Tab. Phyc. ii. 28; Al.
Braun, Rejuvenescence, fyc., Ray Soc. Vol.
1853. p. 178.

PETALS.— Thepetalsof Flowering Plants
afford many interesting microscopic objects,
in the epidermis, glandular and other hairs,
the colour-cells and the veins composed of
spiral vessels. Entire petals of small size
and delicate character form good objects
when dried and mounted in Canada balsam.
Those of the smaller Caryophyllacese, the
ligulate corollas of Compositae, Sec., are well
suited for this. The larger kinds are studied
by means of sections, like LEAVES.

PETROBIUS, Leach.— A genus of In-
sects, of the order Thysanura, and family
Lepismenae.

P. maritimus has a general resemblance to
Lepisma saccharina; but it exercises a leap-
ing movement. The antennas are longer
than the body ; of the setae at the tail, the
middle one is longest. The insect is of a
blackish-brown colour, and is covered with
scales; the legs are yellowish, and the caudal
setae ringed with white ; the abdomen is
furnished with gill-like processes.

It is found upon the rocky sea-coast.

The scales have been used as test-objects.

BIBL. Gervais, Walckenaer's Apt. iii.
p. 447 ; Guerin, Iconogr. Ins. pi. 2. fig. 1 /.
and Ann. d. Sc. nat. 2 ser. v. p. 374.

PETER'S GLANDS. See INTESTINES
(p. 366).

PEYSSONELIA, Dene.— A genus of
Cryptonemiaceae (Florideous Algae), consist-
ing of small plants with a depressed lobed
thallus (fig. 565), growing over stones,

Fig. 565.

Frond. Nat. size.

Fig. 566.

Peyssonelia squamosa.

Vertical section of a portion through two warts.
Magnified 25 diameters.

shells, &c., and attached by the whole under
surface which produces jointed radical hairs
(fig. 566), especially at the thin margins. The
thallus is composed of several rows of com-
pact parenchymatous cells, and bears on
the concentrically-marked surface, warts
composed of radiating rows of cells, among
which occur crucially-divided tetraspores.
P. Dubyi is not uncommon on British shores;
it is 1 to 2" in diameter, roundish at first,
ultimately irregularly lobed, colour dull
brownish. Thuret has observed antheridia
on distinct plants of P. squamosa, a Medi-
terranean form ; they are jointed filaments
collected into wart-like bodies, like those
containing the tetraspores. The spores are
not described.

BIBL. Harvey, Brit. Mar. Alg. p. 144.
pi. 14 D ; Phyc. Brit. pi. 71 ; Thuret, Ann.
des Sc. nat. 4 ser. iii. p. 23. pi. 4.

PEZIZA, Dill.^-A genus of Helvellacei
(Ascomycetous Fungi), containing numerous
species, a large number of which grow upon
2K2

PHACELOMONAS.

[ 500 ]

PHACIDIUM.

on the ground, among leaves,
brightly coloured. They are at
sacs, which burst at the summit,
out to form a kind of cup con-
and paraphyses. Thus they be-
Discomycetes of some authors.

Fig. 568.

Fig. 569.

dead wood,
&c., many
first closed
and spread
taining asci
long to the

Fig. 567.

Peziza furfuracea.

(Small variety.)

Magnified 5 diameters.

Tulasne has recently shown that some of
the Pezizce have a secondary fructification
consisting of stylospores ; these forms have
been described as species of Dacrymyces, a
genus of Tremellini. Other species also
produce spermatia.

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 186;
Fries, Summa Veg. p. 348 ; Tulasne, Ann.
des So. nat. 3 ser. xx. p. 167.

PHACELOMONAS, Ehr.— A doubtful
genus of Infusoria.

Char. Tail-like process absent; a red
(eye-) spot present ; mouth (?) terminal,
truncate, furnished with eight to ten anterior
long cilia or flagelliform filaments.

P. pulvisculus. Body oblong, subconical,
attenuate posteriorly, bright green ; aquatic;
length 1-1150". Occurs in myriads in pools.
Perhaps zoospores of CEDOGONIUM.

BIBL. Ehrenberg, Infus. p. 28.

PHACIDIACEI.— A family of small Asco-
mycetous Fungi, mostly growingin large num-
bers on the half-decayed woody parts of
plants, or on the ground ; consisting usually
of dark-coloured, indurated, or leathery bo-
dies, solitary or connate, or seated on a
common base, closed at first, and containing
a soft nucleus ; the outer case (perithecium)
subsequently opening widely, and presenting
a cavity lined with asci containing spores.

The history of development of these plants
is still obscure, for many of them are con-
nected with certain of the Coniomycetes as
different stages of one and the same plant.
We describe the genera according to the
existing classifications, noting the new facts
relating to these metamorphic phenomena
in the articles on the particular genera.

Synopsis of British Genera.
* Perithecium open, margined, closed by a

lid or veil.

I. PATELLARIA. Perithecium patelli-
form, margined, open, covered with a thin

veil confluent with the nucleus. Disk at
length pulverulent, the annulate asci break-
ing out.

II. TYMPANIS. Perithecium cup-shaped,
margined, open, covered by a thin, evanes-
cent veil. Disk fixed in the receptacle (pro-
per stratum), at length dissolved. Asci fili-
form, fixed.

** Perithecium (excipulum) at length open,
connate with the floccose receptacle.
Nucleus discoid, ascigerous, placed on
the receptacle.

III. CENANGIUM. Perithecium entire,
leathery-horny, opening by a connivent
mouth, distinct from the discigerous stra-
tum. Asci filiform, persistent, expelling the
separate spores with violence.

*** Perithecium entire, dehiscing by closely
connivent slits.

IV. LOPHIUM. Perithecium subsessile,
elongated, compressed, bursting by a longi-
tudinal slit. Asci erect, fixed, cylindrical,
persistent, sporidia simple, rounded. Thal-
lus crustaceous or imperceptible.

**** Perithecium somewhat dimidiate, at
length open, nucleus naked.

V. RHYTISMA. Perithecium innate, of
irregular form, opening by fragments break-
ing off into a flexuose slit; nucleus placenti-
form, persistent. Asci erect, fixed; para-
physes stalked.

VI. PHACIDIUM. Perithecium roundish,
simple, bursting with several teeth at the
summit ; nucleus disk-shaped, in some de-
gree persistent. Asci erect, fixed; para-
physes stalked.

VII. HYSTERIUM. Perithecium sessile,
oval or elongated, with a longitudinal slit at
first closed, afterwards gaping open; nu-
cleus linear, somewhat persistent. Asci
erect, fixed ; paraphyses stalked.

VIII. LABRELLA. Perithecium innate,
bursting by a longitudinal slit ; asci short,
broad and obtuse above, attenuated below,
mixed with short flexuous paraphyses;
spores few, ovate-oblong, occasionally con-
tracted or septate in the middle.

PHACIDIUM, Fr.— A genus of Phacidi-
acei (Ascomycetous Fungi), containing many
species growing on dead leaves, branches,
&c. Some of them are common, as P. den-
tatum, on oak-leaves, and P. Lauro-cerasi on
the cherry-laurel.

BIBL. Berk. Brit. Fl. ii. pt. 2. p. 291 ;
Fries, Summa Veg. 369.

PHACUS.

[ 501 ]

PHILODINA.

PHACUS, Nitzsch, Duj.— A genus of In-
fusoria, of the family Thecamonadina, D.
(Cryptomonadina, E.).

Char. Body flattened and leaf-like, usu-
ally green, with an anterior red (eye-) spot,
a single flagelliform filament, and covered
with a resisting membranous integument,
prolonged posteriorly like a tail.

Dujardin distinguishes this genus from
Euglena, E. by the constancy of the form of
the body, which varies every moment in the
latter genus.

P. pleuronectes (PI. 24. fig. 62). Body
oval, almost circular, green, with slightly
marked longitudinal furrows, and a tail-like
prolongation one-third or one-fourth of its
length. Aquatic; length 1-630".

P. longicauda (PI. 24. figs. 3 & 63) =
Euglena longicauda, E.

P. tripteris. Aquatic.

P. triquetra = Euglena triquetra, E.

BIBL. Dujardin, Infus. p. 334.

PH^EONEME^, Kiitz.— Afamily found-
ed on obscure byssoid structures occurring in
foul water.

PILEOSPOILE. — A name applied by
Thuret to part of the Fucoideae.

PHALLOIDEI.— A family of Gastero-
mycetous Fungi, characterized by the pro-
trusion of a large clavate, columnar, stellate
body, or globular, hollow, latticed frame-
work, from the summit of the burst peri-
dium. The basidiospores must be observed
early here, as they fall off and form a deli-
quescent mass upon the hymenium when
the sporange is mature. The fleshy struc-
ture protruded from the dehiscent capsule is
composed of spherical cells very loosely
connected; the peridium, which is very
tough, is composed of closely packed, very
slender, filamentous cells.

BIBL. Berkeley, On the Fructification of
Lycoperdon, Phallus, fyc., Ann. Nat. Hist.
iv. 155, Brit. Flor. ii. pt. 2. p. 226; Ross-
mann, Bot. Zeit. xi. p. 185 (1853).

PHASCACEJE. — A family of inopercu-
late Acrocarpous (terminal-fruited) Mosses,
of minute dimensions, gregarious or csespi-
tose, with a simple or branched stem. Leaves
oblong, oval, lanceolate or spathulate, con-
cave, with a thick cylindrical nerve; the
cells of the leaves parenchymatous, looser at
the base, by degrees denser towards the
summit, mostly papillose. Capsules mostly
obliquely apiculate, with spores larger than
in most Mosses, but not so large as in AR-
CHIDIUM. Columella soon vanishing in the
smaller species.

British Genera.

I. ACAULON. Plants very dwarf, grega-
rious. Capsule contained in the closed peri-
cha3te. Calyptra mitre-shaped, delLate.
Inflorescence monoecious (antheridia on a
distinct branch at the base of the stem), or
dicecious (antheridia terminal on a distinct
plant), bud-like.

II. PHASCUM. Plants csespitose. Peri-
chaete open. Capsule on a longish stalk,
and mostly obliquely apiculate. Calyptra
dimidiate. Inflorescence monoecious (anthe-
ridia terminal in a bud on a distinct lateral
branch, or naked and axillary on the fruit -
bearing branch), or dioecious.

PHASCUM, L.— A genus of Phascaceaj
(Acrocarpous Mosses), which is now sub-
divided variously by different authors. Wil-
son separates the earlier Ph. alternifolium
only, under the name of Archidium ; foreign
authors further distinguish between PHAS-
CUM, ACAULON, EPHEMERUM, and ASTO-
M UM . Species retained : Ph. crispum, Hedw . ;
cuspidatum, Schreb.; curvicollum, Hedw. ;
rectum, Smith ; bryoides, Dicks. Ph. cuspi-
datum is very common on banks, and espe-
cially on a gravelly soil.

BIBL. Wilson, Bryol.Brit. 32; Hooker,
Brit. Fl. ii. pt. 1. p. 6.

PHIALINA, Bory, Ehr.— -A genus of In-
fusoria, of the family Trachelina.

Char. Body not ciliated, having a kind of
neck crowned with cilia; mouth lateral,
without teeth.

P. viridis (PI. 24. fig. 61). Body oval,
flask-shaped, green, suddenly narrowed in
front and gradually behind; neck short.
Aquatic; length 1-290".

P. vermicularis. White ; aquatic.

BIBL. Ehrenberg, Infus. p. 333.

PHILODINA, Ehr.— A genus of Rota-
toria, of the family Philodinaea.

Char. Eyes two, cervical; tail-like foot
with horn-like lateral processes.

Ehrenberg describes seven species; they
are all aquatic, and in general structure and
appearance closely resemble Rotifer.

P. erythrophthalma (PI. 35. fig. 17). Co-
lourless, smooth, eyes round, processes of
foot short. Aquatic; length 1-120 to
1-50".

P. roseola is reddish, and the eyes oval;
P. collaris has a projecting cervical ring;
P. citrina has the middle of the body yel-
lowish ; P. macrostyla has oblong eyes, and
the foot-processes very long; in P. megalo-
trocha the eyes are oval, and the rotatory
organs very large; and in P. aculeata the

PHILODIN^A.

[ 502 ]

PHRAGMIDIUM.

body is covered with soft setaceous pro-
cesses.

BIBL. Ehrenberg, Infus. p. 498.

PHILODINJEA, Ehr.-A family of Ro-
tatoria.

Char. No sheath or carapace; rotatory
organs two, simple, resembling two wheels
when the cilia are in motion.

The body is usually cylindrical, or some-
what spindle-shaped, contractile even so as
to form a ball. In certain states of exten-
sion it sometimes appears pointed in front,
from the presence of a proboscis ; in others
the two ciliated rotatory organs are pro-
truded.

The animals are capable of swimming by
means of the cilia, or of creeping like a
leech, the ends of the body being alternately
fixed. The tail-like foot is often furnished
with horn-like lateral processes and terminal
toes.

Ehrenberg distinguishes seven genera.

A. Eyes absent.

a. Proboscis and horn-like lateral pro- \ . ^ /.-j-

cess on the foot present J

/3. Proboscis and horn-like processes!

absent /

a. Rotatory organ stalked 2. Hydrias.

b. Rotatory organ not stalked 3. Typhlina.

B. Eyes present.

Eyes two, frontal.
Foot with horn-like processes.

Toes 2 4. Rotifer.

Toes 3 5. Actinurus.

Eyes two, cervical 7« Philodina.

BIBL. Ehrenberg, Infus. p. 481.

PHILOPTERUS, Nitzsch.— A genus of
Anoplurous Insects, of the family Philopte-
ridse.

Char. Antennae filiform, five-jointed;
maxillary palpi none; mouth with strong
toothed mandibles ; tarsi with two claws.

The species are very numerous, and have
been arranged in six subgenera : Docophorus,
Nirmus, Goniocotes, Goniodes, Lipeurus and
Ornithobius. In some of them there are
two moveable organs (trabeculse) situated in
front of the antennae.

They are the external parasites of birds.

P. (Docophorus) communis (PL 28. fig. 5).
Chestnut-coloured, shining, with white hairs;
head triangular, elongate, anterior portion
much produced; trabeculae very large,
curved; posterior femora much incrassated
and toothed below. Length 1-16".

Parasitic upon the Passerina or Insessores.

BIBL. Denny, Anoplur. Monoor. p. 62.

PHLYCTJ2NA, Desmaz.— A genus of
Sphaeronemei(Coniomycetous Fungi), nearly
related to Septoria, differing in the absence
of a proper perithecium. P. vagabunda has
been found in Britain.

BIBL. Berk, and Broome, Ann. Nat. Hist.
2nd ser. xiii. p. 460 ; Desmazieres, Ann. des
Sc. nat. 3 ser. viii. p. 16.

PHLYCT^NIA, Kg.— A genus of Dia-
tomaceae.

Char. Frustules those of Navicula, en-
closed in gelatinous globular cells (masses?).
Marine.

P. minuta. Cells 1-720 to 1-240" in dia-
meter ; length of frustules 1-1200 to 1-600".

P. maritima (Frustulia mar., E.).

BIBL. Kiitzing, Sp. Alg. p. 96; Ehren-
berg, Infus. p. 232.

PHLYCTIDIUM, Not. See DISCOSIA.

PHOMA, Fr.— A genus of Sphseronemei
(Coniomycetous Fungi), which presents both
conidiferous and ascigerous forms. There
are numerous British species, forming small
black or brown pustules upon dead leaves,
twigs, &c.

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 285,
Ann. Nat. Hist. vi. p. 263, ser. 2. v. p. 368,
xiii. p. 459; Fries, Summa Veg.-p. 421.

PHORMIDIUM, Kiitz. See OSCILLA-

TORIA.

PHORMIUM, Forst.—P. tenax is the
name of the plant yielding New Zealand
Flax. It is a Monocotyledonous Flowering
Plant belonging to the order Liliaceae.

PHRAGMICOMA, Dumort.— A genus of
Jungermannieae (Hepaticacese), containing
one British species, P. MacJcaii (Jung. Mac-
kaii, Hook.), occurring rarely on trees and
rocks, especially on limestone.

BIBL. Hook. Brit. Jung. p. 53 ; Ekart,
Syn. Jung. p. 59. pi. 9. fig. 72; Endlicher,
Gen. Plant. Suppl. i. 472-9.

PHRAGMIDIUM, Ua.(Aregma, Fr.).— A
genus of Caeomacei (Coniomycetous Fungi),
forming rusts very common on Rosaceous

Fig. 570.

Phragmidium bulbosum.

Isolated basidium with four catenate spores.

Magnified 100 diameters.

plants. They appear upon living leaves,

PHRAGMOTRICHACEI. [ 503 ]

PHYCOMYCES.

breaking through from beneath the epider-
mis, and are chiefly distinguished from
PUCCINIA by the number of spores, 2 to 12,
which are formed on one basidium. P. bul-
bosum is common on bramble-leaves (see
UREDINEI).

BIBL. Berk. (Aregma), Brit. Flor. ii. pt.
2. p. 358; Grev. Sc. Crypt. Flor. pi. 15;
Tulasne, Ann. des Sc. not. 4 ser. ii. p. 180.
pi. 9; De Bary, Brandpilze, Berlin, 1853.
p. 49. pi. 4 ; Fries, Summa Veg. p. 507.

PHRAGMOTRICHACEI.— A family of
Coniomycetous Fungi, growing on bark of
trees, stems, or more or less dry herbaceous
stems and leaves. Their conceptacles are of
horny texture, and are little globular or
cup-shaped bodies, lined with filaments ter-
minating in simple or septate spores. [In
Excipula they are membranous.] The con-
ceptacles burst either by a longitudinal slit,
or by several radiating slits, or by a circular
slit which detaches a lid. In Excipula the
spores are extruded in a gelatinous mass,
but not in the other genera.

Synopsis of British Genera.

I. ENDOTRICHUM. Conceptacle innate
or immersed, bursting by a longitudinal slit ;
spores globular, simple.

II. SCHIZOTHECIUM. Conceptacle su-
perficial, bursting laterally by a longitudinal
slit; spores globular, simple.

III. PILIDIUM. Conceptacle simple,
sessile, rounded, bursting from the centre to
the margin in several teeth (by a stellate
fission) ; spores spindle-shaped, simple.

IV. EXCIPULA. Conceptacle cup-shaped,
membranous, sessile, naked ; spores spindle-
shaped.

V. DINEMASPORIUM. Conceptacle cup-
shaped, membranous, sessile, closed by villi,
and at length open ; sporigenous layer dis-
coid, dissolving, covered with cylindrical,
elongate, abruptly filiform spores.

VI. MYXORMIA. Conceptacle thin, cup-
shaped, open, formed of elongated cells.
Pedicels of the spores delicate. Spores ob-
long, chained together, at length free, in-
volved in mucus.

VII. CYSTOTRICHA. Conceptacle burst-
ing by a longitudinal slit ; pedicels of the
spores branched, articulated, somewhat
beaded, forming here and there oblong mul-
tiseptate spores.

VIII. PHRAGMOTRICHUM. Conceptacle
horny-carbonaceous, breaking out, closed at
first, subsequently splitting by a longitudinal

fissure; fertile filaments intermixed with
inarticulate paraphyses; spores compound
and chained in series.

PHRAGMOTRICHUM, Kze.— A genus
of Phragmotrichacei (Coniomycetous Fun-
gi). The plants form little tubercles burst-
ing out from beneath the epidermis, and
containing filaments arising from a softish
fibrous stroma. The filaments (basidia)
are interrupted at intervals with cellular
spores (fig. 573), which ultimately separate.

Fig. 571.

Fig. 573.

Fig. 572.

Phragmotrichum Chailletii.

Fig. 571. Scale of a spruce- fir cone, with pustules.

Half nat. size.

Fig. 572. A pustule magnified 10 diameters.
Fig. 573. Vertical section across a pustule, showing

the chains of spores. Magnified 100 diams.

P. Chailletii grows upon the scales of the
cones of Abies excelsa. Other species grow
on the poplar and maple.

BIBL. Fries, Syst. Myc. iii. p. 492, Summa
Veg. p. 474; Kunze, Myc. Heft 2. p. 84.
pi. 5. fig. 4.

PHTHIRIUS, Leach.— Agenus of Insects,
of the order Anoplura, and family Pediculida3.

Char. Legs of two kinds, anterior pair
formed for walking, posterior two pairs
formed for climbing ; thorax large, not di-
stinctly separated from the abdomen.

One species, P. inguinalis (Pediculus pu-
bis). Parasitic upon man. Length 1-10 to
1-20".

The ova are firmly fastened to the hairs
by a glutenous secretion ; they are urn-
shaped, and furnished with a lid.

BIBL. Denny, Anoplur. Monogr. p. 8 ;
Leach, Zool. Misc. iii. p. 65.

PHYCOMYCES, Kze.— A genus of Mu-
corini (Physomycetous Fungi), of which one
species, P. nitens, has been found in Britain

PHYLLOGONIACE.E.

[ 504 ]

PHYSCOMITRIUM.

growing on the walls of oil-cellars. It is an
olive-coloured mildew, distinguished from
Mucor chiefly by the absence of a columella,
the pyriform peridiole, and oblong spores ;
but the entire plants are much larger and
of more solid texture. The fertile filaments
of P. splendens, the only other known spe-
cies, are as thick as a horse-hair, and 3 to 4"
high.

BIBL. Fries, Syst. Myc. iii. p. 309, Summa
Veg. 488 ; Berk. Ann. Nat. Hist. vi. p. 433.

PHYLLOGONIACE.E. — A family of
Pleurocarpous Mosses, distinguished by the
peculiar character of the leaves and their
arrangement. The leaves are either inserted
horizontally or imbricated vertically, clasp-
ing, and are composed of very narrow linear
parenchymatous cells, appearing almost con-
fluent into a homogeneous membrane, auri-
cled at the base, with minute, parenchyma-
tous, thickened, alar cells arranged orbicu-
larly at the auricles, very smooth ; the leaves
stand in two opposite rows.

This family contains only the single small
exotic genus PHYLLOGONIUM.

PHYLLOPHORA, Grev.— A genus of
Cryptonemiaceae (Florideous Algae), consist-
ing of several species, with a red, rigidly
membranous, stalked, leaf-like, often dicho-
tomous thallus, the lobes of which are often
proliferous ; from a few inches to a foot long,
growing near low-water mark, or in the sea.
The fructification consists of — l.favellidia,
scattered over the thallus, containing minute
spores ; 2. antheridia, wart-like bodies com-
posed of radiating moniliform filaments
found on distinct plants from the spores;
and 3. tetraspores, collected into sori either
towards the apex of the thallus or on proper
lobes.

BIBL. Harvey, Brit. Mar. Alg. p. 142.
pi. ISA, Phyc. Brit. pi. 191, &c.; Greville,
Alg. Brit. pi. 15 ; Derbes and Solier, Ann.
des Sc.nat. 3 ser. xiv. p. 277. pi. 37; Thuret,
ibid. 4 ser. iii. p. 18.

PHYSACTIS, Kiitz.— A genus of Oscil-
latoriaceae (Confervoid Algae), nearly related
to Rivularia, perhaps improperly separated,
consisting of aquatic and marine plants,
growing on stones, &c., at first globose, and
afterwards vesicular and lobed by peri-
pheral growth, accompanied by gradual
decay of the originally solid centre. Under
this head are included —

1. P. (Rivularia) nitida. Deep olive-
green, tufted and lobed, gregarious ; fronds
from 1-12 to 1" in diameter. (R. bullata,
Berk.) Marine.

2. P. (Riv.) plicata. Diam. 1-12 to 1-2"
in diameter ; deep green. Marine.

3. P. (Riv.) pisum. Globose, dirty green,
1-12 to 1-2" in diameter. Aquatic.

BIBL. Kiitz. Sp. Alg. p. 332, Tab. Phyc.
Bd. i. pi. 58, &c. ; Hassall, Br. Fr. Alg.
p. 262; Harvey, Br. Mar. Alg. p. 222;
Berk. Gleanings, pi. 2. fig. 1.

PHYSARUM, Pers.— A genus of Myxo-
gastres (Gasteromycetous Fungi), containing
numerous species growing on rotten wood,
bark, leaves, &c. They are nearly related to
Didymium and Diderma, but have a simple
membranous peridium ; the filaments are
adnate to the peridium, but in some spores
they are very few, approaching to the condi-
tion of Licea. Some are sessile, others

Fig. 576. Fig. 574. Fig. 575.

Physarum bryophilum.

Fig. 574. Plants growing on a Plagiochila. Magn. 2
diams.

Fig. 575. A peridium burst. Magnified 25 diameters.

Fig. 576. Filaments and spores from the same. Mag-
nified 100 diameters.

stipitate (fig. 574) ; the clustered forms (P.
hyalinum and utriculatum) are removed to
Berkeley's genus BADHAMIA. P. album is
common.

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 314,
Ann. Nat. Hist. vi. p. 431, 2nd ser. xiii.
p. 159 ; Fries, System. Myc. iii. p. 127,
Summa Veg. p. 153 ; Greville, Sc. Crypt.
Fl. pi. 40. 310.

PHYSCOMITRIUM, Bridel.— A genus
of Funariaceae (Acrocarpous Mosses), inclu-
ding many Qymnostoma of other authors.
Physcomitrium pyriforme, Brid. = Gymno-
stomum pyriforme, Hedw. Ph. sphcericum
is remarkable as having been found only in
one year in one locality in Britain.

This species exhibits a pretty structure in
a vertical section of the immature capsule,
the mass of sporiferous tissue being sus-
pended freely in the middle by cellular
threads.

PHYSIOTIUM. [ 505 ] PILOBOLUS.

PHYSIOTIUM, Nees.— A genus of Jun-
germannieae (Hepaticacese), containing one
species, P. cochleariforme, a large plant,
growing in purple tufts 4 to 6" long, on
moors and among rocks in Ireland and the
Scotch highlands.

BIBL. Hook. Brit. Flor. ii. pt. 1. p. 119,
Br. Jung. p. 68, Engl. Bot. pi. 2500; Ekart,
Synops. Jung. pi. 5. fig. 40; Endlicher, Gen.
Plant. Suppl. 1. nos. 472-18.

PHYSOMYCETES.— An order of Fungi
composed of microscopic plants of very
simple organization, the mycelium being a
byssoid or flocculent mass, bearing simple
vesicular sporanges (peridiola), filled with
minute spores. The nature of the membra-
nous wall of the peridioles is not yet well
ascertained in all the genera, some authors
describing it as merely a veil, others as a
perfect sac formed by the expansion of the
terminal cell of the filament, which is cer-
tainly true in Mucor. According to our own
observations, the spores are formed by free-
cell-formation in the peridiole which ulti-
mately bursts to discharge the spores.

The distinction between the two families
seems to depend chiefly on the conditions of
the peridioles.

In the Antennariei, where they are firmer,
they are sessile on radiating flocci, which
sometimes send processes which grow up
and surround them, or they are attached
to the sides of erect filaments; these fila-
ments form whitish or greyish patches, on
the leaves of trees and herbs, bearing a close
external resemblance to Erysiphe.

The Mucorini are moulds growing on de-
caying organic matter, the mycelium consti-
tuting flocks floating in liquids or overgrow-
ing damp substances, while the delicate spore-
sacs or peridioles are borne at the apices of
erect stalk-like, and often extremely branched
filaments. The genus Sizygites exhibits a
remarkable peculiarity, according to Ehren-
berg, for he states that each spore-sac is
formed by means of the conjugation of two
branches of the ramified fructification (see
SIZYGITES).

Recent observations on some of the plants
of this order seem to indicate that, as in
most of the divisions of this class, much
remains to be cleared up concerning the
relations of the forms. See on this subject
the article EUROTIUM, which genus, accord-
ing to De Bary's researches, seems to be
associated as merely one form of fructification,
with ASPERGILLUS, upon the same myce-
lium.

Synopsis of the Families.

1. ANTENNARIEI. Mycelium filament-
ous, radiating, or erect, bearing sessile, glo-
bular, membranous sacs (peridioles), filled
with ovate spores, discharged by the rupture
of the sac at its apex.

2. MUCORINI. Mycelium filamentous,
vague, giving off erect, simple or branched
filaments terminating in vesicular cells (peri-
dioles) filled with minute spores; often with
a central column in the interior.

BIBL. See the genera.

PHYTELEPHAS, R. and P.— The ge-
neric name of the Palm yielding the VEGE-
TABLE IVORY nut.

PHYTOCRENE, Wallich.— An Artocar-
paceous tree with wood, of very remarkable
structure. See WOOD.

PIGGOTIA, Berk, and Broome. — A
genus of Spheeronemei (Coniomycetous
Fungi), or perhaps the conidiferous form of
Dothidea. P. astroidea occurs on the green
leaves of the elm, forming irregular, round-
ish, granulated or wrinkled jet-black patches
(sometimes with a yellow border), on the
upper surface of the leaf. Perithecia soon
confluent, bursting by a lacerated fissure.

BIBL. Berk, and Br. Ann. Nat. Hist.
ser. 2. vii. p. 95. pi. 5. fig. 1.

PIGMENT. See INTRODUCTION, p.xxix.

PILACRE, Fr.— A genus of Trichogas-
tres (Gasteromycetous Fungi).

BIBL. Berk, and Br. Ann. Nat. Hist.
2nd ser. v. p. 365. pi. 11.

PILOBOLUS, Tode.— A genus of Mu-
corini (Physomycetous Fungi), consisting of
little moulds growing upon dung; bearing
some resemblance in their structure to
Botrydium among the Algae. The plants have
a stoloniferous creeping mycelium, from
which arise fertile pedicels, each cut off from
the mycelium by a septum ; the upper part
of the pedicel expands into the vesicle, which
also becomes shut off by a septum ; in the
vesicle or peridiole spores are next developed
by free cell-formation, and at the same time
the septum becomes pushed up into its
interior (as in MUCOR) to form a columella,,
which ultimately causes the vesicular peri-
diole to split off by a circumscissile dehis-
cence just above the septum ; it is thrown
off with elasticity, enclosing the spores. The
development of P. crystallinus has been
studied by Cohn. He finds the germinating
spore to produce a creeping unicellular
mycelial portion, and next a fruit-pedicel,
which soon has the peridiole separated by a

PILOTRICHUM.

[ 506 ]

PILULARIA.

septum; thus, in its simplest form, this plant
consists of only three cells ; subsequently it
becomes complex by the root-cell or myce-
lium producing numerous stolons. P. cry-
stallinus is yellowish at first, the peridiole
finally black. P. roridus, Bolt., a doubtful
form, is smaller and more slender than the
last, having an elongated filiform stem.

BIBL. Berk. Brit. Fl. ii. pt. 2. p. 231 ;
Fries, Summa Veg. p. 487 ; Cohn, Nova
Acta, xxiii. p. 492.

PILOTRICHUM, Pal. de Beauv. — A
genus of Hypnoid Mosses, including some
Fontinales of authors.

1. Pilotrichum antipyreticum, C. Miill.=
Fontinalis antipyretica, L.

2. P. squamosum, C. Miill,=jP. squamosa,
L.

3. P. ciliatum, C. Mull. = Ancectangium
ciliatum, Brid., var.y. striatum= A. ciliatum,
Wilson.

4. P. heteromallum, P. B.=Daltonia he-
teromalla, H. and T.

PILULARIA, L.— A genus of Marsile-
aceous Plants, containing the only British
representative of the order P. globulifera
(fig. 579). This is an inconspicuous plant
growing in mud at the edges of or in pools,
having a filiform creeping stem, bearing
erect filiform green leaves and delicate adven-
titious roots, and producing shortly-stalked
globular spore-fruits, about the size of a
peppercorn. The anatomical structure of
the stem and leaves is simple; they are
clothed with an epidermis possessing sto-
mates, and a cross-section both of the stem and
the leaves exhibits a central vascular bundle
(of spiral vessels), surrounded by a sheath
of brownish cells, while in the delicate cel-
lular tissue intervening between the central
bundle and the epidermis stands a circle of
air-passages, separated from each other by
simple radiating cellular septa.

Fig. 577.

Fig. 578.

Pilularia globulifera.

Fig. 577. A vertical section of a spore-fruit. Magni-
fied 5 diameters.

Fig. 578. Transverse section of a spore-fruit. Magni-
fied 5 diameters.

The spore-fruits are hollow cases with an

outer tough cellular coat, and an inner more
delicate coat dipping in at four perpendicular
lines, as far as the centre, so as to form dis-
sepiments dividing the first into four
chambers (figs. 5/7, 578) ; up the centre of
the outer wall of each chamber runs a raised
ridge (a kind of placenta), whence arise the
sporanges or thecce (fig. 5/8). These are
pear-shaped sacs composed of a very delicate
cellular membrane. Those in the upper
part of each chamber contain a number of
minute globular bodies, resembling pollen-
grains, immersed in a gelatinous liquid. The
sacs in the lower part of the chamber contain
only one body or spore, but this of very
peculiar form; it nearly fills the theca, is
somewhat oval in form, and possesses several
coats.

The development of the spores, as de-
scribed by Valentine, is very curious ; the
small spores are developed in the usual way,
by the formation of parent-cells in the
theca, which parent- cells subsequently each
produce four spores. In the thecae which
have the single large spore, a number of
parent-cells are originally produced, and these
become divided into four chambers by septa,
but then all but one of these decay. This
produces four spores, but out of these four
only one attains to perfect development, the
rest being subsequently dissolved and ab-
sorbed to make room for the solitary large
spore. This reminds us in some degree of
the numerous germs formed in the Gymno-
sperms (OVULE), and subsequently absorbed.
The two kinds of spore in Pilularia corre-
spond to the two forms in S EL A GIN ELL A
and ISOETES, and to the pollen arid ovules
of the Flowering Plants. They are set free
by the dehiscence of the spore-fruit, and lie
at first imbedded in the jelly poured out by
the thecae.

In this state the small spores exactly
resemble pollen-grains, having an outer
granular, and an inner delicately membra-
nous coat ; the outer coat presenting ridges
corresponding to the points of contact in the
parent-cell. When set free, the spores soon
burst at these ridges, and the inner coat is
slightly protruded; this next bursts and dis-
charges a number of lenticular cellules, from
each of which escapes a ciliated spiral sper-
matozoid.

The mature large spores (fig. 580) are of
oval form, and have a thick, outer gelati-
nous coat composed of prismatic cells stand-
ing perpendicularly on an inner glassy coat;
the gelatinous coat is perforated at the

PILULARIA.

[ 507 ]

PINNULARIA.

summit by a funnel-shaped opening through
which protrudes a pyramidal elevation of the
second glassy coat; the last is lined by a
delicate internal coat, containing protoplasm,

Fig. 579.

starch, oil- globules, &c. Soon after the
expulsion of the spore, cell-formation takes
place inside the pyramidal protrusion of the
outer coat, from the cell-contents of the spore.

Fig. 580. Fig. 583.

Fig. 581.

Fig. 582.

Pilularia globulifera.
Fig. 579. Natural size.

Fig. 580. An ovule-spore. Magnified 25 diameters.
Figs. 581 & 582. The same in germination. Magnified 25 diameters.
Fig. 583. Germinating spore more advanced. Magnified 10 diameters.

The glassy coat next splits at this point into
four teeth, and exposes the cellular structure
(prothallium), which increases in size, and
acquires a green colour. An archegonium
is next formed on this, consisting of a cell
(embryo-sac) lying in the substance at the
apex, with a canal bordered by four papillose
cells leading to it. A spermatozoid fertilizes
the free embryo-cell contained in the arche-
gonium, and this becomes developed into a
new plant, within the substance of the pro-
thallium (fig. 582), sending out a leaf on
one side and an adventitious root on the
other, tangentally to the surface of the spore.
In this stage (fig. 583) the young plant,
with the remains of the spore, somewhat
resembles a germinating Monocotyledonous
seed. Finally, as the young plant increases
in size, the remnants of the spore-coat are
thrown off.

BIBL. G. W. Bischoff, Krypt. Gewachse,
Rhizocarpeen, Nuremberg, 1828. pi. 8; Va-
lentine, Linnean Trans, xvii. ; Schleiden,
Grundzuge, 3 ed. ii. p. 104 (Principles,
p. 203); Nageli, Zeitschr.f. Wiss. Botanik.

heft iii. & iv. p. 188 ( Ann. des Sc. nat. 3 ser.
ix. p. 99) ; Hofmeister, Vergleichend. Un-
tersuch. Leipsic, 1851. p. 103. pis. 21, 22;
Mettenius, Eeitr. z. Kenntn. des Rhizocarp.
Frankfort, 1846 ; Henfrey, Ann. Nat. Hist.
2 ser. ix. p. 447, Trans. Brit. Assoc. 1851.
p. 116.

PINE-APPLE. See BROMELIACE.E.

PINNULARIA, Ehr.— A genus of Dia-
tomacea3.

Char. Frustules single, free, longer than
broad ; front view linear or oblong ; valves
navicular, elliptical, lanceolate or oblong
(side view), with a median line and a nodule at
the centre and at each end, surface exhibit-
ing transverse or slightly radiating striae or
furrows.

This genus differs from Navicula in
the stria3 not being resolvable into dots.
They are mostly distinct under ordinary
illumination. In some of the species they
are absent in the middle, leaving a transverse
clear space or band, resembling in appear-
ance the stauros of Stauroneis.

Twenty-four British species (Smith).

PINUS.

[ 508 ] PITTED STRUCTURES.

P. nobilis (PI. 11. fig. 1, side view).
Valves linear, dilated in the middle and at
the rounded ends ; striae coarse. Aquatic
and fossil; length 1-100 to 1-70".

P. viridis (PI. 11. fig. 2, side view).
Valves elliptical, somewhat turgid, ends
obtuse. Aquatic; length 1-500 to 1-220".
Common.

/3. Striae parallel, absent from a transverse
band.

P. oblonga (PI. 11. fig. 3, side view).
Valves linear- oblong, ends rounded. Aquatic
and fossil; length 1-120". Common.

P. radiosa (PL 11. fig. 4, side view; fig. 5,
front view). Valves lanceolate, ends some-
what obtuse. Aquatic ; length 1-500".
Common.

BIBL. Smith, Brit. Diatom, i. p. 54.

PINUS, L.— A genus of Coniferae (Gym-
uospermous Flowering plants), presenting
many interesting points of structure. The
most familiar example is the Scotch Fir (P.
Abies), but a great number of other species
are cultivated in this country. For the mi-
croscope they yield instructive objects in
the wood (PI. 39. fig. 1), composed of pecu-
liarly pitted vessels (see CONIFERAE) and tra-
versed by turpentine reservoirs, in the BARK,
which has a kind of false cork, in the deve-
lopment of the Gymnospermous OVULES,
and in the structure of the PoLLEN-grains.

The wood of species of the genus Pinus
frequently occurs in a fossil condition, both
in coal and silicified (PI. 19. figs. 29-33).

BIBL. See the articles above cited.

PISOMYXA, Corda (Bryocladium, Kze.).
— A genus of Antennarei (Physornycetous

Fig. 584.

Pisomyxa racodioides.
Magnified 200 diameters .

Fungi), growing upon leaves. Not British,
as stated under the family.

BIBL. Fries, Summa Veg. p. 406 j Corda,
Icones Fung. i. pi. 6. fig. 292.

PITH. See MEDULLA.

PITTED STRUCTURES, OF PLANTS.
— The secondary deposits of cellulose which
form the layers of thickening of the walls of

vegetable cells are seldom uniform or homo-
geneous in character. In most, if not in all
cases, some special microscopic structure
may be distinguished, either by mere inspec-
tion or on the application of reagents.
These layers, spoken of more particularly as
to their nature under SECONDARY DEPO-
SITS, may be divided into two classes, com-
prehending pretty accurately all the varied
conditions, namely, the Spiral deposits,
where the secondary layers assume the
aspect of fibres applied upon the inside of
the cell- wall ; and Pitted, or as they are often
termed, Porous deposits, where layers are
applied over the whole internal surface of
the cell, which layers present orifices of dif-
ferent characters, leaving the primary mem-
brane bare, and forming in this way a pit as
viewed from the inside of the cell. When
the secondary layers are comparatively thin,
their presence is often overlooked, and the
pits have thus often been mistaken for ori-
fices or pores (figs. 585, 586) in the primary

Fig. 585.

Fig. 586.

Pitted cells of elder pith.
Magnified 250 diameters.

membrane ; but such pores are never origi-
nally present ; the closure of the pit by the
layer of primary membrane may always be
demonstrated in young structures ; and when
orifices really do occur in cell-walls, these
arise from the absorption of the primary
cell-membrane converting the pit into a
pore. The best way of demonstrating that
young spotted cell-walls are only pitted and
not perforated, is to apply sulphuric acid
and iodine for the production of the blue
colour in the primary cell-wall.

Simple pits, of no great depth, occur on
the slightly thickened walls of most perma-
nent parenchymatous cells; they may be
seen in the cells of herbaceous stems, in
pith, bark, in the cells of the parenchyma of
leaves, &c. (figs. 585, 586. PI. 38. fig. 14).

In most prosenchymatous wood-cells, or
liber-cells, and in the woody cells of the
stones or shells of fruits and seeds, the pits
are far more clearly evident, and become
more and more distinct (PI. 39. fig. 3) as
the layers of thickening increase in number,
since by the successive application of these,

PITTED STRUCTURES. [ 509 ] PITTED STRUCTURES.

the pits are deepened (with the contraction
of the cavity of the cell) until they become
canals or tubular passages radiating from
the central cavity (PI. 38. fig. 23). In these
cases it is evidently seen that the pits of ad-
jacent cells and ducts correspond to each
other at their outer extremity ; and in old
tissues, when the primary cell-walls have been
absorbed, these coincident pits form tubular
canals leading from one cell to another. It
has been observed that two or more pits
sometimes become confluent in the later in-
ternal deposits, so that the internally simple
orifice leads out to several branches corre-
sponding to the original pits on the wall of
the cell. In rare cases, simple pits occur
on the outer walls of epidermal cells, as in
Cycas (PL 38. fig. 28).

Pits of the above kinds occur on the
structures called ducts (see TISSUES, VEGE-
TABLE), formed of cells applied end to
end and confluent (fig. 184, page 216).
These large pitted tubes, which occur abun-
dantly in most woods, with the excep-
tion of that of the Coniferae, are sometimes
termed bothrenckyma, signifying pitted tis-
sue ; but the character not being exclusively
applicable to them, the name is bad.

In many pitted ducts, and in the pitted

Fig. 587.

Fig. 588.

'.-,:

Fig. 587. Pitted ducts of Clematis. Magn. 100 diam.

Fig. 588. Side wall of a cell of Pine, with bordered

pits. Magnified 200 diameters.

wood-cells of many plants, especially of the

Coniferae, the pits present a greater degree
of complication. The markings on the walls
of the wood-cells of most of the Coniferae,
for example, consist of pits surrounded by a
broad rim (fig. 588. PL 39. figs. 1.4. 5); the

Fig. 589.

... r.m

c.i

Section of Pine wood at right angles to the pitted walls.
p. /, walls of a pitted cell ; c.f, cavity of a cell ; c. I, len-
ticular cavity between two adjacent pits ; r. m, cells of a
medullary ray ; the pits have no rim here.

Magnified 400 diameters.

portion within the rim projects somewhat
into the cavity of the cell, and appears like
a lenticular body attached on the wall ; hence
the markings "were formerly termed the
" glands" of Coniferous wood. In reality,
however, while the pits themselves resemble
ordinary pits, the broad rim, or rather the
circular line outside the pit, depends on a
condition of the cell-wall outside the mem-
brane, and is merely the outline of a lenti-
cular cavity existing between two adjacent
cells, the boundary of which is visible through
the wall on account of the transparency of
the latter : the nature of this structure is
very evident in sections made at right angles
to those which show the bordered pits in
face (fig. 589. PL 39. fig. 1 b). In most of
the Coniferae the wood is exclusively com-
posed of large elongated prosenchymatous
cells, with bordered pits of this character on
the side-walls, that is, on the wall standing
radially or perpendicular to the bark ; the

PITTED STRUCTURES.

[ 510 ]

PITTED STRUCTURES.

pits, however, which lie on parts of the
wall adjoining the cells of medullary rays,
are generally devoid of the rim.

Similar bordered pits occur very generally
on the walls of the pitted ducts of Dicotyle-
dons ; but as the wood is here of mixed com-
position, and the ducts adjoin cells as well as
other ducts, independently of the medullary
rays, we often find a greater variety of con-
ditions on the wall of the same duct, which
may have bordered pits when adjoining an-
other duct, and simple pits, or pits with a
double outline, when adjoining cells. The
pits with a double outline (PL 39. figs. 15 b,
& 20) are of different nature from the bor-
dered pits (PL 39. figs. 13, 14, 15 a, 16, 18),
the double outline depending simply on the
fact that the later or more internal layers of
thickening do not reach the edge of the ori-
fice in the earlier secondary deposits, so that
the pit is conical, or rather, has sloping
edges, the circumference at the primary
membrane being rather less than that of the
margin next the cell cavity. A peculiar
modification of this unequal mode of deposit
is seen in company with the true rim or
border in many cases (PL 39. figs. 14. 16.
18), where the central spot or original pit
appears in the middle of a slit running across
the circle indicating the border; this slit
indicates the alteration of the shape of the
gap in the secondary deposits in the success-
ive layers, and corresponds to the inner
margin of the pit, where this has the form of
an elongated groove or slit, gradually dimi-
nishing to a small round hole towards the
primary cell-membrane (PL 39. fig. 18 o).
Sometimes (PL 39. fig. 18 a, b) the two or
more slits formed in this way on contiguous
pits become confluent. The last condition
indicates a transition to the more sparing
form of the secondary deposit where it ap-
pears as a modification of a spiral fibre or
fibres ; and the later secondary deposits of
pitted ducts do sometimes actually assume
this form, and produce a spiral fibrous layer
of thickening inside the layers perforated by
pits. This is the case in TAX us (PL 39.
fig. 4), in the Lime (PL 39. fig. 13), and
Mezereon (PL 39. fig. 19 b}, &c.

For the guidance of microscopic observers
we mav furnish a series of examples in addi-
tion to" the CONIFERS (PL 39. figs. 1. 4. 5)
of different kinds of marking on pitted ducts.

A. Forms where there is no spiral-fibrous
secondary deposit.

a. Ducts with bordered pits uniformly

distributed, without reference to adjacent
structures : Eleaanus acuminatus, Clematis
Vitalba (PL 39. fig. 18).

b. Ducts where the bordered pits are
fewer on the walls adjoining cells : Acacia
lophantha, Sophorajaponica.

c. Ducts with bordered pits where adjoin-
ing ducts, while the walls adjoining wood-
cells have few or no bordered pits, and
those next the medullary rays have pits
without a border : elder, beech, hazel, pop-
lar, alder, plane, apple, &c.

d. Ducts with bordered pits where adjoin-
ing ducts, but with large pits devoid of a
border where adjoining cells : Cassyta gla-
bella (PL 39. fig. 14), Eombax pentandra
(PL 39. fig. 15).

e. Ducts presenting a modification of the
last, where the bordered pits have the form
of slits as wide as the ducts when adjoining
ducts, while the walls adjoining cells have
large pits without a border : Chilianthus
arboreus (PL 39. fig. 17), the vine (in a less
striking manner). Eryngium maritimum
(PL 39. fig. 21) exhibits a condition ap-
proaching this.

B. Forms where a spiral-fibrous structure is
added after the pits.

f. All the ducts with bordered pits, but
the larger ducts with smooth walls, the
smaller with a spiral fibre : ClematisVitalba,
Ulmus campestris, Morus alba.

g. All the ducts closely pitted, with slen-
der fibres between the rows of pits : Hakea
oleifolia.

h. The larger ducts with pits, the smaller
without ; both kinds with spiral fibres on the
internal surface : Daphne Mezereum (PL 39.
fig. 19), Passerina filiformis, Genista cana-
riensis.

i. The walls adjacent to other ducts pitted,
those next cells with very distant pits, or
devoid of them ; all the walls with fibres :
the lime, horse-chestnut, sycamore, cornel,
holly, hawthorn, Prunus Padus, virainiana,
&c.

The last set of forms allies these struc-
tures to those characterized peculiarly by
the SPIRAL-FIBROUS structures, and, as
will be indicated there and under SECOND-
ARY DEPOSITS, the smooth layers of thick-
ening, such as those between the pits of
Pinus, may be made to show a spiral struc-
ture by the action of reagents.

For the micro-chemical conditions of these
objects, their development, and relations,

PLAGIOCHILA.

[ 511 ]

PLATINUM,

see SECONDARY DEPOSITS, TISSUES, Ve-
getable, and CELLS, Vegetable.

BIBL. Works on Structural Botany;
Mohl, Vegetable Cell, London, 1852. p. 10,
and Vermischte Schrift. Tubingen, 1845.
pp. 268. 272 (Linncea, xvi. p. 1. 1842),
transl. in Ann. Nat. Hist. ix. p. 393, Abh.
d. Acad. zu Munchen, i. 445, and the EM.
of SPIRAL STRUCTURES.

PLAGIOCHILA, Nees and Montagne.—
A genus of Jungermannieae (Hepaticaceae),
containing a number of British species, viz.
P. (Jungermannia, Hook.) asplenoides,
spinulosa, decipiens, resupinata, undulata,
planifolia, nemorosa, and umbrosa, some of
which, especially P. asplenoides (fig. 590),

Fig. 590.

Plagiochila asplenoides.
Magnified 2 diameters.

are among the most frequent and finest
plants of the family, its stems growing from
3 to 5" long.

BIBL. Hook. Brit. Flor. ii. pt. 1. p. Ill,
&c., Brit. Jung. pi. 13, 14, &c.; Ekary Sy-
nops. Jung. p. 6 et seq. pi. 1, &c.; Endlicher,
Gen. Plant. Supp. 1. No. 473-1.

PLANARIA, Miill.— A genus of Annu-
lata, of the order Turbellaria, and family
Planarieae.

Char. Body soft, flattened, oblong or oval,
not jointed, covered with vibratile cilia;
neither suckers, bristles, nor leg-like ap-
pendages present.

Some parts of the structure of these ani-
mals have been noticed under ANNULATA
in speaking of the Turbellaria. The mouth
is situated on the under surface of the mid-
dle of the body, at the end of a retractile
proboscis ; there is no anus ; the mouth
leads to a capacious stomach, giving off den-
dritically branched caeca, somewhat as in one

joint of a Tania (PI. 16. fig. 14). Their
motion is continuous and gliding upon wa-
ter plants, or the sides of glass jars. The
anterior part of the body exhibits a curved
row or a single pair of eyes, and sometimes
ear-like projections. They multiply by divi-
sion, and the formation of ova, which are
enclosed in a coloured capsule.

Some of the species are very common in
pools, and resemble, at first sight, minute
leeches. P. nigra, which is black, has a row
of marginal anterior eyes, and two lateral and
one mesial projections; length about 1-2".
P. brunnea, dusky-brown, with a dark me-
sial line ; eyes as above ; length rather less.
P. lactea, cream-coloured, tinged with pale
reddish brown, truncate in front, with two
slight lateral auricles ; eyes two or four ;
length 1-2 to 3-4". P. torva, grey or black;
obtuse in front, angles rounded, centre pro-
jecting; eyes two, with a white halo ; length
1-2". Of the other species some are marine.

BIBL. Johnston, Non-parasitical Worms;
Duges, Ann. des Sc. nat. 2 ser. xv. and xxi. ;
(Ersted, System. Eintheil. d. Plattwiirmer;
Diesing, Syst. Helminth.; Dalyell, Powers of
Creation, ii. ; Schultz, Naturg. Turbell.

PLANARIOLA, Duj.— A genus of Infu-
soria.

Char. Body lamelliform, oblong, variously
sinuous and folded at the margin, convex
and glabrous above, concave and ciliated
beneath.

This genus is placed among the unsym-
metrical Infusoria, and has been provision-
ally founded to contain animals much
resembling Planariee in aspect and consist-
ence, but without a mouth or any other
external orifice, and only ciliated on the
under surface.

P. rubra (PL 24. fig. 65). Red, granular,
narrowed behind, enlarged in front, and with
two ear-like folds. Aquatic, in decomposing
vegetable matter ; length 1-250".

BIBL. Dujardin, Infus. p. 568.

PLANTAIN. See MUSA.

PLANULINA. See FORAMINIFERA
(p. 271).

PLATINUM.— The sodio-chloride of pla-
tinum crystallizes in prisms and plates which
polarize light ; while the potassio-chloride
of platinum yields several forms, which do
not polarize light. This reaction of the
soda-salt has been been proposed as a means
of distinguishing soda from potash, or de-
tecting minute quantities of the former.

BIBL. Andrews, Chem. Gaz. 1852. x.
378.

PLATYGRAMMA.

PLEUROXUS.

PLATYGRAMMA, Meyer.— A genus of
Graphideae (Gymnocarpous Lichens), con-
taining two British species.

BIBL. Leighton, Ann. Nat. Hist. 2 ser.
xiii. p. 393.

PLATYZOMA, R. Brown.— A genus of
Gleichenaeous Ferns. Exotic.

PLEOPELTIS, Humb. and Bonpl.— An
exotic genus of Polypeae, remarkable for the

Fig. 591.

Fig. 592.

Pleopeltis nuda.

Fig. 591. A sorus seen from above.

Fig. 592. Vertical section of ditto.

Magnified 25 diameters.

presence of peculiarly formed so-called para-
physes in the sori. These bodies are peltate,
or like minute flat mushrooms or umbrellas
expanded over and sheltering the sporanges
(figs. 591, 592).

PLEUROCOCCUS, Menegh.— A form
of Protococcus.

PLEURODESMIUM, Kg.— A genus of
Diatomaceae, allied to Striatella, but the
characters given are very obscure. Marine.
Africa.

BIBL. Kiitzing, Bot. Zeit. 1846. p. 248;
Sp.Alg.p. 115.

PLEUROGRAMMA, Presl.— A genus of
Taenitideae (Polypodaeous Ferns). Exotic.

PLEURONEMA, Duj.— A genus of In-
fusoria, of the family Paramecina.

Char. Body oblong- oval, depressed, with
a broad lateral orifice, from which a bundle
of long, curved, floating and contractile
ciliary filaments issues.

P. chrysalis (crassa], D. = Paramecium
chrysalis, E. (PI. 24. fig. 66). Aquatic.

P. marina, D. Has the body somewhat

narrower than the last, and is pointed in
front. Marine.

BIBL. Dujardin, In/us, p. 473.

PLEUROPYXIS, Corda.— A genus of
Antennarei (Physomycetous Fungi), growing

Fig. 593.

Plcuropyxis microsperma.
Magnified 200 diameters.

upon leaves and stems. This and PISOMYX A
are stated by mistake, under ANTENNAREI,
to be British (fig. 593).

BIBL. Corda, Icon. Fung. pi. 6. fig. 291.

PLEUROSIGMA, Smith. See GYRO-

SIGMA.

PLEUROTROCHA, Ehr.— A genus of
Rotatoria, of the family Hydatinaea.

Char. Eyes none ; a single tooth in each
jaw : foot forked (=zHydatina with uniden-
tate jaws).

P. gibba (PI. 35. fig. 18). Body ovate-
oblong, truncate in front; toes small, turgid.
Aquatic ; length 1-216".

Other species.

BIBL. Ehrenberg, In/us, p. 418; Gosse,
Ann. Nat. Hist. 1851. viii. 199.

PLEUROXUS, Baird.— A genus of En-
tomostraca, of the order Cladocera, and
family Lynceidae.

Char. Anterior part of shell prominent
above, obliquely truncate below ; first pair
of legs very large ; beak sharp, curved
downwards. Aquatic.

P. trigonellus (PI. 14. fig. 32). Beak
long, sharp-pointed, slightly curved down-
wards ; inferior antennae short and slender,
anterior branch with four setae, one from the
first joint, one from the second, and two
from the last ; posterior branch with three
setae all arising from the last joint.

P. uncinatus. Beak curved upwards at
the end ; three sharp spines at the anterior
inferior angle of the shell ; inferior antennae
as the last.

P. hamatus. Beak blunt and strong,
slightly curved downwards; first pair of legs

PLOCAMIUM.

[ 513 ]

PODODISCUS.

?Male of

with a curved claw at the end.
of P. trigonellus.

BIBL. Baird, Brit. Entomostr. p. 134.
PLOCAMIUM, Lamouroux.— A genus
of Delesseriaceae (Florideous Algae), contain-
ing one species, P. coccineum, the common-
est of our red sea- weeds, with delicate flat
feathery thallus, from 2 to 12" high, growing
in bushy tufts on rocks or other Algae. The
fruit consists of — 1. Coccidia, spherical,
stalked or sessile tubercles, at the sides or
in the axils of the ramules, filled with
angular spores; 2. antheridia, which occur
in inconspicuous flat patches, composed of
short erect cells, upon the surface of distinct
plants ; and 3. stichidia, lateral or axillary,
simple or branched pods containing a single
or double row of linear (transversely parted)
tetraspores.

BIBL. Harvey, Br. Mar. Alg. p. 19.
pi. 15 C; Phyc. Brit. pi. 44; Greville, Alg.
Brit. pi. 12; Thuret, Ann. des Sc. nat.
4 ser. iii. p. 19.

PLCEOTIA, Duj.— A genus of Infusoria,
belonging to the family Thecamonadina.

Char. Body diaphanous, with several
longitudinal ribs or keels projecting in the
middle, and a rounded perfectly limpid
margin. Two anterior locomotive filaments,
one flagelliform, the other trailing.

P. vitrea (PL 24. fig. 67). Body hyaline,
with three or four projectinglongitudinal lines
in the middle, and some internal granules.
Marine ; length 1-1200". Movement slow.
BIBL. Dujardin, Infus. p. 345.
PLGESCONIA, Duj. (Infusoria) = Eu-
plotes, Ehr.

PLQESCONINA, Duj. (INFUSORIA).—
This family consists of the family Euplota,E.,
united with the genus Loxodes, E.
BIBL. Dujardin, Infus. p. 428.
PLUMATELLA, Lam. — A genus of
Polypi, of the order Bryozoa.

Char. Polypidom fixed, coriaceous or
membranous, confervoid, tubular, branched;
polypes issuing from the ends of the
branches ; tentacular disc crescentic ; ten-
tacles numerous (about sixty), in a single
row, invested at their origin by a membrane.
Aquatic. Doubtfully distinct from Alcy-
onella.

P. repens. Polypidom adherent, the erect
branches tubular, margins of apertures en-
tire. Stem several inches long.

P. emarginata. Apertures with a deep
notch filled up by a transparent membrane.
P.fruticosa. Branches suddenly dilated
towards the entire apertures.

BIBL. Johnston, Brit. Zooph. p. 402;
Allman, Ann. Nat. Hist. 1844. xiii. 330.

PODAXINEL— A family of Gasteromy-
cetous Fungi, none of which are found in
Britain ; they are distinguished from all
allied tribes by a solid column in the centre
of the sporange.

BIBL. Montagne, Ann. des Sc. nat. 2 ser.
xx. 69 ; Tulasne, Ann. des Sc. nat. 3 ser. iv.
169; Montagne, translated in Ann. Nat.
Hist. vol. ix.

PODISOMA, Link.— A genus of Cseo-
macei (Coniomycetous Fungi), growing upon

Fig. 594.

Fig. 595.

Podisoma Juniperi.

Fig. 594. Branch of Juniper with clavate fructification
protruded from beneath the bark. Nat. size.

Fig. 595. Vertical section through a fruit, showing
the filaments terminating in bilocular spores. Magnified
50 diameters.

the living leaves and branches of species of
Juniper; the filamentous mycelium creep-
ing beneath the epidermis, and sending up a
fleshy, stalk-like, tremelloid body (fig. 594),
composed of agglutinated filaments (fig.
595), terminating in bilocular spores (or two
spores adherent together), each of the cells
having two or four pores, through which
the internal membrane is protruded in ger-
mination. See UREDO.

Four species are described as British, P.
Juniperi-communis, P. Juniperi-Sabinte, P.
foliicolium (on the leaves of J. communis),
and P.fuscum ; the last occurring upon Pinus
halepensis and J. Oxycedrus.

BIBL. Berk.Br«V.F/or.ii.pt.2.p.362; Ann.
Nat. Hist. ser. 2. iii. 520; Tulasne, Ann. des
Sc. nat. 3 ser. xix. p. 205, 4 ser. ii. p. 186.
pi. 10; Fries, Summa Veg. 474.

PODOCYSTIS, Lev.=Melampsora. See
UREDO.

PODODISCUS, Kg.— A genus of Diato-
maceae.

Char. Frustules single or concatenate,
with a marginal stalk ; valves circular, con-
vex. Marine.

2L

PODOPHRYA.

[ 514 ]

POLARIZATION.

No markings visible under ordinary illu-
mination.

P. jamaicensis (PL 13. fig. 16). Stalk
elongate, weak. Diameter 1-840".

BIBL. Kiitzing, Bacill. p. 51 ; Sp. Alg.
p. 26.

PODOPHRYA, Ehr.— A genus of Infu-
soria, of the family Acinetina.

P.fixa (PI. 23. fig. 5) is noticed under
Actinophrys pedicellata (p. 12).

It is doubtful whether this is a distinct
organism, or whether it is not a stage of
metamorphosis of Vorticella. Compare PI.
25. fig. 33.

EIBL. Ehrenberg, In/us, p. 305; Dujardin,
In/us, p. 266 ; Stein, Infus., passim.

PODOSIRA, Ehr.— A genus of Diato-
maceae.

Char. Frustules concatenate, with a lateral
stalk ; valves circular, convex. Marine.

No markings visible by ordinary illumina-
tion. Stalk attached to the centre of the
valves.

P. hormoides (PI. 14. fig. 34). Frustules
depressed-spheroidal, connected by isthmi
(stalks). Diameter 1-650".

P. Montagnei (Melosira globifera, Ralfs).
Frustules elliptical in front view (circular,
R.), connected by short isthmi. Diameter
1-600".

BIBL. Kutzing, Sp. Alg. p. 26.

PODOSPHENIA, Ehr.— A genus of
Diatomaceae.

Char. Frustules attached, sessile, wedge-
shaped in front view ; ends indented so as
to produce a black line (vitta) in the front
view ; valves convex, obovate, with a longi-
tudinal median line and transverse striae, but
no nodules. Marine.

The striae consist of rows of dots, some-
times distinct by ordinary illumination, at
others not so.

P. Ehrenbergii (PI. 13. fig. 17). Frustules
in front view, truncate at the end ; valves
somewhat acute at the ends. Length
1-240".

P. Lyngbyei. Frustules in front view,
truncate at the end ; valves rounded at the
free end. Length 1-350".

Three other British species.

BIBL. Smith, Brit. Diat. i. p. 82 ;
Kiitzing, Bacill p. 119; Sp. Alg. p. 110.

PODOSPORIUM, Lev. = Melampsora.
See UREDO.

PODURA, L .— A genus of Insects, of the
order Thysanura, and family Podurellse.

This genus has been greatly subdivided.
In its extended signification, the characters

consist in the thorax being distinct from the
Fig. 596.

Podura.
Magnified about 15 diameters.

abdomen, and in the presence of a forked
tail, bent under the abdomen when not in
use, and enabling the animals to move by
springing or jumping, whence the common
name of spring-tails applied to them.

They are of a leaden appearance, and
found in shady damp places, as under flower-
pots or stones, in cellars, &c., and are about
1-20 to 1-10" in length. They may be
caught by placing a little flour upon a piece
of paper in their haunts.

The body is covered with scales (PI. 1.
fig. 12), which are used as test-objects.
Those of P. plumbea, the so-called common
spring-tail, are usually recommended; but
we believe that the most common Podura is
not this species. This is, however, a matter
of little importance, because the scales of
several species, belonging to even different
genera, are exactly similar, both in form and
markings.

See SCALES OF INSECTS and TEST-
OBJECTS.

BIBL. Gervais, WalcTcenaer' s Apteres, iii.
and the Bibl. therein.

POLARISCOPE.— A term employed to
designate a polarizing apparatus, consisting
of a polarizer and analyser. See INTRO-
DUCTION, p. xviii.

POLARIZATION OF LIGHT. — The
phaenomena exhibited by microscopic objects,
when viewed by polarized light, are perhaps
the most beautiful and interesting of those
connected with the use of the microscope.
The extreme brilliancy, transparency and
variety in the colours developed cannot be
equalled, much less can they be represented
by illustrations, although the figures in PL
31 may give some idea of the manner in
which they are arranged in certain objects.

The ordinary arrangement of the parts of
the polarizing apparatus scarcely needs de-
scription ; the polarizer being placed beneath
the object and the analyser above it; the
polarizer and analyser usually consisting of

POLLEN.

[ 515 ]

POLLEN.

two Nicol's prisms, or two plates of tourma-
line. Some artificially prepared crystals
exert a powerful polarizing action, and may
be used either as polarizers or analysers, or
as both ; among these the salt of QUININE
occupies the first place. Others form in-
teresting analysers, some of which have been
noticed under ANALYTIC CRYSTALS and
DICHROISM.

Numerous salts and other crystalline
bodies, which powerfully depolarize the
already polarized light, and exhibit beautiful
colours, are mentioned under their respective
heads ; some of these may be enumerated
here; as the oxalate of ammonia, of soda,
and of chromium and ammonia; the oxalu-
rate of ammonia, the acetate of copper,
chlorate of potash, the prismatic form of the
ammonio-phosphate of magnesia, the am-
monio-phosphate of soda, the sulphates of
cadmium and of magnesia, selenite, salicine,
uric acid, &c.

Many organic bodies and tissues also
possess considerable depolarizing power ; as
horse-hair, portions of feathers, sections of
quill, of hoof, horn, &c. ; the siliceous
cuticle of the Equiseta and various grasses,
starch-grains, &c.

The examination of objects by polarized
light is often looked upon as a mere amuse-
ment, and the polariscope as a toy, and to
those who can perceive only the beautiful
colours, such they are. Their use, however,
consists in developing the optical properties
of bodies, the cause of which may be deter-
mined by histological analysis ( INT ROD.
p. xxxvi.) ; and for this purpose they are
invaluable and indispensable.

Objects to be examined by polarized light
should be immersed in turpentine or balsam,
to render them as transparent as possible.

BIBL. Herschel, EncycL MetropoL art.
Light; Pereira, Lectures on Polarized Light,
by B. Powell; Woodward, On Polarized
Light ; Brewster, Optics ; Erlach, Mik.
Beobacht. iib. organ. Element, bei Polar.
Licht. Mutter's Archiv, 1847.

POLLEN.— This name is applied to the
coloured pulverulent substance familiar to
every one as occurring scattered in the
interior of full-blown flowers; it is produced
in the anthers, the (usually) stalked club-
shaped organs which stand in one or more
circles between the floral envelopes and the
pistils, and is discharged from them when
ripe, in order to fertilize the ovules. When
slightly magnified, the pollen of most flowers
appears to consist of granules, of different

size and colour in different plants; hence
the individual particles are called pollen-
grains or granules (PL 32). Examination
under a sufficient magnifying power shows
that the simple or typical forms of pollen-
grains are single, free cells, filled with fluid
matter ; more complex forms occur in many
cases, which, however, may be simply cha-
racterized as groups of simple pollen-grains,
permanently coherent into definitely-formed
groups.

The pollen-grain may be examined as to
the form and structure, its contents and its
development.

The forms of simple grains presented in
different plants are tolerably varied, spherical
(PL 32. figs. 8-10, 22, 23, 25) and elliptical
(figs. 6, 11, 29), being perhaps those most
common ; but besides these, numerous geo-
metrical forms occur, such as tetrahedral
(fig. 14), polygonal (figs. 16, 27, 28), cubic
(fig. 19). But it must be noted here that
the forms frequently vary according as the
pollen is viewed dry or in fluid, since the
elliptical and allied forms often expand into
a spherical form, when they absorb liquid
(figs. 18 & 20 a, b, c). The explanation of
this will be given presently. The external
appearance is further greatly influenced by
minor peculiarities of form, such as ridges,
spines and processes of different kinds;
these, however, are referable to the structure
of the outer coat.

The ordinary structure of the coats or the
cell-wall of the pollen-grain is that of a
delicate internal cell-membrane, with an
outer, thick and resisting layer, which may
be regarded as the CUTICLE of the inner or
proper membrane of the cell. In a few
cases the inner membrane alone exists, as
in the cylindrical pollen-cells of Zostera,
and some other aquatic plants. In other
cases, the outer or cuticular coat presents a
more complex structure, and two or, it is
said, even three layers may be distinguished
in it ; these, however, seem to be merely a
lamination of the outer coat. The conditions
in some of the Coniferae are different from
this, and will be alluded to presently. The
inner membrane is exceedingly delicate and
homogeneous, in ordinary spherical or oval
grains it accurately lines the outer coat ; in
some of those forms which present processes
of various kinds, such as CEnothera, it seems
to us that the inner coat does not extend
into these processes in the mature pollen.
The outer coat exhibits, as to surface, every
variety of appearance from smooth, through
2L2

POLLEN.

[ 516 ]

POLLEN.

granular and spiny, to pseudo-cellular arising
from reticulated ridges ; in addition to this,
the processes just alluded to give a very
peculiar aspect to many kinds of pollen.
Besides these, we find in all cases markings
appearing like pores, or others like slits
(which become furrows when dry), or both
together, and these in varying number in
different cases. The colour of the pollen
presents great differences ; although usually
yellow, it may be whitish, red ( Verbascum),
blue (Epiloblum angustifolium), even black
(tulip) ; this colour resides in the outer
coat. The outer coat also exhibits, in the
majority of cases, a secretion upon its sur-
face, of a viscid character, usually described
as oily, but apparently consisting of a viscid
matter, not readily soluble in water, remain-
ing from the dissolved parent-cells. It
would seem to be this substance which holds
together the pollen-grains in those cases
where it consists of waxy masses, readily
breaking up into small fragments ( Ophry deous
Orchids). In the Onagraceae the pollen-grains
are loosely connected by slender, viscid fila-
ments, which appear to be derived from the
same source.

The more detailed explanation of the
characters of the pores, &c., the projecting
processes, and the compound conditions of
pollen, will be understood better after a
sketch of its development.

The anther, in which the pollen is formed,
consists in its younger stages of a minute,
solid, cellular papilla or cylindrical body; at
an early period a distinction becomes mani-
fest in its cells ; a single vertical row, lying
in the position of the axis of each pollen-
chamber (or loculus), presents a different
aspect, from its cells exceeding the surround-
ing ones in size ; and these rows undergo
a special development to produce the pollen-
grains, while the surrounding layers are
developed into the tissues forming the coat or
wall of the anther, and its midrib or con-
nective (see ANTHER). The cells of the pri-
mary row multiply by cell-division, with
the general increase in size of the anther
(figs. 597-599), until at length they form
relatively large masses of cellular tissue,
composed of large squarish cells, filled with
granular contents, well defined as constitu-
ting a distinct tissue from the walls of the
pollen-chambers. A new change then takes
place; the contents of each cell secrete a
layer of cellulose, which does not adhere to
the wall of the parent-cell to form a layer of
secondary deposit, but lies free against it, so

that a new free cell is formed within each
old one, nearly filling it. The walls of the

Fig. 597.

Fig. 598.

c.i

Fig. 599.
CL Cl CM

Vertical section of a cell of a young anther of the
melon, showing the gradual separation of the regions.
C E, epidermal cells ; C I, cells of the wall of the anther;
C L, cells lining the loculi ; C M, cells from which the
pollen is developed.

Magnified 100 diameters.

old cell (forming a connected parenchymatous
tissue) then dissolve, so that the free cells
become free, no longer merely in their parent-
cells, but in a cavity which is to constitute
the pollen- chamber or loculus of the anther.
These free cells are the parent-cells of the
pollen of authors. A new phenomenon soon
occurs in these. These parent-cells divide
into four by ordinary cell-division, either by
one or by two successive partings by septa
at right angles to each other, but both per-
pendicular to an imaginary axis (as when an
orange is quartered), or by simultaneously-
formed septa, which cut off portions in such
a manner that the new cells stand in the
position of four cannon-balls piled into a
pyramid (tetrahedrally). These new cells
are the special parent-cells of the pollen,
and in each of these the entire protoplasmic

POLLEN.

[ 517 ]

POLLEN.

contents secrete a series of layers, which, in
the ordinary course, by the solution of the
primary walls of the special parent-cells upon
which they were applied, become the walls
of free cells, which constitute the simple
ordinary pollen-cells. These subsequently
increase in size, and their outer coat assumes

Fig. 600.

Fig. 601.

Fig. 602.

Pollen-grain of the Melon in various stages of develop-
ment.

Magnified 100 diameters.

its characteristic form and appearance, while
free in the chamber of the anther (figs. 600,
601, 602).

In referring the peculiarities of many
kinds of pollen to circumstances connected
with the development, it may be noted, in
the first place, that the mode of division of
the parent-cells into quarters often influences
the ultimate form of the pollen-grain : thus
when the division is by two planes at right
angles, the original form of the pollen-grain
will be elongated, and the ripe grain will
probably be elliptical, while, when the divi-
sion is " tetrahedral," the grains may retain
the form thus produced, or be slightly
modified and become polygonal, or, as is
more common, they expand more readily
than the others into a sphere. But there is
no absolute rule here ; we find even the
tetrahedral and the polar division occur
together among the parent-cells of the same
anther. In the next place, a compound con-
dition of the pollen-grains (PL 32. figs. 7, 17)
is readily explicable by referring it to an
arrest of the process of subdivision, so that
if the walls of the special parent-cell do not
dissolve, the pollen-grains will be left in
groups of four ; and if the parent-cells do
not become singly detached in the antece-
dent process of solution, the grains may be
still developed in the same order and manner,
and remain connected in greater or smaller
masses or groups, each enclosed in its special
parent-cell, itself connected with a number

of others of the same generation by the
persistence of the walls of the cells in which
the parent-cells were developed. This ex-
plains the compound pollen of the Acacias
(PL 32. fig. 27), and in an excessive form,
the waxy pollen-masses which occur in the
Orchidaceae and Asclepiadacea?. It is some-
times stated that the pollen-grains of these
compound forms are merely connected toge-
ther by the viscid substance remaining from
the solution of the parent-cells, but this
would render such cohesions indefinite in
character, instead of being regular; at the
same time it will be understood that the
solution may have advanced so far that the
grains merely hold together slightly, and
may readily be separated. This is not the
case, however, with the majority of compound
pollen-grains. When the pollen-grains be-
come free, their viscid secretions are pro-
bably referable to the dissolved parent-cells.

The metamorphoses of the outer coat or
cuticle of the pollen-grain are very remark-
able and not yet at all understood; the
granulations (P1.32. figs. 11, 12), spines(figs.
8, 9, 22, 26), reticulations (figs. 13, 23, 27,
28), &c., characterizing mature grains, make
their appearance in the interval between the
solution of the special parent-cells and the
bursting of the anther, while the pollen-
grains lie free within the latter; their pro-
duction is accompanied by a general growth
and expansion of the pollen-gram. We
have observed that the outer coat is often
deposited as a very thick layer inside the
special parent-cell, and that when the latter
dissolves, the outer coat of the pollen-grain
is also in a softened condition, and becomes
stretched by the expanding inner coat,
finally forming a comparatively thin layer on
the ripe grain (ex. gr. hi Tradescantia). The
mode of origin of the markings, like those
on SPORES and on the cuticle of HELLE-
BORUS, &c. (see EPIDERMIS), is altogether
unknown ; probably all the cases are refer-
able to one cause.

It has been mentioned that the mature
pollen-grain exhibits pores or slits. We
believe they should rather be regarded as
thinner places in the outer membrane. Their
number and position varies much, as will be
indicated presently on referring to some of
the principal types of form of pollen. The
slit-like markings are generally accompanied
by a peculiar shrinking of the pollen when
dry, the coat collapsing at the thin places,
so that grains of this kind appear oval or
angular, not clearly exhibiting the slits

POLLEN.

[ 518 ]

POLLEN.

(which then become furrows) when dry, but
swell out, and display the latter clearly when
placed in water or dilute acids (PI. 32.
figs. 18 & 20). When the so-called pores
exist, they are either like simple pores
(PL 32. fig. 10), or they may be provided
with little disk-like pieces or lids, which fall
off and leave them bare when the pollen-
tube is formed (figs. 13 & 22). In all cases,
however, we believe that the outer coat is
extended over the whole surface, and that
the slits and dots are merely thinner places ;
moreover, in certain cases (Leschenaultia,
a quaternate pollen), we have seen the thick-
ening layers of the young pollen- grain,
inside the parent-cell, exhibit pits (exactly
comparable to those of ordinary pitted cells)
at the places corresponding to the future
pores, and curiously enough, in some cases
at least, the pits of adjacent pollen-cells cor-
responded, although in the mature expanded
compound grains they were far separated.
Sometimes the lids are found at the end of
short projecting processes (PI. 32. fig. 22).
The pollen of (Enothera and allied genera
exhibit remarkable conditions which have
been mistakenly described. The form of the
grain is that of a depressed sphere, with three
large equidistant truncated cones, projecting
pretty nearly in the same plane. The outer
coat is thick, except at the ends of the
conical masses, and two laminae are distin-
guishable (PL 32. fig. 14). The outer coat
thins off towards the end of each process. It
appears to us that the inner coat or true
pollen-membrane does not extend into the
processes at all, but is globular ; and that a
semifluid deposit occupies the space between
the inner coat and the outer in the cavity of
the tubular processes. Now supposing such
a deposit to become hardened and pushed
off as a plate by the advancing pollen-tube,
instead of giving way and expanding, we
should have the lid occurring in Cucurbita
Pepo (PL 32. fig. 22) and other cases.

In Mimulus moschatus (PL 32. fig. 24) the
slits or furrows are curved, and in Nymphcea,
Pinus, and other cases, still more complex.
It has been stated that the pollen is the
agent of fertilization of the ovules in the
Flowering plants. When scattered from
the anthers, that portion of the pollen which
falls upon the stigma (and frequently other
portions falling upon nectaries or secreting
surfaces) swell slightly, and germinate, as it
were, sending out a delicate tubular process
from one or more of the so-called pores or
slits (PL 32. fig. 30), which processes (the

pollen-tubes) insinuate themselves between
the loosely packed cells of the stigma, and,
continually elongating, make their way down
the style and along the conducting tissue to
the ovules. In the Coniferae the pollen-
grains fall directly upon the micropyle of
the naked OVULE, and send their pollen-
tubes into it. The pollen-tube is produced
by the growth of the inner or proper coat of
the pollen into a tubular filament. When
pollen- grains are placed in dilute sulphuric
acid or in syrup (sometimes in water), they
absorb liquid, swell, and their contents partly
exude from pores, &c., either to a slight ex-
tent, as a little " hernia," as it were, of the
inner membrane, or in large quantity in a
worm-like, irregular mass ; in the latter case
the coagulation of the surface often produces
a pellicular coat. These exuded masses are
of course distinct from the true pollen-tubes
produced under natural conditions.

The fluid contents of the pollen-grains
consist of a granular viscid protoplasm, with
minute starch-granules and (apparently) oil-
drops, making together what has been called
the fovilla, which increases in density as
the pollen ripens. The starch-granules ex-
hibit molecular motion in the pollen-tube,
and especially when they escape by rupture.
The granular contents of the pollen-cell,
which are always rendered opaque by the
action of water, are gradually transferred to
the pollen-tube as it elongates.

Connected with this point is the pecu-
liarity exhibited by the pollen of the Coni-
ferae. fn the Abietineae the form of the
granules is very peculiar, elongated, curved,
and with bulging ends; and, according to
Schacht, a distinct internal cell exists, at-
tached at one side in the cavity of the ordi-
nary pollen-cell, this internal cell dividing
and growing out as the pollen-tube when
the pollen-grain comes upon the ovule.
The pollen of the Cupressineas is spheroidal,
but free cellules appear to be formed in the
pollen-tubes during the fertilization. These
conditions, which are not yet satisfactorily
cleared up, indicate a relation to the sper-
matozoid-producing spores of the Marsilea-
cese, &c., analogous to that between the Gym-
nospermous ovules and the ovule-spores of
those Cryptogamic families.

It has been imagined that the form and
structure of the pollen-grains might have
some relation to the general structure of the
plants, and might serve as an indication of
systematic position and affinities. But there
appears to be no definite relation ; very va-

POLLEN.

ried pollen occurs within the limits of the
same family, and very similar pollen-grains
in families widely distant. There appears,
however, to be a certain relation within the
limits of genera. It may be perhaps gene-
rally stated that the Monocotyledons have
frequently one pore or furrow ; the Grasses
often three pores, as is the case with many
Dicotyledons, many of which have more,
while a large number of the families of this
division exhibit both pores and slits. As
microscopic objects, it is most convenient to
class the forms artificially, or according to
structure ; and we give a brief list of the
principal varieties arranged under this point
of view.

The pollen-grains of Zostera, Zanichellia,
and other submerged aquatic plants, have
no cuticle or outer coat; all other known
forms possess one or more outer layers.

A. Outer coat without furrows or pores.

a. Outer coat granular : Strelitzia Regince,
Calla palustris, Crocus sativus, fyc.,
Asarum europceum, Laurus nobilis, fyc.,
many Euphorbiacese.

b. Outer coat granular : Canna indica.

c. Outer coat with cell-like reticulations :
Ruelliafprmosa(P\. 32. fig. 23), R. stre-
pens, Tribulus terrestris.

In Periploca grceca (PI. 32. fig. 15) and
Apocynum Venetum\(fig. 7) grains of this kind
are connected in fours in one plane ; in some
Luzulce tetrahedrally..

B. Outer coat presenting longitudinal fur-
rows (or folds).

* One furrow (the form of most Mono-
cotyledons).

a. Outer coat slightly granular : common
in Monocotyledons ; among the Dico-
tyledons, in Myrica cerifera, Magnolia
grandiflora, Liriodendron tulipiferum,
&c.

b. Outer coat coarsely granular or spiny :
Nymphcea alba.

c. Outer coat with cell-like reticulations :
Hemerocallis fulva, and other Monoco-
tyledons.

d. Outer coat with irregular reticulations :
Alstrcemeria Curtisiana.

Among the Orchidese are found quater-
nate grains belonging to this group.

[ 519 ] POLLEN.

** Outer coat with two furrows : a rare
form, occurring in species of Ponte-
deria and Amaryllis, Tamus commu-
nisanAelephantipes, Tigridia pavonia,
Calycanthus fioridus, fyc.

*** Outer coat with three longitudinal
furrows.

a. Outer coat granular. One of the com-
monest forms : Quercus Robur, Viola
odorata (PI. 32. fig. 6).

b. Outer coat with short spines : Cactus
Jlagelliformis, Viscum album.

c. Outer coat with cell-like reticulations :
Statice (PI. 32. fig. 29), various Cruci-
ferae.

**** Outer coat with more than three
furrows.

a. Four : very rare as normal, Houstonia
ccerulea, Cedrela odorata; occasionally
occurring where three is the normal
number, as in Solanum tuberosum.

b. Six : some of the Labiatae and Passi-
floreae (PI. 32. fig. 20), Ephedra dista-
chya, Heliotropium grandiflorum.

c. A larger number of furrows : many
Rubiaceae; e.g. Sherardia arvensis (PI.
32. fig. 18). '

The pollen of the Pines is related to this
group, also that of Nymphcea Lotus, Victo-
ria regia, and other plants, where the fur-
rows or thin places occupy the greater part
of the wall, and the outer coat forms only
segmental pieces. In Mimulus moschatus
(PI. 32. fig. 24) a very remarkable appear-
ance arises from the furrows running in
a curved or spiral direction, and analogous
conditions are met with in Thunbergia alata.

C. Outer coat with pores.

* A single pore : Grasses, Sedges, Ty-

pha angustifolia, Sparganium ra-

mosum.
** Two pores : Colchicum, and a few

other Monocotyledons; also Brous*

sonetia.

*** Three pores.

a. Outer coat granular : Dipsacese, Urti-
caceae, Onagraceae (here the pores form
projecting processes (PI. 32. fig. 14) ;)
and in Morina persica this is still more
the case ; Cucumis sativus.

b. Outer coat with cell-like reticulations :
many Passifloreae (with large lids, P.
ccerulea (PI. 32. fig. 13), alata, &c.).

POLLEN.

[ 520 ]

**** Four pores.

a. Pores on the equator : Pistacia tere-
binthus, Campanula rotundifolia, &c.

b. Pores not equatorial : Passiflora ker-
mesina, Impatiens Balsamina (PI. 32.
fig. 21), Noli-me-tangere.

***** More than four pores,
t Distributed regularly.

a. On the equator : Alnus glutinosa, Ulmus
campestris, Collomia linearis, Campa-
nula Speculum.

b. All over the grains : Basella alba (PI.
32. fig. 19).

tt Scattered irregularly.

a. Outer coat slightly granular : many
Nyctagineae, Convolvulaceae, Chenopo-
diaceae, Alsineae, Alisma Plantago (PI.
32. fig. 10), Plantago lanceolata, Ribes
nigrum, Cactus Opuntia, &c.

b. Outer coat granular and spiny : Cucur-
bit a Pepo (with lids, PL 32. fig. 22),
Malvaceae (PL 32. fig. 26).

c. Outer coat with cell-like reticulations :
Polygonium amphibium, Persicaria,
Cobcea scandens.

Compound porous forms occur in some of
the Onagraceae, in Drimys Winteri, where
fourgrainsare conjoined tetrahedrally. In the
Mimoseae groups of eight or sixteen (PL 32.
fig. 25) occur in various forms. In Lesche-
naultia formosa the grains are quaternate,
lying in one plane.

D. Outer coat with both furrows and pores.

* Grains rounded or depressed, with
three depressions, each with a pore :
most Dipsaceae and Geraniaceae
(sometimes only two occur, PL 32.

fig. 22).

** Three furrows and three pores.

a. Outer coat granular; a very common
form among Dicotyledons.

b. Outer coat spiny : most Compositae.

c. Outer coat with cell-like reticulations ;
rare : Syringa vulgaris, Ligustrum vul-
gare, Grewia occidental, and other
species.

*** Outer coat with more than three
furrows, each with a pore. Some-
times abnormally, instead of three,
but normally in most of the Boragi-
naceae and Polygalaceae.

POLYBOTRYA.

**** Six to nine furrows, three con-
taining a pore : Lythraceae, Melasto-
maceae, Combretacese.

***** Three or four furrows, with six
or eight papillae : Neurada procum-
bens, &c.

****** Three furrows and three papillae
not in the furrows : Carolinea cam-
pestris, &c.

Related compound forms occur in the
Ericaceae and Epacridaceae, where the grains
are tetrahedrally arranged (PL 32. fig. 17).
Other aberrant forms occur in which the
single grains are cubic or dodecahedral ; and
in the Cichoraceae, polyhedral forms of com-
plicated character are common (PL 32. figs.
16, 27, 28).

Mature pollen-grains should be observed
dry (as opake and transparent objects), and
in water; in some cases, in oil; treatment
with acids is also useful in making out struc-
ture. In observing the development of pol-
len, it is necessary to wet the object with a
solution of sugar or gum, otherwise the ap-
pearances are altogether changed through
endosmotic action.

BIBL. Mohl, Bau u. Form. d. Pollenkor-
ner, Bern, 1834 (transl. in Ann. des Sc. nat.
2 ser. iii.) ; Purkinje, De cellulis antheris,
fyc., Vratislav. 1830; Fritzsche, Beitr. z.
Kenntn. der Pollen, 1832; Hassall, Ann.
Nat. Hist. viii. p. 92 ; ix. p. 93 and 544.
Mohl's work contains an abstract of the
literature up to his date; since that time
notices on the development have been pub-
lished by Nageli, Entwick. des Pollens, Zu-
rich, 1842, and his papers on Cell-formation
translated in Ray Society's Vols. for 1846
and 1847 ; Hoftneister, Botanische Zeitung,
vi. 1848; Gieswald, Linneea, xxv. p. 81
(1852); Schacht (Coniferae), Beitrag. z.
Botanik. Berlin, 1854.

POLYACTIS. See BOTRYTIS.

POLYARTHRA, Ehr.— A genus of Rota-
toria, of the family Hydatinaea.

Char. Eye single, cervical ; foot absent ;
body with six cirrhi or fins on each side.

Jaws each with a single tooth.

P. platyptera (PL 35. fig. 19). Body
ovato-subquadrate, fins ensiform serrate.
Aquatic ; length 1-190".

P. trigla. Fins setaceous. Aquatic ;
length 1-190".

BIBL. Ehrenberg, In/us, p. 440.

POLYBOTRYA, Humb. — A genus of
Acrosticheae (Polypodaeous Ferns). Exotic.

POLYCOCCUS.

[ 521 ]

POLYEMBRYONY.

POLYCOCCUS, Kutz.— Probably be-
longs to Protococcus.

POLYCYSTINA, Ehr.— A group of mi-
croscopic animal bodies, regarding the nature
of which little is known. They consist of
shells of various forms (PL 31. figs. 23-31),
rounded, conical, oval, radiate, star-shaped,
&c., often furnished with spines and other
processes, and sometimes constricted so as to
give them a jointed appearance. The shells
are siliceous, every where perforated by coarse,
rounded or angular foramina; and at one
end, sometimes at both, is a larger aperture.

They are most abundant as fossils in the
rocks of Bermuda; but have also been
found in the chalk and marls of Sicily, at
Oran in Africa, in Greece, in the tripoli of
Richmond in Virginia. A very few have
been found recent in mud at the bottom of
the sea, near Cuxhaven in the North Sea,
and near the South Pole.

The recent shells were filled with an olive-
brown organic matter.

Forty-four genera and 282 species have
been described.

They appear to have most affinity with
the Foraminifera, near which we have
provisionally placed them; but nothing is
known regarding the structure of the animal.

They form beautiful microscopic objects,
viewed by either reflected or transmitted
light.

BIBL. Ehrenberg, Taylor's Scientific
Memoirs (pts. 10 & 11) and Ber. d. Berl.
Akad. 1846 & 1847 (Schomburgk, Ann. Nat.
Hist. 1847. xx. 115).

POLYCYSTIS, Kutz.— A genus of Pal-
mellaceae (Confervoid Algae). This genus is
excluded from our synopsis of the family,
but since that article has been in print we
have found the plant, which plainly corre-
sponds to P. teruginosa of Kiitzing, a form
separated by him from the genus Microhaloa
of Biasoletto, also named in his Tab. Phycol.
Microcystis ceruginosa. The plant in ques-
tion occurred colouring large tracts of the
lake in Kew Gardens, appearing to the naked
eye like a coarse green insoluble powder
suspended in the water near the surface,
acquiring a verdigris colour when dried on
the mud. It consists of little gelatinous
fronds, varying in form, from 1-100 to 1-40"
or more in diameter, the interior of which is
densely crowded with separate green cells,
not more than 1-6000" in diameter. The
primary form of the gelatinous fronds appears
to be globular or ovate ; as they expand
they become hollow, forming gelatinous sacs,

which sometimes burst laterally, but in
normal cases seem to expand, until, the walls
giving way in places, they form coarsely
latticed sacs of irregular form, somewhat
resembling on a small scale the hymenium
of Clathrus cancellatus. These break up
into irregular fragments which form new
starting-points for a similar development.
Besides this, the primary cells increase in
number by division into two, so that the
large fronds have the jelly almost as crowded
as the small. We suspect that certain monad-
like bodies found moving about the fronds
were zoospores, but this point is not yet
ascertained, neither is any true spore-forma-
tion.

BIBL. Kutz. Sp. Alg. p. 210, Tab. Phyc.
i. pi. 8; Meneghini, Monog. Nostoch. (Trans.
Turin. Acad. 2 ser. v. p. 104).

POLYCYSTIS, Leveille.— A genus of
Ustilagines (Coniomycetous Fungi), inclu-
ding several of the old species of Uredo ;
P. colchici, P. parallela and P. Violce are
British. See USTILAGINES.

BIBL. Berk, and Broome, Ann. Nat. Hist.
ser. 2. v. p. 464 ; Leveille, Ann. des Sc. nat.
3 ser. v. p. 269; Tulasne, id. vii. p. 217.

POLYEMBRYONY.— This term is ap-
plied to a phenomenon occurring sometimes
regularly, sometimes abnormally in the deve-
lopment of the ovules of Flowering Plants.
In the Angiospermous plants it is usual to
find several germinal vesicles in the unferti-
lized embryo-sac (see OVULE), but ordinarily
only one of these becomes impregnated and
developed. Occasionally, however, more
than one commences the course of develop-
ment into an embryo, as in the Orchidaceae,
and more especially in the genus Citrus ; in
most cases all but one become subsequently
obliterated, but in the orange this is not
the case, and ripe seeds are met with con-
taining more than one embryo. We have
met with them in other cases.

Another kind of polyembryony occurs in
the Santalaceae. Viscum has two or three
embryo-sacs ; these may all have their ger-
minal vesicles fertilized, and the development
of the embryos may go on to a certain point,
until one takes the lead and the others dis-
appear.

In the Gymnospermia (Coniferae and Cy-
cadaceae), as described in the article OVULE,
there may be one or more (Taxus) primary
embryo-sacs, in which are produced several
corpuscula, with secondary embryo-sacs ;
further, the germinal vesicles of these, after
fertilization, produce suspensors, which

POLYGASTRICA.

[ 522 ]

POLYPI.

branch at their lower ends, and each produce
four rudimentary embryos; all but one of
them vanishing during the ripening of the
seeds. Our space only admits of a brief
notice of these interesting phenomena, on
which much interesting information will be
found in the works referred to below.

BIBL. Meyen, On Impregnation and Poly-
embryony (Berlin, 1840), transl. in Taylor's
Scientific Memoirs, iii. p. 1 ; R. Brown, Ann.
Nat. Hist. xiii. p. 368; Mirbel and Spach,
Ann. des Sc. nat. 2 ser. xx. p. 257 ; Criiger,
Botanisch. Zeit. ix. p. 57 ; Gelesnoif, Ann.
des Sc. nat. 3 ser. xiv. p. 189, and the works
of Hofmeister cited under OVULE.

POLYGASTRICA.— According to Eh-
renberg's system, the Infusoria are subdi-
vided into the Polygastrica and the Rota-
toria. The so-called Polygastrica correspond
to our Infusoria; the Rotatoria form a
distinct class.

POLYIDES, Ag.— A genus of Crypto-
nemiacese (Florideous Algae), containing one
British species, P. rotundus, having a
branched frond 4 to 6" high, consisting of
repeatedly dichotomous, purplish-brown,
solid fibres, about 1-20" in diameter. The
fibres present a central layer of longitudi-
nally arranged filamentous cells, and a cor-
tical layer of perpendicular, dichotomous
filaments, formed of elliptical cells internally,
terminating at the surface in minute nionili-
form rows. The fructification consists — 1 . of
favellce bearing spores, contained in super-
ficial wart-like bodies, composed of colourless
articulate filaments ; 2. tetrahedrally divided
tetraspores, imbedded in the peripheral fila-
ments of the cortical layer of the frond.
Antheridia have not yet been observed.

BIBL. Harvey, Brit. Mar. Ala. p. 146.
pi. 18 D; Phyc.Brit. pi. 95; Greville, Ala.
Brit. pi. 11.

POLYOMMATUS, Latr.— A genus of
Lepidopterous Insects, of the family Lycae-
nidse.

Char. Antennae terminated by a contracted
knob; tarsal claws minute; wings not tailed.

The (thirteen) species are small butterflies,
the upper surface of the wings of a beautiful
blue colour, the under side gray or brownish,
and with numerous eye-like spots.

The scales upon the under surface of the
wings of P. argiolus and P. argus have
been proposed as test-objects. They are of
two kinds, one resembling in structure the
ordinary scales of insects; the other of a
battledore form (PI. 27. figs. 20 & 21). See
SCALES OF INSECTS and TEST-OBJECTS.

The species are figured in Westwood's
British Butterflies.

POLYPHEMUS, Mull.— A genus of En-
tomostraca, of the order Cladocera, and
family Polyphemidse.

Char. Head distinct from the body ; ab-
domen long, slender and projecting exter-
nally from the shell.

P. pediculus (PL 14. fig. 29). The only
species. Aquatic.

BIBL. Baird, Brit. Entomostr. p. 111.

POLYPI (Zoophytes).— A class of the
Animal Kingdom.

Char. Body rounded or elongate, with a
distinct mouth, surrounded by retractile ten-
tacles or radiating lobes ; individuals usually
aggregate, and furnished with a horny or
calcareous external or internal skeleton or
polypidom ; gemmiparous and oviparous.

The polypes are usually enveloped in an
external (PL 33. figs. 4 6, 18 & 30), or sup-
ported by an internal axial skeleton (PI. 33.
fig. 6), called the polyparium or polypidom.
This is either horny, leathery or calcareous.
Most polypes are united into smaller or
larger groups by the polypidom, which often
possesses an elegant plant-like form. The
tubular or bell-shaped processes or cavities,
in which the body of the individual polypes
is contained, form the polype-cells : they
are sometimes furnished with a kind of lid ;
in some of the softer polypidoms a number
of spicula are present.

The structure of the calcareous polypi-
doms has not been satisfactorily determined.
They are usually traversed by vascular canals,
and appear in some cases at least to consist
of spicula aggregated and fused together.

The polypes are rarely free, or capable of
fixing themselves by a disk at the base of
the body, being usually fixed at the bottom
of the polype-cells of the polypidoms ; the
polypidoms being attached by a rooting base
to some foreign body. A distinct transparent
integument exists, which is frequently
covered by ciliated epithelium, especially
upon the tentacles. Imbedded in this are
stinging organs (PI. 33. fig. 22), resembling
in general those of the Acalephae.

In many, distinct muscles are present;
but the fibres are not striated, although fre-
quently exhibiting transverse wrinkles. In
some polypes the substance of the body
consists entirely of sarcodic substance. In
many, both the integument when present,
and substance of the body contain scattered
calcareous spicula (PL 33. figs. 7, 27 & 28).

Curious appendages called birds'- head-

POLYPI.

[ 523 ]

POLYPI.

processes are found attached to various parts
of the polypidoms of some polypes (PL 33.
figs. 5 b * & 26). They consist of a body
(fig. 26/), a hinge- or lower-jaw-like pro-
cess (fig. 26 e), and a pedicle or stalk (/).
They are attached by the pedicle to the in-
terior of a round hollow process, projecting
slightly from the surface of the polypidom
(fig. 26 a). The body is divided by an ob-
lique ridge (fig. 26 d] on its inner surface
into two chambers. The hinge-process is
articulated to the concave surface of the
body by a hinge-joint and two articular pro-
cesses, and is moved up and down by an
elevator and a depressor muscle (fig. 26 c).
The body of the processes is hollow, and
its concave surface has three apertures.
The motion of these processes continues
long after the death of the polypes. They
appear analogous to the pedicellarise of the
Echinodermata.

Three other structures (PL 33. figs. 5d,
5 c, c, a, b) are met with in some polypes,
one of which resembles the above in regard
to the movement. They exist at the upper
and outer angle of the cells, behind the spines
which exist there. The uppermost is a
hollow process (fig. 5 d, b), with its upper end
free and directed outwards and forwards, and
with a notched aperture at the upper and
lower edges, from which a curved filament
(fig. 5 d, d) projects. The interior of the
process is filled with a contractile substance
which moves the filament upwards and down-
wards. The second structure consists of a
mucronate process, prolonged from the upper
and outer angle of the polype-cell (figs. 5 c,
b, 5 d, c) ', it is sometimes transformed into a
spine. The third consists of a small rounded
cavity with a circular aperture (fig. 5 d, d),
situated between the bases of the two above-
mentioned.

The structure of the alimentary apparatus
varies in the two orders of polypes. In the
Anthozoa it consists of a mouth and a simple
blind gastric sac, the food being admitted
and the undigested portion rejected from
the single aperture. In the Bryozoa an oral
and excretory orifice are present, with an
oesophagus, a kind of gizzard, sometimes
with horny teeth, a stomach, small and large
intestine (PL 33. fig. 18 d, e, f, g}. The
anal orifice is situated near the mouth, but
outside the row of tentacles.

The oral orifice is usually surrounded by
a ring of contractile arms or tentacles, which
are hollow internally and communicate with
the cavity of the abdomen. They are either

simple or feathery, and arranged in one or
more rows. The food is brought to the
mouth either by the tentacles, or by currents
induced by the action of their cilia.

The simple gastric sac of the Anthozoa is
usually separated from the cavity of the body;
whereby a larger or smaller abdominal
cavity is formed, which is almost always
prolonged into the hollow arms, and in
many polypes living hi colonies passes into
the canals traversing the interior of the
polypidom, so that the abdominal cavities
of the individual polypes are all brought into
connexion by these canals. Sometimes lon-
gitudinal partitions run like a mesentery
from the outer to the inner surface of the
abdominal walls, thus dividing the abdominal
cavity into chambers. The bottom of the
gastric cavity in some, if not all Anthozoa, is
provided with one or more spontaneously
closeable openings, by which the gastric
cavity communicates with the abdominal
cavity. The gastric cavity appears covered
with a very delicate ciliated epithelium, which
is continued through the gastric apertures
into the abdominal cavity, and here not only
covers the outer surface of the stomach and
the septa, but also the inner surface of the
abdominal walls, the cavities of the arms, and
the canals of the polypidom.

The walls of the stomach are variously
coloured white, yellow or brown, from the
presence of aggregations of pigment-cells in
the gastric walls (liver-cells), which most
probably perform the function of a liver, as
there is no glandular appendage correspond-
ing to a liver present.

In the Bryozoa, the inner surface of the
digestive canal is covered with ciliated epi-
thelium.

A blood-vessel system has hitherto been
found in but few polypes; when present
(Alcyonidium, Alcyonium), it consists of lon-
gitudinal and circular vessels existing in the
abdominal walls, with intermediate capillary
networks. The vessels have distinct walls.

A peculiar circulation takes place in almost
all polypes, by the to-and-fro motion of a
nearly transparent liquid containing minute
colourless corpuscles in the abdominal cavity.
The liquid ascends thence to the apex of the
hollow tentacles, whence it returns to the
abdominal cavity. In the colonial polypes
this circulation continues through the canals
which traverse the polypidoms, from one
abdominal cavity to the other. The motion
is produced by very delicate ciliated epi-
thelium lining the abdominal cavity, the

POLYPI.

[ 524 ]

POLYPODIES.

hollow tentacles and the canals of the poly-
pidom. In the Bryozoa, the abdominal
cavity of which is closed from the digestive
cavity, the current runs continuously and
regularly in one direction; whilst in the
Anthozoa, its direction varies according to
whether the liquid passes from the abdominal
to the gastric cavity or from the latter to the
former.

The propagation of the polypes takes
place in three ways : by spontaneous divi-
sion, which is mostly longitudinal and rare ;
by the formation of gemmae or buds, which
is very common, the individuals either sepa-
rating or remaining attached; and by the
formation of ova. This probably takes place
in all polypes, and requires the presence of
a testis and ovary, which have been dis-
covered in several polypes. These organs,
or their representatives, are variously distri-
buted. In some, both are present in a single
individual (Hydra); whilst in others the
sexes are separate (Actinia). In the colonial
polypes the individuals are of distinct sexes,
both kinds occurring either upon the same
(Alcyonella], or upon distinct polypidoms
(Alcyonium, &c.). Some polypes are always
a- sexual, individuals of a totally dissimilar
form arising from them and their polypi-
doms by gemmation, in which sexual organs
are afterwards formed (Coryne, Campanu-
laria, &c.). In some, these individuals,
which are mostly bell- or disk-shaped, sepa-
rate from the polypidom before their sexual
organs have acquired full development, and
swim about like Acalephce, the mature deve-
lopment subsequently ensuing (some Cam-
panularice, &c.) ; in others, again, it takes
place while they remain attached.

The bodies in which the gemmules or ova
are formed are usually called bulbules, ovi-
gerous vesicles, or ovisacs.

The ova of the polypes are surrounded by
a more or less hard envelope, which in some
is simple, in others possessing a peculiar
structure, being covered with hooks, &c.
(PL 33. fig. 10).

The embryo of the polypes is usually
more or less elongate-oval, coated with cilia,
and moves about on its long axis like an
infusorium; after a short time it fixes itself
to some object, the cilia then disappear, and
the tentacles of the polypes are protruded.
Many of these polypes then increase by
gemmation, thus forming new colonies.

The formation of coral-reefs and islands
by the skeletons of polypes is well known.

The class Polypi is divided thus :

Ord. 1. ANTHOZOA. Body contractile,
symmetrical; a single external orifice only
to the alimentary cavity; gemmiparous and
oviparous.

Ord. 2. BRYOZOA (Polyzoa). Body non-
contractile, unsymmetrical; alimentary canal
with an oral and anal orifice ; oviparous.

BIBL. Johnston, British Zoophytes ;
Siebold, Vergl. Anat. 25; Wagner, Icones
Zootomicce; Farre, Phil. Trans. 1837; v.
Beneden, Mem. s. les Campanulaires ; Vogt,
Zool. Brief e; Owen, Hunterian Lectures, i.;
Lister, Phil. Trans. 1834; Couch, Corn.
Fauna; Hancock, Ann. Nat. Hist. 1850. v.
173; Desor, Ann. d. Sc. nat. 3 ser. xii. ;
Dana, Report on Zoophytes.

POLYPODIACEjE.— A family of Ferns,
divided into six tribes by the characters of the
sporanges.

Synopsis of the tribes.

I. POLYPODIES. Sporanges numerous,
united in sori, and divided into two equal
parts by a vertical annulus.

II. CYATKLEEZB. Sporanges numerous,
united in sori on a salient axis, and divided
into two equal parts by a vertical annulus.

III. GLEICHENIES. Sporanges united in
fours into sori, and surrounded by an oblique
annulus, like a turban.

IV. PARKERIES. Sporanges not united
in sori, and divided into two equal parts by
a more or less extensive vertical annulus.

V. OSMUNDES. Sporanges united in
sori, and covered on the back by a broad and
imperfect annulus.

VI. SCHIZJEEM. Sporanges united in
sori, and crowned by an annulus that looks
like a skull-cap with radiating streaks.

POLYPODIEjE.— A subtribe of Polypo-
dioid Ferns containing the following genera:

* Veins pinnate.
A. Margins of the fertile fronds not revolute.

I. POLYPODIUM, L. Sori globose, seated
on the apex or the back of veins or venules.

II. MARGINARIA. Sori globose, im-
mersed deeply in the backs of veins or
venules.

III. PLEOPELTIS. Sori globose, seated
on the backs of veins and venules, with peltate
paraphyses concealing the sporanges.

B. Margins of the fertile fronds revolute.

IV. STRUTHIOPTERIS. Sori globose,
seated on the backs of veins and venules.

** Veins anastomosing, without free veins in
the areolcs.

V. DICTYOPTERIS. Sori globose, seated

POLYPODIOIDE^E.

[ 525 ]

POLYSIPHONIA.

on the anastomosing venules. Venules ana-
stomosing in irregular hexagonal spots.

*** Veins anastomosing, with free veins in
the areolce.

VI. NIPHOBOLUS. Sori globose, seated
on the apex of the venules. Venules very
much branched, forming transverse rhomboid
spots; secondary venules arising from the
transverse venules, and bearing the sori at
their apices.

VII. DRYOSTACHIUM. Sori quadran-
gular, seated on the apex of the venules.
Venules very much branched, forming some-
what quadrangular meshes. Secondary
venules very numerous, variously divergent,
and bearing the sori at the apex.

POLYPODIOIDE^E.— A tribe of Poly-
podiaceous Ferns, of large extent, broken up
into subtribes and genera, which are cha-
racterized by peculiarities generally requiring
a more or less powerful lens to distinguish
them. In certain cases, where the venation
of the leaves, and the relation of this to the
fructifying points, are in question, it is found
very convenient to scrape off the sori of pin-
nules and place them in spirits of turpentine
or oil, between two slips of glass, for exami-
nation with a low power under the micro-
scope by transmitted light. The general
arrangement of the sori, with the indusium,
in very minute forms, is best observed as an
opaque object, with a low power, and a
lieberkuhn or side condenser ; if held in the
mounted forceps, the pinnule can be turned
about and thoroughly examined.

Synopsis of the sub-tribes.
A. Sori without indusia.

I. ACROSTICHE.E. Sori seated on all the
veins, venules, and parenchyma.

II. GYMNOGKAMME^E. Sori seated on
the backs of all the veins and venules.

III. POLYPODIES. Sori globose, only
on certain arms of the veins.

IV. MENISCIES. Sori kidney-shaped,
seated only on certain arms of the veins.

V. GRAMITIDE^E. Sori linear, seated
only on certain arms of the veins.

VI. TJENITIDE^E. Sori linear, in pairs
on either side of the rib, parallel, continuous.

B. Sori with indusia.

VII. ASPIDIES. Indusium orbiculate,
peltate.

VIII. DIPLASIES. Indusium linear or
oblong, fixed longitudinally in the middle.

IX. NEPHRODIE.E. Indusium cordate,
affixed at the notch.

X. CYSTOPTERIDE.E. Indusium tongue-
shaped, fixed by the lower point.

XI. LINDSSE.E. Indusium linear,
elongated, free outside.

XII. ASPLENIE^B. Indusium elongated,
fixed at the side, free within.

XIII. PTERIDES. Indusium linear, fixed
at the side, free within.

XIV. SCOLOPENDRE^E. Indusium linear,
flat, margins free, opposite.

XV. DAVALLIES. Indusium somewhat
urn-shaped, dehiscing externally at the apex.

POLYPODIUM, Linn.— Agenus of Ferns
with naked sori, of which there are several
indigenous representatives ; P. vulgare, the
Oak-Fern, being one of our commonest spe-
cies. Exceedingly well adapted for examina-
tion of the structure of sori and sporanges
in this family.

POLYPOREL— A family of Hymenomy-
cetous Fungi, characterized by bearing basi-
diospores clothing tubes, pores or pits, on
the under side of a stalked or sessile pileus,
or fleshy cap or disk. The basidiospores are
seen by horizontal sections from the under-
surface of the pileus. (See BASIDIOSPORES
and HYMENOMYCETES.)

BIBL. Berkeley, On the Fructification of
Hymenomycetous Fungi, Ann. Nat. Hist. i.
81; Leveille, Sur I'Hymenium des Champi-
gnons, Ann. des Sc. nat. 2 ser. viii. 324.

POLYSELMIS, Duj.— A genus of Infu-
soria, of the family Euglenia.

Char. Oblong or variable in form, with
several anterior nagelliform filaments, and
a single red eye-spot.

Probably the zoospore of a Confervoid
Alga.

P. viridis (PI. 24. fig. 68) resembles a
Euglena of an oblong form with the ends
rounded ; one of the filaments is longer than
the three or four others which surround its
base. Aquatic; length 1-650".

BIBL. Dujardin, Infus. p. 370.

POLYSIPHONIA, Grev.— An extensive
genus of Rhodomelacese (Florideous Alga?),
with cylindrical, more or less articulated
fronds, the joints consisting of a circle of
longitudinally arranged cells surrounding a
central cell (like the wood-bundles of a
young Dicotyledonous stem surrounding the
pith), so that the transverse section presents
the appearance of a rosette ; the number of
peripheral cells varies among the 300 dif-
ferent species of this genus, from four to
twenty-five. The British forms have four

POLYT^ENIUM.

C 526 ]

POLYTRICHUM.

and six. In some of the species a kind of
rind is formed subsequently, by a growth
from the base of the joints analogous to that
which occurs in BATRACHOSPERMUM and
Callithamnion. The fructification consists
of— 1. ceramidia, attached to the sides of
branches, containing numerous pear-shaped
spores; 2. tetraspores, on distinct plants,
formed in the swollen central cell of distorted
branches (fig. 603) ; and 3. antheridia, elon-

Fig. 603.

Polysiphonia nigrescens.

Distorted ramuli containing imbedded tetraspores.
Magnified 50 diameters.

gated whitish sacs, collected in great num-
bers at the summits of the branches, accom-
panied by a dichotomous hair, and some-
times prolonged into a hair-like process at
the summit. Nageli described the sperma-
tozoids as consisting of a spiral filament.
Thuret disagrees with this, and states that
they are merely hyaline globules, about
1-5000" in diameter. The British species
are placed in two subgenera : Oligosiphonia,
where there are but four or rarely five peri-
pheral cells, and Polysiphonia, where there
are six or more. Twenty-six species are de-
scribed, many of which are common.

BIBL. Harvey, Brit. Mar. Alg. p. 82. pi.
12 A; Thuret, Ann. des Sc. nat. 3 ser. xvi.
p. 16. pi. 6 ; Nageli, Zeitschr.f. wiss.Botan.
Heft 3 and 4 (1846). p. 207. pi. 6 & 7.

POLYT^NIUM, Desv.— A genus of
Tsenitideae (Polypodaeous Ferns). Exotic.

POLYTHALAMIA. See FORAMINI-

FERA.

POLYTOMA, Ehr.— A genus of Infuso-
ria, of the family Monadina (Hydromorina).

P. uvella (PI. 24. fig. 69, undergoing di-
vision), the only species, is oblong or oval,
obtuse at the ends, colourless, furnished with
two flagelliform filaments; it has no cara-
pace. Aquatic; length 1-2200 to 1-960";
size of body when the division is nearly
complete, 1-400".

BIBL. Ehrenberg, In/us, p. 24.

POLYTRICHACE^.— A tribe of Mnioi-
deae (operculate Mosses of usually Acrocar-
pous habit).

I. CATHARINEA. Calyptra narrowly
hood-shaped, subscabrous at the apex, ra-
ther hairy within. Peristome simple, com-
posed of thirty-two teeth, arising from a
narrow, cellular, basilar membrane, ligulate,
membranous, white, with many percurrent,
reddish, inarticulate filaments, somewhat
incurved, scarcely hygroscopic, firm. Colu-
mella dilated at the apex into a drum-like
epiphragm. Capsule equal. Inflorescence
monoecious or dioecious.

II. POLYTRICHUM. Calyptra dimidiate,
but appearing campanulate on account of a
quantity of very close hairs descending from
it as a long villous coat ; otherwise resem-
bling the preceding genus.

POLYTRICHUM, Dill.— A genus of Po-
lytrichaceous Mosses, variously defined by
different authors. In the British Flora, it

Fig. 604.

Polytrichum commune.

Plants in fruit.
One-half natural size.

POLYTRICHUM.

[ 527 ]

POLYTRICHUM.

includes the forms separated in this work
underCATHARiNEA, which in the 'Bryologia
Britannica' are divided between ATRICHUM
and OLIGOTRICHUM. The species of Poly-
trichum comprised in our definition are dis-
tributed in the same work under Pogonatum
(those with a round capsule and thirty-two
teeth) and Polytrichum proper (those with a
square or prismatic apophysate capsule (fig.
605 ), and usually twice as many teeth).

Fig. 605.

Fig. 606.

Polytrichum commune.

Capsule with operculum. Section of young capsule,
Magnified 10 diameters. showing the plaited spo-

rangia! membrane.

P. commune is one of our finest Mosses, com-
mon on heaths, moors, and mountain tracts,
varying somewhat under the different phy-
sical conditions. The stems are from 6" to

Fig. 607.

Fig. 608.

Polytrichum commune.

Fragment of peristome. Columella with section

Mag . 100 diams. of the apophysis.

Magn. 25 diams.

1' long, and the fruit-stalks 2 or 3". The
stems are almost of woody texture, the leaves
large and firm. The calyptra is densely co-
vered with hairs. Wilson remarks that the
true structure of the sporange and columella

Fig. 609.

Fig. 610.

Polytrichum commune.

Sterile inflorescence. Innovation from sterile

One-half nat. size. inflorescence.

Magn. 5 diams.

of Mosses may be most easily learned from
the study of this genus. The columella
(figs. 606, 608) is seen to be separated from
the spores by an inner layer of the spo-
rangial membrane. The diaphragm attached
to the apices of the teeth of the peristome is
the dilated apex of the columella (fig. 608).
The peristome (fig. 607) is composed of
ligulate obtuse teeth, connected by a mem-
brane at the base, continuous with the inner
layer of the wall of the capsule. These
plants are also exceedingly well adapted for
the examination of the male inflorescence
and spermatozoids. They are all dioecious,
and the male plants (fig. 609) are readily
distinguishable by the cup-shaped inflores-
cence, composed of scale-like leaves and
paraphyses surrounding a number of subu-
late sacs constituting the antheridia. The
male flowers of P. commune, juniperinum, &c.,
are found everywhere on heaths in spring.
The antheridia may be readily extracted un-
der a simple lens, and when placed in water
under the compound microscope, soon (if
ripe) burst at the summit and discharge the
spermatozoids; these usually escape still
enclosed in their parent-cells, which when
first discharged cohere in a gelatinous mass,

POMPHOLYX.

[ 528 ]

PORPHYRA.

but the ciliated spermatozoids (PI. 32. fig.
33) escape and swim actively in the water.
They require at least an eighth object-glass
for examination, and the cilia are seen most
clearly after drying the object, or treating with
tincture of iodine.

BIBL. Wilson, Bryol. Britann. p. 205 et
seq. ; Thuret, Ann. des Sc. nat. 3 ser. xvi.
p. 26. pi. 14.

POMPHOLYX, Gosse.— A genus of Ro-
tatoria, of the family Brachionaea.

BIBL. Gosse, Ann. Nat. Hist. 1851. viii.
p. 203.

PONTIA, Fabr.— A genus of Lepidopte-
rous Insects, of the family Papilionidae.

This genus contains some of the com-
monest butterflies, as P. brassica, the large
cabbage-butterfly ; P. rapes, the small cab-
bage-butterfly; and P.napi, the green- veined
white butterfly.

The form and structure of certain scales
existing upon the under side of the wings of
the males are curious; and the markings
were formerly found so difficult to render
distinct, that the scales were used as test-
objects.

In the male P. brassicce the upper surface of
the anterior wings is free from spots, whilst in
the female there are two black spots in that
situation. The peculiar scales are repre-
sented in PI. 27. fig. 24 ; fig. 26 exhibits a
portion of the wing with the ordinary scales.

In P. rapce and P. napi the anterior wings
of the males have a single spot upon the
upper surface, whilst there are two upon
each wing in the females. The peculiar
scales bear considerable resemblance in the
two species (PI. 27. fig. 23 a, scale of P. rapa;
fig. 23 b, portion of wing, snowing the points
of attachment of the two kinds of scales).

The scales may be separated by gently
pressing the under surface of the wings
against a slide.

See SCALES OF INSECTS and TEST-
OBJECTS.

BIBL. Westwood, Brit. Butterflies.

POPPY. — The seeds of Poppies (Papaver,
L., Nat. Order Papaveraceae) are elegant
opaque objects under a low power, the testa
being pitted so as to produce a reticulated
surface (PI. 31. fig. 14).

POROSITY OF BODIES.— That all bo-
dies are porous to a greater or less degree,
allowing vapours and gases to pass through
their substance, is an established fact in
physics and physiology. The passage of
solid particles, also, as charcoal and sul-
phur, through certain organic tissues in which

no apertures have hitherto been detected, as
the ^kin and mucous membranes, has re-
cently been attested by several observers.

M. Keber believes that he has detected
the existence of pores in all bodies of what-
ever kind ; these he finds in the dots, streaks
and irregular markings, from 1-11,000 to
1-45,000" in diameter, visible in minute and
thin scrapings and fragments of solids, as
particles of dust, scrapings from a piece of
bladder, &c. This view does not require a
serious refutation. Of evidence that the
markings are pores, there is none ; and on
examining a thoroughly cleaned and thin
piece of the membrane of a vegetable cell, we
do not perceive anything corresponding to
pores. If the true pores are ever detected
by the microscope, there can be little ques-
tion that they will exhibit a beautifully re-
gular arrangement; whereas the so-called
pores of the author are totally devoid of
definite arrangement.

BIBL. Keber, MikrosJc. untersuch. ub. die
Porositat d. Korper, and Phil. Mag. 1854.
pp. 287 and 370.

POROUS STRUCTURES OF PLANTS.
— What are ordinarily called porous tissues
in vegetable anatomy are described in ac-
cordance with their real nature under the
head of PITTED STRUCTURES. True pores
do, however, occur in the walls of vegetable
cells, from secondary or ultimate changes in
their character. They are seen in the cells
of the leaves of Leucobryum and Sphagnum
(see SPHAGNACE^E). Other regular orifices
are produced in the walls of the cells of
many of the zoospore-producing Confervas,
as Conferva, Cladophora, Enteromorpha, &c.
(see PI. 5). The wall of the sporangial cell
of Achlya presents analogous openings, and
according to Cohn, pores are produced in
the spore-cells of SPH^ROPLEA to admit
the spermatozoids. The pits and the inter-
stices between reticulated fibrous secondary
deposits are often changed into true holes in
old cells, but this is a result of decay of the
primary membrane ; it takes place very
early, however, at the contiguous ends of
SPIRAL-FIBROUS and PITTED CELLS, co-
alescing to form ducts, changing the septum
formed by the adjoining ends into a kind of
grating or irregularly torn diaphragm.

BIBL. See the heads referred to in this
article.

PORPHYRA, Ag.— A genus of Porphy-
raceae (Florideous Algae), with an expanded,
membranous, shortly-stalked frond, com-
posed of a single layer of cells approximated

PORPHYRACE.E.

[ 529 ]

POTTIACE.E.

in fours, the contents of purple or red colour.
Fructification consisting of — 1 . scattered
sori of oval spores ; 2. tetraspores (crucial)
immersed in the frond; and 3. antheridia,
on the same or distinct plants. P. laciniata
and vulgaris are common on our coasts.

BIBL. Harvey, Brit. Mar. Alg. p. 261.
pi. 25 A ; Thuret, Memoires de la Societe de
Cherbourg, ii. 1854, Ann. des Sc. nat. 4 ser.
iii. p. 5 ; Derbes and Solier, Supplement aux
Comptes Rendus, i.

PORPHYRACE.E.— AtribeofFlorideous
Algae (according to Thuret), of low organiza-
tion, forming Ulvoid membranous fronds or
strata of Confervoid filaments, of a purple or
red colour. They are placed among the
Ulvaceae by most authors, but differ in the
absence of the zoospores and, according to
Thuret, the presence of tetraspores and an-
theridia. They are marine, Porphyra grow-
ing on rocks and stones, Bangia the same,
or parasitic upon Zostera, Algae, &c.

Synopsis of British Genera.

I. Porphyra. Frond plane, membranous,
very thin, of a purple colour, with oval spores
in sori, and tetraspores (square) scattered all
over the frond.

II. Bangia. Frond filiform, tubular, com-
posed of numerous radiating cells in trans-
verse rows, enclosed within a continuous
hyaline sheath.

PORPHYRIDIUM, Nag. = Palmella
cruenta ?
PORRIGO. See FAVUS.

POTASH , AND ITS SALTS.

Caustic Potash. — The strength of the solu-
tion may be that of the Liq. Potassae of the
Pharmacopoeia. But we prefer a stronger
solution made with 1 drachm of th'e potassa
fusa or stick-potash of the shops, and 1 liquid
oz. of water. The solution should be allowed
to settle, and the clear portion poured off
into one of the test-bottles (!NTR. p. xxiii.).

Some remarks are made upon the action
of potash in the INTR. p. xxxviii., and others
under the heads of the tissues, &c. On
treating organic substances with this re-
agent, the cystic-oxide-like crystals of the
carbonate (PL 6. fig. 7*) will frequently be
formed.

Chromates of Potash. — The bichromate is
used in the preparation of the chromate of
lead for injection. Its crystals polarize well.
The neutral chromate is also sometimes used
for preparing injections.

Nitrate of potash, nitre, or saltpetre. —
This salt is dimorphous : it usually crystal-

lizes in six-sided prisms with dihedral sum-
mits, or in other forms belonging to the
right rhombic prismatic system. But some-
times it assumes the form of obtuse rhom-
bohedra, resembling those of nitrate of soda,
and referable to the rhombohedric system.

The crystals exhibit very beautifully the
phaenomena of ANALYTIC CRYSTALS.

BIBL. That of CHEMISTRY.

POTTIA, Ehr.— A genus of Pottiaceous
Mosses, including some of the Gymnostoma
and Weissife of Hedwig and others. Wilson
separates as AnacalyptcB the species with a
peristome (fig. 611).

Fig. 611.

Pottia csespitosa.
Fragment of peristome.
Magnified 50 diameters.

POTTIACEJE.— A tribe of Pottioid
Mosses.

Synopsis of Genera.

I. POTTIA. Calyptra dimidiate. Peri-
stome simple or wanting; if present, com-
posed of lanceolate articulate teeth, simple
or with a longitudinal line, rugulose and
somewhat fleshy.

II. TRICHOSTOMUM. Calyptra dimidiate.
Peristome simple, sixteen teeth split to the
base into two cilia, or irregularly and there-
fore into more than two, erect, stiff, and not
twisted.

III. BARBULA. Calyptra dimidiate-hood-
shaped. Peristome simple, ciliiform; cilia
thirty-two, solitary or approximated in pairs
on a more or less exserted basilar membrane,
split into two cilioles behind, very long,
articulate-rugulose, twisted to the left, rarely
to the right, in one or several spires, hygro-
scopic. Cells of the operculum and calyptra
twisted in the same way.

IV. CERATODON. Calyptra dimidiate.
Peristome simple ; teeth sixteen, connate at
the base into a cellular membrane, split into
two long, nodosely articulated, dark-coloured
arms, paler on each side, densely trabecu-
lated at the lower part. Capsule thick-
skinned, shining, nodding, with a somewhat
nodose collum ; annulate.

V. WEISSIA. Calyptra dimidiate. Peri-
stome simple or wanting ; if present, com-

2M

POTTIOIDEJE.

[ 530 ]

PREPARATION.

posed of sixteen lanceolate, or subulate, entire
or cribrose equidistant teeth.

POTTIOIDE^E.— A family of operculate
Mosses belonging to the Acrocarpi, but
sometimes Pleurocarpous by innovating
branches. Leaves of very varied form, with
a terete nerve ; cells parenchymatous, per-
fectly hexagonal or squarish six-sided, always
looser at the base, sometimes very lax, more
or less pellucid, often exceedingly transpa-
rent, large, fragile, rigid, foraminate, bearing
on the upper side solitary papillae or several
confluent papillae (hence often truncate and
tuberculate at the apex), placed in the mid-
dle of the cell ; cells mostly full of chloro-
phyll, sometimes with a primordial utricle,
often very small and thickened. Capsule
erect, rarely inclined, oval, elliptic or pear-
shaped oblong, smooth or striate, the oper-
culum mostly conical or beaked.

This family is divided into three tribes :

1. CALYMPERACE^E. Basilar cells of
the leaves rigid, hyaline, often very brittle,
more or less ample, empty, distinctly fora-
minated.

2. POTTIACEJE. Basilar cells of the leaves
soft, pellucid, longer, mostly empty, rarely
containing a persistent primordial utricle.

3. ORTHOTRICHACE^E. Basilar cells of
the leaves with only the very lowest soft,
the upper mostly thickened, rarely pellucid
and normal.

PRASIOLA, Meneghini.— A genus of Ul-
vaceae (Confervoid Algae), separated from
Monostroma, Thuret, by the arrangement of
the quadrigeminate cells of the frond in lines,
with wide intercellular walls, from Ulva by
the existence of only a single layer of cells,
and from both by the absence (?) of a repro-
duction by zoospores; from Schizogonium
by the frond consisting of expanded plates.
The species are included under Ulva (the
terrestrial forms) in the Brit. Flora and
Harvey's Algce, ed. I. They have recently
been examined by Jessen, who finds the
fronds proliferous at the margins; the ' spores'
he describes as consisting of motionless cells
formed of the entire contents of cells of the
frond, set free by the solution of the parent-
cell. The reproduction of this group seems
to us to require further investigation. Jes-
sen includes here the British species, P. ca-
lophylla, crispa, furfuracea, and a form
which he names P. stipitata, differing from
the last chiefly in the narrowly wedge-shaped,
stipitate character of the frond; probably
the three last constitute only varieties of one
species.

BIBL. Jessen, Prasiolte Monograph. Kiliae,
1848; Harvey, Brit. Alg. ed. 1. p. 171 ;
Hassall, Brit. Freshw. Alg. p. 297. pi. 77,
78; Kiitz. Sp.Alg.pM72.

PREPARATION of microscopic objects
for examination and preservation. — Some
remarks on the former point will be found
in the INTRODUCTION, p. xxviii. ; and under
many of the general articles, such asD i ATO M A-
CE.E, COAL, OVULE, See., special directions
are given. A few general remarks may be
offered in this place. The parts of bodies
are separated by means of the mounted
needles under a dissecting microscope, or by
means of sections, according to the nature
of the views which it is desired to obtain.
With regard to the former operation, it need
be observed merely that it is usually to be
performed under water, in a watch-glass,
glass cell, or other convenient holder.

The preparation of sections is a more com-
plicated process. Soft parts of animals are
best sliced by means of a Valentin's knife ;
but firmer structures, such as horn, may be
cut with a sharp razor. Vegetable structures
in general are sliced with a razor, which
must be kept very sharp, and rubbed on a
strop frequently while in use, and always
before putting it away. Fresh stems, thick
leaves, &c. may be simply held in the fin-
gers; thin objects, such as leaves, petals,
&c., are best placed in a split cork, the
halves of which are kept together by inser-
tion in the neck of a vial or a test-tube,
which at the same time serves as a handle.
Sometimes it is advantageous to immerse
objects, especially soft or very small ones, in
thick mucilage of gum-arabic, and to allow
this to dry until tough enough to be cut by
the razor ; the slices are freed from gum by
immersion in water. Dry objects, such as
wood, dried leaves, seeds, &c., must be soft-
ened by soaking in water before slicing.
Small firm objects, such as seeds, are most
easily sliced when fixed in a bit of white
wax or stearine, which may be done by
placing them on the surface of the latter,
and stirring them into the substance melted
by the application of a hot wire. Most slices
of vegetable objects are obscured by air-
bubbles engaged in the intercellular pass-
ages, &c. In old wood and similar objects
the air is readily driven out by heat ; in fresh
structures, where heat may coagulate or dis-
solve matters, the air may be allowed to
dissolve or escape by itself, which requires
time, or may be removed by exhaustion. A
substitute for a regular air-pump may prove

PREPARATION.

[ 531 ]

PRESERVATION.

useful to the microscopist, consisting of a
piece of thick and stout glass tube, closed at
one end, containing a tight-fitting piston,
with a valve opening upwards; the object
being placed in water (or other liquid) at the
bottom, a single raising of the piston, or at
all events, two pulls, will draw out all the
air, and the water will take its place as the
piston is lowered. This apparatus may be
used also for saturating dry objects with oil
of turpentine (for mounting in balsam), or
with oil, to produce transparency.

Sections of woods, &c. which are to be
mounted in liquids, should be soaked for
some little time in spirit or turpentine, to
remove resins, &c. A special apparatus is
made for slicing such objects, but this is not
of much use except when large numbers of
very perfect sections of the same kind are
required for purposes of sale, &c.

It need scarcely be said that sections re-
quire to be made in various directions in
studying objects by these means. Thus
stems should be sliced horizontally, and per-
pendicularly both parallel to the medullary
rays and at right angles to them, &c.

The structure of laminated shells, &c.
may often be seen in fragments broken off
by the point of a knife. But sections of
shell, bone, &c. are best made by sawing off
thin pieces with a frame-saw having a watch-
spring blade, grinding them down upon a
water-of-Ayr or some other stone, and po-
lishing them upon a clean leather-hone or
strop with putty-powder and water, finally
upon a dry hone alone.

Sections of very hard substances, as agate,
&c., are so easily made by jewellers, that a
description of the process is scarcely neces-
sary. They are made by means of a circular
iron plate, made to rotate by a lathe, its
margins being coated with a mixture of oil
and diamond dust. They are then ground
upon a plate of metal with emery-powder
and water, and polished upon a flat surface
of pitch with putty-powder and water.

In grinding and polishing sections of hard
structures, it is often requisite to cement
them to a slide with Canada balsam, heat
being applied until the balsam has become
so hard as to fix the section firmly to the
slide. As soon as one side has been polished,
the section is removed from the slide, the
balsam being rendered soft by heat, the po-
lished side cemented to the glass, and the
other side polished. The balsam may after-
wards be separated from the section by ma-
ceration in oil of turpentine, aether, &c.

PRESERVATION, of microscopic ob-
jects.— Under this head we shall consider
the arrangement of microscopic objects for
permanent preservation, or the MOUNTING
of them, as it is called, supposing that they
have been prepared (PREPARATION) in such
manner as to render this desirable. We shall
first notice —

Dry objects, or those which exhibit their
structural peculiarities in the dry state.
These are sometimes mounted alone, at
others when immersed in some preservative
compound.

1. In the dry and uncovered state, they
are occasionally mounted upon disks of cork,
leather, or pasteboard, the surface upon
which the object is to be placed being black-
ened by a coating of very fine lamp-black
mixed with warm size or gum-water, or by
a piece of dull black paper pasted upon it ;
the simplest way of making the disks is to
paste black paper upon thick soft leather,
and cut out the disks with a punch, like gun-
wads. The object is fastened to the disk
with a little solution of marine glue in naph-
tha or gum. The disks are sold in the shops.
They are usually transfixed with a pin, by
which they may be fixed in the forceps under
the microscope, and may be fastened to the
bottom of a box lined with sheet-cork when
not in use. The advantage of this plan is
its simplicity; its greater disadvantage,
however, is that the objects are liable to in-
jury, and become covered with dust. It
answers very well for common objects, seeds,
minute lichens, &c.; but when the objects
are of value, they should be mounted in a
cell.

2. The cell may be made of a square piece
of card-board or pasteboard, of suitable
thickness, with a hole punched in the mid-
dle, fastened to a slide by marine glue or
Canada balsam; the object being fixed to
the slide by a little of either of the above
cements, and a thin glass cover cemented to
the card-board. Or the whole may be fast-
ened together with paste : first a piece of
black paper upon the middle of the slide,
then the perforated square, next the object,
and lastly the cover. The square of paste-
board may be replaced by a glass ring, a
perforated square of glass, or a piece of sheet
gutta-percha.

3. When the objects are minute or very
thin, the square of pasteboard may be dis-
pensed with, and they may be mounted thus :
they are to be laid upon a slide, and a cover
of thin glass placed upon them ; a piece of

2M2

PRESERVATION.

[ 532 ]

PRESERVATION.

paper larger than the cover, with a portion
cut from the middle larger than the object,
is then covered with paste, and a minute or
two allowed to elapse, that the paper may
become thoroughly imbued with it, the su-
perfluous paste being removed with the paste-
brush ; the paper with the pasted side down-
wards is then laid upon the cover and the
adjacent portions of the slide, and gently
pressed with a cloth, that it may be accu-
rately applied to the glass surfaces. The
whole is then allowed to dry. The principal
point in this process is the complete removal
of the superfluous paste before the paper is
applied. If this be not effected, it will be
drawn by capillary attraction between the
cover and the slide, and reaching the object,
will spoil it.

4. A very secure method of mounting dry
objects which are not altered by heat, con-
sists in laying a ring or square of black japan
upon a slide, the thickness of the layer being
adapted to that of the object, and applying
a pretty strong or long-continued heat until
the cement becomes perfectly hard when
cold. The object is next placed within the
ring, a cover laid on, and heat applied until
the cement becomes liquid. Gentle pressure
then brings the cement and the margins of
the cover into contact; and when the cement
becomes cold, the cover is firmly fixed to
the slide.

5. Another method of fastening the cover
to the slide is by the use of electrical cement
and balsam (CEMENTS, p. 125, 5 b) mixed
with 1 or 2 parts of tallow.

6. Many dry objects can be well preserved
by—

Mounting in Canada Balsam. — When this
is to be done, care must be taken that they
are thoroughly dry, otherwise they will ac-
quire a milky appearance from being sur-
rounded by minute drops of water. Some
objects in drying curl up or become deformed,
although their minute structure may not be
essentially changed; this may be prevented
by confining them between two slides tied
together with thread, or held together by
india-rubber rings, sealing-wax applied at the
two ends, or by a folded strip of brass with
the ends riveted. If the objects be of tole-
rable size, they are then soaked in oil of
turpentine kept in an ointment-pot covered
with a lid, for some hours, or even days,
until the air is entirely displaced from them
by the turpentine. The latter will often also
remove the colouring matter from some ob-
jects, as parts of insects, which may or may

not be desirable ; hence the duration of the
process must vary accordingly. A clean slide
is then warmed over the flame of a spirit-
lamp, or upon a stove, and some clear bal-
sam placed in the middle of it, and rendered
more liquid by further gentle heat ; the ob-
ject is then carefully removed from the tur-
pentine with forceps, drained, and laid upon
the warm balsam. Some more balsam is
then allowed to fall from the warmed wire
(BALSAM) upon the object, and when this is
well covered with it, a warmed cover is gently
laid upon its surface. The superfluous bal-
sam then escapes at the sides of the cover,
and this should be aided by gentle pressure.
The slide is next maintained at a gentle heat
upon a warm mantelpiece, or a piece of tin-
plate (!NTR. p. xxiv.), until, when allowed to
cool, the balsam is perfectly hard. As soon
as this is the case, the superfluous portions
are cut away or scraped off with a knife, the
surfaces of the glasses cleaned from any
residue by a cloth wetted with oil of turpen-
tine, and some sealing-wax varnish applied
to the edges of the cover and the adjacent
portions of the slide.

7. The success of the operation depends
mainly upon two circumstances, viz. the
object having been thoroughly dried, and
the exclusion of air-bubbles. The former
constitutes no difficulty, time being all that
is required ; but the latter requires that the
object shall previously have been thoroughly
moistened with the turpentine, and that the
balsam shall have been added to the object,
when laid in the balsam upon the slide, be-
fore so much of the turpentine has evapo-
rated as will allow air to enter any minute
cavities in the object. The heat applied
should also be gentle; and if the direct flame
of a spirit-lamp be used, its application
should be made rather to some portion of
the slide near that upon which the object is
placed, than directly beneath the object. If
much heat be applied, bubbles of the vapour
of the turpentine will disfigure the object ;
but these will mostly vanish if the object be
kept for some time at a gentle heat.

If air-bubbles have found their wray into
the object, the slide must be macerated in
oil of turpentine until the balsam is dissolved
and the object liberated, and a fresh mount-
ing made.

8. If the object be large, it must be
mounted in a cell. A glass ring (sold in the
shops) of suitable thickness must first be
cemented to the slide by balsam; more bal-
sam is then added until the cavity is filled,

PRESERVATION.

[ 533 ]

PRESERVATION.

the object next added, and the cover ap-
plied.

9. If the object be minute, its removal for
maceration in the turpentine is not requisite,
and might entail the loss of the object. It
must then be laid upon a slide, a drop or
two of turpentine added, and the whole
warmed until no air-bubbles are visible.
The cover is then removed, most of the tur-
pentine drained off, balsam added from the
warmed wire, and the cover applied as be-
fore.

10. If air-bubbles remain in parts of a
minute object, a cover should be applied,
turpentine added, and the slide held over a
lamp until the turpentine boils, and the
bubbles disappear on cooling. The cover is
then removed, most of the turpentine al-
lowed to evaporate, the balsam added, and
the cover re-applied.

11. Mounting in liquid. — The structure of
many objects is so altered by drying, that
they require to be mounted in some preser-
vative liquid. These, if of considerable size,
must be mounted in glass cells.

12. The cells may consist of glass rings, i. e.
portions cut transversely from pieces of glass
tubes, of various sizes, according to the di-
mensions of the objects. In using these,
the ring is first warmed in the flame of a
spirit-lamp, being held by steel forceps j one
of the ground surfaces of the ring is then
covered with marine glue or balsam pre-
viously melted in the same flame ; the sur-
face of the slide to which the ring is to be
cemented is then heated in the flame, and
whilst it is hot, the surface of the ring coated
with the melted cement is applied to it, and
the ring pressed firmly, so as to displace
the superfluous portions. When cold, these
are to be removed with the point of a knife ;
sometimes a little solution of potash, oil of
turpentine, or naphtha is required for this
purpose. The cell is then complete, ex-
cepting the lid or cover, which consists of
a circular plate of thin glass, of slightly less
diameter than that of the outer margin
of the glass ring. The cell is now to be
filled with the preservative liquid, the object
placed in it, and the cover applied, being
made to slide over the upper surface of the
ring, so as to displace any excess of liquid,
and prevent the admission of air-bubbles.
If the quantity of liquid at first put into the
cell be not sufficient, more must be added,
until slight excess is present ; the superfluous
portions may be removed by a piece of blot-
ting-paper, and the margin of the cover and

ring very carefully wiped clean with a silk
handkerchief, so that the surfaces may be
free from all traces of the preservative liquid.
The exposed parts of the upper surface of
the glass ring, and the adjacent margins of
the cover, are then to be coated lightly with
one of the liquid cements, by means of a
camel's-hair pencil ; and when the first coat
is dry, another must be laid on, so that the
edges of the cover and the adjacent parts of
the glass ring may be firmly cemented toge-
ther, and the cell completely closed, so that
no evaporation of the contained liquid can
take place.

The important points in this process are,
that the heated cement used to fasten the
ring to the slide must accurately coat every
portion of the two surfaces in apposition,
and that the surfaces to which the liquid
cement is applied must be perfectly clean
and dry, so that the cement may come into
contact with the surfaces of the glass.

13. When the objects are very large, the
rings may be conveniently replaced by cells
constructed of slips of glass, arranged so as
to constitute four sides of a box, the bottom
of the box being formed by the slide, and
the top by a plate of thin glass : the pieces
should be cemented together by marine
glue.

14. Smaller cells may be made with ma-
rine glue, melted, dropped upon a slide, and
flattened whilst warm with a piece of wetted
glass, the superfluous portions and central
portion cut away with a knife ; should the
marine glue become loosened from the slide,
it may be re-fastened by heat, and if the
upper surface be not perfectly flat, it may
be made so by grinding with emery-powder
and water upon a plate of metal or upon a
stone.

Minute objects may be mounted in liquid
in a variety of ways, the choice of which
will vary according to the option of the
microscopist. They are generally mounted
in shallow cells, the sides of which are formed
by varnish.

15. The old method consisted in placing
the object upon a slide, adding a drop or
two of the preservative liquid, applying the
glass cover, adding more of the liquid, or
removing excess with blotting-paper, until
the space between the slide and cover is
accurately filled, then applying to the mar-
gin of the cover and the adjacent portions of
the slide a coat of some liquid cement, as
gold-size, black japan, &c. Objects thus
mounted keep well for a time, but the ce-

PRESERVATION.

[ 534 ]

PRESERVATION.

ment soon apparently runs into the space
between the cover and the slide, and the
object becomes spoiled. It is often requisite,
however., to mount an object in this way,
which may be lying upon a slide, perhaps in
some peculiar position which it is important
for it to retain ; when this is the case, the
electrical cement with balsam and tallow
should be used, and there is no fear what-
ever of change, provided spirit be not used
as the preservative liquid.

16. Whenever it is possible, then, a cell-
wall should be previously formed, by laying
a ring or square of one of the liquid cements
upon the slide with a camel's-hair pencil,
and applying a continued heat until it be-
comes thoroughly hard when cold. The
cements generally used are — black japan;
gold-size with which a little finely powdered
litharge has been well mixed, immediately
applied, as it soon hardens; sealing-wax
varnish ; solution of marine glue in naphtha,
or of Canada balsam in aether, or the balsam
alone. If the upper surfaces of the rings or
squares formed of these compounds, when
thoroughly dry and hard, be not perfectly
flat, they may be made so by grinding alone,
or with emery and water, upon a piece of
metal, marble, or a stone. The object is
then placed in the cell, the preservative liquid
added, and the cell closed as above described.

The following are the most important
preservative liquids and compounds : —

Thwaites's liquid — Is thus prepared : to
16 parts of distilled water add 1 part of
rectified spirit, and a few drops of creosote
sufficient to saturate it ; stir in a small quan-
tity of prepared chalk, and then filter. With
this liquid mix an equal measure of camphor-
water, and before using, strain through fine
muslin. Recommended by Mr. Thwaites for
preserving freshwater Algae, as having but
little action upon the endochrome.

Ralfs liquid. — Prepared with bay-salt and
alum, of each a grain, distilled water 1 oz. ;
dissolve. Recommended as a readily pre-
pared substitute for the former, in the pre-
servation of the Algae (Desmidiaceae).

Acetate of alumina. — 1 part of the salt to
4 parts of distilled water. Mr. Topping finds
this the best preservative for delicate vege-
table colours.

Distilled water. — Very often used for pre-
serving Algae ; but perhaps camphor-water
would be better.

Camphor-water — Is prepared by digesting
distilled water with a lump or two of cam-
phor.

Spirit and water. — Proof spirit may be
prepared by mixing 5 measures of rectified
spirit with 3 of water. It is frequently used
for preserving animal structures, organs,
injections, &c. Delicate preparations may
be kept in a mixture of 1 part of spirit with
5 parts of water. Dilute spirit should never
be used as a preservative, when it can possi-
bly be avoided.

Creosote water — Is prepared by filtering a
saturated solution of creosote in 1 part of
rectified spirit, after mixing it with 20 parts
of water. It is recommended for preserving
preparations of muscle, cellular tissue, ten-
don, cartilage, &c.

Arsenious acid. — A preservative liquid is
made of this substance by boiling excess
of the acid with water, filtering the solution,
and adding 2 parts of water. It is a very
good preservative of animal tissues.

Corrosive sublimate. — Harting recom-
mends a solution of this substance as the
best preservative for the corpuscles of the
blood, nerve, muscular fibre, &c.; the strength
of the solution must vary from 1 part in 200
to 500 of water, according to the nature of
the object. Thus, the blood-corpuscles of
the frog require 1-400, those of birds 1-300,
of mammals 1-200.

Salt (chloride of sodium) and water, 5 gr.
to the 1 oz. — Was long since recommended
for the preservation of tissues, but is not
much used, because fungi are apt to grow in
it, which might, however, be prevented by
saturating it with camphor by digestion.
M. Corti has found "a tolerably concentrated
solution" the best preservative for the deli-
cate structures and nerve-cells of the inter-
nal ear.

Carbonate of potash. — 1 part dissolved in
from 200 to 500 of distilled water, is a good
preservative of the primitive nerve-tubes.

Arsenite of potash. — 1 part dissolved in
160 of water has been found useful for pre-
serving the primitive nerve'tubes.

Glycerine — May be used in the same
cases as chloride of calcium. If used in a
diluted state, fungi are apt to grow in it.

Canada balsam (See BALSAM, CANADA).
— When rendered thinner by digestion with
a little aether at a gentle heat, it forms a
liquid cement.

Gum-water (see CEMENTS, p. 126. § 14).
— The solution should be very thick, so as
to flow with difficulty from the end of a
wire. It may be used like balsam, but with-
out heat. The residue is very apt to crack
when dry ; this may be prevented by apply-

PRESERVATION.

[ 535 ]

PRESERVATION.

ing a thick coating of varnish around its
margins.

Chloride of Calcium (CALCIUM, CHLO-
RIDE OF). — Objects maybe mounted in this
solution without closing the cell, by pasting
two narrow strips of paper transversely upon
a slide, leaving a greater interval than the
breadth of the object ; the latter is then laid
upon the slide, a small quantity of the solu-
tion added, and a cover applied. The solu-
tion must not touch the paper. The cover
may be fixed to the paper on the slide by the
electrical cement with balsam and tallow.
It is best, however, to close the cell.

Chloride of zinc. — This is perhaps the
best preservative of animal tissues for micro-
scopic examination known. It exerts a slight
coagulating action, but this is not sufficient
to impair seriously the peculiarities of the
objects, and the large portions of all struc-
tures which may require to be subsequently
examined should be kept in it. The strength
must vary according to the softness of the
tissues. The best ordinary strength is in
the proportion of 20 grains of the fused
chloride to 1 oz. of water, or 400 grains to
the pint. A lump of camphor should be kept
floating upon the surface of the solution in
the stock-bottle.

Goadby's solutions. — These are of three
kinds. The first is made with — bay-salt
(coarse sea-salt) 4 oz., alum 2 oz., corrosive
sublimate 2 grains, boiling water 1 quart.
This is too strong for most purposes, and is
only to be employed where great astringency
is required to give form and support to deli-
cate structures.

The second is made with — bay-salt 4 oz.,
alum 2 oz., corrosive sublimate 4 grains,
water 2 quarts. This is recommended for
general use, and as best adapted for perma-
nent preparations. Mr. Thwaites recom-
mends it for marine Algae; but we have
found chloride of calcium answer for this
purpose, and it is much more secure. When
carbonate of lime exists in the preparations,
as in the Mollusca, the following should be
used : — take of bay-salt 8 oz., corrosive sub-
limate 2 grains, water 1 quart. Marine ani-
mals require a stronger liquid of this kind,
made by adding about 2 oz. more salt to the
last.

These liquids are mostly adapted for the
preservation of large objects, in which the
minute structure will not require to be exa-
mined. If used otherwise, the corrosive
sublimate should be omitted.

Deane's compound. — This is made with —

gelatine 1 oz., honey 5 ozs., water 5 ozs., rec-
tified spirit £ oz., and 6 drops of creosote.
The gelatine is soaked in the water until soft,
and then added to the honey, which has
been previously raised to a boiling-heat in
another vessel ; then boil the mixture, and
when it has cooled somewhat, add the creo-
sote mixed with the spirit; lastly, filter
through fine flannel.

When about to be used, the compound
must be slightly warmed, and the object
placed in a drop upon a previously warmed
slide. The cover is then to be breathed
upon and applied, taking care to exclude
air-bubbles; a coating of black japan or
Brunswick black around the margin com-
pletes the whole.

Chromic acid. See p. 141.

Remarks. — It may be well to make a few
general remarks upon the selection and use
of the preservative liquids, and the method
of mounting objects.

That preservative liquid should always be
chosen which exerts least action upon the
structure of the object which it is required
to preserve.

When drying the object does not destroy
its peculiar structure, and the object is not
very transparent, balsam should be used.

If the structure be destroyed by drying,
and the object be not impaired by endos-
mosis, the chloride of calcium or glycerine
is best. Other circumstances may render
these preservatives desirable ; thus, the mi-
nute parts of the mouth of the Acarina are
best seen and preserved in balsam, whilst
the general form of the body is best retained
when the animals are immersed in chloride
of calcium or glycerine.

Objects to be mounted in a preservative
liquid should be placed in a watch-glass ; if
existing in water, as much of this as possible
should be poured off, or removed with a
pipette or blotting-paper, and the preserva-
tive liquid added, and this operation repeated
that the water may be entirely displaced.
The use of spirit should always be avoided
if possible, because, although slowly, yet
surely, it will act upon the cement used to
close the cell.

If objects be mounted according to the
method described in § 15, p. 533, the elec-
trical cement and tallow compound should
be used ; if black japan or gold size be made
use of, the objects will certainly be spoiled.

The liquid cements used to close the cell
should be applied in several layers, each
being allowed to dry before the next is applied.

PRIMORDIAL UTRICLE. [ 536 ] PRIMORDIAL UTRICLE.

The preservative liquid must not be capa-
ble of exerting any action upon the cements
used in making or closing the cell.

If chloride of calcium or glycerine be used
as the preservative liquid, when the first
coat of liquid cement used to close the cell
has become dry, the slide and cover should
be washed gently with a sponge and distilled
water, then dried with blotting-paper or a
silk handkerchief, and the next coat of var-
nish applied.

The deeper the cell, the less the chance
of the object being spoiled.

As soon as objects are mounted, the slides
should be labelled with a square or circular
piece of paper pasted upon them, the name
and other particulars being expressed in
writing. The name, &c. may also be
written upon slides with a diamond, but the
paper labels should always be used, other-
wise much time will be lost in searching for
and distinguishing particular objects in the
cabinet.

BIBL. Treatises upon the Microscope;
Harting, Het Mikroscop, Edinb. Monthly
Journ. 1852, or Ann. Nat. Hist. 1852. x. 311;
Reckitt, Ann. Nat. Hist. 1845. xvi. 242;
Berkeley, ibid. 1845. xvi. 104 ; Ralfs, Brit.
Desmid. ; Smith, Brit. Diatom. ; Corti,
Siebold and Kolliker's Zeitschr. iii. 134;
Griffith, Ann. Nat. Hist. 1843. xxi. 113;
Tulk and Henfrey, Anatomical Manipula-
tion, 1844. p. 128.

PRIMORDIAL UTRICLE (utriculus
primordialis, primordialschlauch). — This
name has recently come into general use, at
the suggestion of Mohl, to indicate a pecu-
liar portion of the contents of the cellulose
sac constituting a vegetable cell; by that
author it is regarded as a distinct structure,
by others its separate existence is doubted,
while recently it has been proposed by
Pringsheim to transfer the name to a struc-
ture different in its nature from that which
Mohl has described as his primordial utricle.
As the formations comprehended under this
name are of great importance in the deve-
lopment of vegetable cells, a little detail
must be entered into in explaining this sub-
ject.

If a cell of the pulp of any succulent fruit,
a cell of yeast, or cells in sections taken
from the delicate nascent tissues of any
growing part of plants, are placed in water,
the entire contents will soon be seen to
retract from the cellulose wall, leaving a
clear space, filled with transparent liquid,
between the latter and a sharply-defined line

bounding the contracted or coagulated con-
tents (PL 38. figs. 1, 2, 10-12). The addition
of tincture of iodine makes the conditions
still more clear. If the parent-cells of
pollen-grains or spores are treated thus,
just before the development of the cellulose
wall of the special parent-cells (see POLLEN),
the four portions of the contents of the
parent-cell contract and separate, and each
portion, containing its own granular struc-
tures and nucleus, appears bounded by a
well-defined line (fig. 612). This well-

Fig. 612.

CM-

Fig. 612. Parent- cells of pollen-grains just after the
separation of the contents into four portions, treated with
iodine. CM, the parent-cell. P, the protoplasmic por-
tions, each with a nucleus and a well-defined outline
at the surface of the primordial utricle. Magnified 250
diameters.

Fig. 613. Cells of Protococcus multiplying. The green
granular contents are bounded by the definite outline of
the primordial utricle ; the primary and secondary cellu-
lose parent-cell membranes are represented as separated
from each other. Magnified 400 diameters.

defined line presents in this condition the
appearance of a delicate membrane or pellicle
enclosing the entire contents. The action
of acids, or spirit, and iodine, reveals the
existence of a similar set of conditions in all
actively vegetating cells, and in most cases
a more or less thick viscous layer of the
protoplasm is found lining the cellulose wall
before the application of the reagents. Since
the line indicating the boundary of the con-
tents cannot be distinctly seen until the
contents have retracted from the cellulose
wall, and since the protoplasm is always
coagulated by the action of the reagents, it
is a subject of discussion whether the film
forming the well- denned line on the surface
of the contracted contents is a true structure,
or only a pellicle produced by the coagula-
tion of the surface of the protoplasm, just as
a <f skin " forms over size, or other similar
substances when they dry up in the air.
There is great ground for believing the latter
view to be correct, but the term primordial
utricle, as used by Mohl, is applied to the
protoplasmic layer lining the cellulose wall,

PRIMORDIAL UTRICLE. [ 537 ] PRIMORDIAL UTRICLE.

whether it be merely a gelatinous investment
in its natural condition, or a true membrane,
because this formation, whether a membrane
or merely a layer of viscid protoplasm, exerts
in any case a special and most important
function. Among the principal reasons for
doubting the independent existence of a
pellicular nitrogenous membrane, are the
following facts : very young cells often
appear filled with a dense protoplasm (young
cells of antheridia of Cryptogamia, embryo-
sacs of many flowering plants, cells about to
produce zoospores in the Confervoids, &c.),
which may produce numerous new cells by
merely breaking up into separate portions,
and thus the function of the primordial
utricle is shared by the entire mass of
contents. Young cells of nascent tissues,
presenting this condition at first, acquire
the so-called primordial utricle afterwards,
simply by the dense contents becoming
excavated, as it were, as the cell-wall
expands, and following this in its growth, so
that the originally dense homogeneous mass
becomes a hollow sphere with the centre
occupied by watery cell-sap ; in other cases
the originally homogeneous protoplasm be-
comes excavated by numerous water-vesicles,
and thus honey-combed, until it forms a
mere reticulation of protoplasmic threads
upon the wall or stretched across the cavity.
But the point is by no means clear at present.
Indeed, the protoplasmic layer lying upon
the wall of the cell presents a complex
arrangement of parts in some cases: A. Braun
correctly distinguishes three layers in Hy-
drodictyon ; there are three in Chara, where
the intermediate one contains the chloro-
phyll-granules, and the inmost forms the
circulating mass ; a distinct layer is left
after the discharge of the zoospores in Cla-
dophora, &c. Pringsheim has lately asserted
that he has coloured blue by Schulz's
reagent, the outermost layer of the pellicular
structures detached from the cell-wall by
acids, &c. in the Confervae, and hence he
assumes that Mohl's primordial utricle is
really the most recently-formed of the layers
of cellulose belonging to the permanent cell-
wall, and that this is formed by a chemical
transformation of the superficial stratum of
the protoplasm. Possibly the last cellulose
layer of thickening may be brought away
from the wall by reagents, but it would
cause a confusion of ideas to call this the
primordial utricle, even if it be the pellicular
structure seen under some circumstances by
Mohl and others. The term properly applies

to the formative stratum of all independently
vitalized masses of protoplasm, capable of
secreting layers of cellulose which in the cavi-
ties of parent-cells form layers of thickening
or septa, or, in a free condition, the primary
walls of new and independent cells. Thus,
as explained under the head of CELL-FORM-
ATION, the primordial utricle or formative
protoplasmic layer is the active agent in cell-
division, and the layer forming the surface of
the isolated portions of contents of parent-
cells produces the new cell-wall in all cases
of free cell-formation, whether taking place
in parent-cells, or, as in the case of the zoo-
spores of Algae, after escape from the latter.

In many of the Algae, some of the indivi-
dual cells regularly exist for a certain period
as masses of protoplasm devoid of a cellulose
coat, as for example, the spores ofFucus and
its allies, and the active zoospores of Con-
fervoids ; and these bodies, although present-
ing a well-defined outline, do not appear to
have a properly developed membrane on the
surface, which merely appears to be denser
than the semifluid central portion. These
bodies withdraw themselves evidently from
the definition of a vegetable cell as ordinarily
given, and even the existence of a proto-
plasmic pellicle upon the surface of the
primordial utricle cannot be shown ; never-
theless they constitute all the essential living
part of a vegetable cell, and indicate most
clearly the undoubted fact, that the cellulose
walls, that is to say all the really solid and
permanent portions of vegetable structure,
are mere skeleton or shell for the protoplas-
mic or nitrogenous structures. Cohn has pro-
posed for the independently vitalized masses
of l cell-contents ' the title of primordial cells,
and they do correspond to many of the forms
of the ' cells ' of animal tissues, and of the
' unicellular' animal organisms, AMCEBA, &c.,
but none of these are really cells according
to the original idea : hence the transfer of
names causes confusion. Were not the
name nucleus already taken for the supposed
centre of vitality of those bodies, it would be
applicable, as would be that of cytoblast ;
but as these are occupied, the name of pro-
toplast, or as Huxley proposes, endoplast,
might be adopted, and certainly would be
preferable to calling the bodies " primordial
cells."

The relation of the " primordial utricle "
or formative nitrogenous layer, to the SE-
CONDARY DEPOSITS of cell-walls, is not yet
clearly ascertained. Criiger has recently
asserted their essential agency in producing

PROEMBRYO.

[ 538 ]

PROTOCOCCUS.

these, as will be noticed under that head and
under SPIRAL STRUCTURES.

The protoplasmic substances indistin-
guishably connected with the so-called pri-
mordial utricle, are also the active agents in
the ROTATION or circulation of the cell-
contents. Further relations of these nitro-
genous matters are also dwelt upon under
CHLOROPHYLL and STARCH.

BIBL. Von Mohl, Botan. Zeit. ii. p. 273.
(1844), transl. in Taylor's Scient. Mem. iv. p.
91, Vermischte Schrift. p. 362; Henfrey, Ann.
N. H. xviii. p. 364; Nageli, Zeitschr.f. Wiss.
Bot. heft 1 (1844), & 3, 4 (1846), transl. in
Ray Soc. Vols. 1845. p. 215 & 1849. p. 94 ;
Alex. Braun, Verjungung, 8fc. (trans, in Ray
Soc. Vol. 1853. p. 121 et seq.)-, Cohn, Nova
Acta, xxii. p. 605, transl. in Ray Soc. Vol.
1853. p. 517 ; Pringsheim, Ban. u. Bild. d.
Pflanzenzelle, heft 1. Berlin, 1854; Hartig,
Bot. Zeitung, xiii. p. 393 et seq. 1855;
CrUger, ibid. p. 601; Mohl, ibid. p. 689.

PROEMBRYO.— The term applied to
the structure first produced from the ger-
minal vesicle of Flowering Plants, after im-
pregnation, consisting of the suspensor and
the embryonal cell at its extremity. The
proembryos of the Gymnosperms are espe-
cially remarkable (see OVULE). The same
term is often incorrectly applied to the PRO-
THALLIUM, the cellular structure first pro-
duced in the germination of the spores of
the higher Flowerless Plants. In the
MOSSES this is a Confervoid expansion
(fig. 482. page 434), upon which buds are
formed from which arise the leafy stems ;
in the FERNS the prothallium (figs. 240-3,
page 262) is a Marchantia-like body, upon
which are developed archegonia and anther-
idia ; in the LYCOPODIACE^E and MARSI-
LEACE^E (figs. 581, 582, p. 507) the prothal-
lium is produced within the coats of the
ovule- spore.

BIBL. See the heads referred to.

PROROCENTRUM, Ehr.— A genus of
Infusoria, of the family Cryptomonadina.

Char. Eye-spot absent; carapace smooth,
terminating in a point or tooth in front ; a
single flagelliform filament present. Marine.

P. micans (PI. 24. figs. 70 & 71). Ovate,
compressed, attenuate behind, dilated in
front. Length 1-430". Luminous.

P. viride.

BIBL. Ehrenberg, In/us, p. 44; Ber. d.
Berl. Akad. 1840. 201.

PRORODON, Ehr.— A genus of Infu-
soria, of the family Enchelia.

Char. Body covered with vibratile cilia,

truncate in front ; mouth with a cylinder of
teeth. Aquatic.

P. teres (PL 24. fig. 72). Body ovate,
terete, white. Length 1-140".

Two other species, one of them green.

Dujardin places this genus in the family
Paramecina.

BIBL. Ehrenberg, In/us, p. 315, and Ber.
d. Berlin Akad. 1840. 201.

PROSENCHYMA. See TISSUES, VE-
GETABLE.

PROSTHEMIUM, Kunze.— A genus of

Fig. 614.

Prosthenium betulinum.

Spores and paraphyses seen in a vertical section of fruit.
Magnified 200 diameters.

Sphseronemei (Coniomycetous Fungi), grow-
ing upon the branches of trees, forming
circular depressed spots; the perithecia
enclose erect articulated filaments bearing
radiating tufts of two or three septate spores
(fig. 614). P. betulinum occurs upon the
bark of the branches of the birch-tree.

BIBL. Berkeley, Brit. Flor. ii.pt. 2. p. 297-

PROTEACE.E.— A family of Dicotyle-
donous plants, mostly from New Holland or
the Cape, shrubs or small trees (Banksia,
Grevillea, Hakea, &c.), of remarkable rigid,
evergreen habit. The coriaceous leaves are
well suited for the study of the epidermal
structures, and the stomates have interesting
peculiarities (see STOMATA). The epidermis
is often scurfy with scattered hairs, some of
which are of curious forms (PL 21. fig. 29).

PROTEUS.— An old name applied to
certain Infusoria, as Amoeba, &c.

PROTHALLIUM. See PROEMBRYO.

PROTOCOCCUS, Ag.— A genus of Pal-
mellaceae (Confervoid Alga3), at present very
imperfectly known, since without a tolerably
complete history of the development of the
forms it is impossible to distinguish the true
species of Protococcus from the young states
of the more complicated Palmellaceae, and
even from the germinating gonidia of the
Lichens. As we have limited it, Protococcus

PROTOCOCCUS.

[ 539 ]

PROTOMYCES.

includes those unicellular Palmellaceae which
increase in the vegetative way by division
into two or four parts, which then become
more or less separated, but may remain con-
nected in irregular groups by a very sparing
semigelatinous layer resulting from the de-
composition of the walls of the parent-cell
(PL 3. fig. 2) : in addition to this, the contents
of the cells under certain circumstances
become divided into two or four isolated
portions (c), which are released by the solu-
tion of the parent-cell in the form of ciliated
zoospores (b, e, f), which, after a short
period of motion (during wrhich they some-
times divide again), settle down and produce
a cellulose coat, and then pursue the vege-
tative course of reproduction (fig. 613, page
536). It appears that smaller zoospores
(MICROSPORES) are sometimes formed in
great numbers (a), and set free in the same
way ; the fate of these is unknown. The
zoospores are produced in water ; when this
is dried up gradually, the vegetative cells
become converted into a kind of resting
spore, acquiring a thick coat, the contents
mostly turning from green to red (d). When
placed in favourable circumstances, these
resting forms (even after several years)
recommence the course of vegetation, re-
acquiring the green colour by degrees, in
the course of several generations of vegeta-
tive cells. The contents of the red form
appear to consist partly of oil-globules ; in
the green form the protoplasmic substance
is coloured by chlorophyll, and at a certain
stage contains starch.

We have traced P. viridis through all
these stages, as represented in PL 3. fig. 2
a-g : a most elaborate monograph of P. plu-
vialis has been written by Cohn, which is far
too extensive to be analysed here, but goes
to establish the same conclusions, that the
genus Hcematococcus is founded on states of
Protococcus. The P. viridis of our figures
is undoubtedly a Chlamydomonas, one of
Ehrenberg's genera of Polygastrica, synony-
mous with Diselmis, Dujardin. This form
appears at first sight nearly allied to Euglena,
but there are striking differences in the
appearance and movements of the active
forms, and the "vegetative" forms are
somewhat different. It may be remarked,
however, that the zoospores of Protococcus
viridis, allowed to dry upon a slider, often
turn red and look just like small Astasice
(PL 3. fig. 2 g).

We have remarked under PALMELLA,
that the Polar red snow appears to be a

Palmella (PL 3. fig. 3d), although this
species has been called Protococcus and Hce-
matococcus nivalis ; and it appears to us that
Shuttleworth and others have confounded
this with Protococcus pluvialis. Hassall's
species of Hcematococcus, nos. 8 to 19, with
the exception of H. vulgaris ( Cklorococcum)
(PL 3. fig. 1), are probably congeneric with
our P. viridis. We find it impossible to
extricate the British forms from their con-
fusion ; the Palmellacea3 require a thorough
study in a living state. Meneghini's defini-
tions of the genera will not hold, and Kiitzing
has multiplied species to infinity.

Our P. viridis makes its appearance com-
monly on damp earth, sand, &c., forming a
greenish coat of no perceptible thickness,
and the zoospores (Chlamydomonas) occur
constantly in standing pools in spring and
autumn, tinging the surface of the water
bright green, and as they settle to rest, form-
ing a kind of green scum at the margins (con-
stituting the green matter of Priestley). Cells
of resting form 1-2400" in diameter. P.plu-
vialis colours water red in like manner ; it
occurs on mountains, especially in melted
snow-water. Cells of resting form 1-1250
to 1-625" in diameter. Similar colorations,
however, are produced by various other
organisms (see WATER).

It may be observed, that when the active
forms of P. viridis and P. pluvialis divide
without coming to rest, they produce forms
which are undistinguishable from many of
Ehrenberg's species of Polygastrica. When
they acquire a loose cellulose coat before
losing their cilia, they represent Gyges-, at
other times they resemble Chlorogonium,
Uvella, Polytoma, Monas, Bodo, &c.

BIBL. Harvey, Brit. Alg. 1 ed. p. 180;
Hassall, Brit. Fr. Alg. p. 321, &c., pis. 76-
82 ; Meneghini, Trans. Turin Acad. 2 ser.
v. p. 1 ; Cohn, Nova Acta, xxii. p. 605
(abstr. in Ray Soc. Vol. 1853. p. 514) ; Von
Flotow, Nova Acta, xx. p. 414 ; Alex. Braun,
Verjungung, fyc. (Ray Soc. Vol. 1853. p. 206
et seq.) ; Nageli, Einzelliger Algen, passim ;
Kiitzing, Spec. Alg. p. 196, Tab. Phyc. i.
pis. 1-6. See also under RED SNOW.

PROTOMYCES, Unger.— A genus of
Ustilagines (Coniomycetous Fungi), growing
in the intercellular passages of leaves and
leaf-stalks. According to De Bary, these
Fungi consist of ramified filaments creeping
between the cells of soft tissues, and swelling
up at intervals (apparently where they meet
an intercellular space large enough), to form
globular spores: a filament with several

PROTOPLASM.

[ 540 ]

PSILOTUM.

spores in course of division appears like a
varicose tube ; it is septate, however, and
when the globular spores are mature, they
have a double coat ; in P. macrosporus, the
diameter of the ripe spore is about 1-5000".
When advanced in age, the mycelium appears
to be wholly converted into spores, which
become free. The existence of these Fungi
is rendered more or less evident externally
by warty projections of the epidermis, finally
bursting, linger describes four species : P.
macrosporus occurring on CEaopodium and
Angelica ; P. endogenus (Galii) occurring on
Galium mollugo ; P. microsporus on Ranun-
culus repens ; and P. Paridis on Paris qua-
drifolia. De Bary found a species on Me-
nyanthes, with oval spores 1-800" long and
1-1300" broad.

BIBL. linger, Exanthem. der Pflanz.
p. 341 ; De Bary, Erandpilze, p. 15. pis. 1
& 2 ; Leveille, Ann. des So. nat. 3 ser. viii.
p. 374; Tulasne, ibid. vii. p. 112; Fries,
Summa Veg. p. 517.

PROTOPLASM.— The name applied by
Mohl to the colourless or yellowish, smooth
or granular viscid substance, of nitrogenous
constitution, which constitutes the formative
substance in the contents of vegetable cells,
in the condition of gelatinous strata, reticu-
lated threads and nuclear aggregations, &c.
It is the same substance as that formerly
termed by the Germans " schleim" which
was usually translated in English works by
"mucus" or "mucilage" (see PRIMORDIAL
UTRICLE, and CELL, VEGETABLE).

PROTOZOA.— This term was proposed
by Siebold to designate a group of inverte-
brate animals, characterized by the various
systems of organs not being distinctly sepa-
rated, and their form and simple organiza-
tion being reducible to a cell.

We have applied the term to an order of
the Animal kingdom, and somewhat extended
its limits (p. 42). Siebold included in it the
Infusoria and the Rhizopoda, the latter con-
sisting of the Amcebaea, Arcellina and Fora-
minifera.

If the above definition be adopted, it must
be remembered that the cell may be repre-
sented by the cell-contents only, and these
we believe to constitute the essential part of
a cell.

BIBL. Siebold, Vergleich. Anat. iii.

PSILONIA, Fr.— A genus of Sepedoniei
(Hyphomycetous Fungi), consisting of little
compact tufts of twisted filaments, at first
covering the fusiform, globose, or oval spores,
which arise from the wart-like protuberances

on the central filaments, and soon become
free. They are found on dead wood or on
reeds.

BIBL. Berk. Brit. Flora, ii. pt. 2. p. 353,
Ann. Nat. Hist. ser. 2. viii. p. 179; Fries,
Summa Veget. p. 495.

PSILOTE^E.— A family of Lycopodia-
ceous plants, distinguished by their many-
celled sporanges, varying much in habit and
external appearance.

Synopsis of Genera.

I. PSILOTUM. Sporanges sessile, three-
celled, bursting imperfectly into three valves
by a vertical crack, filled with mealy spores.

II. TMESIPTERIS. Sporanges sessile,
three-celled, bursting imperfectly into two
valves by a vertical crack, filled with mealy
spores,

III. ISOETES. Sporanges imbedded in
the bases of the leaves, and adnate at the
back, not valvate, with several transverse
septa; containing two kinds of spores (in
distinct sporangia).

PSILOTUM, Swartz. (Lycopodium nu-
dum, L.). — An exotic genus of Psilotese (Ly-

Fig. 615.

Psilotum triquetrum.
Nat, size.

PSOROPTES.

[ 541 ]

PTERODINA.

copodiacese), remarkable for their trilocular
capsules and minute leaves (fig. 616).

Fig. 616.

Fragment of a branch of Psilotum triquetrum.
Magnified 10 diameters.

PSOROPTES (Gervais). — A genus of
Arachnida, of the order Acarina, and family
Acarea.

Char. Body soft, depressed, with rigid
hairs beneath, and on the legs.

Parasitic upon the horse (and other mam-
malia?).

P. equi (PL 2. fig. 18), itch-insect of the
horse. Found upon the scaly crusts formed
upon the body. Mandibles each terminated
by two teeth, and not chelate ; palpi three-
jointed, and adherent to the labium; ventral
surface covered with parallel, undulating
rugae ; at the end of the body are two fleshy
lobes terminated by a tuft of setae.

BIBL. Hering, Nov. Act. n. cur. xviii.
585; Gervais, Walckenaer's Apteres, iii. 266;
Dujardin, Obs. au Micr. 147.

PSOROSPERMLE.— These bodies were
discovered by J. Miiller, and appear to re-
present the pseudo-naviculae of the Grega-
rinee of fishes.

They are microscopic, oval, depressed, or
discoida! corpuscles, with or without a tail,
exhibiting no movements, and consisting of
a tolerably firm outer coat, containing one or
two oblong contiguous vesicles at that end
of the body opposite the tail. They are
about 1-2500 to 1-2000" in length, and are
contained in immense numbers in minute
cysts, in almost every part of the body of
fishes, as upon the gills, in the muscles, and
between the coats of the eye, in the swim-
ming-bladder, &c. Sometimes they are im-
bedded in a ramified sarcodic mass.

Diameter of the cysts on the pike 1-50 to
1-25" ; of the corpuscles, length 1-2000",
breadth 1-3500".

BIBL. Miiller, Archw, 1841.477, 1842.
193; Creplin, ibid. 1842. p. 61; Dujardin,
Helminthes, 643; Leydig, Mull. Archiv,
1851. 221 (Microsc. Journ. 1853. i. 206);
C. Robin, Vegetaux parasitiques, fyc., 2 ed.
p. 291.

PTERIDE^E.— A subtribe of Polypoda>
ous Ferns, with indusiate sori.

Synopsis of the Genera.

I. PTERIS. Sorus marginal, linear, con-
tinuous. Indusium marginal, linear, free
within. Veins pinnate.

II. LITHOBROCHYA. Sorus marginal,
linear, continuous. Indusium marginal,
linear, free within. Veins anastomosing in
hexagonoid spots.

III. AMPHIBLISTRA. Sorus marginal,
linear, continuous. Indusium marginal, li-
near, free within. Veins very much branched
with free venules.

IV. BLECHNUM. Sori inserted on trans-
verse venules connecting the veins, conti-
guous or continuous by confluence, parallel
with the rib, and more or less approximated.
Indusium linear, the free margin looking
towards the rib. Veins pinnate, anasto-
mosing.

PTERIS, Linn.— A genus of Pteridea?
(Polypodaeous Ferns), represented by one
indigenous species, Pteris aquilina, common
Brake Fern.

Fig. 617.

Pteris.

A pinnule with marginal indusiate sori.
Magnified 10 diameters.

PTERODINA, Ehr.— A genus of Rota-
toria, of the family Brachionaea.

Char. Eyes two, frontal ; foot simply sty-
liform. At the end of the tail-like foot is a
suctorial disk; jaws with the teeth either
arranged in a row, or two teeth only in each.

Three species; two aquatic, one marine.

PTEROPTUS.

[ 542 ]

PUCCINIA.

P. patina (PI. 35. fig. 20). Testula mem-
branous, orbicular, crystalline, roughish
near the broad margin ; a depression present
between the rotatory lobes. Aquatic ; length
1-120".

BIBL. Ehrenberg, In/us, p. 516.

PTEROPTUS, Dufour. — A genus of
Arachnida, of the order Acarina, and family
Gamasea.

Char. Body depressed; last joint of palpi
longest; legs stout, with short joints.

P. vespertilionis (PI. 2. fig. 39). Found
upon bats. Several species have been de-
scribed, but the subject requires revision.

BIBL. Gervais, JValckenaer's Apteres, iii.
227 ; Dufour, Ann. d. Sc. nat. xvi. 98 ; xxv.
9 ; Koch, Deutschlands Crustac.

PTERYGONIUM, Sw.— A genus of
Mosses. See NECKERA.

PTILIDIUM, Nees.— A genus of Junger-
mannieae (Hepaticaceae), containing one ele-
gant British species, P. ciliaris, frequent on
heaths and rocks in subalpine districts, but
rarely found in fruit.

BIBL. Hooker, Brit. Flor. ii. p. 126, Brit.
Jung. pi. 65 ; Ekart, Synops. Jung. pi. 5.
fig. 36.

PTILOTA, Ag.— A genus of Ceramiaceaj
(Florideous Algae), with flat feathery fronds
a few inches high; of a deep red colour,
growing on Laminarice or Fuci, or on rocks
between tide-marks. The fructification con-
sists of — 1. clustered roundish favellce con-
taining spores, terminating the ultimate
pinnules, and surrounded by an involucre of
subulate ramuli, or naked; 2. tetrahedral
tetraspores on short pedicels fringing the
pinnules. Antheridia have not been ob-
served.

BTBL. Harvey, Brit. Mar. Alg. p. 159.
pi. 22 A, Phyc. Brit. pi. 70 ; Greville, Alg.
Brit. pi. 16 ; Nageli, Neuer Algensysteme,
pi. 6. fig. 38-42.

PTYGURA, Ehr.—A genus of Rotatoria,
of the family Ichthydina.

Char. Eyes none; no hairs upon the
body ; tail-like foot cylindrical, and simply
truncate.

Teeth three in each jaw; anus situated
at the end of the tail-like foot.

P. melicerta (PL 35. fig. 21). Body terete-
clavate, turgid in front, hyaline ; mouth with
two little hook-like horns ; cervical process
single and smooth. Aquatic; length 1-144".

Ehrenberg questions whether this is not
a young form of another genus.

BIBL. Ehrenberg, In/us, p. 387-

PUCCINIA, Persoon.— A genus of Caeo-

macei (Coniomycetous Fungi) (see also
UREDINES), containing numerous para-
sitical species, growing upon the leaves
and other herbaceous parts of the higher
plants, forming " mildews," and, with their
Uredinous forms, " rusts," &c. These Fungi
have received considerable attention lately
from Tulasne, De Bary, and others ; and it
appears that the genera Uredo and others
have no distinct existence, but are prepara-
tory forms of Puccinia and other genera
noticed under UREDINES. In the article
^EciDiUM we have described the twofold
reproductive structures, namely the sperma-
gonia and the perithecia (figs. 5 & 6, p. 15;
PL 20. figs. 1-4), producing respectively the
spermatia (supposed to have the office of
spermatozoids) and the spores. In Puccinia
three forms of reproductive organs occur :
first, spermagonia, analogous to those of
^Ecidium ; then the forms called Uredines
(chiefly of the supposed genus Trichobasis),
producing globular unilocular bodies, shortly
stalked, and with transparent walls, but with
yellow or orange-coloured contents; and
lastly, the true Puccinice, containing bilocu-
lar spores borne on short stalks, and having
a dark brown integument. The latter pre-
sent remarkable phosnomena in germination,
which may be best observed in those which
sprout without becoming detached from the
matrix, such as P. graminis, which however
remain quiescent until the spring following
its development, while P. Glechomce, Bund,
Dianthi, and others, germinate in the same
summer. The bilocular spores have each
one pore (analogous to the pores of POLLEN-
grains), from which extends a filamentous
process, ultimately giving rise to four short
processes, each terminating in a pointed pro-
cess bearing a sporidium, of more or less
curved elliptical form. About the time when
these fall off, the filament bearing the four
processes becomes divided by septa into four
chambers, but then appears to die. The
sporidia germinate and produce a filament,
which, instead of becoming the basis of a
mycelium, reproduces a sporidium smaller
than the first. More is said respecting these
remarkable organisms under the head of
UREDINES.

The PuccinicB present the following gene-
ral characters : — The spermagonia rare, scat-
tered on either face of the infested leaf, with
an immersed, ostiolate peridiole, bearing
long cilia at the mouth, pale, orange or
blackish in colour. The Uredinous fruits
are scattered or grouped in circles, devoid of

PULEX.

[ 543 ]

PULEX.

a proper peridium, but surrounded some-
times by thickish cylindrical paraphyses,
very rarely connected below into a mem-
brane, forming a kind of ciliated peridium ;
the stylospores are round and mostly spinu-
lose, with three or four equidistant pores.
The Puccineous fruits are also scattered or
grouped in circles, sometimes containing
only their proper spores, sometimes with
Uredinous spores intermixed, destitute of a
proper peridium, but, like the Uredines,
having sometimes a false envelope formed
of confluent paraphyses ; their spores, form-
ing the chief distinctive character of the
genus, are bilocular, oblong or globose,
rounded-obtuse or acuminate at the apex,
smooth or spinulose, the upper loculus with
a pore at its summit, the lower with a pore
at the upper end of one side (next the sep-
tum).

These plants occur commonly on the
Grasses and many other herbaceous plants,
often changing colour during the summer,
being yellow or orange when the Uredinous
spores are ripe, and afterwards blackish
when the Puccineous form is mature.

The species are very numerous, but some
of those formerly included under this name
are now removed to other genera, such as
Uromyces, Triphraamium, &c. (See URE-
DINES.) P. graminis is common on corn
and other grasses (Mildew}-, among the other
frequent species are P. Caricis, polygonorum,
menthce, anemones, buxi, &c. Ch. Robin de-
scribes a Puccinia, apparently on the author-
ity of Ardsten, a Swedish physician, found
upon the human head in FAVUS. From
his description it appears to be a true Puc-
cinia, and should hold its place (P. Favi,
Ardst.) among the species. But what is
more remarkable, it occurs together with
Achorion Schanleinii, the latter presenting
itself as a constituent of the cups or crusts,
while the Puccinia occurs afterwards on the
desquamations of the epidermis. This ap-
pears to warrant (from what we know of the
species parasitic on vegetables) the opinion
that the ACHORION is merely the sperina-
gonial form of the P. Favi.

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 363,
Ann. Nat. Hist. vi. p. 439, ibid. 2 ser. v.
p. 462, xiii. p. 461 ; Tulasne, Ann. des Sc.
nat. 3 ser. vii. p. 12, ibid. 4 ser. ii. p. 77-
138 & 182 ; Leveille, ibid. 3 ser. yiii. p. 369;
De Bary, Brandpilze, p. 36 ; Fries, Summa
Veg. p. 513; Robin, Vegetaux parasit. 2nd
ed. p. 613. pi. 14. fig. 13.

PULEX, Linn. (Flea).— A genus of In-

sects, of the order Siphonaptera (Suctoria
or Aphaniptera), and family Pulicidae.

Char. As there are only the single family
and genus in the order, the characters of the
latter are distinctive.

Head small (PI. 28. fig. 9), compressed,
rounded above, truncate in front, in some
species with an inferior pectinate fringe of
blackish-brown teeth; eyes one on each
side, round, simple, smooth; behind each
eye is a cavity or depression, at the bottom
of which the antennae are attached; an-
tennae (figs. 9 a, 12) four-jointed, their form
varying in the different species, the third
joint very minute, and forming the cup-
shaped base of the terminal joint or piece,
which in some species is furnished with nu-
merous transverse incisions, representing as
many distinct joints ; in some the antennae
extend out of the depression, and are carried
erect.

Oral appendages (PL 28. fig. 9 e) composed
of several parts : 1. (PI. 26. figs. 32 d, 33 d)
The uppermost is single, and consists of a
thin, flattened seta, coarsely toothed on the
upper surface, and traversed throughout its
entire length by a canal, upon the walls of
which a very slender trachea runs, and from
which very minute canals, terminating at the
end of the little teeth, are given off. This
is the suctorial organ, and perhaps cor-
responds to the labrum, but is sometimes
considered as the lingua or ligula. 2. (figs.
32 f, 33 f) Two quadrangular, narrow, and
elongated plates, each furnished with longi-
tudinal ribs, and with fine teeth ; these are
the lancets or scalpella, and correspond to
the mandibles. 3. (PL 26. fig. 32 g) Two
somewhat triangular or leaf-like plates, the
maxillae; to which are attached — 4. (PL 26.
fig. 32 h ; PL 28. fig. 9 d) Two nearly cylin-
drical four-jointed maxillary palpi. 5. (PL
26. fig. 32 k ; fig. 33 k) Two labial palpi, in
the form of sheaths, four-jointed, thickened
at the back and membranous at the margin;
these palpi arise from near the apex of —
6. (PL 26. fig. 33 /) A small membranous
labium, with the still smaller mentum (PL 26,
fig. 33 m) at its base.

Thorax composed of three segments, each
consisting of an upper (PL 28, fig. 9 c) and a
lower piece (//, that of the metathoracic seg-
ment is not lettered) ; from the lower arise
the corresponding legs. The two posterior
segments of the thorax are each furnished
with a pair of plates, the hindermost of which
is longest, and nearly covers the sides of the
first and part of the second abdominal seg-

PULEX.

[ 544 ]

PULEX.

ment (fig. 9, behind/,/); these represent
rudimentary wings.

The legs are large, especially the hinder
ones, and adapted for leaping. The first
joint or coxa (g) is very thick ; the second
or trochanter (h) is very small ; next come
the femur (i), the tibia (&), and lastly the
five-jointed tarsus (I), which is terminated by
two curved and denticulate claws, with a
lobe or heel at the base.

The abdomen of the female has nine
distinct rings, the first seven of which are
each furnished with a pair of stigmata (a),
and consist of horny arches with membranous
margins. The eighth arch, which has no
membranous margin, is strengthened by a
horny band furnished with fine hairs, to
protect the orifice of the last stigma. The
ninth and last segment, called the pygidium
(fig. 9X and PI. 1. fig. 13), is somewhat
kidney-shaped or two-lobed, folded on the
dorsum, and exhibits twenty-five to twenty-
eight stiff and longish bristles, implanted
in the centre of as many disk-like areolae,
each of which is ornamented with a ring of
rectangular or somewhat cuneate rays. The
portions of the pygidium between the areolae,
are studded with minute spines. The end
of the abdomen in the female (PI. 28. fig. 9)
is more rounded or ovate than that of the
male (fig. 13), which is somewhat turned
upwards.

In some species the segments of the thorax
and abdomen are furnished with a posterior
pectinate fringe.

The alimentary canal is short and straight ;
the stomach cylindrical ; the small intestine
as long as the stomach, and the large intes-
tine short. Four short and broad Mal-
pighian vessels open into the lower orifice of
the stomach, and the ducts of two round
salivary vesicles unite to a single canal
ascending in a coiled form on each side of
the oesophagus towards the mouth.

The eggs of the flea are white, elongated
and viscid outside. The larvae have no legs;
they are elongated, resembling minute
worms and very active, coiling themselves
into a circle or spiral, and serpentine in their
movements. The head is scaly, without
eyes, and supporting two very minute an-
tennae; the body has thirteen segments, with
small tufts of hairs, and at the end of the
last are two little hooks.

The species are numerous (twenty-five,
Gervais), but their characters are not well
defined.

P. irritans, human flea. Pitch-brown;

head shining, smooth, pectinate fringe
absent ; legs pale ; femora of posterior legs
with hairs inside ; second joint of the tarsi
of the anterior pair of legs and first joint of
posterior tarsi longest. Tarsal joints in
respective order of greatest length : anterior,

2, 5, 1, 3, 4 ; posterior, 1, 5, 2, 3, 4 (Bouche).
We have never been able to find a flea with
the above relative length of the joints of the
anterior tarsi.

P. felis, cat's flea (P. canis, Bouche ; P.
irritans, Duges) (PI. 28. fig. 9). Pale pitch-
brown ; head naked, shining, smooth, with
delicate scattered dots; coxa3 and femora
almost naked; fifth joint of anterior tarsi
and first joint of posterior tarsi longest.
Tarsal joints : anterior, 5, 2, 1, 3, 4 ; poste-
rior, 1, 5, 2, 3, 4.

P. canis, flea of dog and fox (PI. 28. fig. 10,
head) (P. felis, Bouche). Pale pitch-brown ;
head shining, smooth, punctate behind ;
lower part of head and protothorax with a
pectinate fringe; posterior tibiae much ex-
panded at the end; fifth joint of anterior
and first of posterior tarsi longest. Tarsi :
anterior, 5, 2, 1, 3, 4; posterior, 1, 2, 5,

3, 4.

P. gallince, fowl's flea. Pitch -brown, with
shining, smooth, elongated head; proto-
thorax with a pectinate fringe ; first joint of
all the tarsi longest. Tarsi: anterior and
posterior, 1, 2, 5, 3, 4.

P. martis, flea of the marten and dog.
Postero-inferior margin of head and proto-
thorax with pectinate fringe ; tarsi as in P.
canis.

P. sciurorum, flea of the squirrel. Head
naked; pectinate fringe on protothorax,
none upon the abdomen. Tarsi : anterior,
1, 5, 2, 3, 4 ; posterior, 1, 2, 5, 3, 4.

P. erinacei, flea of hedgehog. Head
naked, mesothorax with a fringe. Tarsi :
anterior, 5, 2, 1,3,4; posterior, 1, 2, 5,3,4.

P. talpcB, Curtis, flea of mole (PI. 28.
fig. 24).

P. columbcB, pigeon's flea. Protothorax
with pectinate fringe, none upon the abdo-
men ; antennae of male erect, those of the
female lying in the depression.

P. penetrans, the chigoe or jigger. The
females burrow in the skin of the feet, and
the ova, undergoing development, enlarge the
abdomen to the size of a pea, causing severe
inflammation, &c. Rostrum very long.
Tropical.

P. vespertilionis, flea of the bat (PL 28.
fig. 11, head).

BIBL. Westwood, Introduction, fyc., ii.

PUNCTARIA.

[ 545 ]

PYOID CORPUSCLES.

489; Bouche, Nov. Act. Nat. Cur. 1835.
xvii. 501 ; Duges, Ann. d. Sc. nat. 1832.
xxvii. p. 165 ; Gervais, Walckenaer's Apt.
iii. 362; Denny, Ann. Nat. Hist. 1843. xii.
315.

PUNCTARIA, Greville.— A genus of
Punctariaceae (Fucoid Algae), containing
three (one doubtful) British species, P. lati-
folia, plantaginea and tenuissima, growing
on rocks and stones, consisting of membra-
nous, olive or brown, ribless fronds, 4 to 12"
long, 1 to 3" broad, having a shield-like
organ of attachment at the base. The fruc-
tification consists of sori scattered all over
the frond in minute distinct dots, composed of
roundish oosporanges (producing zoospores)
intermixed with paraphyses ; these sporanges
are called spores in most works. No other
form of fructification has yet been observed.

BIBL. Harvey, Brit. Mar. Alg. p. 41.
pi. 8 B, Phyc. Brit. pis. 8, 128, 148; Greville,
Alg. Brit. pi. 9.

PUNCTARIACE.ZE.— A family of Fu-
coideae. Root a minute naked disk, frond
cylindrical or flat, unbranched, cellular; with
ovate oosporanges intermixed with jointed
threads in groups on the surface.

Synopsis of the British Genera.

I. PUNCTARIA. Frond flat and leaf-like.
Oosporanges scattered or in sori.

II. ASPEROCOCCUS. Frond membranous,
tubular, either cylindrical or compressed.
Oosporanges in dot-like sori.

III. LITOSIPHON. Frond cartilaginous,
filiform, subsolid. Oosporanges scattered,
almost solitary.

PUS. — Popularly known as " matter."
One of the products of inflammatory exuda-
tion.

Its general properties are too well known to
require description. Pus consists of an albu-
minous liquid, containing a number of
minute corpuscles in suspension. These con-
sist of molecules and granules, composed of
proteine-compounds, fat or the earthy phos-
phates; globules of fat of very various sizes;
and the proper pus-corpuscles. Pus-cor-
puscles (PI. 30. fig. 4) are spherical, from
1-2500 to 1-2000" in diameter; presenting
a granular appearance on the surface, and
containing a number of larger or smaller
granules and a small quantity of liquid. The
granular appearance of the surface arises
from the internal granules pushing out, as
it were, the cell-wall, for it disappears when
the cell-wall is distended and separated from

the granules by the action of water or very
dilute solution of potash. When treated
with acetic acid, the cell-wall and granules
become excessively transparent and ulti-
mately vanish (PI. 30. fig. 5), leaving from
one to five, generally two or three, round or
oval nuclei, which mostly present a dark
margin and light centre, giving them a
cupped appearance, indicating a diminution
of refractive power in the centre, arising
from either a depression on the surface or the
existence of a vacuole. The cupped centre
is sometimes seen in the nuclei without
acetic acid, after the action of water only.

In the pus of chronic abscesses, unhealthy
ulcers, &c., the corpuscles are often few,
deformed and mixed with numerous granules
of proteine, fatty and calcareous matters,
crystals of cholesterine, of the ammonio-
phosphate of magnesia, and sometimes
monads and vibrios; exudation-corpuscles
are occasionally present also.

Pyoid corpuscles. — Under this term,
Lebert describes a modification of pus-cor-
puscles, consisting of a tolerably transparent
envelope, enclosing from eight to ten or
more small globules (PI. 30. fig. 6). Acetic
acid does not alter them, or at most only
renders them slightly more transparent. The
small globules are composed of a proteine -
compound, for they are soluble in potash.

BIBL. That of CHEMISTRY, ANIMAL ;
and Lebert, Phys. Pathologique.

PYCNIDIA.— A term applied by Tulasne
to the receptacles enclosing stylospores in
the LICHENS and FUNGI.

PYCNOPHYCUS, Ktitz.— A genus of
Fucaceae (Fucoid Algae), containing one
British species, P. (Fucus) tuberculatus,
removed from Fucus on account of its cylin-
drical frond, the compact cellular substance
of the receptacles and the ramified fibrous
pseudo-root. The fructifications, formed at
the ends of the dichotomous lobes of the
frond, are of elongated form, cylindrical,
more or less tuberculated, and exhibit
numerous pores opening from conceptacles,
containing spore-sacs and antheridia (to-
gether), resembling in general those of Fucus.
The spore-sacs are collected at the bottom
of the conceptacles, the antheridia at the
upper part. For the details respecting the
spores and spermatozoids see Fucus.

BIBL. Harvey, Brit. Mar. Alg. p. 18.
pi. 2 A, Phyc. Brit. p. 89; Decaisne and
Thuret, Ann. des Sc. nat. 3 ser. iii. p. 5,
&c., pi. 1 ; Thuret, ibid. xvi. p. 10.

PYOID CORPUSCLES. See Pus.

2N

PYRAMIDIUM.

[ 546 ]

QUININE.

PYRAMIDIUM, Bridel.— A genus of
Funariaceee (Acrocarpous Mosses), allied to
Funaria in habit, but differing in important
points.

Pyramidium tetragonum, Brid. = Gymno-
stomum tetragonum, Schwagr.

PYRENOMYCETES.— That portion of
the Ascomycetous and Coniomycetous Fungi
having a closed, nuclear fruit ; standing
opposed to the Discomycetes, with open
fruits, like the Angiocarpous and Gymno-
carpous Lichens.

PYRENOTHEA, Fries.— A genus of
Limboriese (Angiocarpous Lichens), contain-
ing a number of species separated from Ver-
rucaria, Ach., on account of the spores being
free in the perithecia and not developed in
thecae. The bodies taken for spores are,
however, spermatia contained in sperma-
gonia, the sporiferous perithecia being appa-
rently unknown (see LICHENS).

BIBL. Leighton, Brit. Aug. Lichens, p. 65;
Tulasne, Ann. des Sc. nat. 3 ser. xvii.p. 217-

Q.

QUILL.— The quill of feathers possesses
considerable polarizing power ; the coloured
bands are, however, so broad that they are
better seen with the naked eye.

See FEATHERS.

QUININE. See ALKALOIDS, p. 26.

lodo-disulpkate, sulphate of iodo-quinine,
Herapathite. — This salt is prepared by dis-
solving disulphate of quinine in strong acetic
acid, warming the solution, dropping into it
an alcoholic solution of iodine carefully in
small quantities at a time, and placing the
mixture aside for some hours, when the
crystals separate.

They dissolve in the heated mother-liquor,
also in hot alcohol, being again deposited on
cooling; but they are not soluble in cold
alcohol or aether.

They are so easily decomposed and altered
that they are with difficulty mounted. This
may, however, be effected by cautiously
neutralizing the excess of acid in the mother-
liquor by solution of ammonia, taking care
not to precipitate the excess of the disulphate
of quinine ; a portion of the liquid contain-
ing the crystals is then transferred to a slide,
the liquid removed with blotting-paper, and
the crystals dried in a current of cold air.
They are then mounted in Canada balsam
rendered thin with aether, heat being avoided.

The crystals are of a pale olive-green
colour (PI. 7- fig. 17), and possess a more

intense polarizing power than any other
known substance. The play of colours pre-
sented when they are rolling over each other
whilst contained in a watch-glass, forms a
very beautiful sight, the colours varying
according to the relative positions of the
crystals to each other ; and when the latter
cross each other at a right angle, complete
blackness is produced.

Dr. Herapath, who discovered this beau-
tiful salt, has also described a method of
making crystals of sufficient size to replace
tourmalines or Nicol's prisms. The ingre-
dients are, — as pure disulphate of quinine as
can be obtained, that from Messrs. Howard
and Kent being best ; strong acetic acid, of
sp. gr. 1'042; proof-spirit, composed of
equal bulks of rectified spirit of sp. gr.
"837 and distilled water; and tincture of
iodine, made by dissolving 40 grains of iodine
in 1 oz. of rectified spirit. The proportions are :

Disulphate of quinine. ... 50 grains.

Acetic acid 2 fluid ounces.

Proof-spirit 2 fluid ounces .

Tincture of iodine 50 drops.

The disulphate of quinine is dissolved in the
acetic acid mixed with the spirit ; the solu-
tion heated to 130° F., and the tincture of
iodine immediately added in drops, the
mixture being constantly agitated.

The compound should be prepared in a
wide-mouthed Florence flask or matrass; and
the temperature should be maintained for a
little time after the addition of the iodine,
so that the solution should become perfectly
clear, and of a dark sherry colour. It should
then be set aside to crystallize in a room of
a uniform temperature of 45° to 50° F., and
kept from vibration. The latter may be
effected by suspending the flask by the neck
with strong string, attaching this to a hori-
zontal cord stretching across the room from
one wall to the other; or placing the flask on
a steady support, lying upon a pillow. The
large crystalline plates form upon the surface
of the liquid, where they are allowed to
remain for twelve to twenty-four hours, until
they have acquired sufficient thickness. The
flask is then carefully removed without
shaking, and rested upon a gallipot. A
circular cover is then fastened by its edge to
the end of a glass rod with a little wax or
marine glue, and passed beneath one of the
crystalline films, the adherent mother-liquor
removed with blotting-paper, and the film
allowed to dry in a room at a temperature of
45° to 50° F. The cover and film are then

RACODIUM.

[ 547 ]

RAPHIDES.

placed under a cupping-glass or small bell-
glass, with a watch-glass containing a few
drops of tincture of iodine. The time
required for the iodizing may be about three
hours at 50° F., or less if the temperature be
higher.

The film is then covered with a solution
of Canada balsam in aether, saturated with
iodine by warming with a few crystals of
this substance, and allowing it to cool.

Other films are removed and mounted in
the same manner. Should the films not
separate from the original liquid at the end
of six hours, this must be heated with a
spirit-lamp until the deposited crystals are
dissolved, a little spirit and a few drops more
tincture of iodine added, and the liquid
again set aside.

If the film appear black when removed
on the cover, it is crossed by an adherent or
interposed crystal, which must be carefully
removed.

These crystals are sold ready mounted,
and may be purchased at a very small cost.

Dr. Herapath proposes the production of
the crystals of the quinine- salt as a very
delicate test for the presence of quinine. A
test-liquid is first made with 3 drachms of
acetic acid, 1 drachm of rectified spirit, and
6 drops of dilute sulphuric acid. A drop of
this is placed upon a slide and the alkaloid
added, and when it is dissolved, a very
minute quantity of tincture of iodine added ;
after a time the salt separates in little
rosettes.

BIBL. Herapath, Phil. Mag. 1852. iii.
161, iv. 186, and 1853. vi. 171 & 346; Hai-
dinger, ibid. 1853. 284.

R.

RACODIUM, Pers. See ANTENNARIA.
RADULA, Dumort. — A genus of Junger-
Fig. 618.

Radula complanata.

Leafy shoot with an immature and a burst capsule.
Magnified 5 diameters.

mannieae (Hepaticaceae), containing one
British species, R. complanata (fig. 618),
common upon the trunks of trees, every-
where, forming orbicular pale-green patches
closely appressed to the bark.

BIBL. Hook, Brit. Jung. pi. 81, Brit.
Flor. ii. pt. 1. p. 120; Ekart, Syn.Jung.
pi. 4. fig. 31 ; Endlicher, Gen. Plant. Supp.
1. No. 472-13.

RALFSIA, Berk.— A genus of Myrione-
maceae (Fucoid Algae), containing one British
species, R. verrucosa (R. deusta, Berk.),
forming dark-brown, Lichen-like patches, 1
to 6" in diameter, on rocks between tide-
marks. The fronds are at first orbicular and
concentrically zoned ; they are composed of
densely-packed, vertical, simple jointed fila-
ments. The fruit is formed in wart-like
patches, and consists of obovate oosporanges
attached to the bases of vertical filaments.

BIBL. Harvey, Brit. Mar. Alg. p. 49.
pi. 10 D.

RAMALINA, Ach. — A genus of Parme-
liaceae (Gymnocarpous Lichens), containing
several British species, forms of shrubby
habit, mostly growing upon the trunks of
trees, bearing orbicular, peltate apothecia,
nearly of the same colour as the thallus.
R.fraxinea, fastigiata, and farinacea are
common.

BIBL. Hook. Brit. Flor. ii. pt. 1. p. 228;
Tulasne, Ann. des Sc. nat. 3 ser. xvii. p. 192.
pi. 2. figs. 13-15.

RANA, Linn. See FROG.

RAPHIDES.— This name was first applied
to the minute needle-shaped crystals occur-
ring in great abundance in the tissues of
many plants ; but it is now used in general
application to all the crystalline formations
contained in vegetable cells. The crystals
occur either solitary or grouped, and some-
times the latter are formed on a peculiar
stalked matrix projecting into the cavity of
enlarged cells, forming the organs called
cystolithes.

There are few plants of the higher classes
which do not contain raphides ; they are
very abundant in the herbaceous structures
of the Monocotyledons generally, and espe-
cially those of the Araceae, Musaceae, Lilia-
ceae, &c. ; they also abound in the Polygo-
naceae, Cactaceae, Euphorbiaceae, Urticacege,
&c., among the Dicotyledons. They are
usually found only in the interior of the ca-
vities of cells, but in some cases they occur
in the intercellular cavities, perhaps, how-
ever, accidentally. They may occur in al-
most any part, but are found most exten-
2N2

RAPHIDES.

[ 548 ]

RAPHIDES.

sively in the stems of herbaceous plants
(Monocotyledons in general and Cactaceae) ;
they also occur in the bark and pith of many
woody plants (lime, vine); leaves likewise
frequently contain them in vast quantity
(Araceae, Musaceae, Liliaceae, Iridaceae,
Polygonaceae) ; also sepals (Orchidaceae,
Geraniaceae) ; in the rhubarbs, and also in
Umbelliferae, they occur extensively in the
roots; and they abound in autumn in the
base of the bulbs of the onion and other
Liliacese.

The form of the needle-shaped raphides
is usually that of a square prism, with pyra-
midal ends. These ordinarily occur lying
parallel in bundles (fig. 619) ; another coin-

Fig. 619.

Fig. 620.

Fig. 619. Parenchymatous cells of the stem of Rumex,
containing bundles of raphides. Magnified 400 diams.

Fig. 620. Parenchymatous cells of the stem of Beta,
with groups of raphides. Magnified 400 diams.

mon form is that of rectangular or rhombic
prisms with oblique or pyramidal ends ; the
smaller of these often present themselves in
groups radiating from a centre (fig. 620).
Prisms of similar or of six-sided forms, octo-
hedra, rhombs, &c., also occur solitary or
few together (PI. 39. fig. 28), the larger ones
sometimes nearly filling the cavity of the
cells in which they lie. The cells containing
the bundles of acicular raphides in the Aracege
also contain a viscid sap, which causes them
to burst through endosmose when placed in
water, and discharge the crystals. Turpin
erroneously described these as organs of a
special nature, under the name of Biforines.
Raphides most frequently consist of oxa-
late of lime, especially in the Cactacese,
Polygonaceae, &c. ; carbonate of lime seems
to stand next in the order of frequency, then

sulphate and phosphate of lime. Their
composition may be ascertained by the ap-
propriate tests for these salts. It is some-
times difficult to determine the form accu-
rately, on account of the small size ; it is
found advantageous to mount well-cleaned
and partly crushed crystals in Canada balsam,
also to view them rolling over in alcohol
(INTRODUCTION, p. xxix).

The peculiar crystalline structures called
by Weddell cystolithes, occur most abun-
dantly in the families of the Urticaceae (in-
cluding Morese) and the Acanthaceae. They
ordinarily consist of a stalked, clavate, and
globose, or irregular linear body, suspended
in a greatly enlarged cell, most frequently
situated beneath the epidermis of the leaf
(PI. 39. figs. 26, 27); but they also occur in
deeper-seated regions. Their nature and
development has been followed by several
observers, and they are found to consist of a
cellulose matrix with carbonate of lime cry-
stallized in a kind of efflorescence upon the
surface. They appear to originate by a little
papilla or column of secondary deposit at
the upper end of the cell, which increases
by successive concentric layers of cellulose
applied on the lower surface, leaving a short
stalk-like portion, which remains uncovered
and also free from the crystals which gradu-
ally sprout out from the thickened head.
The crystals may be removed by the action
of acid, and then the matrix assumes a blue
colour with sulphuric acid and iodine. Pay en
imagined the thicker portion encrusted by
the crystals to be composed of numerous
cellules, each producing a crystal : this is
erroneous. The cystolithes vary in form;
the clavate kinds may be best observed
in Ficus elastica (PL 39. fig. 27) and
<Tther species, in vertical sections of the leaf;
globular forms are found in Parietaria qffi-
cinalis (fig. 26), and the Hop; in species
of Pilea they are linear or crescentic, and
suspended by the convex edge.

BIBL. Lindley(andE. Quekett),I«Jroc£. to
Botany, 4th ed. i. p. 97 ; Turpin, Ann. des
Sc. nat. 2 ser. vi. p. 5 ; Raspail, Chemie or-
g unique; Morren, Bull. Acad. de Bruxelles,
vi. No. 3 ; Meyen, Miiller's Archiv, 1839.
p. 255, Ann. des Sc. nat. 2 ser. xii. p. 257 ;
Schleiden, Grundzuge, 3rd ed. pp. 168. 341,
Principles, pp. 6. 122; Weddell, Ann. des
Sc. nat. 4 ser. ii. p. 267 ; Schacht, Beitr. z.
Anat. und Phys. 1854. p. 212 ; linger, Ann.
d. Wiener Museum, i. 1844, Anat. und Phys.
d. Pflanz. 1855. p. 123; Payen, Mem. sur I.
devel. d. ve'getaux, Paris, 1844.

RAPHIGNATHUS

[ 549 ]

RED SNOW.

RAPHIGNATHUS, Duges.— A genus of
Arachnida, of the order Acarina, and family
Trorabidina.

Char. Palpi with an indistinct claw;
mandibles represented by two short setae
inserted upon a fleshy bulb, concealed by a
broad labium; body entire; coxae contigu-
ous; legs but little attenuate at the ends,
anterior longest, last joint longer than the
others.

R. ruberrimus (PL 2. fig. 35 a, labium
with mandibles and a palp ; b, a mandible).
Body oval, slightly depressed, smooth, and
almost free from hairs, rostrum forming a co-
nical process; eyes two, dark red, one on each
side at the anterior part of the body ; labium
triangular, concave ; setae accompanied by a
more slender hair-like process ; palpi large,
inflated, claw of the 4th joint very short.
Size minute !

Found under stones and on plants.

T. hispidum. Form of that of the pre-
ceding; body velvety, with two posterior
papillae.

BIBL. Duges, Ann. des Sc. nat. 2 ser. i. 22,
ii.55; Gervais, Walckenaer's Apter. iii. 172.

RATTULUS, Lamarck.— A genus of Ro-
tatoria, of the family Hydatinaea.

Char. Eyes two, frontal; tail-like foot
simply styliform; neither cirrhi nor fins
present.

Teeth indistinct.

R. lunaris (PI. 35. fig. 22). Eyes distant
from the anterior margin ; foot decurved,
lunate. Aquatic ; length 1-288".

BIBL. Ehrenberg, In/us, p. 448.

REAGENTS. See INTRODUCTION, pp.
xxxvii and xl.

REBOUILLIA, Raddi.— A genus of Mar-
chantiacese (Hepaticaceae), founded on the
Marchantia hemisph&rica, Linn., character-
ized by the conical or flattened, 1-5-lobed
stalked receptacle (fig, 621 ), the perigone

Fig. 622.

Rebouillia hemisphaerica.

Female receptacles, with the perigone burst.

Fig. 621, seen from above ; fig. 622, from below.

Magnified 2 diameters.

being adherent to the lobes of the receptacle
on the under side, opening by a slit (fig.

622) ; perichaete none, and the globose spo-
range bursting irregularly. The antheridia
are imbedded in sessile, crescent-shaped
disks. The fronds are rigid, with a well-
marked midrib, green above, purple beneath.
It grows on moist banks, or by the side of
mountain streams.

BIBL. Hook. Brit. Flor. ii. pt. 1. p. 108 ;
G. W. Bischoff, Nova Acta, xvii. p. 1001.
pi. 69. fig. 1; Endlich. Gen. Plant. No. 468.

RED SNOW.— The remarkable phseno-
menon known under this name has been the
subject of very extensive investigation, and
it is well known to be the result of the enor-
mous development of a microscopic organism
related to Protococcus or Chlamidococcus
viridis. We are inclined to believe that more
than one form is comprehended at present
under the name of Protococcus or Hcematococ-
cus nivalis, for our specimens of Arctic red
snow (for which we are indebted to the kind-
ness of Mr. R. Brown) appear to belong to
the same genus as Palmella cruenta, as first
indicated by Mr. Brown, and confirmed by
Sir W. J. Hooker. Dr. Greville's figures of
the Scotch plant closely resemble this ; but
the continental plants, described by Mr.
Shuttleworth and others, would seem con-
generic with Protococcus (Chlamidococcus,
Braun, Chlamidomonas,lZhr.), since they pro-
duce active zoospores, the forms which
Shuttleworth described as distinct infusoria,
as species of Astasia. Nearly connected
with this continental snow-plant, if not
identical, is the Protococcus pluvialis, de-
scribed so elaborately by Dr. Cohn, which
moreover appears to be synonymous with
the Discer&a purpurea of Morren.

The following is a description of the red
snow (brought home by Capt. Parry) from
our own observation. It may be noticed as
remarkable, that after being kept so many
years in a moist state in a stoppered bottle,
the structure appears almost unchanged, the
only difference being the assumption of a
green colour on the surface of the masses
when exposed to light. Frond an indefinite
gelatinous mass densely filled with spherical
cells, about 1-1200" in diameter (PI. 3. fig.
3 d) ; cells with a distinct membrane, their
contents consisting of numerous tolerably
equal granules, red or green (see above).
Between the large cells lie patches of minute
red granules (as in Palmella cruenta, PI. 3.
fig. 3 a, b), apparently discharged from the
large cells. Bauer and Greville both de-
scribe this as the mode of propagation of the
plant, but it is probable that the cells also

REPRODUCTION.

[ 550 ]

RHIPIDOPHORA.

increase by division when actively vegetating.
Like the rest of the unicellular Algae, this
plant requires a new and thorough investi-
gation, for no characters are of any service
without a complete history of the develop-
ment. We subjoin references to the most
important papers on this subject. See also
WATER, COLORATION OF.

BIBL, R. Brown, Appendix to Ross's First
Voyage, London, 1819; Bauer, Quarterly
Journal of Lit. Sciences and Arts, vii. p. 222;
Agardh, Nova Acta, xii. p. 2, System. Alg.

?. 13; DeCandolle, Bibl. univ. de Geneve,
824 ; Nees v. Esenbeck, German ed. of R.
Brown's Works, i. p. 571 (abundant cita-
tions of older writers) ; Hooker, Append, to
Parry's Second Voyage ; Greville, Sc. Crypt.
Fl. pi. 231 ; Shuttle worth, Bibl. univ. Ge-
neve, Feb. 1840; Desmazieres, Ann. des Sc.
nat. 2 ser. xvii. p. 91 ; Meyen, Wiegmann's
Archiv, 1840. i. p. 166, transl. in Ann. Nat.
Hist. vii. p. 245 ; Morren, Hydrophytes de
Belgique, Mem. Acad. Bruxelles, xiv. 1841 ;
Von Flotow, Nova Acta, xx. p. 1 1 ; Cohn,
Nova Acta, xxii. p. 605.

REPRODUCTION.— Some observations
upon the reproduction are made under the
respective heads of the classes, orders, and
families to which the organisms belong. See
also CELLS and OVA.

RESERVOIRS FOR SECRETIONS,
IN PLANTS. See SECRETING ORGANS, of
Plants.

RETE MUCOSUM. See SKIN.

RETICULARIA, Bull. —A genus of
Myxogastres (Gasteromycetous Fungi), cha-
racterized by the indeterminate, thin, simple
peridium, bursting irregularly., with the
branched, shrubby, reticulated capillitium
adherent to it. Several species are British;
they are rather large plants, growing over
recently felled timber or on hollow trees,
rails, &c.

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 308 ;
Fries, Summa Veg. p. 449, Syst. Mycol. iii.
p. 83.

RETINA. See EYE, p. 252.

RHABDITIS, Duj. See ANGUILLULA.

RHABDONEMA, Kiitz.— A genus of
Diatomaceae.

Char. Frustules tabulate, depressed, fixed
by a stalk arising from one of the angles,
with interrupted vittae (front view), vittae
capitate; valves transversely striate, striae
extending into the front view, and forming
numerous longitudinal series. Marine ; upon
Algse. Striae visible under ordinary illumi-
nation ; the dark lines or vittae correspond

to more or less complete internal septa;
frustules connected with each other by gela-
tinous cushions (isthmi).

R. arcuatum (Striatella arcuat., Ralfs)
(PI. 13. fig. 18). Vittae in two marginal
rows, isthmi convex. Length 1 -300".

R. minutum (Tessella catena, Ralfs).
Vittae in two marginal rows ; transverse striae
faint. Length 1-1200 to 1-960".

R. adriaticum. Vittae forming four rows
(interrupted in the middle, and again between
the middle and the margin on each side) ;
transverse striae distinct; isthmi concave.
Length 1-480 to 1-170".

BIBL. Kiitzing, Bacill. 126, and Sp. Alg.
1 15 ; Ralfs, Ann. Nat. Hist. xi. 455, and xii.
104.

RHAPHIDOGLCEA, Kiitz.— A genus of
Diatomaceae.

Char. Frustules navicular, arranged in
radiating crowded rows in a globose gelati-
nous mass. Marine.

R. micans (PI. 14. fig. 11). Rows of frus-
tules irregular, obsolete ; valves linear-lan-
ceolate, subulate, somewhat acute. Length
1-140".

Three other species.

BIBL. Kiitzing, Bacill. 10; id. Sp.Algar.

RHAPHONEIS, Ehr.— An ill-defined ge-
nus of Diatomaceae.

Char. Frustules single, quadrangular, na-
vicular ; valves without a median aperture
(nodule ?); median sutural line longitudinal !
Marine.

Eleven species.

BIBL. Ehrenberg, Ber. d. Berl. Akad. ;
1844. 74 ; Kutzing, Sp. Alg. 49.

RHINOTRICHUM, Corda.— A genus of
Mucedines (Hyphomycetous Fungi), grow-
ing upon dead wood, characterized by erect,
simple, or sparingly divided fertile filaments,
the last joint of which is clavate and covered
with minute spines, scattered or in trans-
verse rows, bearing single spores. Two (new)
British species are described by Berkeley
and Broome.

BIBL. Corda, Icones Fung. i. fig. 232;
Fries, Summa Veg. p. 501; Berk, and Broome,
Ann. Nat. Hist. 2nd ser. vii. p. 177. pi. 7,
xiii. p. 462. pi. 16.

RHIPIDOPHORA, Kiitz.— A genus of
Diatomaceae.

Char. Those of Licmophora, except that
the frustules are each furnished with a di-
stinct stipes ; but as this is not always the
case, the character is of little or no value.
Marine.

RHIZOCLONIUM.

[ 551 ]

RHODOMELACE^E.

Three British species (Smith) ; twelve
others (Kutzing).

R. paradoxa (PI. 13. fig. 19). Stipes fili-
form, dichotomous ; frustules in front view
broadly wedge-shaped, somewhat acute at
the base. Length of frustules 1-540 to
1-480".

RHIZOCLONIUM, Kiitz.— A genus of
Confervaceae (Confervoid Algae), distin-
guished by the decumbent habit and the
short, root-like character of the branches.

Kutzing includes here many of our British
Confervae :

1. R. rimdare, C. Filaments simple,
diam. 1-900", fine bright green bundles
2 to 3 feet long ; in streams and rivers ; com-
mon (Dill. pi. 39).

2. R. tortuosum, Dillw. Filaments sim-
ple, diam. 1-800", rigid, curled and twisted,
forming large strata; in salt-water pools;
abundant (Dillwyn, pi. 46).

3. R. arenosum, Carm. Filaments simple,
diam. 1-1000 to 1-1800"; in dirty green
strata; sandy sea-shores.

4. R. obtusangulum, Lyngb. (PI. 5. fig. 1 2).
Filaments branched, diam. 1-1400"; pale
green, stratified; sandy sea-shores.

5. R. riparium (Jurgensii, Kiitz.). Fila-
ments branched, diam. 1-1400 to 1-1800".
Apparently not distinct from the preceding.
On sandy sea-shores ; not uncommon (Engl.
Botany, pi. 2100).

6. R. implexum. Dillw. Filaments simple,
diam. 1-2000" ; bright green ; forming large
strata, on mountain rocks (Dillw. C. im-
plexa, tab. B).

7. R. arenicolum, Berk. (Kochianum, Kz.).
Filament 1-2000 to 1-2400"; mountain
rocks (Berkeley, Gleanings, pi. 13. fig. 3).

BIBL. Harvey, Brit. Mar. Alg. p. 206.
pi. 24 F; Kiitz. Sp. Alg. 385, Tab. Phyc.
Brit. Flora, ii. pt. 1. p. 354; Dillwyn, Brit.
Conferees.

RHIZONOTIA, Ehr.— A genus of Diato-
macese, of obscure structure.

BIBL. Ehrenberg, Ber. d. Berl. Akad.
1843. 139.

RHIZOPHORACEJ2.— A family of Di-
cotyledonous plants, to which belong the
celebrated Mangrove-trees of the tropics.
They are remarkable for the general occur-
rence of a ramified form of liber-cell (PI. 39.
fig. 31). The long woody radicles pushed
out by the fruits, while still attached to the
parent tree, contain a vast quantity of these
ramified cells with very thick walls.

RHIZOPODA, Duj. or better, Pseudo-
poda, E. — A subdivision of the animal king-

dom, comprising, according to Dujardin and
Ehrenberg, the Arcellina (with Dujardin's
genera Euglypha, Gromia, and Trinema)
and the Foraminifera.

In Siebold's arrangement, it contains the
Amrebaea, the Arcellina, and the Foraminifera.

The essential characters are the gelatinous
structureless composition of the body, and
the locomotive organs consisting of varia-
ble retractile root-like processes (false legs).

BIBL. Dujardin, Infus. p. 240; Ehren-
berg, Infus.; Siebold, Vergl. Anat. 11.

RHIZOSELENIA, Ehr.— A doubtful ge-
nus of Diatomacese.

Char. Lorica tubular, one end rounded
and closed, the other attenuate and multifid
or root-like. Marine (fossil).

Six species (?).

BIBL. Ehrenberg, Abh. d. Berl. Akad.
1841. 291 ; Kutzing, Sp. Alg. p. 24.

RHODOMELA, Ag.— A genus of Rhodo-
melaceae (Florideous Algae), containing two
tolerably common British species, with fea-
thery, inarticulate, branched fronds, the
branches composed of concentric layers of
oblong, colourless cells, with a cortical layer
of minute coloured cells. Colour of R. ly-
copodioides purplish-brown, becoming black;
height 4 to 18". Colour of R. subfusca
brownish or reddish ; height 4 to 10". The
ceramidia are stalked on the ramuli, occur-
ring in summer ; the sticMdia, with tetra-
hedral tetraspores, occur in a similar situa-
tion in winter ; the antheridia (observed in
R. subfusca) also occur in tufts in the same
position.

BIBL. Harvey, Brit. Mar. Alg. p. 78.
pi. 11. 13; Tulasne, Ann. des Sc. nat. 4 ser.
iii. p. 20.

RHODOMELACE.E.— A family of Flo-
rideous Algae. Red or brown sea-weeds,
with a leafy or filiform, areolated or articu-
lated frond, composed of polygonal cells.
Fructification: 1. Conceptacles (ceramidia)
external, ovate or urn-shaped, furnished with
a terminal pore, and containing a tuft of
pear-shaped spores ; 2. antheridia, borne in
tufts in similar situations; 3. tetraspores
immersed in distorted ramuli or in lanceolate
receptacles (stichidia), usually in rows.

Synopsis of the British Genera.

I. ODONTHALIA. Frond flattened, linear,
with an obsolete midrib, pinnatifid, alter-
nately inciso- dentate.

II. RHODOMELA. Frond cylindrical, in-
articulate, opaque. Tetraspores contained
in pod-like receptacles (stichidia).

RHODYMENIA.

[ 552 ]

RHYNCHOPAGON.

III. BOSTRYCHIA. Frond cylindrical,
inarticulate, dotted; the surface-cells qua-
drate. Tetraspores in terminal pods.

IV. RYTIPHL^A. Frond cylindrical, in-
articulate, transversely striate. Tetraspores
in pod-like receptacles.

V. POLYSIPHONIA. Frond cylindrical,
articulated wholly or in part ; the branches
longitudinally streaked. Tetraspores in dis-
torted ramuli.

VI. DASYA. Frond cylindrical, the stem
inarticulate; the ramuli articulated, com-
posed of a single string of cells. Tetraspores
in pod-like receptacles (stichidid), borne by
the ramuli.

RHODYMENIA, Grev.— AgenusofRho-
dymeniaceae (Florideous Algae), containing
seven British species, beautiful, brightly
coloured sea-weeds, growing on rocks or
larger Algae, having a flat membranous or
somewhat leathery frond, ribless and vein-
less, of parenchymatous texture. Most are
not more than 2" high, but R. laciniata and
palmata grow to 10" and 18". The colour
is mostly rose- or blood-red. The coccidia
are formed on the lacerated margins on the
tips of lobes of the frond. The tetraspores
form cloudy spots along the margin, or
scattered, tetrahedrally divided. The anther-
idia likewise form patches on the surface of
the frond (observed in R. Palmetto, and
palmata).

BIBL. Harvey, Brit. Mar. Alg. p. 124.
pi. 16 A; Thuret, Ann. des Sc. nat. 4 ser.
iii. p. 19. pi. 3.

RHODYMENIACE^E. — A family of
Florideous Algae. Purplish or blood-red
sea-weeds, with an expanded or filiform
inarticulate frond, composed of polygonal
cells; occasionally traversed by a fibrous
axis. Superficial cells minute, irregularly
packed, or rarely arranged in filamentous
series. Fructification: 1. Conceptacles (coc-
cidia) external or half-immersed, globose or
hemispherical, imperforate, containing be-
neath a thick envelope a mass of spores
affixed to a central column; 2. antheridia
collected in flat patches or sori; 3. tetra-
spores either dispersed through the whole
frond, or collected in indefinite cloudy
patches.

Synopsis of the British Genera.

* Frond flat, expanded, leaf-like, dichoto-

mous or palmate.

I. STENOGRAMME. Conceptacles linear,
rib-like.

II. RHODYMENIA. Conceptacles hemi-
spherical, scattered.

** Frond compressed or terete, linear or
filiform, much branched.

III. SPH^ROCOCCUS. Frond linear,
compressed, two-edged, distichously branch-
ed, with an obscure midrib.

IV. GRACILARIA. Frond filiform, com-
pressed or flat, irregularly branched; the
central cells very large.

V. HYPNEA. Frond filiform, irregularly
branched, traversed by a fibro-cellular axis.

RHOPALOMYCES, Corda.— A genus of
Mucedines (Hyphomycetous Fungi), nearly

Fig. 623.

Fig. 624.

tiun

Rhopalomyces nigra.
Fig. 623. Tufts on wood. Nat. size.
Fig. 624. Fertile filaments. Magnified 200 diameters.

allied to ASPERGILLUS, but having the
spores single (fig. 624), and not in monili-
form series. They are mildews growing over
decayed wood, matting, dung, &c. Two
(new) British species are described by
Berkeley and Broome, found growing
together.

BIBL. Berk, and Broome, Ann. Nat.
Hist. 2 ser. vii. p. 96. pi. 5.

RHUBARB.— Garden rhubarb (Rheum
undulatum, and other species) affords in the
large edible petioles, excellent specimens of
SPIRAL-FIBROUS STRUCTURES, spiral, an-
nular and reticulate vessels and ducts ; these
are readily isolated by the help of a needle
from a fragment of cooked rhubarb placed
in water on a slide. The petioles and leaves
likewise contain bundles of acicular RA-
PHIDES. The roots also contain special
receptacles for a characteristic SECRETION.

RHYNCHOPAGON, Werneck (Rota-
tori&).=Diglena with a bilobed rostrum !
Two species.

BIBL. Werneck, Ber. d. Berl. AJcad. 1841 .
p. 377.

RHYTISMA.

[ 553 J

RICCIE.E.

RHYTISMA, Fries.— A genus of Phaci-
diacei (Ascomycetous Fungi), growing upon
the leaves of trees and shrubs, forming dark
patches or spots on the surface, breaking
through the epidermis in little scales or
irregular fissures. -R. acerinum is exceed-
ingly common, forming large black spots on
the leaves of the sycamore and maple ; the
thecasporous fruit is perfected (on the dead
fallen leaves) in spring ; MELASMIA aceri-
na, which occurs in autumn, appears to
be a preparatory form of this plant. R.
salicinum is common on willow-leaves.

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 290 ;
Grev. Sc. Crypt. Fl. pi. 118; Fries, Summa
Veg. 3/0; Tulasne, Comptes Rendus, March
31 st, 1852 (Ann. Nat. Hist. ser. 2. viii.
p. 118).

RICCIA, L. — A genus of Riccieae (Hepa-
ticacere), consisting of minute green thalloid

Fig. 625.

Riccia fluitans.

Lower surface of a fragment of the frond, with three
imbedded sporanges projecting, their orifices being on
the upper surface.

Magnified 5 diameters.

productions growing upon damp ground or
floating on water, distinguished from the

Fig. 626.

Fig. 627.

Riccia fluitans.

Fig. 626. Vertical section through the frond or sporange
contained in its substance.

Fig. 627. Sporange with persistent epigone, extracted
from the frond.

Magnified 25 diameters.

allied forms by the capsules being immersed
in the substance of the frond, destitute of
perichsete and perigone, while the archegone

pt naiiently encloses the sporange as an
adherent epigone, bearing a persistent style-
like neck (figs. 626, 627). The antheridia
are globose sacs contained in special cavities,
the orifices of which, narrowed into a neck,
project as short processes from the surface
(cuspides). The epigone being adherent to
the sporange, the spores appear to lie im-
mediately in the cavity of the former when
ripe ; they are unaccompanied by elaters and
escape by irregular rupture of the epigone.
Several species occur in Britain.

* Terrestrial.

1. R. glauca, L. Frond without mem-
branous scales below, fleshy, ovate-oblong,
two- to three-lobed, 1-2 to 1" in diameter,
the divisions dichotomous, growing in orbi-
cular tufts, surface smoothish, punctate,
glaucous green. On banks.

2. R. crystallina, L. Differing from the
last chiefly in larger size and lighter colour,
and having large cavernous air-cells opening
widely on the upper surface. Damp mould.

•** Aquatic.

3. R. fluitans^. (fig. 625). Fronds with-
out scales below, 1-2 to 2" long, repeatedly
forked, segments linear, notched at the
ends; when placed on damp earth it produces
radical hairs (fig. 626-7). Stagnant water.

4. R. natans, L. Fronds with long reti-
culated scales below, obcordate, 1-2" long,
or with the two lobes again divided; scales
of the lower surface purple. On stagnant

BIBL. Hook. Brit. Flora, ii. pt. 1. p. 102;
Bischoff, Nova Acta, xvii. p. 909 ; Linden-
berg, ibid, xviii. p. 361 ; Hofmeister, Ver-
gleich. Untersuch. p. 43. pi. 10.

RICCIEAE.— A tribe of Liverworts or He-
paticacea3, consisting of delicate green mem-
branous fronds, spreading on the ground or
floating on water. The fruits are always
sessile on the frond, more or less imbedded
in its substance, according to the thickness ;
the spores are unaccompanied by elaters.

Synopsis of British Genera.

I. SPH.EROCARPUS. Archegones dorsal,
on a lobed membranous frond, sparingly
aggregated. Perichsete obtusely conical or
pear-shaped ; perforated at the summit, con-
tinuous with the frond. Perigone wanting.
Epigone crowned by the deciduous style.
Sporange at length free, indehiscent.

RICE.

C 554 ]

ROTATION.

II. RICCIA. Archegones immersed in
the frond, scattered, neither emergent nor
exposed on the surface until burst. Peri-
chaete and perigone indistinguishable. Epi-
gone crowned by the enlarged long persistent
style, adherent to the sporange. Sporange
bursting irregularly.

RICE. — This grain is produced by the
grass called Oryza sativa. The seed is
remarkable for the hard character of the
albumen, which is explained at once, when
we examine a section under the microscope
(PI. 36. figs. 12 & 13). The cells are filled
with very small starch-grains, which are
packed so closely that they assume a paren-
chymatous form, and present the appearance
of a continuous tissue (as in maize). The
cohesion of the starch-granules is the cause
of the peculiar grittiness of rice-flour. See
STARCH.

RIND. — This word is used to denote a
structure intermediate between epidermis
and bark ; a compound structure consisting
of several or many layers of cells and even
of distinct forms of tissue, but not presenting
the characteristic kinds and mode of arrange-
ment which occur in true BARK.

RING-NET. See INTRODUCTION,
p. xxiv. We have somewhat modified this
piece of apparatus since the above was
written, by having the ring made of brass,
and the muslin fixed by means of an inner
ring, adapted to the outer, but incomplete
at one point of its circumference, and with
a projecting rim to prevent its passing
through the outer ring. The muslin is
retained by the spring-action of the inner
against the inside of the outer ring.

RIVULARIA, Roth.— A genus of Oscil-
latoriaceae (Confervoid Algae), subdivided by
Kiitzing, and restricted to the forms in
which there is a distinct manubrium or elon-
gated cell next to the globular basal cell. As
thus defined, it contains only a few aquatic
species, the rest being transferred to PHY-
SACTIS, EUACTIS and allied genera.

1. R. angulosa, Roth. Frond floating,
globose, dirty green ; manubria oblong and
curved, or oblong-ovate and abbreviated;
filaments torulose at the base, interruptedly
articulated at the apex. Eng. Bot. 968.

2. R. Boryana, Kg. (PI. 4. fig. 1 8). Frond
globose, greenish-brown; manubria large;
sheaths ventricose, colourless, with plaited
constrictions ; filaments moniliform or inter-
ruptedly articulate, flagelliform. Frond as
large as a cherry. /3 flaccida, smaller, fila-
ments flaccid, not interrupted. The follow-

ing two are given as doubtful: R. botryoides,
Carmichael, and R. plana, Harvey.

BIBL. Kiitzing, Sp. Alg. p. 336, Tab.
Phyc. ii. pis. 67, 68; Harvey, Brit. Alg.
1 ed. p. 150; Hassall, Brit. Fr. Alg. p. 262.
pi. 64.

ROCCELLA, Ach.— A genus of Parme-
liacea? (Gymnocarpous Lichens), growing on
maritime rocks, remarkable as furnishing the
dye called orchil or archil. R. tinctoria
and R. fusiformis, the British species, grow
only in the extreme south of England.

BIBL. Hook. Brit. Flor. ii. pt. 1. p. 225;
Engl. Botany, pi. 211. 728.

RCESTELIA, Rebent.— A genus of Cieo-
macei(Coniomycetous Fungi), closely related
to JSciDiuM, and presenting similar sper-
magoniaand perithecia; the chains of spores
of the RcestelicB, however, present a pecu-
liarity, having a sterile joint, forming an
isthmus of variable length, between each
spore ; the peridium bursts irregularly, or
(in R. cancellata) the teeth cohere more or
less for a time, so as to form a kind of
lattice. This genus includes jfficidium cor-
nutum, laceratum and cancellatum of older
authors, growing respectively on the leaves
of the mountain- ash, hawthorn and pear. See
JScioiuM and UREDINEI.

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 373 ;
Greville, Sc. Crypt. Fl. pis. 180. 209 ; De
Bary, Brandpilze, Berlin 1853. p. 73 ; Tu-
lasne, Ann. des Sc. nat. 4 ser. ii. pp. 132.
173 ; Fries, Summa Veg. p. 510.

ROSALINA, D'Orb. See FORAMINI-

FERA, p. 271.

ROTALIA, Ehr. See FORAMINIFERA,
p. 271.

ROTATION.— This term is usually em-
ployed in botanical works to denote peculiar
flowing movements of the protoplasm within
the cavity of vegetable cells, and it is useful
to retain the word for all the cases of the
kind, in order to avoid confusion of these
phenomena with the general circulation of
the sap. The term " circulation of the cell-
sap" is, however, often used instead of rota-
tion, and especially in reference to the cases
where it exhibits numerous distinct currents.

The rotation or circulation of the proto-
plasm presents itself in two types, namely —
1. a rotatory movement of a layer of proto-
plasm investing the entire internal surface
of the cell, as in CHARA, &c.; and 2. a radia-
ting movement of the protoplasm in slender
currents, from the nucleus out over the
remainder of the cell, with a return flow to-
wards the nucleus ; but as the nucleus itself

ROTATION.

[ 555 ]

ROTATION.

shifts in the latter type, as in the former,
the two kinds are scarcely definitely distin-
guishable. They may, however, be spoken
of separately.

The rotation in Chara (and Nitella) has
been long known ; a similar movement oc-
curs in many water-plants, such as Vallis-
neria, Hydrocharis, Anacharis, Stratiotes,
Sagittaria, Potamogeton, Ceratophyllum, &c.,
where it is seen best in the more delicate
foliaceous structures, such as young leaves,
stipules, or sepals, or in the young rootlets ;
it has also been observed in the fruit-stalks of
Blasia pusilla, and some other Hepaticaceae.
The general rotation has not yet been ob-
served in any land-plants.

In the Characese the wall of the cells is
lined with chlorophyll-granules, leaving two
oblique or spiral striae bare (fig. 129, p. 134) ;
these striae indicate the boundaries of the
ascending and descending currents (marked
by arrows). The moving substance is a vis-
cid semifluid layer lying within the chloro-
phyll-layer, and itself surrounding the watery
cell-sap occupying the centre of the cell.
This layer, forming a kind of gelatinous sac,
moves in a spiral course up one side of the
cell and down the other, the motion being
rendered very evident by chlorophyll- and
other granules imbedded in it ; these appear
to be carried along passively by the stream,
the larger slowly, the smaller with greater
rapidity. In Vallisneria, Anacharis, &c.
the chlorophyll-granules and the nucleus
are imbedded in and moved with the flowing
protoplasm. If long cells of Chara are bent
or tied round by a ligature, the circulation
is not stopped, but takes place independently
in each half. If a cell of Chara is cut across,
the protoplasm of the current flowing to-
wards the cut surface escapes at once, but
that of the current flowing away, goes on to
the end of the cell, turns round, and then
flows towards and out from the wound.

The size of the stream seems to be in in-
verse proportion to the length of the cell,
decreasing as the latter acquires its full de-
velopment. The rapidity of the current
varies according to the age of the plant and
the activity of its vegetation. It is most
rapid in hot weather and in sunshine. Arti-
ficial elevation of temperature in the water
in which the plant grows, up to a certain
point, hastens the movement; a heat above
80° Fahr., however, retards it for a time.
A temperature of 1 12° Fahr. kills the plant,
as also does a cold of about 20°. Darkness
appears merely to exert effect through its

influence on the activity of the vegetation.
Keeping Chara in water exhausted of air
does not stop the rotation until the plant
dies. Most chemical reagents seem to exert
no special action ; only lime-water appears
to stop it in a few moments. A solution of
sugar or gum, or milk greatly hastens the
rotation inVallisneria,soihsit the protoplasm
is moved on in waves ; but the primordial
utricle finally dissolves, and the movement
ceases. Passing an electric current through
the cell stops the current for a time, but it
recovers itself, just as occurs after any me-
chanical interference. If several cells are
injured by cutting or pricking, the whole
rotation stops in young plants, but it gra-
dually returns as before in the uninjured
cells. Pressure interrupts or stops the mo-
tion for a time only; when removed, the
current is gradually restored; but actual
injury to the cell stops it for ever.

The rotation which takes place between
the external surface of the green layer and
the outer cell-membrane in Closterium and
other DESMIDIACE^J appears to be of the
same kind as the above.

The circulation in reticular currents, first
observed by Mr. Brown in the hairs of the
stamens of Tradescantia, appears to exist
far more extensively, if it be not even a uni-
versal phenomenon. It has been observed
in the Confervoideae, Fucoideae, Florideae,
Lichens, Fungi, Hepaticae, Equisetaceae,
Lycopodiaceae, and Ferns, and in the most
varied families of Flowering plants. It is
seen most easily in young tissues, especially
such as can be prepared readily without
much mechanical injury; for example, in
hairs, cells of the pulp of fruits, cells of the
germen of Onagraceae, of the labellum of Or-
chids, &c. It generally exhibits the follow-
ing characters : in the middle or at one side
of the cell occurs a large heap of protoplasm,
in which is imbedded the nucleus ; from this
protoplasm more or less slender filaments
run out over the cavity of the cell, and as
these contain numerous fine granules, a
flowing movement which takes place becomes
evident by the change of place of the gra-
nules. Attentive examination shows that
these flow out from the central mass, and
return to it ; and moreover, that the currents
change their form and direction; and lastly,
that the nucleus itself moves. This rotation
cannot be observed in very young cells when
the cavity is densely filled with protoplasm;
but Hofmeister states that he has seen the
entire primordial utricle rotate in the special

ROTATORIA.

[ 556 ]

ROTATORIA.

parent-cell of the spore ofPhascum cuspida-
tum. As the young cells increase in size, va-
cuolesare formed in the protoplasm, filled with
watery sap, and these enlarging and beco-
ming confluent, leave the protoplasm in the
form of a reticulated mass.

The cause of the motion is quite unex-
plained, but it is evidently related to the
movements exhibited by free protoplasmic
bodies, such as ZOOSPORES, SPERMATO
ZOIDS, the free filaments of OSCTLLATORIA,
&c. It has been stated to be dependent on
the action of cilia, but we believe this is to-
tally erroneous, and that it is rather referable
to a common cause with the motion of cilia
themselves. It has been well compared
with the movements of the body of Amoeba,
which bears considerable resemblance to
some kinds of the reticular rotation. The
relation existing here is further borne out
by the fact of pulsating vacuoles existing in
Volvox, Gonium, &c., just like those in the
Infusoria.

The rotation in Chara may be observed
by simply placing portions of the plant on a
slide in water. The unencrusted species are
of course most favourable, but the growing
points of the others are tolerably transpa-
rent. In Vallisneria, detached fragments of
leaves, or even horizontal sections of the
leaf, may be used ; in Anacharis entire leaves
or sepals may be detached and observed.
Hairs are frequently more or less covered
with a viscid secretion, which retains air-
bubbles about them; in such cases, it is
often useful to dip them for an instant in
alcohol, and then place them in water.

BIBL. Varley, Trans. Soc. of Arts, xlviii.
(1832), Mic. Trans. ; Slack, Trans. Soc.
Arts, xlix. ; Dutrochet, Comptes Rendus,
1837. p. 775; Becquerel, ibid. p. 784;
Meyen, Pflanzenphys. ii. p. 206 ; A. Braun,
Richtungsverhaltnisse du Saftstrome, Berlin
Bericht. 1852 ; Goppert and Cohn, Bot.Zeit.
vii. p. 665 (1849) ; Unger, Sitzbericht d.
Wien. Akad. viii. p. 32 ; Mohl, Bot. Zeit.
iv. p. 73 (1846), Ann. Nat. Hist, xviii. p. 1;
Hofmeister, Vergleich. Unters. p. 73 ; Os-
borne, Mic. Journal, iii. p. 54 (1 854) ; Bran-
son, ibid. iii. p. 260 (1855); Wenham, ibid.
p. 250.

ROTATORIA or ROTIFERA.— A class
of the Animal Kingdom.

Char. Microscopic, transparent, aquatic
animals; legs absent; anterior portion of
the body furnished with a retractile, often
lobed disk, upon which are placed usually
vibratile cilia, when in motion presenting the

ajypearance of one or more revolving wheels ;
alimentary canal usually distinct, with a den-
tal apparatus, and two orifices ; reproduc-
tion by ova.

Body covered with a firm and usually
smooth skin or integument, sometimes pre-
senting indications of segments ; often more
or less enclosed in a carapace (CARAPACE),
which is either secreted by the skin, by the
alimentary canal, or by a special secreting
organ. In some species the skin is fur-
nished with hairs or rigid bristles.

In most, there is a tail-like process at the
posterior end of the body called the foot-like
tail, tail-like foot, or false foot ; this is
jointed, and can often be contracted and ex-
tended like a telescope ; it does not form a
direct prolongation of the end of the body,
but arises from and is situated upon the
ventral aspect. It is often terminated by a
suctorial disk, or a pair of claw- or toe-like
processes.

Distinct muscular bands are present,
longitudinal, circular, &c.; these sometimes
present transverse striae, but it is doubtful
whether they agree with those of the fibres
of the higher animals.

The rotatory disk or wheel-organ varies
greatly in structure, the varieties forming
characters of the families, &c.

Its margin is usually furoished with one
or two rows of vibratile cilia; sometimes
these are replaced by bundles of non-con-
tractile elongate cilia (PI. 34. fig. 32), or the
rotatory organ is divided into tentacle-like
processes, upon which cilia are placed (PI.
34. fig. 25).

The rotatory disk is the principal organ
of motion, by means of the cilia of which
the animals swim through the water ; some
of the Rotatoria, however, move in a leech-
like manner, by alternately fixing the
toe-like processes and the anterior end of
the body, which in some forms a kind of
proboscis (PI. 34. fig. 1).

The nervous system is not well known.
It appears to consist of a cervical ganglion,
and branches given off in various directions.

In many of the Rotatoria, eyes are present,
mostly red. These appear to have a cornea
and a lens. They sometimes disappear in
the adult animals, and as their number,
position, &c. are used as characters, when
absent in the adults, they must be looked
for in the young or the ova, either within
the carapace or adherent to the body.

Alimentary apparatus. — Behind the mouth
is sometimes a distinct conical pharynx ;

ROTATORIA.

[ 557

ROTATORIA.

but nearly always a rounded muscular giz-
zard containing the jaws and teeth. In the
pharynx are occasionally seen two undulating
lines, presenting a flickering appearance, the
indications of cilia or undulating membranes.
The jaws are constructed mostly after two
forms. In one of these, they consist of two
knee-shaped pieces (PI. 34. fig. 24), to the
posterior portion of which muscles are at-
tached, whilst the anterior, which passes
inwards at a right or obtuse angle to the
former, ends in a single point or in several
teeth (fig. 26). In the other, the jaws have
the form of stirrups (PI. 34. fig. 17), with
their bases turned towards each other, upon
which two or more teeth are placed. A
third single or compound intermediate piece
forms a support (PL 34. figs. 24, 26), upon
which the food acted upon by the jaws is
triturated. In some species the jaws and
teeth are very complex in their arrangement.

The alimentary canal is usually short and
straight, hut sometimes curved. Its walls
are very thick and lined with ciliated epithe-
lium. The stomach forms a distinct expan-
sion (PL 34. fig. 27 c) ; this is succeeded by
an intestine, the termination of which cor-
responds to a cloaca, receiving the expelled
contents of the reproductive organs and so-
called water-vessel system, and opening at
the base of the foot. In some Rotatoria, a
second expansion or stomach is situated
below the upper one.

The walls of the stomach and intestine
frequently contain brown or yellow cells,
representing a liver. And at the commence-
ment of the stomach are two or more caecal
appendages, probably corresponding to a
pancreas (PL 35. figs. 14, 34).

Vascular system. — Distinct blood-vessels
are apparently not present in the Rotatoria,
but on each side of the body, in most of
them, runs a narrow, straight or wavy band,
containing a slender vessel (PL 34. fig. 18 a;
PL 35. fig. 14 6). Anteriorly, these vessels
give off branches, the terminations of which
are not well known. By some they are said
to open into the abdominal cavity, by others
to terminate as caeca. Attached to the walls
of these lateral tubes, or situated within
them, are pear-shaped or oval corpuscles
(PL 34. fig. 18 a; PL 35. fig. 14 c), which
exhibit a flickering appearance from the
action of cilia connected with them. Pos-
teriorly, the tubes terminate in an actively
contractile sac, which opens into the cloaca.
In regard to their function, these tubes have
been variously viewed, as water-vessels,

testes and kidneys. Ehrenberg considered
them as connected anteriorly with a certain
projecting tubular organ (PL 35. fig. 14 «),
situated usually in the cervical region (PL 34.
fig. 3; PL 35. fig. 17), denominated the
calcar or respiratory tube, also viewed as an
antenna, and terminated by a retractile tuft
of non-vibratile cilia (PL 35. fig. 5 a).

Beneath the integument of the Rotatoria,
a kind of irregular circulation, varying with
the motions of the body, or a simple mole-
cular movement of minute granules, has been
noticed. These granules are probably situ-
ated in the abdominal cavity ; in which also
sarcodic globules, sometimes free, at others
connected by filaments, have been observed.

Reproduction. — The Rotatoria are propa-
gated by means of sexual organs, division or
gemmation being unknown in them. They
were formerly regarded as hermaphrodite ;
but it is probable that they are unisexual,
and spermatozoa have been detected in at
least one species. The female organs consist
of one or two longer or shorter ovarian sacs
or ovaries, situated towards the posterior end
of the body in the abdominal cavity, the
oviduct terminating in the cloaca, or at a
distinct vulva. The ova are of an oval form,
and are sometimes smooth externally and
soft ; at others they correspond with the
winter-ova, being larger, darker, and the
outer coat thick, and hairy or tubercular.

A penis (retracted foot?) has been de-
scribed as existing in the males.

The ova sometimes remain adherent to
the cloaca for a time, and in a few instances
they are hatched within the ovary.

Many of the Rotatoria are remarkably
tenacious of life, and some of them are stated
to have revived after having been kept dry
for several years.

The families of the Rotatoria are thus
distinguished : —

Ciliated margin of rotatory disk simple or continuous.
Margin entire. Holotrocha.

Carapace absent 1 . Ichthydina.

Carapace present 2. (Ecistina.

Margin undulate or excised. Schizotrocha.

Carapace absent 3. Megalotrpchsea.

Carapace present 4. Flosculariaea.

Rotatory disk divided or multiple.
Divided into several parts. Potytrocha.

Carapace absent 5. Hydatinaea.

Carapace present 6. Euchlanidota.

Divided into two parts. Zygotrocha.

Carapace absent 7. Philodinsea.

Carapace present 8. Brachionsea.

See ALBERTINA.

They are found wherever water exists,
provided it be not in a state of putrefaction ;

ROTIFER.

[ 558 ]

SAGO.

thus in pools, on moist earth, mosses, in
gutters, &c., and even in the cells of mosses
and algae.

BIBL. Ehrenberg, Infusoria; Dujardin,
Infus.-, Siebold, Vergleich. Anat.; Dalrymple,
Phil. Trans. 1849. 331; Huxley, Trans.
Micr. Soc. 1852. i. 1 ; Williamson, Micr.
Journ. i. 1 ; Pritchard, Infusorial Animalc. ;
Vogt, Zoolog. Brief e; Valenciennes, Ann.
d. Sc. nat. 1850.

ROTIFER, Cuv.— A genus of Rotatoria,
of the family Philodinaea.

Char. Eyes two, situated upon the pro-
boscis ; foot furnished with lateral horn-like
processes, and with two terminal toes, giving
its end a bifurcate appearance.

R. vulgaris (PI. 35. fig. 23). Body fusi-
form, white, gradually attenuated towards
the foot. Aquatic; length 1-48 to 1-24".

This is one of the commonest of the
Rotatoria, and has long been known as a
favourite microscopic object under the po-
pular name of the wheel-animalcule. The
anterior and upper part of the body termi-
nates in a proboscis, ciliated at the end, and
upon which the eyes are placed; the two
rounded lobes of the rotatory organ are
placed laterally. Behind, and at the root of
the proboscis, is the calcar.

In R. citrinus, the middle of the body is
yellowish, the horns of the foot long, and
the eyes round. In JR. macrurus the body
is suddenly narrowed into a long foot. In
R. tardus the body is gradually attenuated,
but somewhat deeply constricted into seg-
ments. The species are all aquatic.

BIBL. Ehrenberg, In/us, p. 484.

ROTIFERA. See ROTATORIA.

RUBEFACTION, OF WATER. See WA-
TER.

RUCKERIA.— A genus of Compositse.
The pericarp possesses HAIRS of an interest-
ing structure.

BIBL. Decaisne, Ann. Nat. Hist. vi.
p. 257 (Trans, from Ann. des Sc. nat. 2 ser.
xii. p. 251).

RUELLIA. — A genus of Acanthaceous
Plants. The testa of the seed of Ruellia
formosa exhibits a peculiar kind of HAIR
(PI. 21. fig. 21).

RUST, OF PLANTS. See BLIGHT.

RYE. — The grain of SECALE CEREALE.
See STARCH.

RYTIPHLJ3A, Ag. — A genus of Rhodo-
melaceae (Florideous Algae), containing four
British species, mostly common, having pin-
nately-branched, filiform or compressed
fronds, transversely striate and reticulated ;

the articulate axis is composed of a circle of
large elongated tubular cells surrounding a
central cell, the whole enclosed by a kind of
rind of several layers of small coloured cells.
Colour mostly dull-red or brown. Fronds
from 2" to 4" or 6" high. The ceramidia
occur scattered on the ramules of some
plants; the antheridia tufted in the same
situations on others, and tetraspores (tetra-
hedral) occur imbedded in a double row in
stichidia, borne on distinct plants.

BIBL. Harvey, Brit. Mar. Alg. p. 80.
pi. 11 D; Grev. Alg. Brit. pi. 13; Derbes
and Solier, Ann. des Sc. nat. 3 ser. xvi.
p. 275. pi. 35. figs. 11 & 12 ; Thuret, ibid.
4 ser. iii. p. 20.

S.

SACCOGYNA. — A genus of Jungerman-
niese (Hepaticacese) founded on the Junger-
mannia viticulosa of Linnaeus ; it is remark-
able on account of the subterraneous fleshy
perianth, in which character and in habit it
is allied to Calypogeia. It is found among
mosses, especially in alpine districts.

BIBL. Hook. Brit. Flor. ii. pt. 1. p. 121,
Brit. Jung. pi. 60; Ekart, Syn. Jung. pi. 1.
fig. 6; Endlicher, Gen. Plant. Supp. 1.
No. 472-23.

SACCULUS, Gosse.— A genus of Rota-
toria, of the family Ichthydina.

Char. Eye single, frontal ; body free from
hairs, and without a foot ; rotatory organ a
simple wreath ; alimentary canal very large ;
jaws set far forward, apparently consisting
of two delicate, unequal, lateral pieces, and
a slender central portion, very evanescent ;
eggs attached behind after deposition.

/S. viridis. Length 1-150"; aquatic.

BIBL. Gosse, Ann. Nat. Hist. 1851. viii.
198.

SAGEDIA, Fries.— A genus of Endocar-
peae (Angiocarpous Lichens), consisting of a
few anomalous plants, closely related to
Endocarpon and Verrucaria.

BIBL. Leighton, Brit. Angioc. Lichens,
p. 21.

SAGENIA, Presl. — A genus of Aspidieae
(Polypodioid Ferns). Exotic.

SAGO. — Farinas obtained from a variety
of tropical plants are known by this name,
but the true East Indian sagoes are ex-
tracted from the central part of the trunks
of Palm-trees belonging to the genus Sagus,
natives of the Moluccas. In PL 36. fig. 23
is figured the starch of a sago obtained from
the Museum at Kew; but it is uncertain
whether this is the produce of a Sagus. Its

SALICINE.

[ 559 ]

SARCINA.

grains resemble those of the East Indian
Arrow-root (PL 36. fig. 18). See STARCH.

SALICINE.— The alkaloid of the willow
and poplar.

The so-called circular crystals of this sub-
stance (PI. 31. fig. 9) form a beautiful polar-
izing object. The largest crystals are ob-
tained by fusion.

SALIVARY GLANDS.— These organs,
consisting of the parotid, the submaxillary,
and the sublingual glands, agree in structure
with the racemose mucous glands (MOUTH),
of which they may be regarded as aggrega-
tions.

Their ducts consist of areolar tissue, with
numerous very dense networks of elastic
tissue. Wharton's duct contains unstriped
muscular fibres.

The salivary corpuscles are noticed under
MOUTH (p. 439).

SALPINA, Ehr. — A genus of Rotatoria,
of the family Euchlanidota.

Char. Eye single, cervical ; foot forked ;
carapace closed on the ventral surface, and
furnished with spines or horns at the ends.
Aquatic.

The carapace resembles a three-sided box
with convex sides, flat and closed beneath,
and often scabrous.

S. redunca (PI. 35. fig. 24). Carapace
with two curved horns in front upon the
ventral surface, smooth, posterior end with
three horns ; dorsum cleft, gaping. Length
of carapace 1-216 to 1-144 .

Five other species.

BIBL. Ehrenberg, In/us, p. 469.

SALTS. See CRYSTALS.

SALVIA, L. — An extensive genus of
Flowering plants of the Nat. Ord. Labiatse,
including common sage, and many species
cultivated for the beauty of their flowers.
They are interesting to the microscopist both
on account of the GLANDULAR HAIRS,
containing the essential oils, and the spiral-
fibrous structures found in the HAIRS of
the pericarp (PL 21. fig. 23).

SALVIN1A, Mich.— A genus of Marsi-
leaceae, growing floating on the surface of
stagnant water (not British). They are di-
stinguished from MARSILE A andPiLULARiA
also by bearing two distinct kinds of spore-
fruits, one kind producing only ovule-spores,
the other only pollen-spores, which exhibit
analogous phsenomena in their germination
to those described under PILULARIA. See
that head and MARSILEACE^.

BIBL. That of MARSILEACE^; and PILU-
LARIA.

SAND, BRAIN-. — Brain-sand, or the acer-
vulus cerebri, is found in the pineal gland
and the choroid plexus, sometimes also in
the pia mater, the arachnoid membrane, and
the walls of the ventricles.

It consists of single, or aggregated and
nodular, rounded, dark bodies, 1-2500 to
1-200" in diameter; sometimes also forming
club-shaped, cylindrical, or reticular masses.
Chemically it is principally composed of
carbonate and phosphate of lime, and like
other concretions, leaves an organic cast of
the original form, after the salts have been
removed by a dilute acid.

Fig. 628.

Brain-sand from the pineal gland, in bundles of areolar
tissue.

Magnified 350 diameters.

BIBL. Kb'lliker, Mikrosc. Anat. ii.

SAND, SEA. — This often contains inter-
esting microscopic objects ; as Foraminifera,
spicules of sponges, minute shells of the
Mollusca, or their fragments, portions of the
skeleton of the Echinodermata, &c.

The various bodies may be separated from
the washed and dried sand with a mounted
bristle (!NTR. p. xxii.).

The sand or powder which may be sepa-
rated by pressing or shaking newly imported
sponges, and which is sometimes called
sponge-sand, is very rich in the above organic
bodies, especially the Foraminifera.

SAP. — A name vaguely applied to the
watery juices contained in living plants.
Sap flowing from wounds may contain va-
rious organized substances, such as starch-
granules, chlorophyll- or protoplasmic glo-
bules, also raphides ; but it cannot be said
to have any proper microscopic characters.

SAPROLEGNIA, Nees. See ACHLYA.

SARCINA, Goodsir. — A curious organ-
ism, placed provisionally among the Pal-

SARCINA.

[ 560 ]

SARCODE.

mellaceae (Confervoid Algae) from considera-
tions relating to its apparent structure, but
which in its habitat and general characters
would appear more nearly related to the
Fungi. Sarcina ventriculi (PL 3. fig. 5 a
and b) is a body found sometimes in great
abundance in vomited contents of the sto-
mach of the human subject, also in the sto-
mach after, death, where no disorder had
appeared during life ; in the urine, faeces, in
the pus of pulmonary abscess, &c. ; it has
also been found in the stomach of the rab-
bit. It ordinarily consists of minute square,
oblong, or even irregular masses, of consi-
derable consistence, composed of four, eight,
sixteen, sixty-four or more squarish cells
contained in a tough transparent frond, ap-
parently composed of the cell-membranes of
these cells. The cells are always most closely
connected in groups of four, which stand a
little more apart from each other in the se-
condary groups of sixteen ; these again have
a stronger line of demarcation between them
when they are collected into tertiary groups
of sixty-four (PI. 3. fig. 5 «, 6). The size of
the primary cells (nuclei of Ch. Robin) ap-
pears to vary slightly ; we find their diameter
about 1-16,000" ; they have a slight brownish
tint, which imparts a colour to the whole
mass. Iodine colours the fronds brown;
alcohol contracts them a little. Nitric acid
does not dissolve them, even when heat is
applied. Alkalies cause the fronds to break
up into the constituent components. The
plant appears to increase by the division
of the contents of its ultimate cells into four,
and the formation of a new membrane around
each portion, the groups remaining attached
a longer or shorter time according to cir-
cumstances. The history of this remarkable
production requires further elucidation ; it is
evidently not connected with any special
derangement of the stomach, as was formerly
supposed ; and its occurrence is now known
to be much more common than was at one
time imagined.

Ch. Robin places Sarcina in Meyen's ge-
nus Merismopadia, with which it certainly
agrees in general appearance and characters,
except that the cell-contents in the latter
are of a glaucous green colour ; possibly the
objects all belong to one genus, in spite of
the unusual locality of the <S. ventriculi ; on
this we are unwilling to give an opinion.
But it must be mentioned here, that the
remarks offered on Merismopcedia under the
head of GONIUM require modification. The
true species of MERISMOP^EDIA are totally

distinct from GONIUM, which has no conti-
nuous frond, and belongs to the Volvocineae;
and of the species given under GONIUM,
probably only G. pectorale really belongs
to it. We have recently examined fresh
specimens of a true Merismopcedia (from
stagnant water) with its green cells (in groups
of sixteen or more), about 1-16,000 or
1-17,000" in diameter (very nearly equal to
Sarcina ventriculi]', this would appear to
correspond to Nageli' s M. Kutzingii (= M.
glauca, Kiitz. Phyc. Germ, and M. punctata,
Kiitz. Phyc. general.). M. glauca (ditches)
is said to have the cells from 1-4800 to
1-7200" in diameter, about twice as large as
the former. The bluish-green cells are oval
when about to divide, at other times glo-
bular.

Wedl says he has found Sarcina abun-
dantly in water surrounding frog's spawn ;
it is a question whether this was not one of
the species of Merismopadia just named.

It may be desirable, in the present state
of our knowledge, to keep Sarcina distinct ;
but should it prove to be an Algaceous plant,
there appears to be no character by which it
can be divided from the older genus Meris-
mopcedia.

BIBL. Goodsir, Edinb. Med. and Surg.
Journ. 1842. p. 430, Anat. and Path. Obs.
Edinb. 1845. pi. 8. figs. 1 & 3; Busk, Mi-
crosc. Journal, 1843; Virchow, Archiv f.
Path. Anat. i. p. 264 ; Simon, ibid. ii. p. 331;
Wedl, Path. Histol. 753 ; Schlossberger,
Archiv f. Phys. Heilkunde, 1846. p. 747-
768 ; C. Miiller, Bot. Zeit. v. p. 273 (1847);
Nageli, Einz. Alg. p. 2 ; Ch. Robin, Vegetaux
Parasit. 2nd ed. p. 331 ; Lehmann, Phys.
Chemie ; Bennett, Lectures on Clin. Med.
1851. p. 214 ; Funke, Atlas der Phys. Chem.
pi. 7- fig- 4. MERISMOP^EDIA, Meyen,
Muller's Archiv, 1839. ii. p. 67, Pflanzen-
phys. iii. p. 440; Nageli, 1. c. p. 55. pi. 1 ;
Kutzing, Phyc. Gen. p. 294, Spec. Alg. p.
471 ; Tab. Phyc. v. pi. 38.

SARCODE.— A term applied by Dujarclin
to the gelatinous, homogeneous, diaphanous
proteine-substance occurring abundantly in
very young animals, the larvae of insects,
embryos of the Vertebrata, worms, zoo-
phytes, &c., and representing the fibro-
areolar tissue of the higher and adult ani-
mals. It appears to constitute the whole of
some of the lower animals, as the Amoeba.
It may be readily studied when exuding
from around the body of the intestinal pa-
renchymatous worms, as the Distoma, Cys-
ticercus, Ttsnia, &c., or almost any of the

SARCOPTES.

[ 561 ]

SARCOSCYPHUS.

Infusoria, placed alive in water between two
plates of glass. In the course of a short
time, the outline of the bodies of the animals
is seen to be bordered with a row of project-
ing diaphanous globules (PI. 25. fig. 2 a),
frequently more or less pressed together,
which after a time become separated and
float in the liquid, especially if it be shaken.
Spherical cavities or vacuoles are soon per-
ceptible in these globules of sarcode (PI. 25.
fig. 2 b), the nature of which is readily de-
termined by comparing the refraction of the
light at their circumference with that at the
circumference of the globules themselves;
for on elevating the object-glass, the centre
of the vacuoles becomes darker, and the
centre of the globules becomes brighter;
whilst on approximating the object-glass,
the reverse takes place. The spontaneously
produced cavities or vacuoles continue to
enlarge and increase in numbers, until some
of them appear perforated in all directions.
Ultimately the globules become so altered
by the action of the water, that they form a
thin granular or wrinkled layer, resembling
coagulated albumen.

The protoplasm of vegetable cells appears
to correspond to the sarcode of animal struc-
tures. In certain cells it exists in two forms
as regards density, the outer portion being
firmer than the inner; or it may become
entirely liquid. In many of the lower or-
ganisms, and probably inost cells in their
youngest state, it is glutinous, and in the
former permanently remains so.

When existing in cells and the lowest ani-
mals, it appears to constitute the essential
part of their structure, and is capable of per-
forming all the functions carried on by the
tissues of the higher or more perfect or-
ganisms. It also appears that the cell-
theory, insofar as it attributes the principal
importance to the cell-wall, is founded upon
error; the cell-wall merely forming a pro-
tection to the sarcode or primordial utricle
of plants, and the sarcode or protoplast as
it might be called of animals, enabling them
to carry on their essential functions uninter-
rupted by surrounding influences.

BIBL. Dujardin, In/us, p. 35.

SARCOPTES, Latr.— A genus of Arach-
nida, of the order Acarina, and family
Acarea.

S. scabiei (Acarus scabiei} (PI. 2. fig. 16).
The itch-insect of man.

Body soft, white, oval-oblong or rounded ;
ventral surface with transverse and undula-
ting rugae ; dorsal surface with marginal

irregularly concentric rugae, the central
space with numerous short and conical
papillae, and stouter but short protuberances
or spines arising from an annular base ; at
the sides and upon the surface of the body
are also scattered setae. Head small, some-
what narrowed hi front ; mandibles toothed.
Anterior two pairs of legs separated from
the posterior by a considerable interval ;
legs short, the anterior two pairs with aceta-
bula or adhesion-disks and five-jointed, the
posterior three-jointed, the last joint termi-
nated by a long seta and without acetabula.
Length of female 1-100 to 1-75".

The females burrow in the skin, in which
the oval eggs, 1-120" in length, are laid;
these are hatched in about ten days, and the
young have only six legs.

Male only about half the size of the female,
and with acetabula to the hindermost pair of
legs.

There is no question that the irritation
produced by these mites and their ova is the
cause of the itch.

They should be searched for at the bottom
of one of the burrows, which are often
visible to the naked eye; the ova are fre-
quently present in the pustules. They are
most easily found by examining the skin
with a power of fifty to seventy diameters,
attached to a firm but moveable arm, and
with the aid of a good bull's-eye con-
denser.

The entire animals may be preserved in
glycerine or solution of chloride of calcium ;
the parts of the mouth should be dried and
mounted in Canada balsam.

Other imperfectly examined or doubtful
species occur upon animals, as the drome-
dary, the chamois, the dog, sheep, rabbit,
&c.

See DEMODEX and PSOROPTES.

BIBL. Bourguignon, Traite, fyc., de la gale
(abstract in Ed. Monthly Journ. 1852. lx.);
Gervais, Walclcenaer's Insect. Apteres, in.
268, and Ann. d. Sc. nat. xv. 9 ; Hering,
D. Kr'dtzmilben d. Thiere, Nov. Act. nat.
cur. xviii. 573 ; Duges, Ann. d. Sc. nat.
2 ser. iii. 245; Wedl, Pathol. Histolog.
798.

SARCOSCYPHUS, Corda.— A genus of
Jungermanniese (Hepaticaceae). S. Ehrharti
(Jung, emarginata, Ehrh.) is a remarkable
species, of dark purple, almost black colour,
growing frequently in wet places, on rocks
of mountainous districts.

BIBL. Hook. Brit. Flor. ii. pt. 2. p. 114,
Brit. Jung. pi. 27 ; Ekart, Synops. Jung.

2o

SARGASSUM.

[ 562 ]

SCALES.

pi. 7. fig. 56, and pi. 13. fig. 113; Endlicher,
Gen. Plant. Supp. i. nos. 474-1.

Fig. 629.

Fig. 630.

Sarcoscyphus Ehrarti.

Fig. 629. Perichaete and perigone opened, showing the
young sporange emerging from the epigone. Magnified
25 diameters.

Fig. 630. Perichaete and perigone opened, showing the
base of the seta surrounded by the epigone. Magnified
10 diameters.

SARGASSUM, Ag.— A genus of Fucaceac
(Fucoid Algae), gulf-weeds, known from the
allied sea-weeds by its stalked globular air-
vessels. The receptacles are small, linear
and mostly clustered at the base of branches,
and pierced by numerous pores leading to
conceptacles containing spore-sacs and clus-
ters of antheridia (see FUCACE^E).

BIBL. Harvey, Brit. Mar. Alg. p. 14.
pi. 1 A ; Greville, Alg. Brit. pi. 1.

SCALES, OF FISHES. — These bodies
were formerly regarded as epidermic forma-
tions, analogous to the nails, &c. of the
higher animals, which later observations have
shown not to be the case.

Each scale is contained in a distinct sac of
the skin or cutis, covered externally with its
pigment layer and epidermis. The cutis
itself consists of interlacing fibres of areolar
tissue with formative cells. The pigment
layer is composed of elegant pigment-cells
with long processes. Immediately above the
upper surface of the scales lies a very fine
membrane, distinct from the cutis, in which
the impressions of the irregularities of surface
existing upon the scales are visible.

In some fishes, as the eel, the scales do
not project beyond the surface; hence the
eel is commonly supposed to possess no
scales. They are easily seen, however, in a
dried piece of the skin, mounted in balsam,
covered by the skin with its pigment- cells
(PI. 17. fig. 19), the whole forming a very
beautiful object.

In many of the common cycloid fishes, as

the roach, dace, &c., the scales project pos-
teriorly from the surface, carrying before
them the thinner and closely applied outer
layer of the cutaneous sac, whilst the anterior
portion of the sac extends into or is formed
by the under portion of the cutis. fn these
fishes also, the portion of the cutis situated
beneath the posterior projecting portion of
the scales, contains a large number of very
thin and minute crystals, to which the silvery
lustre of the skin is owing, and which often ex-
hibit very beautifully the colours of thin plates .
The signification of the various parts of
structure of the scales has not been satis-
factorily determined ; hence we must confine
our remarks to simply pointing out the
structural peculiarities.

Most scales consist of two portions, an
under, composed of numerous layers made
up of very fine fibres taking various direc-
tions, and best seen by scraping away the
upper portion of the scale after maceration
in dilute acid (PI. 17- fig. 11 a). The upper
portion consists of concentric plates, the
margins of which give rise to the concentric
lines so frequently seen in the scales (PL 17.
figs. 6, 10, 22, 23, &c.). These lines cor-
respond to the margins of the layers, and
often present a nodular or crenate appearance
(PL 17. fig. 116); and towards the middle
of the scales they are frequently interrupted
and irregularly curved (PL 1 7. fig. 1 1 c). The
substance of the upper portion appears to
be structureless.

In a transverse section, the projecting
margins of the laminae belonging to the
upper portion of the scale, are seen as so
many teeth (PL 17. fig. 12).

Many scales also exhibit radiating lines
(PL 17. fig. 23), corresponding to furrows in
the upper portion of the scales ; these are
sometimes closed above so as to form tubes,
and have been regarded as nutritive canals.
Near the centre of some scales, as those
of the perch, are numerous rounded corpus-
cles or solid bodies, imbedded in the sub-
stance of the upper portion of the scales
(PL 17. figs. 6 a & 7). At the posterior
portion of the same scales, are often seen
spine-like processes (PL 17. figs. 6b & 9),
with rounded or angular bodies resembling
the last in appearance arranged in rows at
their bases (PL 17- fig. 8).

The scales of the eel appear to be princi-
pally composed of similar bodies, differing
only in form, and arranged in concentric
rows (PL 17. figs. 20 & 20 a). They are
solid, impregnated throughout with calca-

SCALES.

[ 563 ]

SCALES.

reous matter which is left after incinerating
the scales, retaining the original form of the
bodies (PI. 17. fig. 21).

In the scales of some fishes, particularly
those of extinct genera and species, lacunae
and canaliculi resembling those of bone
(PI. 17. fig. 1 c), with Haversian canals,
are met with. A vitreous or enamel-like
layer, having the structure of dentine, is also
met with in the form of an external coating.

The structure of the spines or spine-like
scales of the skate is curious. The larger of
them consist of a button-like base, sur-
mounted by a sharp process (PI. 17. fig. 3).
The outer and lower part of the base is
opake-white, and consists of an imperfectly
fibrous tissue with large areolae (PL 17-
fig. 37). The spine is hollow, the cavity
being continuous with that of a rounded
body, partly immersed in the white substance
(PL 17. fig. 3 a). The cavity is filled with
a pulp, consisting of lax areolar tissue with
minute cells ; whilst its walls are composed
of a hard substance traversed by branched
canals resembling those of dentine (PL 17.
fig. 4). The substance of the smaller spines
(PL 17« fig. 2) exhibits the same dentinous
structure (fig. 5).

PL 17. fig. 10 represents one of a longitu-
dinal row of scales extending along the
middle of the side of the body of most fishes,
and traversed by a tube (a), formerly sup-
posed to give exit to the mucous secretion
of the surface, which view has lately been
thrown into doubt. The tubes are visible to
the naked eye, and produce the lateral line
as it is called.

The scales of fishes contain a large amount
of inorganic matter, composed principally of
phosphate of lime, but mixed with the car-
bonate. The organic basis consists of a
cartilaginous substance.

Some years since, M. Agassiz founded a
classification of fishes upon the structure of
the scales, having found that with differences
in the scales, other great and important
distinctions were in harmony. The system
has been found of eminent service to the
geologist; although later researches have
shown that scales presenting the character-
istics of those belonging to fishes of different
orders in this system, have been found upon
the same fish.

The arrangement was as follows : —

Scales enamelled.

Ord. 1. Ganoid fishes. Those the skin
of which is regularly covered with angular
thick scales, composed internally of bone,

and externally of enamel. Most of the species
are fossil, the sturgeon and bony pike being
recent.

Ord. 2. Placoid fishes. Skin covered irre-
gularly with large or small plates or points
of enamel. Includes all the cartilaginous
fishes of Cuvier, except the sturgeon; as
examples may be mentioned the sharks and
rays. Many are fossil.
Scales not enamelled.
Ord. 3. Ctenoid fishes. Scales horny or
bony, serrated or spinous at the posterior
margin. Contains the perch and many other
existing species, but few fossil.

Ord. 4. Cycloid fishes. Scales smooth,
horny or bony, entire at the posterior mar-
gin ; as the salmon, herring, roach, and most
of our edible and freshwater fishes.

Most of the fossil fishes belong to the first
two orders ; and most of the recent to the
third and fourth.

BIBL. Agassiz, Reck, sur les poissonsfos-
siles, Ann. d. Sc, nat. 2 ser. 14 ; Mandl,
Ann. d. Sc. nat. 2 ser. xi. xii. xiii. & xiv. ;
Heusinger, Histolog. ii. 226 ; Stannius,
Vergl. Anat.; Peters, Mailer's Archiv, 1841.
ccix.; Miiller, Wiegmann's Archiv, 1843.298;
Reside, Ann. Nat. Hist. 1838. ii. 191 ; Vogt,
Zoolog. Brief e, ii.; Williamson, Phil. Trans.
1849. 435.

SCALES, OF INSECTS.— The fine dust
which adheres so readily to the fingers on
handling a butterfly or moth, consists of a
number of microscopic flattened bodies,
called scales or feathers, and upon which
the beautiful colours and opacity of the
wings depend, the membranous wing itself
being transparent and colourless.

These scales have always been favourite
microscopic objects, both on account of the
beauty and variety of their forms, and the
curious markings found upon them. The
manner in which they are attached is best
examined in the wing of a butterfly. Each
has a narrow portion at its base, forming a
pedicle or stalk. The stalks are implanted
into small and short tubes or cups (PL 27.
fig. 23 6), denominated the squamuliferous
tubes, the orifices of which are directed
backwards. Around the points of attach-
ment of the cups to the wings, the surface
exhibits a number of irregularly radiating
rugae or folds of the upper membrane of the
wing (PL 27. fig. 26). The cups are arranged
in more or less regular transverse rows.

The scales are variable in form, both in
different insects and in different parts of the
same insect, being oval, oblong, cordate,
2o2

SCALES.

[ 564 ]

SCALES.

obcordate, or cuneate, &c. (Pis. 1 & 27) ;
sometimes they are filiform or capillary (PI.
27. fig. 27). Their free end is rounded,
truncate, toothed, or terminated by a num-
ber of hair-like processes ; and they are ar-
ranged like the tiles of a roof, overlapping
each other (PI. 27. fig. 26).

The interesting markings seen upon the
scales vary considerably in different insects.
The most common, as seen by transmitted
light, are longitudinal, simple, continuous,
parallel or slightly radiating dark striae or
lines (PI. 1. figs. 6, 7, 8, 9 a). These are
met with upon the scales of nearly all butter-
flies, and many other insects. In some in-
sects the striae are not simple and continuous,
but are made up of rows of smaller striae in
twos or threes meeting at an angle (PI. 27.
figs. 286, 30 & 31). In others they are
composed of a number of bead-like dots, or
are interrupted, still preserving their general
longitudinal direction (PL 27. fig. 24) ; or
they are slightly undulate or irregular, and
give off short lateral branches (PI. 27. figs.
23 a & 29). In others, again, they present
dilatations in certain parts of their course
(PL 27. figs. 20 & 21).

These longitudinal striae consist of eleva-
tions or ridges upon the surface, probably
representing folds of the upper layer or
membrane of the scale. They often project
slightly from the free end of the scale (PL
27- figs. 3 & 22) ; and, when moistened,
bubbles of air may not unfrequently be found
imprisoned between the surface of the scale
and the cover, which, being confined between
two of the ridges, assume an oblong form.
They sometimes contain air, which may be
displaced by liquid (PL 27. fig. 21). We
have never been able to detect tracheae in
these folds or in the scales. A minute coni-
cal point or spine sometimes occurs in each of
the dilatations when present (PL 27. fig. 20 a).
In the scales of Podura (PL 1. fig. 12), the
striae consist of longitudinal rows of minute
wedge-shaped bodies.

In addition to the longitudinal striae, on
most scales, especially when examined by
unilateral oblique light, are seen a number
of minute transverse striae (PL 1 . figs. 7 & 9 a).
These are neither indications of ridges nor
depressions, but arise from the existence of a
number of pigment-granules situated between
the two layers of the scale ; and the appear-
ance of striae has the same origin as that in
the case of the valves of the Diatomaceae.
This point is best examined in brown or
other dark-coloured scales. If perfectly direct

i. e. not oblique) light be transmitted through
one of these scales, the transverse striae va-
nish, their place being occupied by the di-
stinct and isolated granules of pigment (PL
1 . fig. 9 &) ; the scale should also be im-
mersed in balsam or liquid, to diminish the
effects of the refraction arising from the in-
equalities of the surface of the scale. On
then transmitting unilateral oblique light
through the scale, the appearance of trans-
verse striae may be easily produced.

The colours of the scales of insects arise
partly from iridescence, partly from the pre-
sence of pigment ; in general, the brilliant
colours depending upon the former, and the
more sombre hues upon the latter. The
darkness of the longitudinal striae is caused
by refraction, for scales containing no pig-
ment appear perfectly white by reflected
light, although the striae may be very dark.
Upon certain scales, other irregular, more
or less transverse curved striae exist (PL 27.
figs. 3 & 22); these appear to consist of
wrinklings or folds of the under mem-
brane of the scale.

In examining the scales of insects, they
should be viewed both in the dry state and
immersed in water or oil of turpentine, and
both by transmitted and reflected light.
When the insects are pressed against the slide
to remove the scales, a number of globules
of oil adhere simultaneously to the slide ; and
when the cover is applied, the scales often
become partially or entirely covered with the
oily matter, producing an appearance as if the
upper layer of the scale were removed, and
rendering the markings so pale and indi-
stinct, as to be apparently absent. The ap-
pearance of transverse striae is best produced
by turning the mirror to one side, so as to
reflect unilateral light.

A brief notice of some interesting insects
in respect to the structure of their scales is
given under the individual heads, as CULEX,

CURCULIO, MORPHO, LEPISMA, PoDURA,
POLYOMMATUS, PONTIA, TlNEA, &C.

See also TEST-OBJECTS.

BIBL. Westwood, Introduction, fyc., and
British Butterflies ; Deschamps, Ann. desSc.
nat. 2 ser. iii. p. Ill; Bowerbank, Entomol.
Mag. No. 23. 304 ; Craig, Phil. Mag. 1839.
xv. p. 279 ; Dujardin, Obs. au Microscope ;
Ratzeburg, Die Forst- Insekten ; Siebold,
Vergleich. Anat.

SCALES, OF PLANTS.— Under the head
of HAIRS mention has been made of scales
(lepides) occurring on the epidermis of
plants. They consist of flat, usually more

SCARIDIUM.

[ 565 ]

SCHISTOSTEGE^E.

or less circular plates of cellular tissue, the
cells presenting a radiated arrangement from
the centre, by which they are ordinarily
attached; the margins are usually toothed
or fringed more or less regularly by the
prolongation of the free ends of the cells.
They are closely related to stellate hairs,
such as those of ivy, of Deutzia (PI. 21.
figs. 26,27), &c., and may be regarded as more
highly developed forms of these. They are
particularly remarkable on the epidermis of
certain plants, which exhibit a kind of scurfy

Fig. 631.

Scale of the epidermis of Hippophae rhamnoides.
Magnified 50 diameters.

surface, for example the Eleagnaceae (fig.
631), the Bromeliaceae, some Rhododendra,
and the lower surface of the leaves of many
ferns; they must be distinguished in the
last case from the ramenta of the stems,
which are attached by the base, and not by
a central pedicle.

BIBL. See HAIRS and EPIDERMIS.

SCARIDIUM, Ehr.— A genus of Rota-
toria, of the family Hydatina3a.

Char. Eye single, cervical; rotatory organ
armed with a hooked bristle in front ; foot
forked, very long, adapted for leaping.

Lateral processes of jaws bifurcate, so as
to present two teeth each.

S. longicaudum (PI. 35. fig. 27). Foot as
long as or longer than the body, toes shorter
than the foot. Aquatic ; length 1-72".

BIBL. Ehrenberg, Infus. p. 439.

SCENEDESMUS, Meyen.— A genus of
Desmidiaceae.

Char. Cells fusiform or oblong, arranged
side by side in a single row of from two to
ten, after division forming two alternating
rows ; division oblique ; terminal cells often
lunate, or with a bristle at each end.

Six species (Ralfs).

S. quadricauda (PI. 10. fig. 50). Cells
generally four, oblong, rounded at the ends,
in a single row, terminal cells with a bristle
at each end. Common; length of cells
1-1120".

S. obliquus (PL 10. fig. 51). Cells ellip-
tico-fusiform, after division arranged in two

distinct and generally oblique rows, end cells
lunate. Length 1-1670".

S. obtusus (PI. 10. figs. 53 & 54, just after
division). Cells three to eight, ovate or
oblong, all alike, arranged in one row, or
after division alternately in two rows. Com-
mon; length 1-2330 to 1-1960".

BIBL. Ralfs, Brit. Desmid. p. 189.

SCEPTRONEIS,Ehr. — An obscure genus
of fossil Diatomaceae.

BIBL. Ehrenberg, Ber. d. BerL Akad.
1844. p. 264.

SCHISMA. — A genus of Jungermannieaj
(Hepaticaceae), founded on a rare British
form, S. (Jung.)juniperina, /3 europaa, found
among rocks on the mountains of Scotland,
Ireland and Wales. It grows 3 to 6" high,
and is rarely found in fruit.

BIBL. Hook. Brit. Flor. ii. pt. 1. p. 124,
Brit. Jung. pi. 4 ; Ekart, Syn. Jung. pi. 8.
fig. 62; Endlicher, Gen. Plant. Supp. 1. No.
472-17.

SCHISTOSTEGE^.— A family of oper-
culate Acrocarpous (terminal-fruited) Mosses,
of gregarious habit. Stem naked below,
foliaceous in two manners above; sometimes
frond-like or fern-like, composed of leaves
attached vertically and connected at the base,
with dense areolations, consisting of rhom-
boidal prosenchymatous, pellucid or green
cells; sometimes with small leaves, like
those of other Mosses, horizontal and
arranged quincuncially. All the leaves
nerveless and flat. Capsule without an
annulus, very minute, globular-oval, with a
very small convex operculum (figs. 632-635).

British Genus.

SCHISTOSTEGA. Calyptra cylindrically
bell-shaped. Inflorescence dioecious, plants
similar.

The only species of this genus, the elegant

Fig. 632.

Schistostega osmundacea.
saves of barren branches.

little Sch. osmundacea, Web. and Mohr,

Fig. 632. Leaves of barren branches. Magnified 50
diameters.

SCHIZ.EA.

[ 566 1

SCHIZOCHLAMYS.

Sch.pennata, Hook, and Taylor, occurs here
Fig. 633. Fig. 634. Fig. 635.

P S*

Schistostega osmundacea.

Fig. 633. A plant or fruit. Magnified 10 diameters.

Fig. 634. Open capsule with operculum. Magnified 50
diameters.

Fig. 635. Young capsule opened, showing the colu-
mella. Magnified 50 diameters.

and there in Great Britain. The name was
derived from what appears to have been an
erroneous observation of Hedwig, who de-
scribed radiating fissures in the operculum,
which do not exist in living specimens. The
germinating confervoid prothallium of this
moss was described by Bridel as an alga,
under the name of Catoptridium smarag-
dinum; Agardh described it as a Protococcus
(smaragdmis), and it was long supposed to
be phosphorescent. This appears to be an
error ; Schistostega grows on the roofs of
sandy caves and similar places, and the
luminous appearance seems to arise from the
condensation and reflexion of the little day-
light admitted by the pellucid convex cellules
of the prothallium.

SCHIZ.EA, Smith.— A genus of Schi-
zaeous Ferns of curious and elegant structure.
Exotic (figs. 636, 637).

SCHIZ.EE.E.— A tribe of Polypodiaceous
Ferns, with sporanges in the form of a top,
and crowned by a radiated cap-like 'annulus,'
which hardens at maturity, splitting the case.

Genera.

I. Aneimia. Sporangia twin, sessile in
two rows, on lateral lobes of the leaf, con-
tracted into a many-times paniculate, immar-
ginate rachis, naked, splitting longitudinally
outside. No indusium.

II. Schizcea. Sporanges sessile in two or
Fig. 636.

Schizeea dichotoma.

Fig. 636. A fertile pinna. Magnified 5 diameters.
Fig. 637. A pinnule with sporanges. Magnified 25
diameters.

four rows in linear, membranous-margined
lobes, pectinately opposite or digitate at the
apex of the leaf, set among hairs, splitting
longitudinally on the outside. No indusium.

III. Lygodium. Sporangia sessile, alter-
nately biseriate on marginal lobes of the
leaf, splitting longitudinally, each veiled by
a scale-like, hood-shaped indusium adhering
transversely to the nerves.

IV. Mohria. Sporangia sessile in one
row, close to the margin of the leaf, splitting
longitudinally on the outside. A spurious
indusium formed by the revolute margin of
the leaf.

SCHIZOCHLAMYS, A. Br.— A genus
of Palmellacese (Confervoid Algae). S. gela-
tinosa has been found on the continent,
growing on aquatic plants or floating free, in
little gelatinous masses composed of globular
green cells, 1 -2000" in diameter, surrounded
by a hyaline cell-membrane. The remark-
able peculiarity in this genus is the splitting
of the hyaline membrane into two or four
equal parts by regular, clean dehiscence ', the
internal cell-mass becoming divided at the
same time or remaining unchanged. By
frequent repetition of this splitting (the
internal cell acquiring a new coat each time),
the cell becomes surrounded by a number of
fragments of the old coats, held together by
a gelatinous matter.

BIBL. A. Braun, Verjungung, §-c. (Ray

SCHIZOGONIUM.

[ 567 ]

SCHIZOTIIRIX.

Soc. Vol. 1853. p. 181. pi. 2); Kutzing, Sp.
Alg. p. 891.

SCHIZOGONIUM, Kiitz.— A genus of
Ulvaceae (Confervoid Algae), nearly related
to Prasiota, distinguished by filiform fronds,
which, when young, present only a single
row of cells, but subsequently, by collateral
subdivision, have two, four or eight parallel
rows. Of the species given by Kiitzing,
the following appear to be British :

1. S.murale (Bangia velutina, Ktz., olim)

Fig. 638.

Schizogonium murale.

Filaments of frond in various stages of development.
Magnified 300 diameters.

(fig. 638). Fronds of a single row of cells
1-2400 to 1-2160'' in diam., double 1-1440
to 1-1200", triple 1-720" ; cells half as long
as broad, dull green. On damp earth.

2. S. percursum (Enteromorpha, Ag.).
Frond with a double row of cells 1-1200 to
1-900" in diam., length of cells equal to the
breadth, bright or pale green ; collapsed
when dry. Marine.

3. S. Itetevirens (Bangia, Harv.). Frond
with a simple row of cells, 1-1800 to 1-1440"
in diam., rigid, with a double row 1-600",
bright or yellowish green. Marine.

Bangia lacustris, Harv., is given as a
oubtful species.

BIBL. Kutz., Sp. Alg. p. 350, Tab. Phyc.
ii. pis. 98, 99; Harvey, Brit. Alg. 1 ed.
p. 1/2, and Br. Marine Alg. p. 211.

SCHIZOLOMA, Gaudichaud.— A genus

of Lindsaeeae (Polypodaeous Ferns). Ex-
otic.

SCHIZONEMA, Ag.— A genus of Diato-
macese.

Char. Frustules short, resembling those
of Navicula, aggregated in longitudinal rows
in a filiform branched, slender and lax gela-
tinous tube (caeloma). Marine.

Sporangia (spermatia, see MICROMEGA)
external, simple, sessile upon the filaments.

Kutzing describes thirty-eight species,
three of which are doubtful.

S. Dillwynii (PI. 14. fig. 12). Caelomata
hyaline, tufted, wavy, lubricous, bright green,
much branched; end branches short, nume-
rous, patent, attenuate and somewhat acute;
frustules towards the base of the frond
remote and scattered, towards the ends
crowded, oblong-truncate in front view ;
valves lanceolate 1-1020" in length.

Compare HOMCEOCLADIA, MICROMEGA
and RHAPHIDOGLCEA,

BIBL. Kutzing, Bacill p. Ill, and Sp.
Alg. p. 97.

SCHIZOSIPHON, Kiitz.— A genus of
Oscillatoriaceae (Confervoid Algae), contain-
ing Calothrix scopulorum, fasciculatum, and
perhaps other species of Harvey's ' Manual.'
Another British species has also been de-
scribed by Caspary, S. Warrenia (PI. 4.
fig. 13). This last plant extends over large
surfaces of maritime rocks, in tufts of vari-
able size, from 1-4 to 1-2" in thickness, of dull
blackish-green colour. The erect filaments
are fastigiately branched (a), the basal cell
of the branches broader and hemispherical
(c); the ochreal sheaths are obscure (b),
frequently exhibiting a spiral-fibrous struc-
ture in decay (d, e) ; the apices of the
branches are much attenuated.

BIBL. Kiitz. Sp. Alg. p. 326, Tab. Phyc.
ii. pi. 47 et seq. ; Harvey, Brit. Mar. Alg.
p. 224 ; Caspary, Ann. Nat. Hist. ser. 2.
vi. p. 266. pi. 8.

SCHIZOTHRIX, Kiitz.— A genus of Os-
cillatoriacea3 (Confervoid Algae), of which
two British species, growing over maritime
rocks, have been described.

1. S. Creswellii (PL 4. fig. 17). Tufts
1-2 to 3-4" high, olive-coloured; filaments
curled, 1-3600" in diameter at the base,
1-12000" at the summit, in twisted bundles,
penicillately corymbose above.

2. S. Smithii(Coleonema, Thw.). Stratum
dense, dirty red ; filaments closely entwined,
more or less laterally concreted, 1-9600 to
1-8400" in diameter; sheaths lax, multipli-
catc, the internal prolonged and exserted.

SCHULTZE'S TEST. [ 568 ]

SCYPHIDIA.

BIBL. Kiitz. Sp. Alg. p. 320, Tab. Phyc.
ii. pi. 40; Harvey, Brit. Mar. Alg. p. 223,
pi. 26 B, Phyc. Brit. pi. 190.

SCHULTZE'S TEST.— This was origin-
ally proposed by Pettenkofer as a test for
bile ; but Schultze found that it reacted also
with several other substances, and especially
the proteine-compounds. In this application
it is often of use in discriminating one kind
of tissue or substance from another. It
consists in treating the matter with strong
sulphuric acid, and then adding a little sy-
rup. The characteristic reaction is the pro-
duction of a purplish red colour. The best
method of proceeding is to wash the sub-
stance in question, then to moisten it with a
drop of syrup, and finally to add the acid.

The tissues and substances affected by it
are, — muscular tissue, both striated and
unstriated ; nerve-tubes and cells ; the cor-
puscles of blood, pus, and mucus ; epithelial
and epidermic scales; hairs; feathers; horn;
whalebone; and the cellular (cell-contents?)
portions of Fungi and Algae.

Those in which the reaction is not pro-
duced are, — areolar tissue, elastic tissue,
gelatine and chondrine, chitine, silk, cellu-
lose, gum, starch, and vegetable mucus.

BIBL. Schultze, Liebig's Annalen, 1849,
abridged in the Chem. Gaz. viii. 98.

SCHULZE'S TEST.— This consists of a
solution of chloriodide of zinc, used as a test
for cellulose, which it colours blue.

The original directions given for its pre-
paration are indefinite ; they are as follows :
— dissolve zinc in muriatic acid, evaporate
the solution with excess of zinc until it ac-
quires the consistence of syrup, and dissolve
in this enough iodide of potassium to satu-
rate it ; iodine is then added, and the solu-
tion diluted with water if necessary.

Radlkofer recommends zinc to be dis-
solved in muriatic acid, the solution to be
evaporated at a temperature but little above
that of boiling water, when a liquid of about
2*0 sp. gr. is obtained. This is diluted with
water until its sp. gr. is 1*8; if its original
sp. gr. was 2'0, 12 parts by weight of water
must be added to 100 parts of the solution.
In 100 parts of this liquid, 6 parts by weight
of iodide of potassium are to be dissolved at
a gentle heat, and the mixture heated with
excess of iodine until the latter is no longer
dissolved, and violet fumes become percep-
tible over the liquid.

The reagent has the consistence of strong
sulphuric acid, and is pale yellowish-brown.
It must be kept in a well- stoppered bottle.

BIBL. Schulze, Flora, 1850. p. 643;
Schacht, Das Mikroskop. 30 & 197 ; Radl-
kofer, Liebig's Annal. xciv. 332, or Chem.
Gaz. 1855. xiii. 372.

SCLEROTICA. See EYE (p. 250).

SCLEROTIUM, Tode.— A large collec-
tion of fungoid structures were formerly
gathered together under this name, among
others the preparatory form of the ERGOT
fungus. They are all now regarded as con-
sisting of the mycelia of fungi in an imper-
fect state. The sclerotoid state exists when
the mycelium forms hard tubercular masses.
Analogous masses of mycelial structures
occur, in a pulpy condition, in the Vinegar-
plant; in a filamentous condition in those
fungi forming large masses of barren byssus,
&c. ; in other cases, as in some of the Myxo-
gastres, the structure is membranous.

BIBL. Leveille, Ann. des Sc. nat. 2 ser.
xx. p. 218; Berkeley, Hort. Journal, iii. p.
97; Fries, Summa Veg. p. 477.

SCOLOPENDRIE^E.— A subtribe of Po-
lypodaeous Ferns with indusiate sori.

I. SCOLOPENDRIUM. Sori linear, elon-
gated, opposite, the upper one on an inferior
venule, the lower on the next superior venule.
Indusia linear, flat, with the opposing mar-
gins free, contiguous or distant. Veins pin-
nate.

II. ANTIGRAMMA. Sori linear, elongated,
opposite, the upper on an inferior venule,
the lower on the next superior venule. Indu-
sia linear, flat, with free margins, opposite
to each other, contiguous or distant. Veins
anastomosing into hexagonoid spots.

III. CAMPTOSORUS. Sori linear, elon-
gated, opposite, the upper on an inferior
venule, the lower on the next superior venule.
Indusia linear, flat, with free margins op-
posite to each other, contiguous or distant.
Veins anastomosing, with free venules.

SCOLOPENDRIUM, Smith, Hares-
tongue. — A genus of Scolopendriea3 (Poly-
podaeous Ferns), represented by the indige-
nous species, Sc. vulgare (fig. 225, p. 259).

SCURF, OF ANIMALS. — Consists of ag-
gregations of dry and flattened epidermic
scales, sometimes containing globules of
fatty matter.

SCYPHIDIA, Duj.— Agenus of Infusoria,
of the family Vorticellina.

Char. Body oblong or campanulate, nar-
rowed at the base, very contractile, covered
with a reticular integument.

S. rugosa (PI. 24. fig. 74). Body with
oblique striae or rugae, not numerous. Aqua-
tic; length 1-550".

SCYTONEMA.

[ 569 ]

SEBACEOUS FOLLICLES.

SCYTONEMA, Berk.— A genus of Oscil-
latoriacese (Confervoid Algae), especially di-
stinguished by the mode of branching of the
filaments. We can only make out with cer-
tainty one British species of the genus as
now restricted, S. Myochrous (PI. 4. fig. 19),
which grows hi alpine bogs and rivulets, and
is composed of decumbent filaments inter-
woven into a dark brown stratum.

BIBL. Harvey, Brit. Alg. led.p.155; Has-
sall, Brit. Fr. Alg. p. 235. pi. 68 ; Kiitzing,
Spec. Alg. 303, Tab. Phyc. ii. pi. 16 et seq.
SEBACEOUS FOLLICLESorGLANDS.
— These organs exist pretty generally in the
skin, and secrete a fatty matter. They are
mostly seated close to the hair-follicles, into
which their ducts usually open. They vary
in form, some being simple pouches or de-
pressions of the skin, whilst in others the

Fig. 639.

Compound sebaceous gland, from the nose, opening
upon the surface with a hair-follicle, a, b, c, as in the
next figure ; d, lobules of the compound gland ; e, hair-
follicle (root-sheath) ; /, the hair.

Magnified 50 diameters.

deeper part of the pouch is branched, so as
to constitute a true racemose gland. The

narrower portion, or duct, is variable in dia-
meter ; it usually opens into the hair-follicle,

Fig. 640.

Simple sebaceous follicle, from the nose, a, glandular
epithelium, continuous with b, the rete mucosum ; c, con-
tents of the gland, consisting of cells containing fat, with
free fatty matter.

Magnified 50 diameters.

rather above its middle, but sometimes upon
the surface of the skin itself.

Each gland consists of an outer coat of

Fig. 641.

Glandular vesicle of a sebaceous gland, a, epithelium
continuous with the glandular cells b, containing fat.
Magnified 250 diameters.

Fig. 642.

Cells from the glandular vesicles and the sebaceous
secretion, a, small nucleated cell, containing but little
fat, and resembling an epithelial cell ; b, cells abounding
in fat, without evident nuclei ; c, cell in which the fat-
globules are becoming confluent; d, cell containing a
single drop of fat ; e, /, cells from which part of the fat
has escaped.

Magnified 350 diameters.

SEBACEOUS FOLLICLES. [ 570 ] SECONDARY DEPOSITS.

areolar tissue, forming a more or less thick
membrane in proportion to the size of the
gland ; this is derived either from the hair-
Fig. 643.

Development of the sebaceous follicles in a six-months'
fetus, a, hair ; b, inner root-sheath ; c, outer root-
sheath ; d, rudimentary follicle.

Magnified 250 diameters.

Fig. 644.

a, bt c, d, as above, but in a more advanced stage.
Magnified 250 diameters.

follicle, or the cutis, according to the situa-
tion of the gland. It is lined by layers of
roundish or polygonal, epidermic or epithelial
cells, the outermost of which are closely
connected, so as to form one or more mem-
branous layers, and contain few or no glo-
bules of fat ; whilst the inner ones are larger,
and almost filled with these globules.

The development of the sebaceous glands

commences at the end of the fourth or in
the fifth month. The glands at first consist
of solid depressions or outgrowths of the
rete mucosum of the skin, or the inner root-
sheath of the hairs; the inner cells then
become filled with fat, loosened, and are
finally evacuated through that part of the
immature gland which in its subsequent de-
velopment forms the duct.

BIBL. Kolliker, Mikroskop, Anat. i. 180,
and the Bibl. of that article.

SECONDARY DEPOSITS OR LAYERS,
OF VEGETABLE CELLS. — The structures
known by this name are spoken of under
the head of CELLS, in a general point of
view, and in detail under PITTED and SPIRAL
STRUCTURES. A few remarks may be given
here, connecting the phenomena included
under the last two heads.

It is well known that the original or pri-
mary cell-wall, the layer of cellulose by
which the cell first becomes really constituted
as a closed membranous sac, is, so far as our
present instruments enable us to judge, de-
void of detailed structure ; it is a homoge-
neous pellicle. This has a power of extension
by interstitial nutrition, which leaves no
traces in the perfect membrane, enabling
the cell to increase in size. But the increase
in solidity is effected by a different process,
leaving distinct evidences of its occurrence,
namely by an application of successive thin
layers of cellulose membrane, more or less
completely all over the inside of the primary
membrane, giving the cell-wall a laminated
character, either evident in the natural con-
dition, or capable of being demonstrated by
the aid of maceration or corrosive application s.

No cell which is to form part of a perma-
nent tissue remains long without receiving
secondary layers upon its walls. In certain
cases the wall exhibits in its natural state
merely the laminated structure, without any
markings (PI. 38. fig. 24); but in the majority
of cases, where the secondary deposits are
considerable, these layers exhibit markings
of very peculiar characters. As a general
rule, the layers present themselves under
two different types, according to the extent
to which they cover the primary membrane.
In one case they are applied as a general
layer over the wall, absent merely at dot-
like or slit-like points, where they leave the
primary wall uncovered, and thus give rise
to a pitted condition as seen from the inside
of the cell. Successive layers leaving the
same spots bare, the pits become gradually
deeper, and form canals running through

SECONDARY DEPOSITS. [ 571 ] SECONDARY DEPOSITS.

the thick cell-wall to the primary membrane
(see PITTED STRUCTURES) (PI. 38. fig. 23).

In the other case, the secondary deposits
are more sparing in quantity, and are applied
over lines forming a definite pattern upon
the primary membrane, in which a spiral
course in the direction of the long axis of
the cell is more or less evident; infinite
modifications of this type occur, which are
treated under the head of SPIRAL STRUC-
TURES (PL 39. figs. 7, 9).

In certain less common cases we find' the
earlier secondary layers exhibiting the pitted
character, while others later formed produce
spiral-fibrous thickening, as in Taxus, the
lime and other cases (see PITTED STRUC-
TURES) (PL 39. figs. 4, 13, 19 6).

The last-mentioned cases point to a rela-
tion between the spiral-fibrous and the
pitted layers, which appears really to exist,
for in a great number of cases it is possible
to distinguish a spiral structure in the mem-
branous layers of pitted cells or even of cells
where the layers of thickening merely exhibit
the laminated structure without any pits or
fibrous markings. Thus, in the liber-cells
of the Apocynacese (PL 39. fig. 30), the
thickened walls appear under a low power
homogeneous, while under sufficient magni-
fication, and especially by the help of acids,
we may detect an evident though delicate
spiral structure. The action of acids reveals
a similar spiral arrangement of the consti-
tuent molecules, in the cotton hair (PL 21.
fig. 1), and in most liber-cells (PL 21. figs. 2,
5, 25), in many wood-cells, as of Pinus, &c.
The membranes forming the sheaths of many
of the Oscillatoriacese (PL 4. figs. 13 d, e,
15) exhibit a spiral-fibrous structure when
undergoing dissolution, and an analogous
condition may be detected by the help of
reagents pretty generally in the cell-walls
of the tubular Confervae. All these phseno-
mena seem to indicate a fundamental iden-
tity in secondary layers of all kinds, to which
we direct attention under SPIRAL STRUC-
TURES, but it is convenient in practice to
keep the PITTED and the SPIRAL-FIBROUS
structures distinct.

The mode of formation of the secondary
deposits is not clearly known at present ;
some imagine them to be precipitated from
the cell-sap upon the walls ; others, and ap-
parently with more reason, believe that they
are attributable to the agency of the PRI-
MORDIAL UTRICLE, continuing its action
after the formation of the primary mem-
brane. Criiger goes so far as to consider

the spiral markings, &c. as dependent on
the RoTATiON-currents of the protoplasm.
These points require further investigation.
There can be little doubt of the mistaken
character of Trecul's recent view, which re-
gards the spiral and other fibrous thickenings
as folds of the primary wall thrown inwards.

The secondary deposits appear to be
always composed of some modification of
cellulose. Mohl has investigated this point
very thoroughly, and we have followed him
over much of the ground. The cellulose,
however, loses its distinctive character with
age, either by infiltration with foreign mat-
ters, or by a slight chemical metamorphosis,
so that old secondary layers do not readily
become blue when sulphuric acid and iodine
are applied ; but as a general rule the cel-
lulose reaction may be obtained by using a
preliminary treatment. All internal struc-
tures, such as wood-cells, liber-cells, stones
of fruits, &c., should be boiled in nitric
acid, washed, dried, and tincture of iodine
applied; then if again dried and wetted with
water they turn blue ; external structures,
such as epidermal cells, cork and the like,
require a similar boiling, but with solution
of potash.

Secondary deposits present a considerable
difference in their consistence and degree of
development in different cases. In most
wood- and liber-cells they are abundant in
quantity, in some cases almost filling up the
cavity (PL 38. fig. 27) ; here they are hard,
and appear to be in that state of the cellu-
lose compound which may be distinguished
as lignine. The same condition prevails in
the stones of fruits, bony shells, the " grit "
of pears, &c. ; and the less abundant second-
ary substance of spiral-fibrous tissues ap-
pears to be in the same state. The secondary
layers of parenchymatous cells are usually
rather soft and elastic, and often turn blue
with sulphuric acid and iodine alone ; those
of the collenchymatous tissue beneath the
epidermis of many herbaceous plants, such
as the Chenopodiaceae, &c., are abundant in
quantity, but of somewhat cartilaginous tex-
ture. Those of the larger Algae, and of the
thallus of the larger Lichens, approach to
the same condition, while the fleshy and
horny ALBUMEN of many seeds contains
abundant deposits of analogous character
(PL 38. figs. 21-23) ; in the latter the com-
position is sometimes of amyloid, approach-
ing starch, stained blue by iodine alone, and
more or less soluble in dilute sulphuric acid.
The secondary layer of epidermis and corky

SECRETING ORGANS.

[ 572 ]

SEEDS.

layers differs again, being usually more
sparing in quantity, but very firm and elastic,
and strongly resisting decomposing agents ;
the composition appears to be of that modi-
fication of cellulose called suberine.

BIBL. Gen. Works on Structural Botany ;
Mohl, Vegetable Cell, London, 1852. p. 10,
Botan. Zeit. p. 97 (1847) (Transl. in Tay-
lor's Scientific Memoirs, 2nd ser. i. p. 95) ;
Schacht, Pflanzenzelle, Berlin, 1852 ; Crii-
ger, Bot. Zeit. xiii. p. 601. 1855; Trecul,
Ann. des Sc. nat. 4 ser. ii. p. 273 ; Wigand,
Intercellular-substanz u. Cuticula, Bruns-
wick, 1850; Mulder, Phys. Chemistry, Edin-
burgh, 1849, p. 347.

SECRETING ORGANS, OP PLANTS ;
RESERVOIRS OR RECEPTACLES for SE-
CRETIONS.— The structures falling under
this head have been in part treated under
the heads of GLANDS and LATICIFEROUS
TISSUE, but there still remain certain
organs of analogous character, which could
not be properly included under either of the
above. The name of receptacle or reservoir
for peculiar secretions is ordinarily applied
to groups of cells, of variable, but most fre-
quently elongated prismatic form, contain-
ing special secretions, either in their cavities
or effused into their intercellular passages,
traversing in the form of cords or bundles the
parenchymatous or prosenchymatous tissues.
They are almost special characteristics of
families, and by no means frequent; the
Coniferae, the Cycadacese, the Aloineous Li-
liaceae, the Polygonaceae, Compositae, Um-
belliferae, Amygdaleous Rosaceae, Legumi-
nosae, &c., afford striking examples.

In the Coniferae the turpentine-reservoirs
are very remarkable, and to a certain extent
they render it possible to determine the
genus by their arrangement. In Pinus they
consist of bundles of elongated, thin-walled
cells, running through the wood parallel to
the axis of the stem. These thin- wall cells
are densely filled with turpentine ; in some
cases the cells of the medullary rays are like-
wise filled with turpentine, and, besides
these, perpendicular intercellular passages ;
the latter form of turpentine-canal is chiefly
met with in the bark. Turpentine- canals
also exist in the leaves of the Coniferae, the
scales of the cones, &c.

The reservoirs of the Aloes are bundles of
prismatic cells accompanying the vascular
bundles of the leaves and stems. The
colouring matter of the root of rhubarb is
contained in cells of imperfect medullary
rays. The structure of the balsam-reservoirs

of the myrrh tree, &c., has not been
thoroughly studied. The resin and oil-canals
of the Umbelliferae are of great importance,
but the former, chiefly occurring in the
roots, are imperfectly known. The oil-reser-
voir of the fruits (vittee) consists of elongated
excavations in the cellular tissue, filled with
oil. Canals containing odoriferous oils occur
in some of the Compositae. Resin-canals
occur also in the common lime.

Gum-canals, consisting of simple or
branched intercellular passages with a special
coat of small (secreting ?) cells, occur in the
leaf- stalks of Cycadaceae, the bark of the
Amygdalece, in the stems of the Malvaceae,
Cactaceae, &c. Structures of similar nature
contain the milky juices of certain plants,
as of the Anacardiaceae, and these appear to
be different from the ordinary LATEX
vessels.

BIBL. Meyen, Secretions - Organe der
Pflanzen, Berlin, 1837. p. 18; Unger, Anat.
und Phys. der Pflanzen, 1855. p. 204.

SECTIONS. See PREPARATION (p.
530).

SEEDS. — These are interesting objects
for microscopic examination in respect to
many different characteristics. Among these
may be mentioned first the variety of beau-
tiful markings upon the surface, which ren-
der almost all seeds, like the elytra of bee-
tles, interesting opaque objects for observa-
tion with a low power. A few striking
forms are represented in Plate 31. figs. 14-
18, and we give a list of kinds easily to be
obtained.

Hypericum.
Lychnis.

16 &17).
Stellaria.
Dianthus(P\.3l

fig 14).
Reseda.
Papaver(Pl.3l.

fig. 14).
Lepidium.
Delphinium.
Nigella.
Erica.
Anagallis.
Orobanche.
Scrophularia.
Antirrhinum.

Linaria.

Chironia.

Gentiana.

Datura.

Nicotiana.

Petunia.

Digitalis (PI. 31.

fig. 18).
Hyoscyamus.
Mesembryanthemum.
Sempervivum.
Sedum.
Saxifraga.
Limnocharis.
Capparis.
Elatine.
Gesnera.
Begonia.

The following are well seen when mounted
i transparent objects in Canada balsam.

SEGESTRELLA.

[ 573 ]

SENECIO.

Parnassia. Monotropa.

Drosera. Hydrangea.

Orchis. Saxifraga.

Pyrola.

The testa or outer skin of some of the
latter (also Begonia), when removed from
the seed and viewed with a high power, ex-
hibits elegant pitted cells. The surface of
the seed of Cobcea is mealy with little scales
consisting of pyriform cells containing a
spiral fibre (PL 21. fig. 20).

The surface of various seeds, such as Col-
lomia, Ruellia (and the pericarp of many
seed-like fruits, such as that of Salvia, Se-
necio), present remarkable forms of HAIRS.

The * stones' of plums or cherries, the
so-called shell of the Cocoa-nut and similar
fruits, exhibit remarkably thick SECONDARY
DEPOSITS.

The examination of the structure of ripe
seeds is a matter of great importance in
botany. The investigation will vary much
according to circumstances. Where seeds
are large, the microscope is only required
for the examination of their tissues, but small
seeds must be examined by dissection with
needles under the simple microscope, or by
sections, which are most easily made by fix-
ing the softened seed into a piece of wax.
Seeds have two coats, the testa and tegmen,
or external and internal membrane, and, ac-
cording as the seed is or is not albuminous,
an albumen enclosing the embryo, or an
embryo of larger size immediately invested
by the coats. The characters of the ALBU-
MEN and EMBRYO will be found under these
heads, as also other particulars underOvuLE.
Embryos are either Monocotyledonous or
Dicotyledonous; sometimes, however, the
two cotyledons are soldered together more or
less completely ; in the Coniferae and certain
genera of Dicotyledonous Angiosperms, as
Schizopetalum, the cotyledons appear to be
four, six, or more in number ; but the recent
observations of M. Duchartre go to show
that there exist only two, bifid, trifid, or
multifid cotyledons. In other cases, as in
Orchis, the embryo remains imperfectly de-
veloped, and appears as a mere cellular mass
in the ripe seed before germination ; this is
destitute of albumen, but in Orobancke an
amorphous embryo is found imbedded in the
albumen.

BIBL. General works on Botany.

SEGESTRELLA, Fr.— A genus of Verru-
cariese (Angiocarpous Lichens), containing
one doubtful British plant, the Lecanora
thelostoma of the Brit. Fl.

BIBL. Leighton, Brit. Angioc. Lichens,
p. 34; Hook. Brit. Fl. ii. pt. 1. p. 189.

SEIROSPORA, Harv.— A genus of Ce-
ramiaceae (Florideous Algae), containing one
rare species, S. Griffithsiana, a little crimson
feathery sea-weed, composed of single arti-
culated tubes, the joints of which are tra-
versed by articulated filaments. The spores
are unknown, but the tetraspores, which
serve to distinguish this plant from the Catti-
thamnia, occur in terminal beaded strings,
being formed out of the ramuli.

BIBL. Harvey, Brit. Mar. Alg. p. 170.
pi. 23 C.

SELAGINELLA, P. de Beauv.— A genus
of Lycopodiaceae, distinguished from Lyco-
podium by the presence of two kinds of
spores and the dissimilar habit. This genus
includes only one of our native Club-mosses,
S. spinosa (Lye. selaginoides) ; but most of
the so-called Lycopodia, now so extensively
cultivated inWardian cases, fern-houses, &c.,
belong to this division (fig. 434. p. 405).
The principal particulars relating to these
plants, especially the remarkable history of
the reproduction by the spores, are given un-
der LYCOPODIACE^:.

BIBL. See LYCOPODIACE^J.

SELENITE.— This well-known mineral
substance consists of crystallized hydrated
sulphate of lime. Its crystals belong to the
oblique prismatic system; and the colours
exhibited by thin laminae, into which they
may be easily split, are very beautiful under
polarized light. Polarizing crystals and or-
ganic substances, in which the thickness is
not suited to the production of distinct co-
lours under the polariscope, may be made to
exhibit them by placing a plate of selenite
beneath the object. For this purpose the
plate is usually kept mounted in Canada
balsam.

BIBL. That of POLARIZATION.

SELIGERIA.— A genus of Leptotricha-
ceous Mosses, including certain Weissice and
Gymnostoma of authors.

SELLIGU^EA, Bory.— A genus of Gram-
matideae (Polypodaeous Ferns). Exotic.

SENDTNERA, Woods.— A genus of Jun-
germannieae (Hepaticaceae), mostly tropical,
one species of which, S. (Jung.} Woodsii,
occurs rarely in the mountains of the S.W.
of Ireland (devoid of fruit).

BIBL. Hook. Brit. Flor. ii. pt. 1. p. 126,
Brit. Jung. pi. 66 ; Ekart, Synops. Jung. pi.
12. fig. 108 ; Endlicher, Gen. Plant. Supp. 1.
No. 472-16.

SENECIO.— The surface of the achenia

SEPEDONIET.

[ 574 ]

SERTULARIA.

or seed-like fruits of the common groundsel
(Senecio vulgaris) are sparingly clothed with
HAIRS of a peculiar character. These ap-
pear to consist of two semi-cylindrical cells
applied together by their flat faces, so as to
form a kind of tube with a vertical septum.
When placed in water, they expand some-
what, and the contents are expelled from
the ends, consisting of an indistinctly spiral-
fibrous structure, which untwists and ex-
pands, by the absorption of water, to twice
or three times the length of the hairs, in a
manner comparable in some degree to the
behaviour of the contents of the hairs of
ACANTHACE.E.

BIBL. Leighton, Ann. Nat. Hist. vi. p.
259

SEPEDONIEL— A family of Hyphomy-
cetous Fungi, consisting of a heterogeneous
assemblage of imperfectly known genera,
and differently denned by different authors.
Those genera we have included in our list
are enumerated in Lindley's ' Vegetable
Kingdom/ but Fries includes Oidium and
others. The general character of the family
is, that the plants produce spores lying in
heaps among the filaments of the mycelium,
te often arising from them." Evidently this
can only mean that there are no erect special
fertile pedicels, but this does not apply to all
the forms. The characters show how imper-
fect is the observation on which some of the
genera are founded.

Synopsis of British Genera.

I. ARTOTROGUS, Entophyte. Filaments
creeping, persistent ; spores springing from
the middle of the filaments, simple, at length
free, spinous.

II. SEPEDONIUM. Filaments woolly, sep-
tate, evanescent; spores globose, connate,
scabrous, stipitate, solitary, at length heaped
together.

III. FUSISPORIUM. Spores fusiform or
cylindrical, glued together in heaps resting
on the gelatinous matrix.

IV. EPOCHNIUM. Spores heaped toge-
ther, oblong, apiculate, septate, adnate to
the matrix, interwoven with the effused, en-
tangled slender filaments of the mycelium.

V. PSILONIA. Spores simple, pellucid,
not glued together, at first covered by the
converging filaments of the mycelium.

VI. MONOTOSPORA, Entophyte. Fila-
ments creeping, evanescent ; spores globose,
solitary, terminal, at length free.

ASTEROPHORA, Dittm., appears to belong
to the Onygenei.

SEPEDONIUM, Link.— A genus of Se-
pedoniei (Hyphomycetous Fungi), contain-
ing two species, growing upon decaying
Fungi. S. chrysosperma has golden-yellow
spores, S. roseum red ones. The first is
common.

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 350;
Fries, Summa Vegetab. p. 497 ; Grev. Sc.
Crypt. Flor. pi. 198.

SEPTONEMA, Corda.— A genus of To-
rulacei (Coniomycetous Fun- -p- /^r
gi), related to Torula, and
connecting this in some mea-
sure with Dendryphium. S.
spiloma, forming green tufts
on old rails, has been found
in Guernsey. Several spe-
cies are recorded as French
by Leveille, one forming
patches on vine-leaves, the
others on the potato. The
chains of septate spores soon
break up.

BIBL. Corda, Icones, i. &
ii. ; Fries, Summa Veg. 504 ;
Leveille, Ann. des Sc. nat.
3 ser. ix. 261 ; Berkeley and
Broome, Ann. Nat. Hist. 2nd Septonema viride.
ser. v. p. 461 ; Berk. Lond. Magnified

Journ. Bot. iv. t. 12. fig. 5. 20° ^metera.

SEPTORIA, Fr.— A genus of Sphferone-
mei (Coniomycetous Fungi), but probably
in reality consisting of preparatory forms of
Sphcerice. They grow upon the leaves of
plants, the fusiform septate "spores" oozing
out from a pore in the form of a tendril.

S. Ulmi and <S. Oxyacanthce are common;
several other species are recorded.

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 356 ;
Berk, and Br. Ann. Nat. Hist. 2nd ser. v.
p. 379, xiii. p. 460; Fries, SummaVeff. p. 426;
Tulasne, Ann. Nat. Hist. 2nd ser. viii. p. 117.

SEPTOSPORIUM, Corda. See MACRO-

SPORIUM.

SEROUS MEMBRANES.— These con-
sist of the same elements arranged in the
same number of layers as in the Mucous
MEMBRANES. The thickness of the layers,
however, is considerably less, the fibrous
elements are finer, and the epithelium forms
a single layer only of polygonal cells.

BIBL. Kolliker, Mikrosk. Anat. ii. ; Todd
and Bowman, Physiolog. Anat. fyc. of Man.

SERTULARIA, Linn.— A genus of Po-
lypi (Zoophytes), of the order Anthozoa.

Char. Polypidom growing in the shape of
a plant, and fixed by its base, variously
branched, the branches formed of a single

SHEEP-TICK.

[ 575 ]

SHELL.

tube, denticulated or serrated with the cells,
and jointed at regular intervals ; cells alter-
nate, semi-alternate or opposite, biserial,
sessile, urceolate, short, with everted aper-
tures; ovarian vesicles scattered; polypes
hydriform.

Many of these elegant zoophytes, which
would at once be referred to the vegetable
kingdom by any casual observer, are com-
monly found on the sea-coast, either loose
or attached to shells, sea- weeds, &c. Only
on examination with a lens or microscope
can the cells in which the polypes were
contained be found ; and the polypes them-
selves are rarely to be met with.

There are seventeen British species (John-
ston).

5. rugosa (PL 33. figs. 11 & 12). Cells
alternate, one to each joint, ovate, trans-
versely wrinkled, mouth narrow, with four
small'teeth at the rim.

Common upon Flustra, Fuci, &c. at low-
water mark.

S. pumila (PI. 33. figs. 13 & 14). Cells
opposite, approximate, shortly tubular, the
top everted, with an oblique somewhat mu-
cronate aperture ; vesicles ovate.

Common on Fuci near low-water mark.

S. operculata (PI. 33. figs. 1 5 & 16). Cells
opposite, inversely conical; aperture patu-
lous, obliquely truncate, pointed near the
outer edge, and with two small lateral teeth ;
vesicles obovate.

Common on Fuci near low-water mark.

BIBL. Johnston, Brit. Zoophytes, 61.

SHEEP-TICK. See MELOPHILA.

A species of Trichodectes (spharocephalus)
is also found as a louse upon sheep.

SHELL, OF ANIMALS. — In this article
we shall notice the various substances com-
prised under the term shell, in its common
acceptation.

Egg-shell. — As an example of the struc-
ture of the egg-shell of birds, we may se-
lect the shell of the egg of the common
fowl.

This is lined internally by a loosely adhe-
rent layer of a thin yet firm albuminous
membrane, called the membrana putaminis.
It consists of a number of very slender fibres,
interlacing in various directions. In imper-
fectly formed or soft eggs, as they are called,
the fibres present thickenings at irregular
intervals, resembling, on the whole, the nu-
clear fibres of elastic tissue with the remains
of their formative cells still visible. On
macerating the shell in dilute muriatic acid,
an outer layer of this membrane, inseparably

adherent in the natural state to the inner
surface of the shell, may be detached.

The membrane may be heated to boiling
in solution of potash, without undergoing
solution, and is insoluble in acetic acid ; but
it is coloured by Schultze's test.

The substance of the shell consists of nu-
merous 'masses of secretion or protoplasts,
impregnated with calcareous matter. In
soft eggs, these form rounded, loosely adhe-
rent masses (PI. 37. fig. 12), may easily be
detached from the surface of the egg, and
contain but little calcareous matter ; whilst
in the perfect egg they are somewhat angu-
lar from mutual pressure, and abound in
calcareous granules having an imperfectly
radiating arrangement (PI. 37. fig. 13) ; this
is most easily perceived in the inner portions
of the shell.

The structure of the shell of the ostrich
presents a curious variety. In a section
parallel to the surface (PI. 37. fig. 14) the
protoplast structure is distinctly visible (al-
though omitted in the figure), but the cal-
careous matter is arranged in the form of
triangular plates, often fused together, and
leaving angular interspaces. The perpendi-
cular section is represented in PI. 3/. fig. 15.
The former section constitutes an interesting

Tortoise-shell. — This substance is an epi-
dermic formation, structurally resembling
horn, insofar as it consists of epidermic
cells, flattened, and united into numerous
superimposed plates. The long-continued
action of solution of potash (from twenty-
four to forty-eight hours), and the subse-
quent addition of water, are necessaiy to
resolve tortoise-shell into its component
cells.

Shells of the Mollusca. — The structure of
these shells varies in the different orders, &c.
of the class ; and a knowledge of the respect-
ive varieties has been used as an aid to the
recognition of fossils, and the determination
of the affinities of the genera, families, &c.

In the bivalve Mollusca, two kinds of
structure may be distinguished, an outer
prismatic or fibrous, and an inner lami-
nated.

The outer prismatic portion consists of
flattened masses or plates of crowded poly-
gonal prisms, placed sometimes perpendicu-
larly, sometimes obliquely to the surface of
the inner layer. These prisms are transpa-
rent and polarize light, possessing a crystal-
line structure, although their forms are not
crystalline, but those resulting from mutual

SHELL.

[ 576 ]

SHELL.

pressure. Transverse sections of the pris-
matic structure exhibit a cellular appear-
ance (PL 37. figs. 4 & 11 a), and a somewhat
similar appearance is presented by perpendi-
cular sections (PL 37. figs. 5 & 11 b). The
prisms are pretty easily separable in the lines
of mutual contact, and often form several
superimposed strata. They frequently con-
tain pigment, either uniformly diffused
through their substance, or in granules.
They also sometimes appear transversely
striated.

The inner laminated portion, which some-
times constitutes the entire shell, is either
white or presents the brilliant iridescent
tints of nacre or mother-of-pearl. It is often
called the nacreous portion, or nacre, and
when polished forms the mother-of-pearl of
the shops. Under the microscope it exhibits
a number of fine lines or grooves, running
in various directions, and probably corre-
sponding to the edges or intersections of the
strata or lamina, of which this portion of
the shell is composed; and it is to the inter-
ference of light ensuing at the surfaces of
these grooves that the iridescent colours are
usually owing.

In some shells there are tubes traversing
the substance perpendicularly (PL 37. fig. 7)
or obliquely, or forming branched horizontal
channels (PL 37. fig. 9 a, b) ; in the latter
case they are sometimes connected with
rounded cavities (PL 37. fig. 9 a).

In some Gasteropoda, as Cyprcea, the
outer portion of the shell consists of three
layers of similar prismatic structure, but with
the prisms in each layer in alternately con-
trary directions. The same may be seen in
some of the outer layers of oyster-shell,
except that the prisms are nearly horizontal
or slightly oblique. But in the Acephala
generally, the structure corresponds to the
inner portion of that of the Cephalophora.

Shell consists of an organic basis, in which
calcareous matter, principally composed of
carbonate of lime, is deposited ; and by
digesting it with dilute muriatic acid, the
latter may be removed, an organic cast of
the original being left. On treating a thin
plate of nacre in this way, Dr. Carpenter
found that the iridescent colours remained
visible until the membrane was stretched,
and the supposed folds obliterated when
they vanished ; hence this author concludes
that the edges of the folds were the cause of
the interference of light producing the
colours. It appears to us, however, objec-
tionable to this view, that the same structure

and colour is produced by laminated calca-
reous and organic matter artificially formed;
that they are also present after the edges of
the folds must have been ground away, as
in sections ; and that the colours, in the
instance mentioned, might have been those
of a thin plate, and some of the colours of
iridescent shell are known to be those of
thin plates. It may be stated here that
Dr. Carpenter considers the lines or striae in
nacre to be produced by the edges of folds
of a single layer of membrane, arranged so
as to lie over each other in an imbricated
manner. The same author views the shell
of the Mollusca as corresponding to the epi-
dermis of the higher animals calcified.

The outer prismatic layers of shell are
secreted by the borders or margins of the
mantle, whilst the inner laminated portions
arise from the outer surface. The growth
of shell is not uninterrupted or constant, but
periodical; hence the laminated arrangement
of its constituents.

In some portions of the shell of the oyster,
&c., the calcareous matter assumes the form
of distinct rhomboidal or hexagonal crystals
(PL 37. fig. 10). These appear to be depo-
sited in the inner laminated portion ; and
when detached, they leave angular spaces
corresponding to them in form. In the
tooth of the shell of My a, groups of radiating
prisms are present, forming an elegant
microscopic object.

The prisms existing in the outer portion
of shells have been supposed to represent
cells filled with calcareous matter ; they
have also been regarded as consisting of
aggregations of epidermic cells, the transverse
striae (in Pinna) corresponding to thickenings
of the cell-membranes where the layers come
into contact, and the folded membrane has
been compared to a basement membrane.
It is probable, however, that shell should be
regarded as a simple secretion from the
mantle, and as corresponding in structure to
egg-shell.

Shell of the Crustacea.— The hard portion
of the integument of the Crustacea, alluded
to at p. 175, possesses a laminated structure,
corresponding to periods of growth, and
giving rise to the appearance of transverse
parallel lines in a perpendicular section
(PL 37. fig. 1 6). The substance is traversed
by numerous straight or slightly wavy, very
slender tubes (PL 37. fig. 16), resembling
those of dentine.

Shell of Echinodermata. — The perforated
structure of the homogeneous basis forming

SIDA.

[ 577 ]

SIPHONACE.E.

this substance has been already noticed
(p. 219). In the spines of Echinus, Cidaris,
&c., the calcareous network consists of
slender fibres with large areolae at intervals,
arranged in a somewhat regular pattern, and
traversing a solid homogeneous substance,
which is thus divided into a number of ribs
or pillars. The transverse section of these
is seen in PI. 37. figs. 6 & 6 a.

Dr. Carpenter regards the calcareous net-
work as corresponding to the fibrous struc-
ture of the cutis of the higher animals
calcified. This view does not, however,
account for the intervening substance.

The method of procuring sections of
shell is noticed under PREPARATION (p.
531).

BIBL. Carpenter, Trans, of the British
Association, 1844 & 1847, Ann. Nat. Hist.
1843. xii. 376; Gray, Phil. Trans. 1833;
Deshayes, Todd's Cycl of Anat., fyc., iv.
556; Bowerbank, Trans. Micr. Soc. 1844.
i. ; Lavalle, Ann. d. Sc. nat. 3 ser. vii. ;
Siebold, Vergl. Anat.; Brewster, Phil. Trans.
1814, and Optics, 1853; Woodward, On
Shells.

SIDA, Baird (Daphnia, auct.). — A genus
of Entomostraca, of the order Cladocera,
and family Daphniadae.

Char. Anterior branch of inferior antennae
two-jointed, posterior three-jointed, and with
a row of spines at its anterior margin ; legs
six pairs.

S. crystallina (PI. 14. fig. 27). The only
species. Aquatic.
, Daphnella belongs here.

BIBL. Baird, Brit. Entomostr. p. 107.

SILK. — This valuable substance is se-
creted in Insects by two glandular organs,
described under INSECTS, Spinning Or-
gans.

The fibres of which it is composed are
cylindrical or somewhat flattened, solid,
tolerably highly refractive, and free from
structural markings of any kind.

Chemically, silk consists of a proper silk-
cylinder, consisting of fibroine and forming
the principal part of the fibres, surrounded
by a coat of albumen, upon which is a layer
of gelatine. The fibres also contain a small
quantity of fat and colouring matter.

Fibres of silk may easily be distinguished
from those of linen or cotton by the appli-
cation of Millon's or Schultze's test, both of
which colour the silk, but neither of them
the linen or cotton. The test for cellulose
is equally applicable to the same purpose.

BIBL. That of CHEMISTRY.

SIPHONACE^.— Afamily of Confervoid
Algae, either marine, aquatic, or growing
on damp ground ; characterized by the indi-
vidual fronds being composed of large
branched cells, the contents of which, ex-
pelled in various forms, serve for the repro-
duction. The fronds mostly have a more or
less compound character, either from regular
ramification, or by a kind of stoloniferous
multiplication at the base of the cells ; and
in Hydrodictyon, which seems best placed in
this family, the cells are always connected
together by their extremities, so as to form
a net-like frond. In the majority of the
genera the cell-contents are green; muchly a,
however, they are brownish or almost colour-
less. The modes of reproduction exhibit
considerable diversity, and are probably still
imperfectly known in most of the genera.
Codium,Bryopsis, &D.& Achlya are reproduced
by the discharge of the contents of certain
cells in the form of numerous small ciliated
zoospores. Vaucheria is increased by large
elliptical, solitary zoospores, covered with
vibratile cilia; in Hydrodictyon, the cell-
contents are converted into a multitude of
ciliated zoospores, which unite to form a
new net or frond before leaving the parent-
cell; while in Botrydium the cell-contents
are said to be discharged in the condition of
motionless gonidia; but we imagine this
point is not quite certain. In addition to
the gonidial reproduction, spores have been
discovered in Achlya and Vaucheria, and
will probably be found in the rest. In Achlya
these occur in special lateral sporangial
branch-cells. In Vaucheria they also occur
in special branch-cells, here however accom-
panied by antheridial cells, which produce
spermatozoids, fertilizing the sporangial cell.
From the fact that orifices have been ob-
served in the wall of the sporange of Achlya,
it is possible that an impregnation occurs
there also. Spores have not yet been ob-
served in the other genera, but it is to be
expected that they will be found in them
also. More particular details on the very
interesting genera of this somewhat hetero-
geneous family will be found under their
respective heads.

Synopsis of British Genera.

I. CODIUM. Filaments green, branched,
closely interwoven into a spongiform frond,
producing biciliated zoospores in sporangial
cells borne on the sides of the erect clavate
branches. Marine.

II. BRYOPSIS. •Filaments green, free,

2p

SIPHONOSTOMA.

[ 578 ]

SKIN.

pinnately branched, producing two- or four-
ciliated zoospores in the extremities of the
branches. Marine.

III. VAUCHERIA. Filaments green, more
or less branched, continuous, producing in
their apices large solitary zoospores covered
with cilia; also bearing lateral globose spo-
rangial cells, and hook-like antheridial cells
("horns").. Marine or aquatic, and still
more commonly on muddy ground, damp
garden-pots, &c.

IV. BOTRYDIUM. Frond a spherical
green vesicle seated on a ramified filamentous
base, the cavity of the whole continuous,
the ramified base producing new vesicles
(sporanges) by stoloniferous growth. Mul-
tiplied by the granular contents of the vesicle
discharged by a rupture at the summit. On
damp (mostly clayey) ground, subject to
floods.

V. HYDRODICTYON. Frond a green
bag-like net, with usually pentagonal open
meshes, formed of cylindrical cells connected
by their ends. Reproduced by ciliated zoo-
spores formed in the "link"- cells, uniting
together and forming a perfect miniature net
before escaping from the parent-cell.

VI. ACHLYA. Filaments colourless or
light brownish (like the mycelia of Fungi),
free, slightly branched ; producing numerous
biciliated zoospores in the apices of the fila-
ments, and spores in globose lateral sporan-
gial cells. On dead flies, fishes, or some-
times on decaying vegetable matter in water.

BIBL. See the genera.

SIPHONOSTOMA (Parasita, or Precilo-
poda). — An order of Crustacea.

Char. Body often almost entirely enclosed
in a buckler, consisting generally of one,
sometimes of two pieces ; mouth suctorial ;
legs formed for walking or prehension, or
partly branchiferous and fitted for swimming.
Parasitic upon fishes, &c.

These animals (PI. 14. figs. 7, 23, 24, 36,
and PI. 15. fig. 1), which often present the
most extraordinary forms, are found mostly
affixed to the gills of fishes by means of
hooks, arms, or suckers, arising from or
consisting of modified foot-jaws. In some,
the cephalothorax is distinct from the abdo-
men, and the head is more or less distinct
from the thorax ; whilst in others the body
presents more of a worm-like form, is occa-
sionally ringed or segmented, and sometimes
exhibits simple or branched lateral lobes or
processes. The antennae are mostly rudi-
mentary. Flattened elytriform dorsal ap-
pendages are sometimes present. The ros-

trum is conical, tubular, and furnished with
two setaceous or styliforrn mandibles. The
alimentary canal is straight, without a gas-
tric expansion, and its orifices at the two
ends of the body. In some, branchial plates
form the respiratory organs, but in most the
same office is performed by the skin.

The sexes are distinct, although they are
not known in all the species. The males
are smaller than the females. The ova are
often attached to the lower part of the body
of the females, either contained in external
ovaries, or simply glued together by the
secretion from a special gland, and forming
long, cylindrical, straight or convolute ap-
pendages. The young animals have but few
legs, swim freely, and frequently resemble
the young of Cyclops.

BIBL. Baird, Brit. Entomostr. ; M. Ed-
wards, Hist. Nat. Crust, iii. ; Siebold, Ver-
gleich. Anat.

SIROCROCIS, Kiitz.— Probably the my-
celium of a fungus.

BIBL. Kiitzing, Sp. Alg. p. 153.

SIROGONIUM, Kiitzing. S. notabile
=. Mesocarpus notabilis, Hass. ; S. sticticum
= Spirogyra (Zygnema, Hassall) sticti-
ca ; S. breviarticulatum =. Spirogyra cur-
vata.

SIROSIPHON, Kiitz.— A genus of Os-
cillatoriaceae(ConfervoidAlga3), which should
perhaps have been placed under the older
name of HASSALLIA. This genus is princi-
pally distinguished by the solitary branches
passing off from the sides of the rather rigid
filaments, the branches arising from longitu-
dinal division and lateral growth of intersti-
tial cells. The plants are found on wet
moors, rocks, &c. Two species seem to be
established,— S. ocellata (PL 4. fig. 12), and
S. compacta ; others appear doubtful.

BIBL. Hassall, Brit. Fr. Alg. p. 231. pi.
77,78; Kiitzing, Spec. Alg. p. 315, Tab.
Phyc. ii. pi. 36, 37.

SIZYGITES. See SYZYGITES.

SKIN Or INTEGUMENT OF ANIMALS.

Three parts are distinguishable in the skin :
an outer or cellular, forming the epidermis ;
an inner fibrous, or cutis vera; and an inter-
nal or subjacent, known as the subcutaneous
cellular tissue. The two former constitute
the skin proper.

The cutis vera or corium (fig. 646 c) con-
sists of areolar and elastic tissue, with fat-
cells, blood-vessels, nerves, absorbents, and
unstriated muscular fibres. The fibres of
the areolar tissue are variously interlaced
and united into interwoven bundles, form-

SKIN.

[ 579 ]

SKIN.

ing a tolerably dense and firm tissue, with
small areolae, and sometimes presenting
laminae. The elastic tissue is less abundant

than the areolar, and consists of networks of
finer or coarser fibres.

The outer surface of the cutis gives off a

Fig. 646.

Fig. 647.

— - ~c

Fig. 646. Perpendicular section of the skin of the under surface of the end of the thumb, through three furrows,
a, cuticle ; b, rete mucosum ; c, cutis vera ; d, upper part of subcutaneous tissue ; e, papillae of the cutis ; /, fatty
tissue ; g, sudoriparous glands ; A, sudoriparous ducts ; i, orifice of the latter. Magnified 20 diameters.

Fig. 647. Papillae from the skin of the under part of the end of the finger, a, axial body ; b, nerve ; c, its terminal
loop ; d, d, loops of capillary blood-vessels. Magnified 250 diameters.

number of conical processes or papillae (fig.

646 e), which are frequently bifid, lobed, or
arise several from a common base. In many
parts of the skin they are arranged in more
or less regular rows. The areolar tissue of
the papillae is often homogeneous, especially
in the median portion, where in certain pa-
pillae it forms an oval transparent body (fig.

647 d), surrounded by a layer of imperfectly
developed elastic tissue, consisting of spindle-
shaped cells and fibres taking a horizontal or
circular direction, and giving the oval bodies
a transversely striated or laminated appear-
ance. These oval or axial bodies, as they
are called, have been supposed to be con-
nected with sensation, an assumption which
Kolliker has rendered at least improbable.
The papillae are traversed by the terminal

loops of the cutaneous capillaries (fig. 647 d)
and nerves (fig. 647 c).

The cutis is continuous beneath with the
subcutaneous cellular or properly areolar
tissue (fig. 646 d}, which is of a much more
lax texture than the cutis, presenting large
areolae filled with fatty tissue (fig. 646 f).

The cutis is everywhere covered externally
by the epidermis, which is a semitransparent
coat, containing neither vessels nor nerves,
moulded as it were upon its surface (fig. 648)
and filling up the intervals between its
papillae (fig. 649). The variously arranged
lines seen upon its outer surface are depres-
sions corresponding to those existing upon
the cutis between its rows or groups of
papillae.

The epidermis consists entirely of nucleate d
2p2

SKIN.

[ 580 ]

SKIN.

cells, and two distinct layers are recognized
in it (fig. 648), an inner forming the rete
mucosum (fig. 648 c), and an outer or cuticle
(fig. 648 d). The rete mucosum is softer
than the cuticle, and is frequently of a brown-
ish colour, from its cells, especially the
deepest, containing granules of pigment.
These cells are not all of the same form,
those immediately applied to the cutis being
somewhat elongated and arranged perpendi-
cularly upon its surface (fig. 648 6), the next
being roundish, and those nearest the cuticle
becoming longer, horizontally flattened, and
polygonal from mutual pressure (fig. 648 c).

The cells of the cuticle are colourless,
flattened, often wrinkled or folded, and cor-
respond to the pavement epithelium of the
mucous membranes. Between the epidermis
and the cutis is situated a basement mem-
brane, which is rarely distinguishable.

In the examination of the skin, sections
must be made with Valentin's knife, and
these treated with acetic acid, solution of
potash, dilute nitric acid, &c. The blood-
vessels are well seen as regards general
arrangement in injected preparations, some

Fig. 648.

Perpendicular section of the skin of the negro. a,papillae
of the cutis ; b, deepest and most intensely coloured layer

of elongated perpendicular cells of the rete mucosum ;
c, upper layer of the rete ;

d, cuticle.
Magnified 250 diameters.

Fig. 649.

a-

Under surface of the epidermis of the palm of the hand, a, ridges corresponding to the furrows between the ridges
of the cutis ; ft, ridges corresponding to the furrows between the rows of papillae ; c, sudoriparous ducts ; d, their broad
insertions in the epidermis ; e, depressions corresponding to the papillae.

Magnified about 20 diameters.

SLIDES.

[ 581 ]

SNOW.

of which, as those of the pulp of the finger,
form very beautiful objects. The epidermis
is easily separated by maceration.

The integument of animals is noticed
under the respective heads of the'classes.

It must be remarked that the terms epi-

Fig. 650.

Section of the skin of the heel parallel to the surface,
through one entire ridge of the skin and part of two
others ; showing the arrangement of the papillae in rows
corresponding to the ridges of the cutis. a, cuticle between
the ridges ; b, rete mucosuni ; c, papillae ; d, portion of
the rete mucosum between papillae arising from a
common base ; e, sudoriparous ducts.

Magnified 60 diameters.

dermis and cuticle are generally used syno-
nymously.

BIBL. Kolliker, Mikrosk. Anat. i. and
Gewebelehre ; Krause, Wagner's Handwor-
terbuch d. Physiol. ii. 127; Weber, ibid, iii.;
Todd and Bowman, Phys. Anat. &c.

SLIDES. INTRODUCTION, p. xxi.

SMARIS, or SMARIDIA, Latr. — A genus
of Arachnida, of the order Acarina, and fa-
mily Trombidina.

Char. Palpi slender, inserted upon a re-
tractile rostrum ; mandibles sword-shaped ;
body entire, narrowed in front ; coxae stout,
distant, the anterior articulated to a fixed
eminence upon the body; legs palpatorial
(used also as palpi), the anterior longest.

S. papillosa (PL 2. fig. 36; a, mandible).
Body vermilion-coloured, broader in front,
depressed, covered with short cylindrical
papillae rounded at the end.

Found upon the trunks of trees, and in
moss.

Fusiform scales replace the papilla3 upon
the legs, palpi, and rostrum.

Several other species, found in moss, upon
fallen leaves, and on the debris left after in-
undations.

BIBL. Duges, Ann. des So. nat. 2 ser. i.
16 & 34; Gervais, Walckenaer's Apt. iii.
173.

SMUT. See UREDO.

SNAILS, WATER-.— Most microscopic
observers, ever anxious to determine the
unknown cause of the curious circulation or
rotation (ROTATION) taking place in certain
water-plants, as Vallisneria, Anacharis, &c.,
keep these growing in large glass vessels, as
confectioners' jars, or other reservoirs (Vi-
varia). These plants, and the sides of the
vessels, are, however, very apt to become
overgrown and obscured by Confervoid Algae,
as (Edogonium, Palmellaceae, &c., which may
be prevented by keeping water-snails in the
water, as species of Lymneeus, Physa, Bithy-
nia, Planorbis, &c. The latter are best for
this purpose (the shell is flat-spiral). If Des-
midiaceae, Diatomaceae, Infusoria, &c. are to
be preserved, the snails must be carefully
excluded, because many of these are con-
sumed by them, and will not live, as the
bottom of the vessels soon becomes covered,
wrhen snails are kept, with a load of excre-
ment. The characters of the snails are too
long to be given here. The gelatinous masses
of ova are found adhering to water plants,

See the Bibl. of MOLLUSCA.

SNOW. — The various forms presented by
ice or crystallized water in the form of snow
constitute beautiful although fugitive micro-
scopic objects.

The crystals belong to the rhombohedric
or hexagonal system. Several hundreds of
forms have been observed, and many of them
figured. Among them may be mentioned
hexagonal or dodecahedral plates, hexagonal
prisms, single, arranged in a stellate form,
or terminated by rectangularly placed plates
or secondary groups of needles, hexagonal
pyramids, &c. The angles of these forms
frequently constitute secondary centres,
around which other similar or dissimilar
forms are aggregated. By some authors
these forms are regarded as skeleton crystals.

See also RED SNOW.

BIBL. Scoresby, Account of the Arctic
Regions; Kamtz, Meteorologies Glaisher,
Micr. Journ. 1855. iii.; Naumann, Elem. d.
Mineralogie.

SODA.

[ 582 ]

SPERMATOZOA.

SODA. — Kolliker recommends a solution
of caustic soda, in preference to potash, for
the resolution of some of the tissues into
their component elements. We have been
unable to detect any marked difference be-
tween the action of these two solutions;
and the former has the disadvantage of lift-
ing the stopper from the bottle by the cry-
stallization of the carbonate formed, so that
it is with difficulty preserved.

SODIUM, CHLORIDE OF, or common
salt. — The crystals of this salt belong to the
regular. system. The most common form is
the cube terminated by quadrangular pyra-
mids or quadrangular pyramidal depressions,
rectangular tables, &c. Schmidt endeavours
to show that the primary form of the cry-
stals is the octohedron, and that the cubes
are twin octohedra. The crystals do not
polarize light.

BIBL. Schmidt, Entwurf. e. dllg. Unter-
such. fyc. 90, and the Bibl. of CHEMISTRY.

SCEMMERING, MIRROR OF.— INTRO-
DUCTION, p. xix.

SORUS.— The name applied to the ag-
gregation of sporanges of the FERNS ; some-
times applied also to the groups of spores
in the Florideous Algae.

SPATHIDIUM, Duj.— A genus of Infu-
soria, of the family Leucophryina.

Char. Body oblong, thicker and rounded
behind; thinner, broader, and obliquely
truncate in front.

S. Tiyalinum (Leucophrys spathula, E.)
(PL 24. figs. 75 & 76). Hyaline; anterior
margin with irregularly arranged minute
black points.

Ehrenberg figures a row of cilia at the
anterior end of the body.

BIBL. Dujardin, Infus. p. 458.

SPERMATIA.— The minute corpuscles
supposed to represent spermatozoids in the
LICHENS (PI. 29. figs. 3, 15, 16) and FUNGI
(PI. 20. figs. 2, 3, 4).

SPERMATOZOAorSPERMATOZOIDS,
OF ANIMALS. — The form of the spermatozoa
varies in different animals (PI. 41), but they
usually consist of a rounded or oval body or
head, to one end of which is appended a
moveable filament. This is their form in
man and in the Mammalia generally.

In Birds, the body is sometimes cylindri-
cal, sometimes spiral, or presenting a zigzag
outline.

In Reptiles the body is usually cylindrical
and straight, sometimes spiral. But in some
of them the straight or slightly undulating
terminal filament is surrounded by a spiral

filament, which some observers have regarded
as an undulating membrane (UNDULATING
MEMBRANES).

In Fishes, the spermatozoa are usually
very small, and the body round, although in
others the body is spiral.

In the Invertebrata, a distinct body and
terminal filament are present in some, whilst
in others each spermatozoon represents a
simple filament tapering at the ends. In
some of these the body seems alone to exist
in the form of a short cylinder or rod. In
others the spermatozoa are represented by
simple cells, or cells with radiating pro-
cesses.

The curious filaments, one of which is re-
presented in PI. 14. fig. 20, we found within
the body of a Cypris. There were several
together, in those containing as well as in
those not containing ova, and they consisted
of two spiral fibres. We at first considered
them as spermatozoa ; but finding that they
resisted the action of a boiling solution of
potash, which renders all other spermatozoa
invisible or dissolves them, we hesitate as to
their nature. They bear some resemblance
to the elaters of Trichia.

The exact manner in which the sperma-
tozoa are developed is not decided.

According to Kolliker's observations, they
are developed within cysts or (epithelial?)
cells contained in the tubuli testis, or other
form of seminal organs. A number of nu-
clei or globules arise within these, in each of
which a spermatozoon is afterwards found
lying coiled up. On the solution or rupture
of the globules, the spermatozoa become
free within the cysts. In some animals the
spermatozoa are formed in bundles, the bo-
dies and filaments lying parallel with and
opposite each other.

According to Reichert and Quatrefages,
the transparent and homogeneous sperma-
togenous masses undergo a process of seg-
mentation analogous to that occurring in the
ovum, reducing them to a granular state,
the filaments being subsequently formed.

Most spermatozoa exhibit active move-
ments produced by the action of the fila-
ment, whence they were formerly considered
as independent living animals. This notion
is now abandoned, the movements being
undoubtedly comparable to those of the
ciliated zoospores of the Algae, or the ciliated
epithelial cells of animals.

In some animals tubular sheaths are se-
creted around the masses of spermatozoa
whilst contained in the seminal apparatus,

SPERMATOZOIDS.

[ 583 ]

SPH^ERIA.

and called spermatophores. These, when
discharged from the organ, are fixed by the
male to the posterior end of the body of the
female by means of a glutinous secretion.

The spermatozoa are the essential ferti-
lizing elements of the liquid in which they
are contained. On reaching the ova, they
bore through the vitelline membrane by the
aid of their terminal filament, becoming
dissolved or lost in the substance of the
yolk.

Spermatozoa may be best examined and
preserved by washing them with distilled
water, and drying them upon a slide.

BIBL. Kolliker, Mikrosk. Anat. ii. 393;
id. Siebold and Kolliker 's Zeitschr. vii. 201 ;
id. Beitr. z. Kenntn. d. Geschlechtsverhdlt-
nisse, <!^c. d. wirbel. Thiere ; Siebold, Vergl.
Anat., passim ; Czermak, Siebold and Kb'lli-
ker's Zeitschr. ii. ; Wagner, Todd's Cycl. of
Anat. fyc. iv., art. Semen ; id. Physiology by
Willis; Leuckart, Wagner's Handwb'rterb.
d. Phys. iv. 819 ; Beneden, Anat. Compares;
Dujardin, Observ. au Microsc.; and the
Bibl. of OVUM.

SPERMATOZOIDS, or ANTHERO-
ZOIDS. — The terms applied to the struc-
tures produced in the antheridia of the
Cryptogamia, regarded as analogous to the
spermatozoa of animals, and as the agents of
fertilization of the germ-cell. In the Mar-
sileacea3, Lycopodiacese, Equisetaceae, Ferns
(PL 32. fig. 34), Mosses (PL 32. fig. 33),
Hepaticaceae (PL 32. fig. 32), and Characese
(PL 32. fig. 31), they are ciliated, spirally-
coiled filaments, exhibiting very active spon-
taneous motion. In the Fucoid Algae, they
are globular cells bearing two unequal cilia
moving actively. In the Florideae they are
minute globular cells, and neither cilia nor
movement have been certainly demonstrated.
In the Lichens and Fungi the SPERMATIA
(PL 20. fig. 4 ; PL 29. fig. 15) appear to
represent the spermatozoids of the other
classes, and they seem to be devoid of spon-
taneous movement. The details respecting
these bodies are given under their respective
classes.

BIBL. Thuret, Ann. des Sc. nat. 3 ser. xiv.
p. 214, and xvi. p. 5. See also under the
families.

SPERMOGONTA.— The supposed anther-
idial structures of LICHENS (PL 29. figs. 2,
13, 16) and FUNGI (PL 20. figs. 1 & 4).

SPERMOSIRA, Kutzing.— A genus of
Nostochaceae, growing in salt marshes, con-
taining two British species; known from
the other genera by the disk-shaped or len-

ticular cells ; but the filaments are liable to
be mistaken for a Nostoc in the young state.

1. Spermosira litorea, Kutzing. Filaments
1-3600" thick, straightish, aeruginous ; ordi-
nary cells confluent, very short; spermatic
cells at first green, depressed-spheroidal,
1-3000" in diameter, granulate, fuscous when
mature ; vesicular cells transversely ellipti-
cal, not wider than the ordinary cells. Kut-
zing, Tab. Phyc. vol. i. pi. 100. fig. 3; Har-
vey, Phyc. Brit. pi. 93. fig. C, Manual of
Br. Algae, 2 ed. pi. 27 E. In muddy brackish
ditches.

2. S. Harveyana, Thwaites. Filaments
much curved; ceils nearly as long as broad ;
spermatic cells exactly spherical, almost
twice the diameter of the ordinary cells;
vesicular cells subquadrate, rather longer
than wide, about as wide as the ordinary
cells. Harvey, Phyc. Brit. pi. 173 C. In
muddy brackish ditches.

BIBL. As above.

SPHACELARIA, Lyngb.— A genus of
Ectocarpaceae (Fucoid Algae), containing a
number of species, two of which, S. scoparia
and S. cirrhosa, are common. They have
jointed, rigid, distichously branched, feathery
filamentous fronds, of olive colour, a few
inches high, and are especially characterized
by the sphacela formed at the ends of the
branches, which consist of an expanded ter-
minal cell containing a granular mass. This
structure appears to represent the antheridium
of these plants, for Pringsheim has observed
the conversion of the granular mass into one
or more large free cells, the contents of
which are after a time converted into ciliated
spermatozoids, ultimately discharged through
a tubular process breaking its way out at
the side of the sphacela. The spores (or
spore-sacs?) are borne at the sides of the
branchlets, apparently on distinct plants.

BIBL. Harvey, Brit. Mar. Alg. p. 55. pi.
9 B; Pringsheim, Bericht. Berlin. Akad.
March, 1855.

SPH^RIA, Hall.— A genus of Sphariacei
(Ascomycetous Fungi), now somewhat re-
duced from its ancient limits, but still con-
taining a vast quantity of species, which it
is impossible to treat satisfactorily within
our limits. The forms vary chiefly in regard
to the perithecia, which are sometimes only
covered by a veil, and hence appear superfi-
cial on the matrix, while in other cases
they are imbedded in the matrix, only evi-
dent externally by the black papilla, which
is permanent, becoming indurated and open-
ing by a pore to discharge the spores in a

SPH^RIA.

[ 584 ]

SPELERIACEI.

fine powder. Many of the immersed kinds
are only evident externally as minute black
points or dots upon the surface of the leaf,
stem, &C.., which they infest ; others are ex-
posed freely when mature, breaking out from
beneath the epidermis. Sometimes they are
solitary, sometimes associated in small or
large numbers, distinct or confluent. 5. qua-
ternata (fig. 651) is an example of the oc-
currence of free perithecia grouped together,

Fig. 651.

kfB5¥^S?9(

,. ,.

Sphseria quateruata.

Three groups growing on a piece of beech- wood.

Magnified 20 diameters.

mostly in fours; being decumbent, their
ostioles are collected together, and they per-
forate the bark by a little black rugged tu-
bercle. This is common on beech-trees.
S. convergens (figs. 652, 653) is an analogous

Fig. 652.

ftitoimq afoi _^
,§aoJ
fono'J

Sphseria convergens.
Magnified 20 diameters.

Fig. 654.

Sphaeria verrucosa.
Magnified 20 diameters.

form. S. elonyata (figs. 660-662) affords an
example of those species which are at first
immersed and adnate, and finally burst forth
and become nearly free.

For species now separated from this genus
see CLAVICEPS, HYPOXYLON, XYLARIA,
HYPOCREA, and NECTRIA.

Certain points of great interest have lately
been ascertained respecting this genus and
its allies, which are mentioned under the
heads of the family and other genera, namely
the coincidence and evident connexion be-
tween true species of Sphceria and various
Coniomycetous Fungi ; for just as Melasmia
is a precursory form of Dolhidea, Tubercu-

laria of Nectria, &c., Cytispora, Septoria,
and other forms precede Sphceria, and many
distinct stylosporous forms are associated,
usually described as belonging to distinct
genera, such as Stilbospora, Sporocadus,
Sphceropsis, &c. Thus these plants seem to
produce three kinds of reproductive organs,
as is now known to be the case with the
Uredines, viz. — 1. a form analogous to the
spermogonia of the Lichens (in Sphceria re-
presented by Cytispora, &c.); 2. an ascopho-
rous fruit, the perithecium of the true Sphceria ;
and 3. a stylosporous fruit, representing the
genera Stilbospora, Sporocadus, &c.

S. Laburni has been found by Tulasne to
exhibit all these stages, namely perithecia
containing asci, surrounding a cytispore, with
other conceptacles on the same stroma re-
sembling the perithecia, but lined with sty-
lospores instead of asci. Berkeley and
Broome also describe the existence of the
perithecia of Sphceria inquinans and the con-
ceptacles of Stilbospora macrosperma on the
same stroma (PL 20. figs. 25-28).

It is stated by Tulasne that the 'spermatia'
of the cytisporous forms may be contempora-
neous with the stylospores or basidiospores,
but they always precede the ascospores in
their development ; hence there is ground
for supposing that they represent the sper-
matozoids of the higher Cryptogamia. With
regard to the relations of the stylospores, it
is possible that they are merely modifica-
tions of the ascospores; but it wTould appear
probable that they must be regarded as real
gonidial structures, for which it may be de-
sirable to retain Fries's name of conidia,
just as that of tetraspores is retained among
the Florideous Algae. Attention should be
directed here to the complete correspondence
between the series of forms of these genera
and those of the UREDINES, where, as in
PUCCINI A, we have the spermogonia (cyti-
spore), the uredo (stylosporous fruit), and
the perfect fruit (perithecium).

Mr. Currey has recently published some
observations on the germination of the spores
of the Sphcerice.

BIBL. Berk.JBn7.FZor.ii.pt.2.p.232; Ann.
Nat. Hist. i. p. 205, vi. p. 360, ser. 2. v.
p. 374, vii. p. 186, Hook. Journ. Bot. iii.
p. 319 ; Fries, Summa Veg. 388, Syst.Mycol.
ii. p. 319; Tulasne, Ann. des Sc. nat. 3 ser.
xv. p. 375 (Ann. Nat. Hist. ser. 2. viii. p.
117) ; Currey, Mic. Journ. iii. 263 (1855).

SPH J3RIACEI. — A family of Ascomyce-
tous Fungi, containing a vast number of
mostly epiphytic plants, of minute dimen-

SPH^ERIACEI.

[ 585 ]

SPHJERIACEI.

sions, growing upon leaves, stems, "bark,
wood, &c., and sometimes on the bodies of
insects. The essential distinctive character
lies in the globular, ovate, or flask-shaped
conceptacle or perithecium, containing asci,
which ultimately open by a pore at its sum-
mit to discharge the spores. These peri-
thecia occur either solitary or in groups on
an indistinct matrix, growing out from the
epidermis of leaves, &c. (Sphceria), or they
are immersed in a tubercular stroma (Nec-
tria), while in the larger forms the stroma
becomes developed into an erect clavate or
bushy structure, of a fleshy or horny con-
sistence, the perithecia being imbedded in
the superficial layer of this, and opening by
pores on the surface. Much remains to be
done in reference to the history of this fa-
mily, not merely on account of the polymor-
phous characters of the ascophorous forms,
but from the circumstance that it has re-
cently been shown, as was suspected before,
that there is a relationship existing between
them and the supposed genera of Coniomy-
cetous Fungi of similar habit. These last
are in fact mostly forms of Sphseriaceous
Fungi, as is indicated under the heads Co-

NIOMYCETES, ASCOMYCETES, DoTHIDEA,

SPHCERIA, CYTISPORA, SEPTORIA. Our
treatment of this family is very imperfect,
the knowledge of them being confined to
few persons, and much of it lying scattered
in fragments.

insqqfi bfirow Ji .iud j gfnocrsoosus e)rft'io anoii
Synopsis of British Genera.

* Stroma erect.

I. CLAVICEPS. Stroma simple, clavate ;
perithecia superficial, in a distinct layer at
the summit of the clavate stroma ; asci tu-
bular, spores very long, multiseptate.

II. XYLARIA. Stroma simple or branched,
perithecia spread all over, often wanting at
the summit, black ; asci eight-spored, spores
uniseptate.

III. THAMNOMYCES. Stroma branched,
shrubby, or stalk-like ; perithecia formed
from the stroma, more or less naked ; asci
tubular; spores simple, ovate.

Kj *' * . * .' 'L. -;1 u V'.iVl *V*V^

** Stroma between erect and horizontal.

IV. PORONIA. Stroma cup-shaped, sti-
pitate or sessile, margined ; perithecia in the
disk, superficial ; ostioles even slightly pro-
minent.

*** Stroma horizontal

V. HYPOCREA. Stroma distinct from the

matrix, tubercular; perithecia immersed;
asci filiform ; spores simple or uniseptate.

VI. HYPOXYLON. Stroma distinct from
the matrix, at first covered with a floccose,
mealy veil; perithecia black; asci linear-
clavate; spores subseptate, expelled in a
cloud of black powder.

VII. DIATRYPE. Stroma partly formed
from the matrix, not distinct; perithecia
deep-seated, produced into a long neck, and
frequently a beak ; spores simple and pel-
lucid.

VIII. DOTHIDEA. Perithecia indistin-
guishable from the stroma; asci collected
into a globose nucleus with a neck above,
leading to an ostiolate papilla.

**** Stroma wanting', the perithecia often
seated on a tuberculose, crustaceous, bys-
soid, macular mycelium.

IX. NECTRIA. Perithecia free, membra-
nous, flaccid, brightly coloured, with a pale
papilla, nucleus pale; asci eight-spored;
spores pellucid.

X. OOMYCES. Perithecia erect, several
contained in a shining sac, free towards the
upper part; ostiole punctiform ; asci linear;
spore filiform, very long.

XL SPH^RIA. Perithecia black, papilla
covered by a veil or by the matrix, some-
times beaked, indurated, ostiolate, black ;
asci usually eight-spored; spores usually
septate, discharged as a powder.

Fig. 655. Fig. 656.

Fig. 657.

Xylaria guianensis.
Fig. 655. A stroma. Nat. size.
Fig. 656. Vertical section of the same. Nat. size.
Fig. 657. Section of a perithecium. Magnified 10 dia-
meters.

SPILEROCARPUS.

[ 586 ]

SPII^ERONjEMA.

Fig. 658.

Fig. 659.

Xylaria grammica.

Fig. 658. Nat. size.

Fig. 659. Horizontal section. Magnified 5 diameters.

Fig. 660.

Fig. 661,

Sphseria elongata.

Fig. 660. Erumpent lines of perithecia. Nat. size.
Fijj. 66l. Portion of one in end view. Magnified 20

diameters.
Fig. 662. Asci and paraphyses from a perithecium.

Magnified 200 diameters.

SPILEROCARPUS, Kiitz. = STAURO-

CARPUS.

SPH^ROCARPUS, Mich.— A genus of
Riccieae (Hepaticaceae). S. terrestris (fig.
663) is a minute Liverwort growing on the
ground, it is said especially in clover-fields.

The fronds are from 1-4 to 1-2" long, palish
green, very thin and membranous, the lower
surface adhering to the ground by radical hairs.

Fig. 663.

Sphserocarpus terrestris.

A frond with perichsetes containing sporanges ; one cut
open.

Magnified 10 diameters.

The middle part of the upper surface bears a
quantity of fruits which consist at first of
archegonia and antheridia, like those of other
Liverworts, surrounded by a cup -like open
perichaete (?), which gradually grows up over
the fertilized archegonium and closes at the
top, so as to form a pyriform sac, presenting
an orifice at the summit. The archegonium
ripens into a globular sporange, containing
spores without elaters, crowned by a curious
little styliform process. The spores are dis-
charged by irregular rupture. The walls of
the sporange are composed of simple paren-
chymatous cells, without spiral-fibrous layers.
While the sporange is ripening, the perichsete
enlarges into a loose, obconical, green, mem-
branous sac, through the thin walls of which
the globular sporange is visible (fig. 663).

BIBL. Hook. Brit. Flor. ii. pt. 1. p. 103;
Bischoif, Nova Acta, xiii. p. 150 ; Linden-
berg, ibid.xvm. p. 496; Yitt, Hooker's Journal
ofBot.vi. p. 287(1847).

SPILEROCOCCUS, Stackh.— A genus
of Rhodymeniaceae (Florideous Algae), con-
taining one British species, S. coronopifolius,
having a flat, linear, distichously branched
frond of crimson colour and cartilaginous
texture, of fan-like outline; parenchymatous,
with an internal denser rib and cortical layer;
6 to 12" long. The upper branches have their
margins set with minute tooth-like processes,
about 1-24" long, in some of which the
spherical conceptacles are imbedded.

BIBL. Harv. Brit. Mar. Alg. p. 128. pi.
16 B; Greville, Alg. Brit. pi. 15.

SPELERON.EMA, Fr. — A genus of
Sphaeronaemei (Coniomycetous Fungi), cha-
racterized chiefly by the spores which emerge

SPILERON.EMEI.

[ 587 ]

SPILERON.EMEI.

from the pore becoming glued together into
a firm globule. The species which grow
upon the surface of decaying plants are pro-
bably only forms belonging to Sphaeriaceous
genera.

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 281;
Ann. Nat. Hist. vi. p. 363, ibid. 2nd ser. v.
p. 371 ; Fries, Summa Veget. 400.

SPH^ERON^EMEL— A family of minute
Coniomycetous Fungi, growing on bark,
or more or less dry stems or leaves, charac-
terized by the conceptacle ordinarily bursting
by a pore or ostiole, or a lid, to extrude, in
most cases, a gelatinous ball of filaments
mixed with spores. From recent observa-
tions it appears that the genera of this order
do not consist of complete species, but are
forms which occur in combination with As-
comycetous forms to complete the whole
development of an individual, the Sphaero-
naemeous genera constituting the stylospo-
rous or conidial fruits of Sphaeriacei, &c.,
corresponding perhaps to the tetraspores
found in the Florideous Algae, which also
possess proper spores (see SPH^RIA).

Synopsis of British Genera.

I. CONIOTHYRIUM. Conceptacle free,
membranous, opening by an irregular pore
at the summit ; spores globular.

II. LEPTOSTROMA. Conceptacle innate,
subumbonate in the centre, dimidiate, at
length falling off, leaving a very thin disk.

III. PHOMA. Conceptacle ostiolate, very
thin, innate, immersed, rounded, with a
simple pore ; spores oblong, simple.

IV. LEPTOTHYRIUM. Conceptacle oper-
culate, innate, shield-shaped, not radiato-
fibrous ; spores spindle-shaped, simple.

V. ACTINOTHYRIUM. Conceptacle oper-
culate, innate, shield-s»haped, radiato-fibrous ;
spores spindle-shaped, simple.

VI. MICROTHECIUM. Conceptacle inde-
hiscent, membranous, immersed, endophytic;
spores simple.

VII. CRYPTOSPORIUM. Conceptacle
membranous, opening irregularly at the
summit ; spores spindle-shaped, simple.

VIII. SPH^RON^MA. Conceptacle
horny, innate-superficial, more or less pro-
duced into a neck, ostiole simple; spores
oblong, simple.

IX. ACROSPERMUM. Conceptacle lea-
thery externally, fleshy within, elongate-
clavate, ostiole simple ; spores stick- shaped,
simple.

X. DIPLODIA. Conceptacle horny, in-
nate-superficial or immersed, perforated by

a pore or irregularly opened or ostiolate,
ostiole more or less produced ; spores ovoid
or ellipsoid, double, then halved into com-
pressed-ternate, semi-ellipsoid sporules.

XI. HENDERSONIA. Conceptacle fleshy,
superficially innate or immersed, perforated
by a pore, opening irregularly or ostiolate,
ostiole more or less produced ; spores glo-
bose, cylindrical or discoid.

XII. SEPTORIA. Conceptacle horny,
innate-immersed, rounded, ostiole simple;
spores cylindrical, septate.

XIII. VERMICULARIA. Conceptacle
bristly, depressed, bursting irregularly; spores
minute, linear.

XIV. NEOTTIOSPORIA. Conceptacles
immersed ; spores appendaged at one end
with short hyaline threads.

XV. PROSTHEMIUM. Conceptacle horny,
immersed, ostiole simple; spores transversely
septate, verticillate at the apex of their fila-
ments.

XVI. ASTEROMA. Conceptacle very
small, slightly prominent, close, sub-con-
fluent, seated on more or less distinct radia-
ting fibrils.

XVII. ANGIOPOMA. Conceptacles free,
membranous, somewhat horny, cup -shaped,
dehiscing by a circular mouth, provided with
a fugacious epiphragm; spores affixed at the
base, stalked, septate.

XVIII. DISCOSIA. Conceptacles innate,
somewhat carbonaceous, at length collapsed
and plicate, ostiole perforated ; spores fusi-
form, produced at both ends into a thread-
like point.

XIX. PIGGOTTIA. Conceptacles very
irregular, thin, obsolete beneath, confluent
into a rugulose patch, bursting by an irregular
crack; spores on short stalks, largish, ob-
ovate, somewhat constricted towards the
base.

XX. PHLYCT^NA. Conceptacle spurious,
formed by the blackened epidermis ; spores
fusiform, cuspidate, septate, emerging ac-
companied by a gelatinous mass.

XXI. MICROPERA. Conceptacle innate,
membranous, ovate, elongate, bursting at
the apex ; spores linear, continuous, curved,
emerging in a mass accompanied by gela-
tine.

XXII. GL^OSPORIUM. Conceptacle ab-
sent, spores covered only by the cuticle,
which separates ; spores stalked, longish,
elliptical, simple, exuding a gelatinous
tendril.

XXIII. MELASMIA. Conceptacles mem-
branous, superficial, rather tumid, at length

SPILEROPHORACE.E.

[ 588 ]

SPILEROPLEA.

depressed, with a simple ostiole ; spores
almost linear, simple.

XXIV. DILOPHOSPHORA. Conccptacle
immersed in a spurious stroma, covered,
perforated by a pore ; spores cylindrical,
continuous, crowned at both ends with ra-
diating filiform appendages.

XXV. SPH^EROPSIS. Conceptacle sphe-
rical, immersed, subinnate, astomous, at
length (by the separation of the epidermis)
bursting by circumscissile dehiscence or ir-
regularly. Spores simple.

SPILEROPHORACE.E.— A family of
Angiocarpous or closed-fruited Lichens, cha-
racterized by their apothecia formed in the
swollen points of the thallus, bursting irre-

gularly" BritUh Genus.

il) SIR

SPILEROPHORON. — Thallus erect,
shrubby, externally crustaceo-cartilaginous,
internally solid and cottony. Apothecia ter-
minal, spherical, the perithecium, formed of
the thallus, closed, dehiscing irregularly.
Nucleus globular, internally floccoso-cartila-
ginous, the discharged (black) sporidia
crowded in the circumference.

S. coralloides (fig. 399. page 388) is not
uncommon on sand-rocks, among mosses.

S. compactum is less common. The sper-
mogonia have only been discovered as yet in
the latter ; they occur at the ends of the
more delicate branchlets of the thallus.

BIBL. Hook. Brit. Flor. ii. pt. 1. p. 236;
Leighton, Brit. Angioc. Lichens ; Tulasne,
Ann. des Sc. nat. 3 ser. xviii. p. 209. pi. 15.

SPH^ROPLEA, Ag.— A genus of Con-
fervaceae of uncertain position, but proba-
bly allied to the Zygnemacese. It is cha-
racterized chiefly by the formation of the
spores. The plants consist of simple jointed
filaments, with long articulations, at first
containing green colouring matter, excavated
by large vacuoles, producing a banded ap-
pearance (PI. 5. fig. 14 a), the contents
finally resolving themselves in the fertile
cells into numerous spinulose globular spores,
arranged in longitudinal rows (b), which be-
come red when ripe.

The development of the spores of S. annu-
lina has been observed by several authors ;
and Cohn has recently published an account
of the formation of spermatozoids in distinct
cells, exercising a fertilizing function. The
filaments (which always terminate in pointed
hair-like ends) present, when actively vege-
tating, the excavated or banded appearance
of the green contents above noticed; the
vacuoles separating the bands have a proper

colourless mucilaginous coat. When about
to produce spores the regularity of the bands
vanishes, the vacuoles multiply in number in
the substance of the bands, and the contents
present the appearance of a green froth, with
starch-granules scattered through it. After
a time a number of green corpuscles (the

rres) appear in the median line of the cell;
se assume a stellate shape, with radiating
threads of protoplasm connecting them to-
gether ; they soon appear in pairs, separated
by transverse false septa, formed by the
flattened vesicles of the vacuoles. The spores
gradually become better defined, and the
false septa disappear; then the young spores
present themselves as globular bodies, de-
void at this time of a cellulose coat. From
two to six minute orifices are perceptible at
this time in the partially softened wall of the
parent-cell. While these phenomena are
occurring in some of the cells, a different
change takes place in others. The green
bands assume a reddish-yellow colour, their
starch disappears, and they are gradually
converted into myriads of short stick-shaped
bodies, which break apart and " swarm " in
vast numbers, filling the whole cell, moving
actively in all directions. The gelatinous coat
of some of the vacuoles sometimes remains
intact, and these then lie free in the cavity
of the cell, and are often carried about by
the rapid motion of the corpuscles. Orifices
are meanwhile formed in these cells also,
through which the stick -shaped bodies
(spermatozoids) escape into the water. Their
length is about 1-3000". Their hinder end
now appears somewhat swollen, and they
bear two long cilia on the pointed beak ; in
fact resembling the microgonidia of the other
Confervoids. Colm states he has seen them
accumulate around the orifices of the spore-
cells, enter into the cavities of these, and
swarm about in the interior, in considerable
numbers, at length adhering to the young
spores. The spores then acquire a mem-
brane, and under this a second, which
is at first smooth, but afterwards presents a
spinulose or stellate appearance; the first
coat is then thrown off, and a third, smooth
coat appears under the stellate coat, closely
investing the contents. These conditions
resemble those of the spores of SPIROGYRA
and other Confervoids ; Spirogra, however,
retains the outer coat until germination.
The green contents of the spores ultimately
turn red. Their size and number in a cell
vary much.

Cohn has also observed the germination

SPHJEROPSIS.

[ 589 ]

SPH^EROZYGA.

of these spores, which is interesting in seve-
ral respects. Their ordinary size is from
1-1 200 to 1-1 500", and they present, as above
mentioned, two coats, the outer elegantly
marked; most authors describe it as stel-
late ; Kiitzing asserts that it is spirally folded.
The real fact is, that it is plaited in the di-
rection of ' meridians' from pole to pole, and
thus appears stellate when seen at one pole,
marked with lines when seen sideways. The
spores do not appear to germinate until the
spring following their production. The red
contents begin to assume a green colour
from the surface inwards, divide into two,
then into four or eight portions, which break
out from the spore-cell, and swim about as
free biciliated zoospores, of globular or
shortly cylindrical form, from 1-2280 to
1-1680" long, either bright red or parti-
coloured red and green, the point bearing
the cilia, however, always colourless. After
a time they become coated with a cellulose
membrane, cease to move, and grow into a
spindle-shaped body, the ends prolonged
into hair-like points. The growth appears
to be always in the middle, the hair-like
points remaining ; thus the spindle-shape is
retained until the length reaches 1-24" or
more, and the first septum appears in the
middle of the filament.

S. annulina (PI. 5. fig. 14) appears to be
the only well-known form. It is a rare Con-
ferva, growing on flooded fields; it does
not seem to have been recorded in Britain.

For Sph. crispa and punctata, see ULO-
THRIX.

BIBL. Kiitz. Sp. Alg. p. 362, Tab. Phyc.
iii. pi. 31 ; A. Braun, Verjungung, fyc. (Ray
Soc. Vol. 1853, p. 165); Cohn, Bericht. Ber-
lin. Akad. May, 1855.

SPH^ROPSIS, Lev.— A genus of Sphse-
ronaemei (Coniomycetous Fungi), growing
upon stems, &c., apparently only stylospo-
rous forms of Sphaeriaceous genera.
BIBL. Fries, Summa Veget. p. 419.
SPILEROSIRA, Ehr. See VOLVOX.
SPH/EROZOSMA, Corda.— A genus of
Desmidiaceae.

Char. Filamentous; filaments flat, fra-
gile ; their component cells closely united
by means of minute (glandular) processes,
and deeply divided on each side into two
segments.

S. vertebratum (PI. 10. fig. 9, front view;
fig. 10, side view). Cells about as long as
broad; connecting processes oblique, one
on each side. Length of cell 1-1430".
Not uncommon.

8. excavatum. Cells longer than broad ;
connecting processes sessile, two on each
side. Length of cell 1-2570".

After separation the cells conjugate ; spo-
rangia elliptical.

BIBL. Ralfs, Brit. Desmid. 65.

SPHJEROZYGA, Agardh (Anabaina,
Bory, Brebisson). — A genus of Nostochacese,
differing from the allied genera only in the
microscopic characters of the filaments, the
spermatic cells being separated by vesicular
cells. As the spermatic cells are developed
from the ordinary cells, and this gradually,
the vesicular cell will appear at certain epochs
to have a spermatic cell on one side, and an
ordinary cell on the other ; but this arises
merely from the fact that the spermatic cells
are developed singly and successively, first
one on one side of the vesicular cell and then
one on the other, and so on to whatever
number of adjacent spermatic cells there
may be developed on either side of the vesi-
cular cell, and those nearest the latter will
therefore always be the largest, until the
whole have acquired the full size. Ralfs
describes seven British species.

.

* Filaments moniliform, sporangia elongated,
not turgid.

1. S. Carmichaelii, Harvey. — Filaments
with tapering extremities ; ordinary joints
distinct, subquadrate; spermatic cells ob-
long; vesicular cells spherical. — Ralfs, Ann.
Nat. Hist. ser. 2. v. pi. 8. fig. 7 ; Harvey,
Phyc. Brit. pi. 113 A, Br. Mar. Alga,
2nd ed. pi. 27. fig. D.

Belonia torulosa, Carmichael ; Sphcerozyga
compacta, Kiitzing, Phyc. generalis. Ana-
baina marina, Brebisson ; Cylindrospermum
Carmichaelii, Kiitzing, Sp. Alg. 294, Tab.
Phyc. i. pi. 99.

Var. tenuissima,w'ith very slender filaments.
Forming a tender, very thin stratum of a
dark or bluish-green colour on the damp
soil of salt-marshes flooded at spring-tides,
more rarely in brackish ditches or upon
decaying marine Algae.

The best distinctive marks of this species
are the " subacute extremities combined with
the short filament and littoral habit."

2. S. Jacobi, Agardh. — Filaments elon-
gated, their ends usually attenuated ; ordi-
nary cells subspherical; vesicular cells sphe-
rical; spermatic cells oblong or cylindrical. —
Ralfs, I.e. pi. S.fig. 8; Eng. Bot. 2826. fig. 2.
Forming thick, bluish-green, gelatinous
masses, from which the filaments issue in
long rays. Fresh water.

SPHAGNACE^E.

[ 590 ]

SPHAGNOC2ETIS.

3. S. elastica, Agardh. — Dissepiments
conspicuous ; ordinary cells quadrate ; vesi-
cular cells elliptic ; spermatic cells cylindri-
cal, truncate.— Ralfs, I c. pi. 8. fig. 9. Cy-
lindrospermum elongatum, Kiitz. Tab. Phyc.
i. pi. 99. fig. 3. Forming a tender stratum
of a deep bluish colour in bogs.

** Filaments moniliform, spermatic cells
turgid, much broader than the ordinary
cells.

4. S. Broomei, Thwaites. — Filaments
elongated ; ordinary cells suborbicular j ve-
sicular cells barrel-shaped or elliptic ; sper-
matic cells elliptic, catenate. — Ralfs, /. c.
pi. 7- fig- 10. Forming a firmish bluish- or
yellowish-green stratum in brackish ditches.

5. S. Berkeleyana, Thwaites. — Ordinary
cells spherical or slightly compressed ; vesi-
cular cells spheroidal, compressed, as broad
as the large, turgid-elliptic spermatic cells.
—Ralfs, 1. c. pi. 8. fig. 11. In brackish
ditches.

6. S. Mooreana, Ralfs. — Ordinary cells
subspherical ; vesicular cells barrel-shaped,
much narrower than the large, broadly ellip-
tical spermatic cells. — Ralfs, I.e. pi. 8. fig. 12.
An Irish species.

*** Dissepiments obscure, cells longer than
broad.

7. S. leptosperma (Kiitzing). — Filaments
elongated, not constricted at the dissepi-
ments ; ordinary cells longer than broad,
confluent ; vesicular cells elliptic ; spermatic
cells linear.— Ralfs, 1. c. pi. 8. fig. 13. Cy-
lindrospermum leptospermum, Kiitzing, Tab .
Phyc. i. pi. 99. fig. 2. Forming large shape-
less gelatinous masses in still waters, varying
from deep green to yellowish-green, or, when
the filaments are comparatively few, nearly
colourless. Distinguished especially by the
" confluent ordinary cells with obscure dis-
sepiments."

BIBL. As above.

SPHAGNACE^.— A family of Opercu-
late Mosses of peculiar habit, growing on
bogs, &c., distinguished especially by the
mode of branching, the structure of the
leaves, sporanges and antheridia, and by the
absence of roots, except in the early stages
of growth.

The stem of the Sphagna is composed of
three layers of cells, a cortical, a medullary,
and a prosenchymatous layer intermediate,
which finally becomes somewhat woody.
The primary axis is indefinite in its growth,
the lateral axes, sterile or fertile, are annual.

The secondary axes are fasciculate, and being
pendent or recurved upon the stem, they
fulfil in some measure the function of roots.
The leaves are remarkable for the cellular
structure, being composed of two kinds of
cells, namely, narrow and elongated cells
filled with chlorophyll, conjoined into a kind
of network, the meshes of which are occu-
pied by large hyaline cells. The hyaline
cells contain in all but one exotic species, a
spiral or annular secondary deposit (PI. 39.
fig. 25) characteristic of this family. These
large cells also become opened by regular
circular pores at a certain stage of growth.

The inflorescence is monoecious or di-
cecious. The antheridia are produced singly
in the axils of perigonial leaves at the club-
shaped tips of short branches. They are
pedicellate and roundish, like those of the
Liverworts ; they produce biciliated sperma-
tozoids. The archegonia are found about
four together, sessile, in a tuft of perichaetial
leaves occupying the axis of a fascicle of
branches ; the receptacle subsequently elon-
gating into a peduncle, bearing a globular
capsule, entirely surrounded by the calyptra;
the calyptra is ruptured near the middle, the
lower part persistent and continuous with
the fleshy vaginule, within which the capsule
is seated on a bulb -like pedicel ; peristome
none, operculum flattish, thrown off with
elasticity. Spore-sac wanting, columella
short, not reaching the mouth of the capsule.
Spores apparently of two kinds, some en-
closed four together in parent-cells, others
smaller, sixteen in one mother-cell, the
former fertile, the latter sterile, occurring
either together or in distinct capsules.

British Genus.

SPHAGNUM, Dill. Character that of the
order. Nine species occur in Britain, some
common on every bog, distinguished by their
brilliant yellow-green colour and the wet,
spongy character of the beds they form. The
leaves are very interesting microscopic ob-
jects.

BIBL. Wilson, Bryologia Brit. p. 14;
Schimper, Ann. des Sc. nat. 4 ser. i. p. 313.

SPHAGNOCLETIS, Nees.— A genus of
Jungermannieae (Hepaticaceae), containing
one species, S. (Jung.) Sphagni, an elegant
little plant growing over Sphagnum and other
mosses on bogs ; attaching itself by long
radicles, numerous on the under side of the
procumbent, nearly simple stem. The gem-
miferous branches only have amphigastria.

BIBL. Hook. Brit. Flor. ii. pt. 1. p. 113;

SPHENELLA.

[ 591 ] SPIRAL STRUCTURES.

Brit. Jung. pi. 33, and Suppl. pi. 2 ; Ekart,
Syn. Jung. pi. 6. figs. 43 & 48.

SPHENELLA, Kiitz.— A genus of Dia-
tomacese.

This genus appears to consist of the
detached frustules of Gomphonema.

Kiitzing describes seven species.

BIBL. Kiitzing, Bacill. 83, and Sp. Alg.

SPHINCTOCYSTIS, Hass. (Cymato-
pleura, Sm.). A genus of Diatomaceae.

Char. Frustules free, single ; in front
view linear, with undulate margins ; valves
oblong or elliptical, sometimes constricted in
the middle. Aquatic.

Valves with coarse, transverse, or nearly
transverse, rounded elevations appearing as
dark bands, an interrupted median hue, coarse
lateral dots and transverse striae, but neither
alas nor nodules.

Five British species.

S. solea (PI. 12. fig. 23). Valves linear-
elliptic, narrowed on each side towards the
middle, transverse striae evident ; extreme
length 1-216".

Undulations six. Common.

/3. Much shorter, undulations four, ends
apiculate.

S. elliptica(P\. 12. fig. 24). Valves broadly
elliptic or elliptic-oblong, striae obscure,
undulations four or five; length 1-280".

Common.

S. Hibernica. Valves broadly elliptic,
acuminate, undulations three ; length 1-250".

BIBL. Hassall, Brit. Freshw. Algce, 436;
Smith, Brit. Diat. i. 36 ; Kiitzing, Sp. Alg.

SPICULA (plural of spiculum), — In some
of the Invertebrata, firmness is given to the
body by a rudimentary external skeleton
consisting of a number of curiously shaped
microscopic bodies, many of which are of
a needle-like form, often containing a cavity,
and denominated spicula. They are met with
in endless variety of form in sponges (PL 37,
the lettered objects), where they consist of
silex. They also occur in the Echinodermata
(PI. 37. figs. 1 h, i, k, I and 19 a, b, c), the
Foraminifera (PI. 18. fig. 24), and in the
Mollusca, in these instances being calcareous.

There can scarcely be doubt that spicula
are homologous with the elements of shell ;
but little or nothing is known of their deve-
lopment.

Spicula form very interesting microscopic
objects, on account of their remarkable
forms.

To prepare them, the animal substance
in which thev are contained should be

boiled with nitric acid if they are com-
posed of silex, and with dilute solution of
potash if they consist of lime-salts. They
may be preserved by mounting in Canada
balsam.

They are commonly met with in sea-mud.
SPIDERS. SeeARACHNiDAandEpEiRA.
SPILOCJEA, Fr.— A genus of Torulacei
(Coniomycetous Fungi). S. Pomi occurs
upon apples, in contiguous effused patches,
from which the epidermis separates in frag-
ments, exposing the simple globular spores,
adherent to each other and to the matrix.

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 360 ;
Fries, Summa Veget. p. 482.

SPINES, OF ANIMALS.— These are pro-
perly stout rigid and pointed processes of
the integument, formed externally by the
epidermis, and internally of a portion of the
cutis or corresponding structure; but the
term is frequently applied to stout rigid and
pointed processes of the epidermis only.

See HAIRS, and the notices of the struc-
ture of the integument under the heads of
the various classes.

SPIRACLES or STIGMATA of animals.—
The external orifices of the tracheae of insects
and Arachnida. The respiratory tubes of
these animals have no communication with
the mouth, but terminate externally in ori-
fices situated upon the surface of the thorax
or abdomen. These are mostly rounded or
eUiptical(P1.28. figs. 3,7, 8, & 9 a), sometimes
in the form of small clefts, and are often
furnished with a kind of moveable valve, or
bounded by a thickened rim ; sometimes a
sieve-like structure (PI. 27. fig. 34) prevents
the admission of foreign bodies, or they are
surrounded by hairs or scales, effecting the
same purpose.

They are often situated at the lateral and
upper portions of the abdomen, at the pos-
terior, lateral and upper part of the thorax,
&c.

See ARACHNIDA, INSECTS, and the heads
of the genera.

SPIRAL STRUCTURES, OF PLANTS.
— Among the most elegant of the microscopic
objects furnished by the Vegetable Kingdom
are the various forms of the secondary depo-
sits upon the walls of cells, vessels and ducts,
&c., which present the appearance of fibres
coiled into perfect spirals, or of spiral fibres
either with the coils detached and forming
rings, or with the coils more or less con-
nected by cross-pieces, producing a reticu-
lated structure,

Under the head of SECONDARY DEPOSITS

SPIRAL STRUCTURES.

[ 592 ]

SPIRAL STRUCTURES.

it is stated that this spiral-fibrous deposit may
be taken as the character of a group of struc-
tures to be contrasted with those structures
described as PITTED, and that the essential
distinction in the nature of these two groups
lies in the greater extent to which the pri-
mary wall is covered in the pitted structures.
This is not quite absolute in reference to all
spiral-fibrous structures, as in the true un-
rollable spiral vessels and similar organs the
coils of the spiral fibres are often closely in
contact, although not adherent to each other.
It has been stated that the various forms of
the open spiral, annular, and reticulated de-
posits are modifications of the simple close
spiral ; but this must be understood only in
a morphological sense, since there is no ac-
tual change of condition ensuing with age,
as has been assumed by some authors, the
fibrous layers being always originally depo-
sited on the primary wall in the form and
pattern which they ultimately possess. There
appears to be no real opening of the spirals
or breaking up into rings, in consequence of
the expansion of the primary wall to which
they are attached.

Fig. 664.

Fig. 665.

Fig. 664. Fragments of spiral vessels from the melon.
Magnified 200 diameters.

Fig. 66.5. Magnified diagram of a section of the base of
a leaf-stalk arising from a Dicotyledonous shoot, showing
the position of the spiral vessels in the leaf-stalk and next
the pith of the shoot, the spiral fibres being uncoiled and
a little drawn out.

It will be convenient, in the first place, to
speak of the distinct well-marked structures
ordinarily known as spiral cells and vessels,
occurring in the stems, leaves, &c. of the

higher plants, before describing certain other
forms found in special organs, and to reserve
to the end some points relating to the ulti-
mate constitution of the secondary mem-
branes of cells. Spiral structures are usually
divided into true spiral, annular, reticulated
and scalariform organs.

Spiral cells and vessels are perhaps the
most generally diffused of the forms. The
name spiral vessel is given to elongated cy-
lindrical cells tapering to a point at both
ends, with a spiral -fibrous deposit lining the
primary wall (fig. 664, and PI. 39. figs. 8, 11,
12) ; the spiral fibre may be either single, as
is most common, double (fig. 664), or a
number of fibres may run parallel (Musa,
Nepenthes, Zingiberacece, Marantacea).
These spiral vessels occur as the first vascu-
lar formation outside the pith (MEDULLARY
SHEATH) in almost all the Dicotyledons
(fig. 665), and as the first vascular formation
in the vascular bundles of the stems of
Monocotyledons ; also of all other vascular
bundles, forming the ribs or veins of petioles,
leaves, bracts, sepals, petals, &c. In the in-
ternal organs they can only be observed in
sections, or when extracted by maceration ;
in delicate vessels and petals they may often
be observed through the transparent epider-
mis. The coiled spiral fibre is mostly elastic
enough to bear stretching open like a wire
spring ; in this case the primary wall is torn
between the coils, and its ragged edges may
sometimes be detected. The uncoiled fibres
are often seen still unbroken, when a hya-
cinth or similar leaf is broken across and the
pieces gently drawn apart. Annular vessels
closely resemble the preceding, except that
the fibrous deposits are in the form of de-
tached rings (fig. 666) ; they are the rarest
forms ; they are especially remarkable in the
Equisetaceas. The reticulated, again, have
irregular spiral coils or rings connected more
or less by perpendicular or oblique bars (fig.
667, and PL 39. fig. 9) into a network ; these
two modifications are usually of larger dia-
meter than the true spiral vessel, and the
reticulated larger (of later origin also in the
organs) than the annular. However, mixed
forms occur not uncommonly, partly annular,
partly spiral or reticulated (fig. 668). They
are found in similar situations, but generally
do not extend into the more delicate organs.
Spiral, annular, and reticulated vessels may
be prepared in most beautiful forms and
large size from portions of the leaf-stalk of
rhubarb, of the stem of the garden balsam,
the melon, &c.

SPIRAL STRUCTURES.

[ 593 ]

SPIRAL STRUCTURES.

Spiral and other vessels are usually sim-
ple at first (branched spiral vessels do occur
more rarely), but ordinarily unite together

Fig. 666.

Fig. 667. Fig. 668.

Fig. 666. Fragment of an annular vessel from the
melon. Magnified 200 diameters.

Fig. 667. Portion of a reticulated vessel from the me-
lon. Magnified 200 diameters.

Fig. 668. Fraement of a spiral and annular vessel from
the melon. Magnified 200 diameters.

by a kind of fusion ; the conical extremities
overlap to a certain extent (fig. 664), and
thus the articulation is more or less oblique.
This fusion is much more evident and com-
plicated in roots, rhizomes, and abbreviated
stems, than in stems with developed inter-
nodes. The elementary cells are then gene-
rally much shorter, and the vessels formed
from them branch out in various directions
through the tissue. This is very well seen in
the roots of many herbaceous plants, such as
the dandelion, chicory, &c., and at the point
of origin of the vascular bundles of adventi-
tious roots generally.

The above-mentioned confluent spiral ves-
sels pass insensibly into the ducts, which are
similar confluent rows of cells forming parts
of the solid wood of stems, but composed of
cells with flat ends applied together. They
resemble in their markings the preceding
forms, but in their arrangement and consti-
tution they are closely associated with the
PITTED DUCTS. The scalariform vessels
or ducts (fig. 669, and PI. 39. fig. 10), so
called from the ladder-like markings, are a
very regular form of the reticulated type ;
this regularity appearing to depend, how-
ever, upon the relation between the mark-
ings and the adjacent organs. In the PITTED
DUCTS we find the pits only opposite to other
pits, therefore on the sides adjacent to other
ducts or to cells ; in the scalariform ducts a
spiral-fibrous deposit is conjoined into a net-

Fig. 669.

Fragments of scalariform
vessels from a Fern.

Magnified 200 diameters.

work by vertical fibres placed opposite the
intercellular passages or the meeting angles
of contiguous cells or ducts, leaving regular
slit-like spaces oppo-
site the cavities of the
adjacent cells. This
form is especially cha-
racteristic of theFerns,
but it occurs also com-
monly in the Dicoty-
ledons in a less re-
gular form, passing
quite insensibly into
PITTED DUCTS, as in
the wood oiEryngium
maritimum(PL 39. fig.
21). The scalariform
vessels of Ferns are
often slightly unrel-
iable.

It is mentioned un-
der PITTED STRUC-
TURES, also, that a
combination of the two
types sometimes occurs in the same cell.
This is the case in the ducts of the Lime,
Mezereon, and other plants (PI. 39. figs. 4,
13 & 19).

Besides the generally diffused spiral and
other vessels and ducts above described,
cells, properly so called, that is, such as
never become elongated very greatly in one
particular direction, belonging to particular
organs and plants, present the same kind of
markings. The ducts and vessels, indeed,
in many cases are formed of very short cel-
lular elements; but these may be distin-
guished from proper cellular tissue charac-
terized by spiral secondary deposits. Under
this head may be cited first certain wood-cells.
In the Cactacese, the prosenchymatous tissue
of the stem presents remarkable spiral and
annular cells, in which the fibre becomes so
much thickened that it projects like a ri-
band set with its edge against the cell-wall
(PI. 39. fig. 7). The wood of the Misletoe
(figs. 670, 671) also exhibits spiral-fibrous
cells ; that of the Yew (TAXUS) is composed
of true spiral-fibrous cells, and others with
bordered PITS and an internal spiral-fibre
in addition (PI. 39. fig. 4). In the stems of
the Leguminosae parenchymatous portions
occur in the midst of the wood, the cells of
which exhibit spiral fibres (Ulex, Spartium).
The cellular tissue near the surface of the
roots of the epiphytic Orchids (PI. 39. fig. 6)
affords another example, as also some of the
subepidermal cells of the leaves (fig. 672).

SPIRAL STRUCTURES.

[ 594 ]

SPIRAL STRUCTURES.

The layer of cells lining the ANTHERS of
Fig. 670. Fig. 671. Fig. 672.

Fig. 670. Annular-fibrous cell from the stem of Misle-
toe. Magnified 200 diameters.

Fig. 671. Cell intermediate between reticulated and
pitted, from the Misletoe. Magnified 200 diameters.

Fig. 672. Spiral-fibrous cell from the leaf of an Orchid.
Magnified 200 diameters.

Flowering plants are characterized by most
varied patterns of spiral markings (PI. 32.
figs. 1-5) ; in these cells, moreover, we some-
times see the connexion between the fibrous
and homogeneous deposits well illustrated,
as the cells may have one or more sides
marked with spiral fibres, while the remainder
of the wall is covered with a continuous
layer. A similar structure, generally with
perfect spiral fibres, occurs in the walls of
the sporanges of Jungermannia, Marchantia
(PL 32. fig. 35), and other Liverworts. With
these are nearly connected the structures
called ELATERS, which are found mixed
with the spores in the same plants. These
are tubular cells containing a single or dou-
ble elastic spiral fibre (PI. 32. figs. 36-38),
exactly analogous to the spiral vessel in
structure. Elaters of similar nature occur
even among the Fungi, as in the sporange
of TRICHIA (PL 32. figs. 39, 40). The ela-
ters of the Equisetaceaj (fig. 209, p. 242)
are of different character, consisting of four
short filaments with clavate ends, attached
at one side of the spore and originally coiled
round it, ultimately unrolling with elasticity.
They appear to be formed by the deposition
of a spiral-fibrous layer on the wall of the
parent-cell of the spore, within which the
true (single) spore membrane is formed, un-
adherent; and when the spore is ripe, the
spiral-fibrous layer splits up and starts away
from the inner coat. An elegant spiral and
annular fibrous structure is also met with in
the large cells of the leaves of the SPHAG-
NACE.E (PL 39. fig. 25); this is exactly
analogous to the similar deposits in the
higher plants. Spiral layers are found, less
distinctly, in the radical hairs growing from
the lower surface of the frond of MARCHAN-
TIA. Nageli regards them as folds of an

inner layer of membrane, but they appear to
be regular secondary deposits.

Lastly, the hairs and similar epidermal
appendages sometimes exhibit spiral-fibrous
deposits. An unreliable spiral fibre is beauti-
fully arranged in the cells forming the mealy
coating of the seed of Cobaa scandens (PL
21. fig. 20). The seeds of many of the
Acanthaceae (PL 2] . figs. 21 & 24), Collomia
(PL 21. fig. 22), the pericarp of some of
the Labiatae (PL 21. fig. 23), and Composite
(SENKCIO) bear tubular hairs, consisting of
cells with a spiral or annular fibre in their
interior (see HAIRS, of Plants). The struc-
ture of the hairs of Collomia, Ruellia, &c. has
been much discussed, but it seems very sim-
ple ; they appear to consist of a short tubular
cell, upon the wall of which a closely coiled
elastic spiral-fibrous layer is deposited;
during the ripening of the seed the primary
membrane undergoes a metamorphosis into
a substance related to amyloid (or bassorin?),
which softens and swells up when placed in
water, allowing the spiral fibre to extend
itself (PL 21. figs. 21, 22 b, c). Sulphuric
acid and iodine give the swollen gum-like
envelope a purplish tint.

Another and less distinctly marked spiral
arrangement of the substance of the cell-
walls, occurs in the form of cracks or gaps
in certain of the layers of the secondary de-
posits, running more or less round the cell,
appearing like irregular spiral streaks ; these
are sometimes present in the earlier second-
ary layers, and not in the later, so that the
"cracks" are covered in by the latter, and
converted into canals in the substance of the
cell-wall. These occur in the wood-cells of
Hernandia sonora, in the prosenchymatous
cells of the vascular bundles of Caryota
urens, Ph&nix, Metroxylon, and probably in
other cases. Something similar may be de-
tected in the wood-cells of Pinus (PL 39.
fig. 1), especially after treatment with boiling
nitric acid. In liber-cells a spiral texture is
far more generally evident. In Vinca, for
instance (PL 39. fig. 30), and other Apocy-
naceous plants, a delicate spiral striation of
the wall is evident in its natural state, beau-
tifully regular in its arrangement ; a similar
appearance may often be detected in the
walls of thickened hairs, especially when
acids are applied, as in Cotton (PL 21. fig.
1 b), particularly in gun-cotton (fig. 1 c) ;
sometimes with intermediate slits, as in Ur-
tica (PL 21. fig. 8), &c. ; and by boiling with
nitric acid, a minute spiral-fibrous structure
may be detected in the secondary layers of

SPIRAL STRUCTURES.

[ 595 ]

SPIRAL STRUCTURES.

the liber-cells of very many plants, as of
Flax (PL 21. fig. 2 b, c), Coir (PI. 21. fig.
5 a, b), Boehmeria (PL 21. fig. 2 6, c), &c.
All these spiral structures belong to the se-
condary deposits of the cells ; they are mostly
distinguishable from those previously de-
scribed by being thinner places or lines left
bare, instead of being lines of deposit.

We have observed a somewhat similar
spiral streaking of the walls of Hydrodictyon,
depending on slits in certain of the lamina?.
Some of the genera of Oscillatoriaceae, as
Ainactis (PL 4. fig. 15 b) and Schizosiphon
(PL 4. fig. 13, d, e), also present a spiral-
fibrous decomposition of their cellulose coats
when old ; and we have seen a spiral mark-
ing on the wall of Cladophora, as described
by Mitscherlich. Agardh has recently stated
that he detected a complicated spiral-fibrous
structure in the cell-wall of Confervae, ex-
tending, however, from one cell to another ;
and he regards this as a proof of the spiral
structure of primary cell-membrane gene-
rally ; and he says he has likewise detected
an analogous spiral-fibrous structure in the
primary cell-wall of the structures of the
Phanerogamia. With regard to the fibrillous
structure of the walls of the Confervoids,
this appears comparable with that we have
described in the liber-cells, especially of
Vinca ; and apparently a delicate spiral struc-
ture of this kind exists in all cell-membranes
which have received thickening layers ; but
in reference to the coarse interlaced fibrils
figured by Agardh, we believe there is an
error of observation. If cells of the fruit of
the white snow-berry (Symphoricarpus) are
allowed to dry upon a slider, they fall into
minute creases, often running spirally; if
boiled in nitric acid, they are cleared of ad-
hering protoplasm, &c., and minute creases
or folds of the same kind are produced in
greater abundance ; but a very careful exa-
mination and observation of the ends of the
folds, their irregular directions, &c., and
especially when coloured with iodine, has
convinced us that in this case no real spiral
structure exists, although at first sight the
appearance is very deceptive. These fine
folds must not be confounded with the deli-
cate striation above alluded to. As to this
striation, however, existing as it does so ge-
nerally, it raises an interesting question as
to whether the secondary membranes are
always composed of delicate fibrils. Criiger
asserts that they are, and declares that he
has resolved every form of secondary deposit
into primitive fibrils, in liber-cells, wood-

cells, parenchymatous cells, pitted cells, and
also the large fibres of the spiral vessels, Sec.,
the broken ends of which he represents as
split up into a kind of brush of fibrils ; these
however cannot be isolated so as to trace
their course ; and the most we can say is,
that the membrane often tears most readily
in the direction of the striae ; and in some
liber-cells, moreover, the secondary deposits
tear readily into perpendicular fibrils after
maceration (PL 21. fig. 26 c). The delicate
striation of the membranes of the Confervae
and slightly thickened liber- or parenchy-
ma-cells of many Flowering plants, form
a desirable object of investigation for those
accustomed to the delicate observation of
the markings of the valves of the Diatoma-
ceae. The use of reagents, such as nitric
acid and solution of potash, boiling, ma-
ceration, and other means must be employed
for this purpose, controlled always by a care-
ful observation of the structures in their
natural state and in different stages of de-
velopment. It is not impossible that all
secondary deposits may prove, as Meyen
assumed, to have a fibrous constitution, and
true membrane to be confined to the primary
walls. One set of layers, however, seem
always to resist the endeavour to resolve
them into fibrils, namely those of the horny
and fleshy ALBUMEN of seeds.

As to the mode of the formation of spiral
secondary deposits, little is certainly known
at present. Criiger attributes them to spiral
circulation of the secreting protoplasm over
the cell-wall in the position of the future
fibres. We believe this to be a somewhat spe-
culative notion. Others have asserted that
they are formed by gradual collocation of
visible granules; this is certainly an error.
We have observed the gradual formation of
the spiral band in the elater of Marchantia,
where it is at first a faint spiral trace with
indistinct edges; as it grows thicker, the
edges become more and more defined, and it
is produced originally in the exact position
and pattern which it subsequently retains.
Trecul has lately published an elaborate me-
moir, reviving an old notion that the spiral
and other fibrous markings are folds of mem-
brane thrown inwards from the cell- wall. We
believe this to be altogether a misconception.

The actively moving spiral filaments or
SPERMATOZOIDS of the Ferns, Mosses,
Characeae, &c., have nothing in common,
except the spiral form, with the structures
described in this article ; they belong to the
protoplasmic structures or cell-contents, as

SPIRILLINA.

[ 596 ]

SPIROGYRA.

is also the case with the spirally-arranged
green contents of SPIROGYRA ; while this
article refers exclusively to cellulose struc-
tures belonging to the cell-wall.

See also CELL,VEGETABLE, SECONDARY
DEPOSITS, PITTED STRUCTURES and TIS-
SUES, VEGETABLE.

BIBL. General works on Vegetable Ana-
tomy. Schleiden, Ann. Nat. Hist. vi. p. 35
(from the Flora, 1839), Taylor's Scient.
Mem. ii. p. 281 (from Mullens Archiv, 1838),
Principles, p. 42; Griffith, Ann. Nat. Hist.
x. p. 109; E. Quekett, Trans. Mic. Soc. i.
p. 1, Ann. Nat. Hist. xv. p. 495; Mohl,
Verm. Schrift. p. 285 (Ann. des Sc. nat. 2 ser.
xiv. p. 242), Vegetable Cell, London, 1852,
p. 14, Botan. Zeitung, xi. p. 753 (1853),
Agardh, De Cell. Vegetab. Lund. 1852;
Cruger, Botan. Zeit. xii. pp.57, 833 (1854),
xiii. p. 601 (1855); Caspary, Bot. Zeit. xi.
p. 801 (1853) ; Trecul, Ann. des Sc. nat. 4
ser. ii. p. 273 ; Schacht, Pflanzenzelle, Berlin,
1852, Bot. Zeit. viii. p. 697 (1850) ; Unger,
Linncea, xv. p. 385 (1841); Meyen, Pflan-
zenphysiologie, i. ; Mitscherlich, Ann. Nat.
Hist. ser. 2. i. p. 436.

SPIRILLINA, Ehr.— A doubtful genus
of marine Infusoria, of the family Arcellina.

Char. Shell siliceous, porous, forming a
flat spiral.

S. vivipara. Shell microscopic, hyaline,
smooth, containing numerous embryo shells.
Found in America.

BIBL. Ehrenberg, Abhandl. d. Berl.Akad.
1841.402,422.

SPIRILLUM, Ehr.— A genus ofVibrionia.

Char. Consisting of a colourless, tortuous,
contractile, but not extensile filament or cy-
lindrical spiral.

These organisms, found in infusions and
decomposing liquids, are very interesting
objects on account of the remarkable cha-
racter of their corkscrew-like movements.
They multiply by transverse division, sepa-
rating into two portions while in motion.
They are jointed (or septate ?), but the joints
are not always easy of detection. They are
insoluble in boiling potash. Their structure
is best examined when they are preserved in
a dry state. It is difficult to know where to
place them in a system, but they are appa-
rently nearest related to the Oscillatoriaceous
Algae. They are very different, however,
from SPIRULINA, to which they have been
compared. Spirillum bryozoon consists of
the spermatozoids of Mosses.

1. S. tenue. Filament slightly tortuous,
indistinctly jointed ; spiral of three or four

turns; movement active; length 1-1000";
diam. 1-12,000".

2. S. undula. Filament very tortuous,
distinctly jointed ; spiral of one or one and a
half turns; length 1-1500"; diam. 1-20,000".

3. S. volutans (PL 3. fig. 23). Filaments
very tortuous, distinctly jointed; spiral of
three, four, or more turns; length 1-1400";
diam. 1-14,000".

4. S.plicatile (Spirochceta plicatilis, Ehr.)
(PL 3. fig. 22). Filament very long; coils
very numerous ; movement undulating ;
length 1-180"; diam. 1-12,000".

BIBL. Ehrenb. Infus. p. 84 ; Dujardin,
In/us, p. 223.

SPIROCH^TA, Ehr. S. plicatilis =
Spirillum plicatile.

SPIROCHONA., Stein.— A genus of In-
fusoria, of the family Vorticellina.

5. gemmipara (PL 25. fig. 35) is found
upon the branchial plates of Gammarus pu-
lex, where also its remarkable Adneta-form
(PL 35. fig. 36) occurs.

S. Scheutenii is met with upon the feathery
setae arising from the terminal joints of the
post-abdominal legs of Gammarus.

BIBL. Stein, Die Infus.

SPIRODISCUS, Ehr.— Under the name
S. fulvus, Ehrenberg places among the Infu-
soria, in the family Vibrionia, a brownish
organism, consisting of a short discoidal or
much flattened helical spiral, 1-1200" in dia-
meter, and found in Siberia. It exhibited a
slow movement. Ehrenberg's figure greatly
resembles that in PL 32. fig. 34 (the upper
two), without the cilia, and magnified 200
instead of 400 diameters.

BIBL. Ehrenberg, Infus. p. 86.

SPIROGYRA (Zygnema, Agardh in part)
(fig. 673). — A genus of Zygnemaceae(Confer-
void Algae), mostly very elegant and all very
interesting on account of their structure and
modes of development. They are green
filaments, floating unattached in standing
fresh water. They consist of jointed tubes
(that is, rows of cylindrical cells), sometimes
of considerable size, in the interior of which
the green colouring matter is arranged in
one or more spiral lines running round the
walls, these spiral lines presenting bright
points at intervals along their course (PL 5.
figs. 17, 26, 27). The green lines consist
of bands of protoplasm coloured green by
chlorophyll; the bright points are in some
stages composed of globules of similar sub-
stance, but generally they are occupied by
starch-granules imbedded in the protoplasm;
smaller starch-granules also occur at certain

SPIROGYRA.

[ 597 ]

SPIROGYRA.

Spirogyra communis.

Fragments of two

filaments conjugating.

Magnified 200 diameters.

The laminated struc-

stages throughout the green band. A remark-
able lenticular nucleus
is also present sus- Fig. 673.

pended in the centre of
the cell by threads of
protoplasm running
out to the primordial
utricle lying against
the cell- wall. Some-
times this nucleus is
placed with its faces
towards the side wall
(S. nitida, PL 5. fig.
26), sometimes it ap-
pears to be placed with
its faces looking up
and down, as it pre-
sents the appearance of
a narrow ellipse when
seen sideways (S. pel-
lucida, PL 5. tig. 27).
ture of the cell-walls is also curious, but
will be better understood after a sketch of
the mode of development.

The attractive appearance of the Spiro-
gyrcB and the easily observed phenomenon of
conjugation have caused much attention to
be paid to this genus, and many points of
their history have been determined. The
cells composing the filaments all multiply
simultaneously when the plant is growing,
each becoming twice its length and dividing
into two. It has been certainly observed by
A. Braun and Pringsheim that the division
is preceded by a division of the nucleus.
From this interstitial mode of growth it is
evident that the walls of the cells of plants
actively vegetating must soon become com-
posed of a number of layers belonging to
distinct generations of cells. Thus, supposing
we have an original cell a, this encloses its
progeny, two cells a2 & b, and when these
divide again and come to enclose respectively
a3 & c and V* & d, the parent-cell a,
stretched to four times its original length,
still encloses the whole. The laminae belong-
ing to the respective generations do not
become very intimately blended, for by ma-
ceration we may cause the outer membranes
to soften and dissolve, and set free the
younger cells intact. The older membranes
seem to have become thinner by stretching,
or by solution, midway between their septa,
since on maceration we may often see them
give way in the middle, and the young cells
slip out from them, leaving them as short,
hyaline tubes with a diaphragm in the middle.
The ends of the cells of some species gene-

rally present a curious appearance, which
might be compared with the " punt " of a
bottle, only it is a circular fold thrown in
from the cross septum. It is attributed to
the excessive growth of the membrane of the
young cells, confined in space by the outer
parent-membrane. The filaments of Spiro-
gyra are consequently very instructive in
reference to vegetative cell-formation. In
some cases the half-dissolved parent cell-
membranes form a delicate, but well-defined
gelatinous coat on the tube (PI. 5. fig. 27 s).
The reproduction of this genus exhibits,
besides the proper conjugation, other phaeno-
mena, the import of which is not yet fully
determined. The conjugation itself has been
observed by almost every microscopist. It
consists essentially here in the production of
papillary elevations on the contiguous walls
of the cells of two filaments lying side by side ;
the growth of these papillae until they come in
contact ; and their coalescence so as to form
a canal of communication between the two
cells (fig. 6/3. PL 5. fig. 18). When this is
accomplished, the contents of one of the
cells (the contents of both having meanwhile
lost their characteristic arrangement on the
cell -walls) pass over through the cross tube
into the other cell, when the contents of
both become blended and form an elliptical
free body (PL 5. fig. 18), which acquires
cellulose integuments and becomes a spore,
lying free in the parent-cell. This process
is accompanied by the death of the parent-
filaments, conjugation often taking place in
the majority of the cells; the spores are
sometimes set free by decay of the parent
cell-wall, but very often the latter remain
undissolved until the germination of the
spore (PL 5. fig. 19). A modification of this
mode of conjugation takes place in some
cases, apparently as an abnormal process, for
it has been observed (Braun) taking place in
those species which conjugate as above. It
occurs in solitary filaments, in which two
contiguous cells produce papillae at the ad-
joining ends, growing towards each other
and coalescing, the contents of one of the
cells thus passing into the next cell of the
same filament. A. Braun calls this " chain-
like" conjugation, in contradistinction to
the "ladder-like" conjugation above de-
scribed. As it occurs associated with this,
Kiitzing's genus Rhynchonema, founded upon
it, cannot stand.

The ripe spore presents the appearance of
j an elliptical body enclosed in three membra-
j nous coats, the outer of which is of delicate

SPIROGYRA.

[ 598 ]

SPIROGYRA.

texture and separated by an interval from
the next, which is brownish and of firm tex-
ture. The inmost coat, or true spore-mem-
brane, is again delicate. The spores appear
to rest through the winter after they are
formed and to germinate in spring, in which
process the middle coat of the spore splits at
one end, longitudinally, opening by two
valves to allow the inner to grow forth,
which bursts through the outermost sac, in
the form of a tube (PI. 5. fig. 19) which
soon acquires the characteristic appearance
of the parent plants. The contents of the
spore are brown and homogeneous during
the stage of rest (fig. 21); in germination
they become green again, and arrange them-
selves in the spiral bands (fig. 22), which
become more distinct as the cell elongates.

Certain other occurrences take place in
the cell-contents of the Spirogyrce, the rela-
tion of which to the reproduction is not so
clear as the above. In filaments in an un-
healthy condition, about to die, such as are
often seen when a collection of them is placed
in a jar of water to keep for examination, it
is not uncommon to see the green contents
gradually lose their spiral arrangement, and
break up into a number of globular portions
(PI. 5. fig. 28). We have sometimes ob-
served these rolling over slowly in the cell.
In one case we have observed the contents
converted into sixteen distinctly organized
biciliated zoospores (PI. 5. fig. 20), differing
only from the ordinary zoospores of the
Gonfervoids in the almost total absence of
colour. They were somewhat crowded in
the cell, and moved lazily about in it, the
cilia vibrating. It is still more common to
observe the contents of decayed filaments
converted into encysted globules (PI. 5. figs.
24, 25), which would appear to be a kind of
resting-form of the zoospores. These glo-
bules, which have a tough spinulose coat,
have been observed by Pringsheim as pro-
duced from the contents both of ordinary
cells and (abnormally ?) from the contents of
a large spore (PI. 5. fig. 23) : the latter case
might give colour to the idea that this was
a sporange, had not its germination been
observed. Pringsheim has further noticed
that actively moving zoospores are produced
from the small encysted bodies; perhaps
these may fulfil an antheridial function. We
are compelled to treat thjs subject some-
what briefly, but must direct attention to the
relations of the CONJUGATION to that of
the DESMIDIACE^, and those of the large
spores and smaller globules to the similar

bodies in the Desmidiaceae and in the Vol-
vocineae, as well as in the other Confer-
voids.

The species of Spirogyra have been greatly
multiplied by authors. The peculiar fold
projecting from the septum appears to us to
depend upon age and activity of growth ;
and the length of the joints depends greatly
on the stage of growth, as they continually
divide into two equal parts.

Spiral band single.

1. S. tenuissima. Vegetating filaments
1-3000" in diam.; joints four or five times
as long; spiral band open; spore oblong -
elliptical (Hassall, pi. 32. figs. 9, 10).

2. S. longata. Filaments about 1-1000''
in diam. ; joints six or eight times as long ;
spiral lax; spores oblong-elliptical (Hass.
pi. 31. fig. 394, pi. 28. figs. 3, 4?).

3. S. inflata (S. gastroides, Kiitz.). Fila-
ments 1-1680" in diam.; joints four or five
times as long ; turns of spiral about five ;
fertile cells ventricose ; spores oblong-ellip-
tical (Hass. pi. 32. figs. 6, 7).

4. S.communis(fig.673). Filaments 1-1 440
to 1-1200" in diam.; joints two or three
times as long ; turns of spiral four, broad ;
spores elliptical (Hass. pi. 28. figs. 5, 6).

5. S. quinina (PI. 5. fig. 17). Fila-
ments 1-600" in diam.; joints one and a
half or two times as long; turns of spiral
broad and dense; spores elliptical (Hass.
pi. 28. fig. 2). Varies to some extent in the
length of the joints, which are sometimes
two to seven times as long.

Spiral bands two.

6. S. decimina. Filaments 1-720" in
diam. ; joints two or four times as long ;
spiral bands lax, crossing so as to present
the appearance of a row of the letter X
(Hass. pi. 23. figs. 3, 4).

7. S. elongata. Filaments 1-1320 to
1-1200" in diam. ; joints ten times as long;
spiral bands lax (Berkeley, Gleanings, p. 12.
fig. 2).

Spiral bands numerous.

8. -S. nitida (PL 5. fig. 26). Filaments
1-360" in diam.; joints twice or three times
as long ; spiral bands four, dense, closely
veiled ; spores elliptical (Hass. pi. 22. figs.
1,2).

9. S. maxima. Filaments 1-200 to 1-300"
in diam. ; joints equal, one and a half times
or twice as long; spiral bands lax; spores
globular (Hass. pi. 18, 19).

SPIROSTOMUM.

[ 599 ]

SPIRULINA.

10. S. bellis. Filaments 1-480" in diam.;
joints equal or twice as long ; spiral bands
two or three, lax ; spores somewhat glo-
bose; var. /3, spirals condensed (Hass.
pi. 24).

11. 8. pelludda. Filaments 1-840" in
diam. ; joints four or six times as long ; spi-
ral band lax and slender ; fertile cells ven-
tricose; spore globose (Hass. pi. 25).

12. S. rivularis. Filaments 1-2040" in
diam. ; joints three or four times as long ;
spiral bands four, broad, dense (Hass. pi.
27).

13. S. curvata (Sirogonium sticticum and
breviarticulatum, Kiitz.). Filaments 1-720"
in diameter, joints four or five times as
long ; spiral bands three or four, slender ;
conjugation direct, without a cross branch,
approaching Mougeotia (Hassall, pi. 26.
figs. 1, 2).

BIBL. Hassall, Brit. Freshw. Alg. p. 135;
Kiitzing, Sp. Alg. p. 437, Tab. Phyc. v. ;
Pringsheim, Flora, xxxv. p. 465. 1852 (Ann.
Nat. Hist. ser. 2. xi. p. 210); Al. Braun,
Verjungung (Ray Soc. Vol. 1853, passim) ;
Meyen, Pflanzenphysiologie, iii. p. 422 ;
Vaucher, Conferves, p. 37; Agardh, Ann. des
Sc. nat. 2 ser. vi. p. 197.

SPIROSTOMUM, Ehr.— A genus of In-
fusoria, of the family Trachelina.

Char. Body ciliated all over, oblong or
cylindrical and elongated, without a neck ;
mouth spiral, with neither teeth nor a tre-
mulous lamina.

S. ambiguum (PI. 24. figs. 77, 78). Body
cylindrical and elongated, colourless, obtuse
in front, truncate behind, prolonged ante-
riorly beyond and above the mouth. Aqua-
tic; length 1-12".

8. virens. Body oblong, green. Aquatic ;
length 1-120".

Dujardin gives the characters : — Body cy-
lindrical, greatly elongated, and very flexible,
often twisted, covered with cilia arranged
upon the oblique or helical striae of the sur-
face; mouth situated laterally beyond the
middle, at the end of a row of larger cilia.
The genus consisting of S. ambiguum, E.
and S. ( Uroleptus, JZ.Jfilum ; S. virens being
placed as Bursaria spirigera.

BIBL. Ehrenberg, Infus. p. 332; Dujardin,
In/us, p. 514.

SPIROT.ENIA, Breb.— A genus of Des-
midiaceae.

Char. Cells single, elongated, cylindrical
or fusiform, straight, entire, not constricted,
ends rounded ; endochrome spiral.

Division oblique. In one species the

endochrome is spiral at first, subsequently
becoming uniform.

S. condensata (PI. 10. fig. 59). Endochrome
forming a single broad band. Length 1-208".
Common.

S. obscura. Endochrome at first forming
several spiral threads, afterwards uniform.
Length 1-240".

BIBL. Ralfs, Brit. Desmid. 178.

SPIRULINA, Link.— A genus of Oscilla-
toriaceae (Confervoid Algae), consisting of
minute spirally coiled filaments immersed in
a gelatinous matrix, having an oscillating
motion; forming extensive strata in lakes,
brackish water, &c. The intimate structure
and development of these curious organisms
are not yet well understood ; they are sup-
posed to increase by the filaments breaking
across ; in some the filament appears conti-
nuous ; in others it has striae, like the Oscilla-
torieae (appearing beaded when badly defined).
It does not appear that Ehrenberg' s and
Dujardin's genus SPIRILLUM consists of
species referable to this genus. Several
British species are described.

1. S. Jenneri (PI. 3. fig. 16). Filaments
with striae, 1-6000" in diameter, usually of
eight or ten coils, forming a thin aeruginous
stratum.

2. S. (?) Thompsoni. Filaments striated,
of rarely more than four coils, then about
1-50" in length (from the figure, the diame-
ter would appear to equal 1-2000" at least),
forming a greenish, then pale blue, finally
ferruginous stratum. Anabaina spiralis,
Thompson, Ann. Nat. Hist. v. p. 84.

3. S. tenuissima. Filaments not striated,
with close coils; coils 1-9500" in diam.,
pale aeruginous, forming a pellicle of a rich
green colour, ultimately ferruginous (Ralfs,
Ann. Nat. Hist. xvi. pi. 10. fig. 1 ; Harvey,
Brit. Mar. Alg. pi. 27 C). In brackish
pools.

4. S. Hutchinsice. Filaments not striated,
with close coils ; coils from 1-9600 to 1-1080"
in diam. ; forming an aeruginous stratum in
the sea (Kiitzing, Tab. Phyc. i. pi. 37. fig. 2).

5. S. oscillarioides (PI. 3. fig. 15). Fila-
ments not striated; coils 1-7200" in diam.;
lax. Among Oscillatoriae in stagnant pools.

Spirillum minutissimum and rupestre,
Hassall, probably belong here; but the former
may be Spirillum volutans of Ehrenberg.
These organisms require further investiga-
tion.

BIBL. Kiitzing, Sp. Alg. p. 236, Tab.
Phyc. i. pi. 37 ; Hassall, Brit. Fr. Alg. p.
277. pi. 75 ; Harvey, Brit. Mar. Alg. p. 229.

SPLACHNACE^.

[ 600 ]

SPLACHNACEJ3.

pi. 27, Phyc. Brit. pi. 105 ; Thompson, Ann.
Nat. Hist. v. p. 81; Ralfs, Ann. Nat. Hist.
xvi. 308, 2nd ser. viii. p. 205.

SPLACHNACEJE.— A tribe of Funa-
rioideae, Acrocarpous operculated Mosses, of
broad and densely tufted habit, mostly found
upon dung, with a very much branched,
loosely-leaved stem (fig. 674). Inflorescence
hermaphrodite, dioecious, rarely monoecious.
Antheridial flower a capituliform, terminal
bud. Antheridia large, club-shaped, rather
curved. Archegonia narrow, long-apiculate.
Peristome, if present, of regularly lanceolate,
neither obtuse nor trabeculate, twin, rufes-
cent, rather fleshy teeth. Columella ordi-
narily projecting (fig. 675). Capsule on an
apophysis (fig. 678), mostly furnished with
stomates.

British Genera.

I. (EDIPODIUM. Calyptra soft, longish-
n arrow, split almost to the summit, obtuse,
somewhat lacerated at the base. Capsule
subglobose, very loosely reticulated, soft,
with a very long collum arising from a gra-
dually thickened fruit-stalk, the mouth
naked. Columella dilated at the apex. In-
florescence monoecious.

II. TETRAPLODON. Calyptra smallish,
hood-shaped, split to the middle, operculate,
delicate. Capsule apophysate, oval-cylin-
drical. Apophysis obconical, obovate or
subovate. Columella scarcely dilated at the
apex. Peristome of sixteen double teeth
approximated in fours, lanceolate, formed of
two rows of cells, connate in pairs at the
base,reflexed when dry, erect, incurved when
moist, much shorter than the capsule. An-
theridial flower sessile in the axil of a leaf
or terminal in a little special branch, in a
capituliform bud.

III. TAYLORIA. Calyptra inflatedly co-
nical, erect, split at one side, constricted at
the base, lacerated or erose all round the
margin. Peristome arising below the orifice
of the capsule, of sixteen and thirty-two
teeth, teeth single, approximated in pairs or
coherent, often very long, when moist in-
curved and involuted, when dry (in the ripe
capsule) reflexed, appressed to the capsule
or tortuously bent down, very hygroscopic.
Inflorescence monoecious. Columella mostly
free, exserted from the ripe capsule, flattish-
apiculate.

IV. DISSODON. Calyptra inflatedly co-
nical, erect, slit at one side, constricted at
the base and torn or erose. Peristome arising
at the orifice of the capsule. Teeth thirty-

two, connate, in eight bigeminate or sixteen
geminate teeth, lanceolate, smooth, trans-
Fig. 674. Fig. 675.

Fig. 676. Fig. 677.

Fig. 678.

Splachnum vasculosum.

Fig. 674. Nat. size.

Fig. 675. Ripe capsule open, dried, and the apophysis
shrivelled. Magnified 20 diameters.

Fig. 676. Calyptra. Magnified 20 diameters.

Fig. 677. Young capsule and apophysis. Magnified 20
diameters.

Fig. 678. Vertical section of an unopened capsule with
its spongy apophysis. Magnified 20 diameters.

versely articulate, connivent into a depressed
cone when moist, subincurved when dry.
Inflorescence perfect or monoecious. Colu-
mella included or exserted, flattish.

V. SPLACHNUM. Calyptra conical, rather
small, entire or slit here and there at the
base. Peristome of sixteen teeth, composed
of a double row of cells, lanceolate, largish,

SPLACHNUM.

[ 601 ]

SPLEEN.

yellowish, approximated in pairs and to some
extent conglutinated, when dry reflexed and
appressed to the capsule, when moist erect
and incurved at the apex. Inflorescence
dioecious, rarely monoecious. Columella
ordinarily emerging, capitate.

SPLACHNUM, Linn. — A genus of
Splachnacese (Acrocarpous operculate Moss-
es), remarkable for the large apophysis,
often umbrella-shaped. /S. ampullaceum,
Linn., not uncommon on the dung of ani-
mals on bogs, is a very handsome moss, with
purple or red capsules. S. vasculosum (figs.

Fig. 679.

674-678) is less common, occurring only in
high mountain districts.

SPLEEN. — This organ appears to occur
exclusively in the Vertebrata. The spleen
is covered externally by the peritoneum, ex-
cept at the hilus, where the vessels are con-
nected with it.

Beneath the peritoneal tunic is a thin,
semitransparent, firm, fibrous coat, which at
the hilus accompanies the vessels, and forms
sheaths around them.

The spleen is traversed by fibrous pro-
cesses, bands or trabeculse (fig. 679), which

Fig. 680.

Fig. 681.

Fig. 679. Natural size. Portion from the middle of the spleen of an ox, washed ; showing the bands and their
arrangements.

Fig. 680. Peculiar fibres from the pulp of the human spleen, belonging to the microscopic trabeculse. Magnified
350 diameters.

Fig. 681. One of the same enclosed in a cell. Magnified 350 diameters.

Fig. 682. Portion of a small artery from the spleen of a dog, with one of the branches covered with Malpighian bodies.
Magnified 10 diameters.

Fig. 683. Malpighian corpuscle from the spleen of an ox. a, wall of the corpuscle ; b, contents ; e, wall of the artery
upon which it is situated ; d, its sheath. Magnified 150 diameters.

SPLEEN.

[ 602 ]

SPONGLE.

arise from the inner surface of the fibrous
coat and from the outer surface of the vas-
cular sheaths; and being connected with
each other, form a number of irregular
meshes or areolae, in which are situated the
splenic corpuscles and the spleen-pulp.

The fibrous coat and the trabeculse consist
of ordinary areolar tissue, with mostly
parallel fibres, traversed by networks of fine
elastic fibres. In certain animals, as the
dog, cat, pig, &c., the fibrous coat and tra-
beculse contain also unstriped muscular fibres.
These do not occur in man, unless they are
represented in the microscopic trabeculse by
peculiar wavy fibres, about 1-500" in length,
with lateral or stalked nuclei (fig. 680).
Some of these are found enclosed in cells
(fig. 681), from which they become liberated
by the action of water.

The splenic or Malpighian corpuscles
(fig. 682) are white rounded bodies, imbedded
in the spleen-pulp, and attached to the
smallest arteries. They vary in size from
l-120to l-36",and cannot always be detected.
They are either placed upon the sides of the
arterial branch, or situated in the angles of
their bifurcation.

The splenic corpuscles consist of an enve-
loping membrane (fig. 683 a) composed of
areolar tissue, with fine reticular elastic
fibres, and derived from the arterial sheath.
They are traversed by capillaries and filled
with a tenacious gray mass, consisting of an
albuminous liquid, with cells 1 -3000" in dia-
meter, containing one or two nuclei, and free
nuclei (fig. 108, p. 114). Sometimes the
cells contain globules of fat or blood-cor-
puscles, and occasionally free blood-corpus-
cles are met with.

The spleen-pulp forms a soft reddish mass
and consists of three elements, microscopic
trabeculae, fibres or bands, parenchyma-cells,
and the smaller blood-vessels. The trabeculae
agree in structure with the larger ones. The
fibres or bands are the terminations of the
sheaths of the vessels ; they are indistinctly
fibrous and free from elastic tissue. The
parenchyma-cells resemble those in the
splenic corpuscles. Extravasated blood is so
frequently met with in the parenchyma that
its presence may be regarded as normal, and
the blood-corpuscles are found enclosed in
cells, from one to twenty in each, or sur-
rounded by a transparent substance, their
contents exhibiting various changes in colour
and consistence. The arteries terminate in
elegant tufts or penicilli, becoming conti-
nuous with a mesh-work of capillaries.

The blood-corpuscles from the blood of
the splenic vein frequently contain crystals
of hsematoidine.

In the examination of the spleen, the tra-
beculse are best seen after washing away the
pulp with water ; the splenic corpuscles by
tearing the spleen, or boiling it ; either in
the pig or ox. The cells containing blood-
corpuscles must be searched for in the pulp
unacted upon by water. The muscular fibres
are most evident in the smaller trabecula?,
especially after treatment with dilute nitric
acid (one part to five parts of water).

BIBL. Kolliker, Mikrosk. Anat. ii. 253,
and Todd's Cycl. Anat., fyc., art. Spleen-,
Gray, A. Cooper's Prize Essay, Saunders,
Goodsir's Annals of Anat. fyc. 1850. i. ;
Crisp, On the Spleen.

SPONGLE (Sponges).— An order of Ani-
mals, belonging to the class Protozoa.

Char. Form variable ; fixed by a kind of
root at the base, or encrusting; consisting
of a soft gelatinous mass, mostly supported
by an internal skeleton composed of reticu-
larly anastomosing horny fibres, in or among
which are usually imbedded siliceous or cal-
careous spicula; or sometimes the spicula
alone form the skeleton.

The horny fibres forming the skeleton of
sponges, which may be well seen in any
common sponge, are cylindrical, and va-
riously united, so as to form a coarse net-
work with roundish or angular microscopic
meshes. In addition to these generally dif-
fused meshes or intervals, large (to the naked
eye) rounded apertures (oscula) are scattered
over the surface of most sponges, leading
into sinuous canals permeating their sub-
stance in every direction; and between these
are other smaller apertures, just visible to
the naked eye, also the orifices of canals,
which traverse the substance and communi-
cate with the oscular canals.

In the living sponge this skeleton is co-
vered with a glairy or gelatinous, colourless,
amorphous substance, resembling that of
which the Amcebee are composed, but some-
times more liquid ; the proportion of which
is variable in the different genera. This
substance appears to be composed of minute
masses, those on the surface being furnished
with long and very slender vibratile cilia ;
and during life, by means of these, water
entering by the smaller apertures, and reach-
ing the oscular channels, is expelled from the
oscula in currents, which may be rendered
visible by sprinkling a little finely powdered
charcoal over them. If detached portions

SPONGLE.

[ 603 ]

SPONGIOLES.

of this gelatinous substance are examined
under the microscope, they exhibit Amoeba-
like processes in motion.

The fibres have been described as solid
and as tubular. Those of the common
sponges appear under the microscope to be
solid ; but when treated with sulphuric acid,
it is easily seen that they consist of two
parts, an outer tubular portion, which is
contracted in length by the acid, and an
inner cylindrical thread, which is not so con-
tracted, but usually becomes elegantly wavy
or spiral from flexion, frequently also partly
protruding from the cavity of the outer por-
tion in broken fibres, and resembling PI. 21 .
fig. 22.

The spicula are of various forms (PI. 37,
the lettered figures), and either scattered
through the substance, or arranged in bun-
dles forming spurious fibres; sometimes
projecting more or less from the surface
(PI. 37. fig. 8). In some sponges they are
absent, and in one genus they are replaced
by gravel. There is some obscurity about
the gravel, however, for its particles are de-
scribed as being uncrystalline, and as neither
siliceous nor calcareous !

In some sponges an external membrane is
present, and this has been observed to exhi-
bit a reticular or cellular appearance, from
the presence of fine reticular fibres.

Sponges are mostly marine, rarely aquatic.
In the natural state they possess lively co-
lours, which appear in some instances to
arise from the presence of granules of colour-
ing matter, probably chlorophyll, in others
from iridescence. They usually grow in
groups upon rocks, shells, polypes, sea-
weeds, &c.

A vascular system has been described as
existing in some marine sponges, consisting
of anastomosing tubes or vessels enclosed in
a membranous sheath surrounding the horny
fibres, and containing minute corpuscles.
We regard the existence of this system as
problematical.

Sponges appear to be propagated in three
ways : by division or the growth of detached
portions of the parent, which appears rather
probable than proved ; by the formation of
ciliated gemmules; and by the production
of internal oviform bodies, one kind being
analogous to winter-ova, and also called
geinmules.

The ciliated gemmules, which are not of
general occurrence, are yellowish, oval, nar-
rowed at one end, and covered, except at this
part, by vibratile cilia. They are mostly

formed in spring, and after swimming about
for a time, become fixed to some suitable
spot, and undergo development.

Of the other reproductive bodies, one
kind consists of roundish or ovate masses,
containing spicula, and resembling the parent
in structure, either lying loose in its sub-
stance or adherent to the horny fibres, and
escaping at its death and solution, to acquire
maturity.

The bodies resembling winter-ova are
round or ovoid, with a funnel-shaped de-
pression on the surface communicating with
the interior. At first these lie in a cavity
formed by condensed surrounding substance;
subsequently a membrane presenting a hexa-
gonal reticular structure is formed around
them, upon which a crust of spicula is after-
wards deposited. When expelled from the
body of the parent, they are motionless;
they then swell up, burst, and the minute
locomotive germs escape. These now ex-
hibit Amoeba-like processes, and take on an
independent life.

No nucleus has been detected in sponges,
the soft substance appearing to correspond
to cell-contents.

Sponges are probably nourished by en-
closing Algae, &c. in their substance in the
same manner as Amceba. This has been
seen to take place in the -case of the young
animals developed from the winter-ova.

The genera and species have been so
loosely and unintelligibly characterized, that
the descriptions would be useless to any
microscopic observer.

BIBL. Johnston, Brit. Sponges, fyc. ;
Grant, Edinb. New Phil Mag. 1827 ; Hogg,
Ann. Nat. Hist. 1841. viii. 3, and 1851. vii.
190; Bowerbank, Trans. Micr. Soc. 1840.
i.; Carter, Ann. Nat. Hist. 1848. i. 303, and
1849. iv. 81 ; Dobie, Ann. Nat. Hist. 1852.
x.317.

SPONGILLA, Lam.— A genus of fresh-
water sponges.

Two British species, S. fluviatilis and
S. lacustris.

Found attached to stones, old wood-work,
&c. in still or slowly running waters ; green
or grey.

See SPONGI.E.

BIBL. Johnston, Brit. Sponges, 149, and
the Bibl. therein.

SPONGIOLES.— Many works on vege-
table physiology still retain the old error
that the extremities of roots are devoid of
epidermis, and that the tissue then presents
an open spongy character, whence the name

SPONGIOLES.

[ 604 ]

SPORENDONEMA.

of spongloles applied to the absorbing apices
of roots. So far is this from being a correct
account of the conditions, that, in reality,
not only is the surface completely invested
with a continuous epidermis, but the grow-
ing point and principal absorbing surface is
found a little above the absolute extremity,
which is pushed forward by interstitial
growth. On the ends of many adventitious
roots (i. e. roots which break out from the
interior of stems), especially remarkable in
the Duck-weed, exists a kind of cap formed
of tissue rather denser than that of the sub-
stance of the apex of the rootlet. This cap
either separates above, when the root breaks
out, and is then carried forward (like the
calyptra on a moss-capsule) as a distinctly
defined cap, called a pileorhiza, or the dense
layer at the end of the root loses itself gra-
dually upward in the epidermis of the sur-
face of the roots (fig. 684). Many young

Fig. 684.

FP

C....

Longitudinal section of the rootlet of an Orchis.
C, C, Cellular tissue (cambium) in which development
is still going on. F P, Fibro-vascular bundles gradually
becoming organized from above downward.

Magnified 500 diameters.

roots, especially such as grow in a moist
medium, are clothed with numerous radicle
hairs, which on superficial examination might
lead to the idea that the end was of spongy
character. The cells of the extremities of
the aerial roots of Orchids, &c., and of va-
rious water-plants, contain sufficient chloro-
phyll to give them a green colour.

BIBL. Meyen, Pflanzenphysioloyie, ii.
p. 1 ; Trecul, Ann. des Sc. nat. 3 ser. vi.
p. 303.

SPORANGIUM and SPOROCARP.—
The term sporangium is applied to the
structure immediately enclosing the spores
of the Cryptogamia. The different forms
and conditions are describedunder the classes
of Flowerless plants. Sporocarp or spore-
fruit is the name given to the capsules or
similar organs which contain the sporanges
of the Marsileaceae (see PILULARIA).

SPORENDONEMA, Desm.— A supposed
genus of Sepedoniacei (Hyphomycetous
Fungi). It is a very common occurrence in
autumn, to find the house-fly, dead,adhering to
walls, window-panes, &c., firmly fixed by its
proboscis, and with its legs spread out ; thus
differing from dead flies in general, which
have the legs contracted. In about twenty-
four hours after death, a kind of fleshy
substance, of a white colour, is found in the
form of a ring projecting out between each
of the rings of the abdomen, and in a day
or two after, the whole will be found dried,
and the surface of the wall or glass lightly
covered in a semicircle, at about 1-2 to 1"
from the fly's abdomen, with a cloud of
whitish powder. The whitish fleshy sub-
stance is found on examination to consist of
a vast number of short erect filaments grow-
ing out from the interior of the fly's body,
between the rings ; these filaments contain
large oil-globules, often arranged in a row ;
and their having been mistaken for spores
gave origin to the name Sporendonema,
applied to this fungus. Cohn has lately
described its growth somewhat minutely,
and changed the generic name to Empusa,
or rather Empusina, the first of these names
being already occupied. He correctly states
that the vertical filaments terminate in the
abdomen in a continuous, often branched
tube, and consists therefore of a single tubu-
lar cell. The upper free end, however, be-
comes cut off by a septum, and the terminal
cell acquires a campanulate form and a
darkish colour ; when ripe, it is thrown off
with elasticity, and a number of these
form the white cloud above mentioned.
Cohn endeavoured in vain to make them
germinate, and nothing like them was found
in the cavity of the abdomen of numerous
flies, in which the filaments were traced in
their earlier stages. From our own observa-
tions, we rather incline to regard them as
peridioles or spore-cases, comparable per-
haps to that of Pilobolus ; or they may be

SPORES.

[ 605 ]

SPORES.

stylospores, like some of those of the Ure-
dinei, which after a stage of rest produce an
intermediate mycelial structure, and then
give birth to the ripe spores.

The most remarkable point about this fly-
fungus, to which, however, Cohn does not
allude, is the circumstance that when the
body of the fly with the rings of fungi freshly
developed, is placed in water, ACHLYA pro-
lifera is almost always, if not always, pro-
duced, and apparently from the filaments
which in the air produce the bell- shaped,
deciduous body above described. We find
the Achlya with its ciliated zoospores, and,
later, with its globular sporanges filled with
spores, apparently representing an aquatic
form of the Sporendonema or Empusina.

Several points require yet to be cleared
up, especially the ultimate history of the
spore-like body of the Empusina-form ; and
the relation between this plant and the
Achlya are not quite demonstrated,

A. Braun has detected another species on
the gnat (Culex pipiens).

Sporendonema Casei, Desrn., is referable
to TORULA.

BIBL. Berk. Brit. Flora, ii. pt. 2. p. 350;
Fries, Syst. Myc. iii. p. 435, Summa Veget.
p. 494; Varley, Trans. Mic. Soc. Lond. iii.;
Cohn, Nova Acta, xxv. p. 299 ; Berk, and
Broome, Ann. Nat. Hist. 2nd ser. v. p. 460.

SPORES, SPORULES, SPORIDIA, and
SPORIDIOLA. — A number of nearly con-
nected terms are applied to the various or-
gans which either really or apparently repre-
sent, in the Flowerless Plants, the seeds of
the Flowering classes. The names have
been mostly applied with a view of marking
slight distinctions between organs supposed
to be homologous. Of those placed at the
head of this article, the first only should be
retained, the second being merely a useless
diminutive of it, and the third and fourth
being superseded by the more definite no-
menclature now applied to the reproductive
bodies of the Cryptogamia.

It may be desirable perhaps here, if merely
for the sake of explaining the exact meaning
of words constantly used in this work, to
pass in review the various structures com-
prehended under the general name of Spore.

The definition of the word spore itself, as
commonly used, may be stated thus : — a re-
productive body, thrown off by a Flowerless
plant to reproduce its kind, and containing
no embryo at the moment when cast off by
the parent. It is evident from this how lax
is its application.

The highest of the Flowerless plants, the
Marsileacese and the Lycopodiacese, produce
two khids of spore, one destined to produce
spermatozoids, the other archegonia and
ultimately embryos growing up into new
plants. These are now sometimes distin-
guished as pollen-spores and ovule-spores or
oospores ; the latter are large sacs with com-
plicated outer membranes, the former simple
cells with a double coat, like pollen-grains
(see PILULARIA, ISOETES, and LYCOPO-

The Ferns and the Equisetacea? produce
only one kind of spore, a simple cell with a
double coat, the outer of which is generally
elegantly marked in the former (figs. 236-
239, p. 261), and is split up into elastic fila-
ments in the latter (fig. 209, p. 242). In
germinating, this spore produces a kind of
thallus (figs. 240-3, p. 262), on which an-
theridia and archegonia ultimately appear,
and an embryo is formed, fertilized, and de-
veloped (see FERNS and EQUISETACE^E).

In the above cases the spores are always
formed in sporanges of various kinds, deve-
loped directly from the axis or the leaves by
a process of vegetative growth.

In the Mosses and Liverworts the spores
are mostly of one kind (an obscurity exists
as to the nature of the difference between
the two kinds in SPHAGNACE^E), consisting
of a cell with a single or (generally) double
coat, like a pollen-grain. The spores, unlike
those above-mentioned, are formed in spo-
ranges which are the product of fertilized
archegonia, and more resemble the fruits of
Flowering plants. The spores of Mo
germinate by emitting the inner coat
a Confervoid filament
usually branches
and gives origin to
numerous stem-
buds. The spores
of the Liverworts
exhibit many modi-
fications in the first
stages of germina-
tion, as is illustrated 8P°res of a moss germinating.
by the accompany- Magn. 100 diams.

ing figures (figs. 686-688); the Marchan-
tiacese and other frondose kinds grow at
once into thalloid fronds (see MOSSES and
HEPATICACE^E).

The systematic position of the Characeae
is perhaps still an open question, but there
can be little doubt of the analogies between
these reproductive bodies and those of the
other Cryptogamia. There is no sporange

(fig. 685),
Fig. 685.

as
which

SPORES.
Fig. 686.

[ 606 ]

Fig. 687.

SPORES.

Fig. 688,

Pellia epiphylla. Preissia commutata. Blasia pusills

Spores of Hepaticacese germinating. Magnified 200 diameters.

here, nor apparently any archegonia. The
globule (figs. 125-6, p. 134) produces an-
theridia giving birth to spermatozoids. The
nucule (fig. 124, p. 133) appears to be a
spore (see CHARACE^E).

In the Lichens only one kind of organ
has been termed a spore, namely the repro-
ductive cells formed in the thecae (PI. 29.
figs. 6 82 12), which are known to reproduce
the plant when thrown off by the parent.
Two other kinds of body connected with the
reproduction do occur ; these, the gonidia\(Pl.
29. figs. 2, 3) and the spermatia (see LI-
CHENS), have fortunately obtained and pre-
served distinctive appellations. The spores
are simple cells or septate tubes with a dou-
ble membrane.

In the Algae much confusion still exists,
not only between different kinds of spore,
but even between spores and sporanges ;
and this is not easily cleared away, since in
certain cases the organs appear really capable
of serving as one or the other, according to
circumstances; the true spores are always
simple cells with a double or triple coat.

In the Florideae, the characters of the
structures seem pretty clear : we find spores
(fig. 698. p. 609), TETRASPORES (figs. 252-4,
p. 266) which appear to represent the go-
nidia of the Lichens, and spermatozoids (see
FLORIDE^E). Among the olive-coloured

sea-weeds (Fucoids), the FUCACE^B and
DICTYOTACE^E produce spores and sper-
matozoids ; but in the majority of the fami-
lies only a totally different mode of repro-
duction is known. The plants produce ovate
sacs (commonly called spores) and chambered
filaments ; from both are discharged actively
moving ciliated cells, corresponding exactly
to the ZOOSPORES of the Confervoids.
Thuret now regards the oosporanges and
trichosporanges (fig. 462, p. 424), as he calls
these sacs and filaments respectively, as
merely different forms of one kind of struc-
ture. But it seems possible that true spores
may be discovered; even indeed that the
oosporanges may be sometimes parent-cells
of zoospores and sometimes spores.

In the Confervoids we find true spores in
very many cases, produced generally after
some process of fertilization or of CONJU-
GATION, in special cells (fig. 673, and PI. 5.
figs. 16 & 18; PI. 6. figs. 1-5). But the
" spores" thus produced, while they some-
times germinate into new filaments, also
sometimes produce numerous bodies of dif-
ferent kind, connected in some way with
reproduction ; this is the case in SPIROGYRA
(PI. 5. fig. 23), perhaps also in CLOSTERIUM
and other instances. Besides the spores pro-
per, we have also in this family ZOOSPORES,
the actively moving ciliated bodies which are

SPORES.

[ 607 ]

SPORES.

Fig. 689.

regarded as gonidia,
and are further divided
into macrogonidia and
microgonidia (see HY-

DRODICTYON ), the

latter of which may
perhaps have the func-
tion of spermatozoids
(see SPH^EROPLEA
and VAUCHERIA).

In the Fungi the
greatest confusion ex-
ists in the nomencla-
ture. The Agarics and Nodularia spumigera.
their Congeners pro- Filaments with sporangial
duce free naked Cells cel^containing quaternate

at the tips of short fila- :M^-JMJ 200 ^eiers.
ments, whence they ul-
timately fall off, to reproduce the plant ; these
are called spores or sporules, or distinctively
BASIDIOSPORES (figs. 53-55, p. 77). There
is no essential difference between them and
the spores produced by the Hyphomycetes,
either singly or in rows or capitula (Bo-
TRYTIS, figs. 79, 80, p. 97, and figs. 690,
691, and PL 20. figs. 5, 6, 15, 16) at the
ends of erect filaments ; these again appear

Fig. 690.

Fig. 691.

Fig. 690. Mystrosporium Stemphylium, Corda (Stem-
phylium, Fries). Magn. 200 diameters.

Fig. 691. Stachyobotrys atra. Fertile filament with
heads of acrogenous spores. Magnified 200 diameters.

Fig. 692. A head of spores. Magn. 500 diameters.

to pass almost insensibly into the conidia or
reproductive cells produced by the breaking
up of the mycelium, either wholly or in part,
into free cells, capable of continuing the
growth (TORULA, PI. 20. fig. 7, and Oidium,
PI. 20. fig. 8) ; on the other hand, the sper-
matia (PI. 20. figs. 2, 3, 4), such as occur in
some of the Coniomycetous forms of the
Pyrenomycetous and Discoiuycetous Fungi,

are closely related, as far as structure goes,
to the conidia of Torula, &c. and the spores
of the Hyphomycetes ; while the stylospores
of the UREDINES and TREMELLINI pro-
duce bodies resembling them, and still more
like the basidiospores of the Agaricini. The
stylospores, another free form of spore, may
be regarded probably as compound organs,
formed of a row of cells contained in a per-
sistent parent-cell ; it is surmised that they
are merely metamorphosed asci (see SPH.IE-
RIA and STILBOSPORA, PL 20. figs. 25-8),
yet their mode of occurrence would lead
to the idea that they are a distinct kind of
organ. Lastly, we have the ascospores or
thecaspores (fig. 42, p. 66), closely resem-
bling those of the Lichens, consisting of
free cells with a double coat, developed free
in the cavity of a parent-cell or sac. In the
British Flora the terms sporule and spori-
dium are used synonymously in the sense of
spore, and are applied to basidiospores, asco-
spores, stylospores, and to the bodies (found
in Cytispora, Tubercularia, &c.) called by
Tulasne spermatia. The term sporidiola is
applied apparently to nuclei or granular
masses occurring in the cavities of spores,
or to the separate portions of contents of
imperfectly septate stylospores.

With regard to the homologies of the
above structures, the spermatia are supposed

Fig. 693.

Fig. 694.

Fig. 693. Leptotrichum glaucum. Free spores t
the filaments of the matrix. Magnified 200 diameters.

Fig. 694. Fusarium herbarum. Free spores resting on
the matrix. Magnified 200 diameters.

to represent spermatozoids ; the conidia are
regarded as corresponding to gonidia of
Lichens ; the stylospores are also connected
with these through the medium of the tetra-
spores of the Florideae.

In conclusion, a reference may be made
to descriptions and figures like those given
(figs. 693, 694) of free spores resting on the

SPORIDESMIUM.

[ 608 ]

SPOROCYBE.

matrix and among the filaments. Such
characters are totally out of date in the pre-
sent state of science, and simply serve as
indices of points requiring further investiga-
tion.

BIBL. See under the heads of the classes
of Cryptogamic Plants.

SPORIDESMIUM.— A genus of Toru-
lacei (Coniomycetous
Fungi), growing upon
bark, wood, &c. The
character of the spores
appears to vary in
different species ;

sometimes they are Sporidesmium paradoxum.

simply septate, some- Spore8 sessile on the matrix.

times cellular (fig. Magnified 200 diameters.

Fig. 695.

BIBL. Berk, and Broome, Ann. Nat. Hist.
2nd ser. v. p. 459 ; xiii. p. 460 ; Fries, Summa
Veg. p. 506; Corda, Icones Fung. i. ii. &c.;
Fresenius, Beitr. z~ Mycol. Heft 2. p. 50.

SPOROCADUS, Corda. See HENDER-

SONIA.

SPOROCHISMA, Berk, and Br.— A ge-
nus of Torulacei (Coniomycetous Fungi),
containing one species, S. mirabile, forming
a black velvety stratum on rotten beech-
wood.

BIBL. Berk, and Broome, Ann. Nat. Hist.
2nd ser. v. p. 461 ; Gardeners' Chronicle,
1847. p. 540; Fresenius, Beitr. z. Mycol.
Heft 2. pi. 6.

SPOROCHNACE.E.— A family of Fu-
coidese. Olive-coloured, inarticulate sea-
weeds, whose oosporanges and trichospo-
ranges are attached to external, jointed
filaments, which are either free or compacted
together into knob-like or warty masses.

Synopsis of British Genera.
* Spores attached to pencilled filaments is-
suing from the branches (Arthrocladiese).

I. DESMARESTIA. Frond solid or flat,
dichotomously branched.

II. ARTHROCLADIA. Frond traversed
by a jointed tube, filiform, nodose.

III. STILOPHORA. Frond filiform, tubu-
lar or solid, branched ; oosporanges and tri-
chosporanges arising from necklace-shaped
filaments collected in wart-like groups upon
the frond.

** Spores produced in knob-like receptacles
composed of whorled filaments compacted
together (Sporochnea?).

IV. SPOROCHNUS. Receptacles lateral,
on short peduncles.

V. CARPOMITRA. Receptacles terminal,
at the tips of the branches.

SPOROCHNUS, Ag.— A genus of Spo-
rochnaceae (Fucoid Algae), containing one
British species, S.pedunculatus, having a fili-
form, solid, cellular, main axis (containing a
central cord of dense tissue), bearing long
slender branches, clothed at intervals, ar-
ranged in a somewhat pinnate manner, with
elliptical fertile ramules, consisting of an
axis densely covered with whorled horizontal
branching filaments, bearing ovoid oospo-
ranges, and terminating in a deciduous pencil
of byssoid filaments. Main stem 6 to 8"
long, olive-brown, changing to yellow-green
on exposure.

BIBL. Harvey, Brit. Mar. Alg. p. 25.
pi. 5 A ; Greville, Alg. Brit. pi. 6 ; Thuret,
Ann. des Sc. nat. 3 ser. xiv. p. 238.

SPOROCYBE, Fries.— A genus of Dema-
tiei (?) (Hyphomycetous Fungi), growing on
dead sticks, decaying stems, &c., forming
usually a blackish stratum. Several British
species are recorded. They have a rigid,
septate, simple or branched peduncle, end-
ing with a capitate head clothed with spores
(figs. 696, 697). This genus is synony-

Fig. 696.

Fig. 697.

Sporocybe bulbosa.

Fig. 696. Stratum upon a stick. Nat. size.

Fig. 697. Two fertile peduncles, crowned with heads of
spores. Magnified 100 diameters.

mous with Periconia, Corda. Periconia,
Tode, is an obscure form, not well under-
stood.

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 333,
Ann. Nat. Hist. vi. p. 433. pi. 13 ; Fries,
Summa Veget. p. 467, Syst. Mycol. iii. p.
340.

SPOROTRICHUM.

[ 609 ]

STAMENS.

SPOROTRICHUM, Link.— A genus of
Mucedines (Hyphomycetous Fungi), grow-
ing on decaying vegetable substances, dung,
&c. The forms referable to this genus, ac-
cording to the character, include a very he-
terogeneous assemblage; indeed, the charac-
ter, which omits the nature of the original
attachment of the spores, is worth nothing.
Fries has separated a genus TRICHOSPO-
RUM, including a number of species with
distinctly acrogenous spores; this includes
S. nigrum and S. geochorum of the Brit,
flora. The remainder are placed by him
among the Sepedoniei, under Sporotrichum
and another genus which he calls Physo-
spora. These genera are very obscurely
known, so much resembling mycelia with
detached conidia scattered on them.

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 346 ;
Fries, Summa Veg. p. 492. 495. 521 ; Gre-
ville, Sc. Crypt. Flor. pi. 108. figs. 1, 2.

SPUMARIA, Pers.— A genus of Myxo-
gastres (Gasteromycetous Fungi), the peridia
of which are divided internally into chambers
by ascending folds, which in S. alba are
either sessile and pass above into torn white
laminae, or are stipitate and divided, and
form corniculate peridioles bursting above ;
the latter is probably the perfect form. The
whole plant looks at first like white froth ;
it grows on grasses, &c., generally at a little
height from the ground.

BIBL. Berk. Brit. Fl. ii. pt. 2. p. 309;
Greville, Sc. Crypt. Fl. pi. 26? ; Sowerby,
Fungi (Reticularia), pi. 280 ; Fries, Summa
Veg. p. 449.

SPUTUM. — We omitted to notice under
EXPECTORATION the occurrence of fibri-
nous casts of the smaller bronchi and pul-
monary air-cells in the expectoration of
pneumonia. They are best seen on mixing
the sputa with water, forming dichotomous
cylinders with rounded enlargements. They
consist of fine filaments, and are mostly co-
vered with granule-cells ; and are generally
met with between the third and the seventh
day.

BIBL. Rernak, Diagnost. u. Pathognet.
Untersuch., fyc.. abstract in Edinb. Monthly
Journ. 1847. vii. 350.

SPYRIDIA, Harv.— A genus of Cerami-
aceae (Florideous Algae), containing one
British species, S. filamentosa (fig. 698),
having a dull-red, cylindrical, filiform, much-
branched frond, consisting of a chambered
tube, the articulations of which are short,
and the walls of which are composed of small
angular cells. It arises from a broadly ex-

panded disk. The branches are clothed with
setaceous ramules. Thefavellce are stalked,

Fig. 698.

Spyridia filamentosa.

Fragment with a favella and ramules.

Magnified 25 diameters.

gelatinous, and lobed, surrounded by a few
ramules, and contain two or three masses of
spores. The tetraspores occur attached to
the ramules. Antheridia have not yet been
observed.

BIBL. Harvey, Brit. Mar. Ala. p. 166
pi. 22 D.

SQUAMELLA, Bory, Ehr.— A genus of
Rotatoria, of the family Euchlanidota.

Char. Eyes four, frontal ; foot forked.

S. oblonga (PL 35. fig. 29). Carapace
depressed, elliptical, or ovate-oblong, hya-
line ; toes slender, long. Aquatic : length
1-216".

S. bractea. Toes short and thick. Aquatic.

BIBL. Ehrenberg, In/us, p. 479.

STACHYLIDIUM, Link.— A genus of
Mucedines (Hyphomycetous Fungi), nearly
related to Botrytis, distinguished apparently
only by the subpedicellate spores. Fries
states that these are developed within a fu-
gacious veil (?). BOTRYOSPORIUM diffusum,
Corda, is included here by most authors. S.
bicolor and S. terrestre, having quaternate
sporiferous branches at the upper joints of
the erect simple filaments, grow upon decay-
ing herbaceous plants and rotten sticks.

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 341;
Fries, Summa Veg. p. 490; Greville, Sc
Crypt. Flor. pi. 257.

STAMENS.— The fertilizing organs, pro-
ducing the POLLEN, surrounding the pistil
in perfect Flowering plants, or occurring in
the centre of the barren flowers of the
monoecious and dioecious genera. Stamens
present a great variety of interesting points
for examination under a simple microscope

2 R

STARCH.

[ 610 ]

STARCH.

with a low power, in their forms, appendages,
pores, &c. For the compound microscope
they afford good material for the study of
development of cells in the pollen, the POL-
LEN-GRAINS themselves, and the spiral-
fibrous tissue of their ANTHERS.

STARCH. — This substance, with the ex-
ception of the protoplasm, the most generally
diffused of all the products met with in the
interior of vegetable cells, occurs in the form
of transparent granules, of varied size and
form and in varying quantity, in all classes
of plants but the Fungi. It has been stated
that it exists sometimes in a diffused or
formless condition, but this seems question-
able. All starch-grains appear when newly-
formed as minute spherical bodies, and very
many never advance beyond this stage ; but
a considerable proportion of the grains, in
all cases where the starch becomes an import-
ant and considerable element in the cell-
contents, increase in size, and acquire a more
or less definite form, diverging from the
spherical, and often characteristic of the
particular plant in which the grain is pro-
duced. The grains in a single cell mostly
vary very much in size, on account of their
different degrees of development, but the
full-grown characteristic grains of the same
species of plant agree tolerably well in size.
One of the most remarkable peculiarities of
starch is the fact that it assumes a blue
colour when iodine is applied to it, which in
most cases affords a ready means of detect-
ing its presence. The smallest grains are
almost too minute to measure, and even their
determination by the application of iodine is
sometimes unsatisfactory; the largest grains,
such as those of Canna and the potato, for
example, attain a length of more than 1-400".

The starch-granule is a definitely organized
structure, although its existence in relation
to that of the cell is transitory. It consists
of assimilated food, deposited in a definite
form, insoluble in the ordinary cell- sap,
through a process of organization analogous
to that by which the development of the cell
itself is effected. It is connected closely
with the cellulose structures of the cell- wall
by the remarkable secondary layers found in
the ALBUMEN of certain seeds, composed of
the substance called amyloid(P\.39. fig.266),
which sometimes takes a blue colour when
iodine is applied to it, and like starch, is
ultimately dissolved and removed to furnish
material for development.

The structure of the starch-granule has
formed the subject of much debate, which,

however, seems to have originated rather
through considerations relating to the deve-
lopment, than from a difficulty in observing
the complete objects. Very minute granules,
as above stated, appear as solid globules, but
when the granules acquire appreciable dimen-
sions, concentric lines may be observed, more
or less distinctly in different cases ; which
lines increase in number with the increase of
size, in many cases, however, soon becoming
excentrical, from the preponderating growth
of one side of the granule. In freshly ex-
tracted granules the original centre mostly
appears solid or with a minute black point ;
but if the starch is dry, the centre appears
hollow, sometimes is even occupied by air,
and some starch-grains, as in Iris pdllida,
florentina, &c., have a large cavity. If strong
alcohol is applied to fresh grains, the abs-
traction of water likewise produces a hollow
in the central point of growth, and in all
these cases, cracks not unfrequently run
out towards the surface. The point in ques-
tion, the starting-point of growth, solid or
hollow as the case may be, is sometimes
called the hilum or the nucleus ; the former
term arose out of the mistaken hypothesis
of its being a point of attachment to the cell-
wall; the latter term is admissible in a general
sense as merely indicative of its precedence
in age of the general mass of the grain. It
is sometimes asserted that this point or
nucleus is a pore or funnel-shaped cavity,
but this is altogether a mistake, as may be
readily proved by gently roasting a few starch-
granules of the potato on a slide, and observing
how the expanding air blows up the dextrine
into which the starch is changed, in the form
of a bubble or bladder. Sometimes small
granules occur in the potato with a large
cavity and thin walls.

The lines seen in the starch-granules are
the boundaries of superimposed layers of its
substance; sometimes these are very distinct,
sometimes very faint ; often more distinct
lines appear at intervals in the series of the
same granule (PI. 36. fig. 21), and in these
cases even a thin vacancy, or in the dried
granules a stratum of air, seems to exist
between the layers. The markings have
been described as " folds " on the starch-
granules, but their dependence on the exist-
ence of the concentric layers is beyond
doubt. They are seen in the proper relative
positions when the granules are rolled over in
all directions beneath the microscope ; their
relative numbers and forms correspond to
the size and stage of development of the

STARCH.

STARCH.

granules in the same plant, and other cha-
racters connected with the physical structure
confirm the conclusions from simple inspec-
tion.

Starch is usually stated to be unaffected
by cold water, and this is generally the case ;
but if the granules of Tous-les-mois are
crushed before placing them in water, so as
to expose the internal substance, the water
is sometimes absorbed by the inner layers,
and these swell up considerably without the
outer layers being affected. When starch-
granules are heated (dry] gradually upon a
slide, until some of them assume a yellowish
colour, either the air-bubble above-men-
tioned appears, occasionally with a partial
separation of the concentric layers through
expansion of the films of air existing between
them, while other parts become fused; or the
general shape remains unchanged, and the
striae gradually vanish, becoming melted into
a mass, as it were, the starch itself being
converted into dextrine. When starch-gra-
nules are heated in water to the boiling-point,
they usually soften and " blow-up " into a
large sac, the inner part softening first, and
pushing out the more superficial ; if the sac
bursts, the inner substance sometimes partly
escapes in the form of cloudy flocks, but is
not dissolved. Diluted sulphuric acid acts
somewhat in the same manner as hot water ;
but if stronger acid is allowed to attack the
granules locally or partially, by flowing in
from one side upon the object, very remark-
able appearances present themselves : the
acid touching certain parts of the granule
first, or acting most quickly on softer por-
tions, causes the softening internal layers to
expand and bulge out the external layers at
particular points (like hernia] until the entire
grain is softened, when these coalesce and
the whole expands into a thin sac. Gradual
action of the acid causes a more uniform
expansion, which is usually accompanied by
a sudden crack running out from the nucleus
into the substance (indicating the abstraction
of water ?), followed almost immediately by
a collapse of the wall above this crack, and
a sudden expansion of the whole into a sac,
or an irregular gelatinous film. Solution of
potash produces much the same effect as
dilute sulphuric acid.

All the above appearances indicate that
the starch-granule is composed of concentric
" shells " of a substance of the same nature,
but less dense and more rich in water in the
interior layers; firmer, less hydrated and
more resisting in proportion to the distance

from the starting-point of growth or nucleus.
The application of the polariscope to the
starch-granule also brings distinct evidence
on this point, showing that it is composed of a
substance increasing in tension or density
from the " nucleus " to the surface. With
polarized light, the starch-granule exhibits a
black cross, and with a plate of selenite a
beautiful coloured system, especially well
seen in large grains like those of the potato
or Tous-les-mois (PL 31. fig. 4).

Pure starch is coloured blue by iodine,
whether in its natural state or softened by
hot water, the depth of the colour depending
on the quantity of iodine; where much is
added the colour is almost black. When
dilute sulphuric acid has been added pre-
viously, the colour is rather purple than
blue, especially the faint tinge given at first
by weak solution of iodine. When the
starch-grains are heated dry, the colour
given by iodine changes proportionately to
the violence of the action from blue to
purple, red- wine colour, and finally brown.
The best application is the solution of iodine
in iodide of potassium, and this should be
used very weak in investigation of starch.

Starch-granules occur either isolated (PI.
36. figs. 8 & 21) or in groups (figs. 7, 10, 11)
(in the latter case mostly with flat faces, so
as to fit together into round, oval or similar
forms), or packed closely in the parent-cell,
in such numbers that they press upon each
other, and appear like parenchymatous cells
(PL 36. figs. 3 & 12). In the actively vege-
tating parts of plants starch-granules occur
very generally imbedded in the green glo-
bules called CHLOROPHYLL-granules, either
singly or in groups ; this is seen especially
well in the cells of the Confervacese, of the
Hepaticaceae, the prothallia of Ferns, in the
leaves of aquatic plants, such as Vallisneria,
in autumn, &c. The free granules occur
more particularly in the colourless organs of
plants, in tubers, rhizomes, roots and the
cambium region, in the season of rest, in the
endosperm of ovules, or the ALBUMEN or
cotyledons of seeds, &c. The parenchyma-
tously-grouped granules are found in the
albumen of seeds, especially of maize and
rice. The comparison of the states and of
the course of development of the crowded
granules of maize throws much light upon
the manner in which starch-granules are
formed.

In the first place, two rival doctrines exist
as to the order of development of the parts
of the granule. Most authors assert that
2R2

STARCH.

[ 612 ]

STARCH.

the granules grow by the superposition of
layers from within outwards, consequently
that the outermost layers are the youngest.
Other authors, especially Nageli, comparing
the granule to a cell, assert that the layers
are formed internally, the older ones expand-
ing pari passu to make room for them.
There can be no doubt but that the first view
is correct. In the next place a variety of
notions have been put forth as to the origin
of the starch-granule and its relation to the
rest of the contents of the cell, especially
the chlorophyll. It is curious to note the
error into which earlier observers fell from
the want of the guiding thread furnished by
a knowledge of the function of the protoplas-
mic structures connected with the primordial
utricle. The idea that the starch-granule
sprouted out from the cell-wall corresponded
with the original view of the origin of the
septum in cell-division, while the hypothesis
that starch is developed from chlorophyll,
and the contrary notion that starch-granules
form the nuclei of chlorophyll-granules, both
rest on actual phenomena, in which, how-
ever, the chlorophyll proper, that is, the
mere green colouring matter, bears no im-
portant share.

The development of the starch-granule is
very beautifully illustrated in the gradual
ripening of the seeds of Maize, and in imper-
fect seeds different parts of the same grain
often afford various stages of growth. The
figs. 1-4 of PI. 36, show the gradual forma-
tion of the starch-granules by deposition
from the internal surface of vacuoles in the
protoplasm filling the cell, exactly in the
same way as the primordial utricle secretes
cellulose layers upon its outer surface. Fig.
20 shows minute starch-granules originating
in the same way in the protoplasm-current
connected with* the nucleus in the white
lily; and Criiger, who first published this
view in a decided form, has shown that the
large granules, with an excentric " hilum,"
originate in a similar position, and owe the
excentricity of their form to the fact of their
remaining imbedded at one (the thicker) end
in the protoplasmic threads of the primor-
dial utricle, while the small free end is gra-
dually pushed out further from the nutrient
mass. The existence of starch-granules in
chlorophyll masses is thus clearly enough
accounted for, now that we know the chlo-
rophyll-globules to be really protoplasmic
structures coloured green by the presence
of an extremely small quantity of a sub-
stance acquiring a green colour under the

influence of light. Starch originates in va-
cuoles in this as in any other protoplasm.
The groups of granules are formed through
the simultaneous origin of a number, in va-
cuoles excavated in one large globule of chlo-
rophyll or colourless protoplasm. We have
traced this in the fronds of the Hepaticacese.
These brief remarks must suffice on this part
of the subject, and further details must be
sought in the very copious literature which
exists.

It remains to speak of the diversities of
form of the large and perfect granules in
different plants. A glance at Plate 36 will
give some idea of these, and an inspection of
the individual figures will show how remark-
ably the characteristic forms may vary in
nearly related plants, even genera of the
same family, as is the case with the ordinary
Cereal grains. Thus in Maize (figs. 1 to 6),
where the small grains are, as usual, origin-
ally roundish or oval (fig. 6), they gradually
press upon one another and become poly-
gonal; in the cells of the centre of the grain,
where they are less densely packed, remain-
ing with obtuse edges and angles (fig. 5), in
the cells of the horny outer part of the grain,
where they adhere more or lessfirmly together,
forming angular parenchymatous masses (fig.
3). The central cavity is large here. In the
grain of Wheat we find delicate, transparent,
lenticular granules (fig. 8), the striae faint ;
in Barley they are irregularly discoid, with a
thickened edge, the striae obscure ; while in
the Oat (fig. 10) the granules are of very
small size, but of angular forms and com-
pacted together in large numbers, so as to
form roundish masses with a smooth surface,
which readily break down into the com-
ponents when pressed ; the separate segments
all exhibit their separate black crosses in
polarized light. In Rice (fig. 12) we find
somewhat similar conditions to those in
Maize, but the granules are much smaller
and more firmly united, whence the gritty
character of rice-flour. In the Potato the
starch-granules are found larger (fig. 21)
than any of the above ; they are numerous
and loosely packed in the cells (fig. 20).
Among the more remarkable forms of starch
are the large grains of the Canute (fig. 25),
Musa (fig. 24), and most of the Zingiberacea3
(fig. 19). True East Indian Arrow-root (fig.
18) has compound grains of large size (mostly
detached in the prepared farina). Various
other kinds are illustrated in Plate 36.
Diejfenbachia Seguina (Aracese) has remark-
able lobed granules.

STAURASTRUM.

[ 613 ]

STAURONEIS.

Starch-granules are usually isolated by
slicing the tissues in which they exist, and
washing them out. When they are to be
observed in situ, either delicate transparent
structures (as in the Cryptogainia) must be
selected, or sections very carefully made.
The cells filled with starch of the potato (PI.
36. fig. 20), &c., may be isolated by macera-
ting the structures in water for a day or two.
Starch -granules may be preserved for a
certain time in glycerine, but they are, per-
haps, best taken fresh from a store of dry
granules when required for examination.

BIBL. Rapport sur Pay en, Persoz, fyc.,
M&moires des savans Strangers (Paris Acad.},
v.; Poggendorff, Annal. d. Chem. u. Pharm.
xxxvii. p. 114 (1836) ; Fritzsche, ibid, xxxii.
p. 129 (1834); Payen, Ann. des Sc. nat.
2 ser. x. p. 5, Mem. Paris Acad. viii. p. 209;
Meyen, Pflanzenphys. i. p. 189 ; Mulder,
Physiol. Chemist. (Edinburgh, 1849), p. 208;
Bischoff, Bot. Zeit. ii. p. 385 (1844) ; Miinter,
iii. p. 193 (1845); C. Miiller, ibid. 833 (Ann.
Nat. Hist. xvii. p. 73); Nageli, Zeitschr.f.
Wiss. Bot. p. 149 (1844), iii. p. 117 (1846),
//////. Nat. Hist. xvii. p. 185, Ray Soc.
Vol. 1849. p. 183; Schleiden, Grundz. der
Bot. 3rd ed. p. 177 (Principles, p. 10);
Mohl, Vegetable Cell (London, 1852), p. 44,
Vermischt. Schrift. p. 449, Ann. Nat. Hist.
2nd ser. xv. p. 371; Martin, Phil. Mag.
2nd ser. iii. p. 277; Busk, Microsc. Trans.
2nd ser. i. p. 58 ; Allman, Mic. Journ. ii.
p. 163; Criiger, Bot. Zeit. xii. p. 41 (1854)
(Mic. Journal, ii. p. 173) ; Kiitzmg, Grundz.
d. Phil. Bot. i. p. 261 ; Lindley, Introd. to
Botany, 2nd ed. p. Ill; E. Quekett, Ann.
Nat. Hist. xvii. p. 193; Raspail, Ann. des
Sc. nat. vi. (1825) and vii. (1826).

STAURASTRUM, Meyen.— A genus of
Desmidiaceae.

Char. Cells single, constricted at the
middle ; end view angular or circular, with a
lobato-radiate margin, or rarely compressed
with a process at each end.

Sporangia generally spinous and often
globose.

Thirty-eight British species (Ralfs).

S. dejectum (PI. 10. fig. 26). Segments
smooth, lunate or elliptical, constricted por-
tion very short ; end view with inflated
awned lobes. Common; length 1-830".

S. margaritaceum (PI. 10. figs. 28, 29).
Segments rough, tapering at the constriction,
a ii(l with short lateral processes ; end view
with five or more short, narrow, obtuse rays.
Length 1-1176".

S. gracile (PI. 10. fig. 30). Segments

rough, elongated on each side into a slender
process terminated by minute spines ; end
view biradiate. Length 1-770 to 1-540".

BIBL. Ralfs, Brit. Desmidiacetn, 119.

STAUROCARPUS, Hassall (Staurosper-
mum, Kiitz.). — A genus of Zygncmaceae
(Confervoid Algae), growing in (boggy)
freshwater pools; distinguished by the re-
markable quadrate spore formed in the
cross-branch produced by conjugation. Has-
sall enumerates six species. He speaks of,
but does not describe or figure the spores of
S. ccerulescens filled with " zoospores."
Thwaites, however, saw the spores of S.
gracilis resolved into four portions, and
therefore until this body has been seen to
germinate, perhaps it should be regarded as
a sporange. Probably, however, the condi-
tions are the same as in SPIROGYRA.

1. S. glutinosus. Filaments 1-1800 to
1-1560'' in diameter, bluish-green, lubricous ;
spores four-sided, with the angles rounded
(Hass. pi. 47. fig. 1).

2. S. ccerulescens. Filaments about the
same size as the last; spores cruciate, with
obtuse lobes (Hass. pi. 47- fig. 2).

3. S. quadratus. Filaments 1-2400" in
diameter, spores between square and globose
(Hass. pi. 48. fig. 1).

4. S. virescens. Filaments 1-3240 to
1-3000" in dia-
meter; spores cru-
ciate, emarginate

(Hass. pi. 48. fig. 2).

5. S. gracillimus.
Filaments 1-4200 to
1-3960" in diame-
ter ; spores acutely
quadrangular (Hass.
pi. 49. fig. 2).

6. S. gracilis
(fig. 699 and PL 5.
fig. 16). Filaments
thicker than in S.
gracillimus; spores
cruciform (Hass. 49.
fig. 1). Perhaps the
same as the preceding.

BIBL. Hassall, Brit. Fr. Alg. p. 176;
Kiitzing, Sp. Alg. p. 437, Tab. Phyc. v. pis. 8
& 9 ; Thwaites, Ann. Nat. Hist. xvii. p. 262 ;
Ralfs, Brit. Desmidiece, p. 146 ; Al. Braun,
Verjungung, fyc. (Ray Soc. Vol. 1853.p.287).

STAURONEIS, Ehr.—A genus of Dia-
tomaceffi.

Char. Frustules resembling those of Na-
vicula, but the median nodule expanded into
a transverse band or stauros.

Fig. 699.

Staurocarpus gracilis.

Conjugating filaments with
sporea (or spo ranges).

Magnified 100 diameters.

STAUROPTERA.

[ 614 ]

STENTOR.

Striae resembling those of Navicula, or
intermediate between those of Navicula and
Pinnularia ; often invisible by ordinary
illumination.

The species or forms are numerous ;
Kiitzing describes forty, Smith admits ten
British species.

S.pha>nicenteron(P\. 11. fig. 43). Valves
lanceolate, gradually attenuated towards the
somewhat obtuse ends; stauros reaching the
margins of the valves; striae faint. Aquatic;
common; length 1-170".

S.pulchella (PL 11. figs. 44, 45). Valves
oblong, ends obtuse; frustules in front view,
broadly linear, constricted in the middle, and
rounded-truncate at the ends; striae distinct;
stauros not reaching the margins. Marine ;
length 1-70".

BIBL. Ehrenberg, Ber. d. Berl Akad.
1843 ; Kiitzing, Bacill. p. 104, and Sp. Alg.
89.

STAUROPTERA, Ehr.— A genus of Dia-
tomaceae, including those species of Stauro-
neis in which Ehrenberg was enabled to
detect the transverse striae ; it is no longer
retained.

STEARIC ACID.— The crystals of this
fatty acid are represented in PL 7- fig- 166.
BIBL. See that of CHEMISTRY.
STEMONITIS, Gled.— A genus of Myxo-
gastres (Gasteromycetous Fungi), consist-
ing of little, somewhat stamen-shaped plants,
either separate or fasciculated, growing on
rotten wood, &c. They appear at first in the
form of a mucilaginous flocculent expansion
(fig. 700), from which the membranaceous

Fig. 700.

Stemonitis ferruginea.
Mycelium overgrowing decaying pine-leaves.

peridia grow up (fig. 701). Many of these
remain abortive, others are raised upon
stalks, ripen, and on the separation of the
fugacious peridium, display themselves some-
what in the form of DIACH^EA, but with a
bristle-like columella and no remains of the

peridium. The flat, cylindrical or globose
Fig. 701.

Stemonitis ferrug'mea.

Immature (fasciculate) peridia arising from the myce-
lium.

reticulated capillitium is penetrated partly
or through its whole length by a columella
continuous with the peduncle; the spores
are interspersed in the reticulations of the
capillitium. Capillitium and spores mostly
of blackish colour. There are numerous
British species ; S. fusca is common. See
ENERTHENEMA and DIACH^A.

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 317,
Ann. Nat. Hist. i. p. 257, vi. p. 431. 2nd
ser. v. 366; Greville, So. Crypt. Fl. pi. 170;
Fries, Summa Veg. p. 455, Syst. Myc. iii.
p. 156.

STENOGRAMME, Harv.— A genus of
Rhodymeniaceae (Florideous Algae), contain-
ing one very rare British plant, 8. interrupt a,
characterized by stalked, flat, fan-shaped
fronds, more or less divided dichotomously
into riband-like lobes, 3-5" high, of a clear,
pinky-red colour. It is composed of a central
layer of large, globular cells, with a kind of
rind of small cells. The conceptacles form
a sort of sorus or dark line resembling a
rib up the centre of each fertile lobe. Tetra-
spores and antheridia unknown.

BIBL. Harv. Brit. Mar. Alg. p. 123.
pi. 15 D.

STENTOR, Oken.— A genus of Infusoria,
of the family Vorticellina.

Char. Body conical or trumpet-shaped,
free, or sessile and attached by the narrow
base; covered with cilia; anterior portion
widened and fringed with a marginal row of
longer cilia, with a spiral row of cilia extend-
ing from it to the mouth. Aquatic.

These Infusoria are among the largest and
the most beautiful in the class. The body
is very contractile and liable to variation in
form, often becoming ovate, oblong, or glo-
bular. The so-called nucleus is moniliform
or strap- shaped. The encysting process has
been noticed in some of the species.

S. Mullen (PL 25. fig. 3). Body colour-
less unless from containing foreign coloured
particles, with a fringe of cilia or a ciliated
crest extending from the mouth to near the

STEPHANOCEROS.

[ 615 ]

STEREOCAULON.

middle of the body; nucleus moniliform.
Length 1-24".

Five other species.

Dujardin places this genus in the family
Urceolarina.

BIBL. Ehrenberg, In/us. 261; Stein,
Infus. passim.

STEPHANOCEROS, Ehr.— A genus of
Rotatoria, of the family Flosculariaea.

Char. Eyes single; rotatory organ divided
into five tentacle-like lobes, furnished with
whorls of vibratile cilia ; body attached by
the base to a cylindrical hyaline carapace.

S. Eichhornii (PL 35. fig. 25). The only
species. Aquatic ; length 1-36". This beau-
tiful animal uses the lobes of the rotating
organ to catch its prey, in the manner of
Hydra. At a (fig. 25) are seen the tremu-
lous bodies, above which is a row of round-
ish globules, called by Ehrenberg nervous
ganglia.

BIBL. Ehrenberg, Infus. 400.
' STEPHANOD1SCUS, Ehr.— A doubt-
fully distinct genus of Diatomaceae.

Char. Frustules discoidal, single ; valves
circular, alike, not areolar (under ordinary
illumination), and with a fringe of minute
marginal teeth. Aquatic.

S. berolinensis has the valves finely
radiate, with mostly thirty-two teeth,
and is 1-1150'' in diameter; whilst in S.
Niagara the centre of the valves is granular,
the circumference radiate, the teeth sixty-
four, and the diameter 1-430".

These species should be referred to Cos-
cinodiscus or Cyclotella.

BIBL. Ehrenberg, Ber. d. Berl. Akad.
1845. Ixxii.; Kiitzing, Sp. Ala. 21.

STEPHANOGONIA, Ehr.— An obscure
genus of fossil Diatomaceae.

Char. Frustules resembling those of Mas-
togonia, but with the apices of the valves
truncate, angular, and spinous.

Two species found in Bermuda and North
America.

BIBL. Ehrenberg, Ber. d. Berl. Akad.
1844. 264 ; Kiitzing, Sp. Ala. 26.

STEPHANOPS, Ehr.— A genus of Rota-
toria, of the family Euchlanidota.

Char. Eyes two, frontal, foot forked ;
carapace depressed or prismatic; anterior
part of body expanded so as to form a frontal
hood.

Jaws each with a single tooth.

S. cirrhatus (PL 35. fig. 28). Carapace
with two posterior spines. Aquatic ; length
L240".

S. muticus has the carapace without spines

posteriorly, and the eyes have not been
recognized; whilst S. lamellatus has three
posterior spines.

BIBL. Ehrenberg, Infus. 478.

STEPHANOPYXIS, Ehr. = Pyxidicula,
a genus of Diatomaceae.

S. diadema=Pyxidicula diadema.

As Pyxidicula is passed over in its
proper place, we may take the opportunity
of inserting it here. Its characters are :

Frustules single, free or sessile; valves
circular, convex, hoop absent !

Twenty-two species have been described,
one aquatic, one marine, the remainder
fossil, found in America. Some of them do
not appear to differ from Coscinodiscus,
except in the greater convexity of the valves.

P. major (PI. 19. fig. 13). Valves conical,
regularly punctate. Diameter 1-420". Aqua-
tic.

P. adriatica. Frustules sessile ; valves
almost hemispherical, free from markings
(ordinary illumination). Upon marine algae,
diameter 1-600".

P. minor, K. Frustules spherical, with
two median parallel furrows.

This appears to be the P. operculata of
Ehrenberg, which Kiitzing considers to be
the same as his Cyclotella operculata.

The bodies represented in PL 19. fig. 12,
found in flint, have been described as P. glo-
bator, Pritch. (not P. alobosus, E.) ; they
do not appear, however, to belong to the
Diatomaceae.

See also XANTHIOPYXIS.

BIBL. Ehrenberg, Infus. p. 165, Ber. d.
Berl. Akad. 1844 & 1845 ; Kiitzing, Bacill.
51, Sp. Ala. xxi. ; Pritchard, Infusoria, 432.

STEPHANOSPILERA, Cohn.— A genus
of Volvocineae (Confervoid Algae), not yet
observed in Britain. S. pluvialis is related
to Volvox, consisting of a large hyaline globe
with eight biciliated green cells, placed at
equal distances on the equator.

BIBL. Cohn, Sieb. fy Kollik. Zeitschr. iv.
p. 77 (1852) (Ann. Nat. Hist. 2nd ser. x.
p. 321. pi. 6).

STEREOCAULON, Ach.— A genus of
Lecidineae (Gymnocarpous Lichens), so
called from the solid character of the
branched bushy thallus. S. paschale, the
most distinct species, is abundant on rocks
and stones on mountainous districts. The
thallus is grayish and rough, the apothecia
conglomerated, blackish-brown. The sper-
inogonia occur in little brown heads, near
the apothecia.

BIBL. Hook. Brit. Flor. ii. pt. 1. p. 237;

STEREONEMA.

C

STIGMA.

Tulasne, Ann. des Sc. nat. 3 ser. xvii. p. 197;
Enffl Bot. pi. 282.

STEREONEMA, Kiitz.— Probably the
mycelium of a fungus.

BIBL. Kiitzing, Sp. Alg. p. 160.

STERIGMATA.— The term applied by
Tulasne to the filaments forming the pedicels
of the spermatia in the FUNGI (PI. 20. figs.
2,3).

STICHIDIA.— Pod-shaped processes of
the fronds of Florideous Algae, containing
the tetraspores imbedded in them (fig. 160,
page 189).

STICHOCOCCUS, Nageli=PROTococ-
cus.

STICTA, Ach.— A genus of Parmeliaceae
(Gymnocarpous Lichens), with a tough, foli-
aceous thallus, growing over rocks and
trunks of trees, mostly in mountainous
districts. S.pulmonaria forms large shaggy
fronds of olive-green colour when fresh, pale-
brown when dry, pitted and reticulated; the
apothecia mostly marginal, red-brown. The
spermogonia of this genus occur scattered
on the upper surface, mostly near the ends
of the lobes.

BIBL. Hook. Brit. Flor. ii. pt. 1. p. 208 ;
Tulasne, Ann. des Sc. nat. 3 ser. xvii. p. 169.
pi. 1 ; Engl. Bot. pi. 572.

STICTEI, Fries.— A group of Helvellacei

Fig. 702. Fig. 704.

I)

Fig. 703.

Sticta versicolor.

Fig. 702. An open disk, emerged on the surface of
ood, havin

wood, having an irregular border.
Fig. 703. Vertical section of the same.
Magnified 20 diameters.

Fig. 704. Asci and paraphyses from the last. Mafmi-
fied 200 diameters.

(Ascomycetous Fungi), containing several
genera of plants, growing on wood, branches
of trees, &c., bursting through from beneath
the bark when mature. S. (Cryptomyces,

ff. ' ••

Berk.; Propolis, Fr., S. Veg.} versicolor
(figs. 702-704), is common on wood; the
upper surface of the open fruit is white, and
at length mealy.

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 214,
Ann. Nat. Hist. vi. p. 359; Fries, Summa
Veg. p. 372.

STIGEOCLONIUM, Kiitz.— A genus of
Chaetophoraceae (Confervoid Algae), growing
mostly in brooks, and composed of delicate
branched filaments, drawn out into delicate
hyaline points ; attached to stones and form-
ing masses of a sinuous or lubricous cha-
racter. The jointed filaments are composed
of short cells, possessing bright green con-
tents ; the entire contents of a cell are con-
verted into a single zoospore (with four
cilia) and discharged (PI. 5. fig. 5), and the
cell-wall is so delicate that it generally
vanishes at the same time. Many species
are described by Kiitzing, formerly regarded
as members of the genus DRAPARNALDIA,
which differs in the number of zoosporfis
produced in each cell, and in possessing
large primary filaments with lateral tufts of
delicate ones, resembling those of Stigeo-
clonium (fig. 182, p. 216). We select the
most distinct of the British forms.

1. S.protensum (PL 5. fig. 5). Tufts of
filaments 1-36 to 1-60" high, very much
branched and elongated ; primary filaments
1-1800" in diameter, joints equal or three
times as long (Drap. condensata, Hassall,
pi. 11. fig. 1)

2. S. lubricum. Tufts about 1-36 to
1-72" high; primary filaments 1-2160" in
diameter; torulose ; set above with nume-
rous tufts of abbreviated branchlets (Drap.
tennis, Hass. pi. 11. fig. 2).

3. S. elongatum. Filaments very slender ;
primaries 1-2880" in diameter; branches
erecto-patent, often opposite, subramulose,
flagelliform; all the joints three or five times
as long as broad (Drap. elongata, Hass.
pi. 10. fig. 3).

4. S. nanum. " Filaments highly mucous,
very slender, sparingly branched, branches
acuminate, not usually ciliated (produced
into a filiform end); cells rather broader
than long" (Drap. nana, Hass. pi. 10. fig. 4).

BIBL. Kiitzing, Sp. Alg. p. 352, Tab.
Phyc. iii. pis. 1-11 ; Hassall, Brit. Fr. Alg.
fig. 118; Thuret, Ann. des Sc. nat. 3 ser.
xiv. p. 223. pi. 18.

STIGMA.— The part of the pistil of An-
giospermous Flowering plants, upon which
the pollen rests to produce its pollen-tubes,
and where the orifices exist leading to the

STIGMATA.

[ 617 ]

STILBUM.

cavity of the ovary. It is situated either at
the summit of the style or its branches, or,
when this is absent, it is sessile on the ovary.
The surface of the stigma is clothed with
papilliform or short tubular cells, from which
a saccharine secretion exudes at the period
when the ovules are prepared to receive the
influence of the pollen-grains. In this fluid
the pollen-grains produce their tubes, which
make their way between the papillae to
descend through the conducting tissue of
the style to the placenta (PI. 32. fig. 30).
These papillifcrm cells in a young state often
form favourable subjects for the study of the
protoplasmic cell-contents, and also of the
fluid colouring matter. The forms of the
stigma are exceedingly varied and sometimes
very elegant. In the family of Composite,
its characters are used for the systematic
division of the numerous genera.

STIGMATA, OF ANIMALS. See SPIRA-
CLES.

STIGMATEA, Fr. See DOTHIDEA.

STIGONEMA, Ag.— A supposed genus
of Scytonemeous Oscillatoriacese (Confer-
void Algae), founded upon what has proved
to be the thallus of a genus of Lichens. See
EPHEBE.

STILBACEL— A family of Hyphomyce-
tous Fungi, growing upon decaying animal
or vegetable matter, or on bark or -leathery
leaves. Characterized by a wart-shaped
receptacle, composed of conjoinedfilamentous
or hexagonal cells and spores borne singly
on the apices of free filaments. Some of the
Fungi here included are heterogeneous and
imperfectly studied, for example, Tubercu-
laria and Fusarium are apparently only im-
perfect states of other Fungi, while the more
distinct genera appear to be referable to the
family Dematiei.

Synopsis of British Genera.

I. STILBUM. Receptacle stalked at the
base, clavate or capitate at the summit, com-
posed of coalescent, densely crowded, parallel
filaments; spores simple, arising singly at
the apices of free filaments.

II. PACHNOCYBE. Receptacle stipitate,
clavate, floccose, the filaments twisted, the
head finally pruinose, with simple spores.

III. PERICONIA. Receptacle stalked at
the base, clavate or capitate at the apex,
composed of coalescent, densely crowded
parallel filaments, or cellularly fleshy; spores
simple, crowded on simple sporophores ari-
sing at the summit (and on the stalk, Fries).

IV. TUBERCULARIA. Receptacle wart-

shaped, globular or stalked, fleshy, composed
of continuous, sterile and thread-like, beaded,
fertile filaments. Finally indurated, floccose,
with the spores scattered over it, or falling
into powder.

V. PERIOLA. Receptacle cellular, ses-
sile ; fertile filaments abbreviated, torulose,
mixed with septate, lax, sterile filaments.

VI. VOLUTELLA. Receptacle wart-like,
cellular, compact, with long rigid bristles ;
spores spindle-shaped, septate, on continu-
ous short filaments, arising all over the
receptacle.

VII. FUSARIUM. Receptacle wart-like,
cellular, gelatinous ; spores spindle-shaped,
simple, somewhat curved, borne on simple
filaments arising all over the receptacle, and
forming a discoid stratum.

VIII. ILLOSPORIUM. Receptacle wart-
shaped, subgelatinous, diffluent ; spores
simple, pellucid, generally with a hyaline
envelope, borne on short filaments.

IX. EPICOCCUM. Receptacle wart-shaped,
cellular, for the most part seated on an
effused patch ; spores four-sided, cellular,
attached singly to very short, continuous
filaments.

STILBOSPORA,
Pers. — A supposed
genus of Melanconiei
(Coniomycetous Fun-
gi), but apparently only
consisting of stylospo-
rous fruits of Sphariae.
These grow upon wood,

Sticks, &C., breaking Stilbospora macrosperma.
forth On the surface Group of conceptacles

without any distinct breaking forth on a frag-

. , J . . ment of woed ; nat size.

penthecmm, Consisting The detached spores on
of a nucleus composed t^6 right-hand magnified

of agglutinated (sep- 15° diameters-
tate) stylospores (see SPH^RIA).

BIBL. Berk. Brit. J7or.ii.pt. 2. p. 356, Ann.
Nat. Hist. vi. 355, Hooker's London Journ.
of Bot. iii. p. 322; Fries, Summa Veg. p.
508 ; Fresenius, Beitr. z. Myc. heftii. p. 63.

STILBUM, Tode.— A genus of Stilbacei
(Hyphomycetous Fungi), containing a con-
siderable number of species, forming little
shining mildews, sometimes brightly co-
loured, on decaying wood, herbaceous plants,
Fungi, &c. The stalk-like stroma differs in
character, being sometimes villous, some-
times glabrous and rigid, sometimes pellucid
and soft ; it is formed of conjoined filaments,
the free ends of which bear the spores in a
capitulum, which finally exhibits a gelati-
nous character.

Fig. 705.

STILOPHORA.

[ 618 ]

STOMACH.

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 330,
Ann. Nat. Hist. vi. p. 432. pi. 12, ibid. 2nd
ser. v. p. 465; Fries, Summa Veget. p. 469.

STILOPHORA, J. Ag.— A genus of Spo-
rochnaceae (Fucoid Algae), included by some
authors among the Dictyotaceae. There are
two British species, S. rhizodes and S. Lyng-
byei, characterized by a branched, filiform,
at first solid, afterwards tubular frond, the
former 6 to 24", the latter 2 to 4" long, ari-
sing from a small naked disk. The fructifi-
cation consists of little wart-like bodies,
scattered all over the frond, composed of
tufts of moniliform filaments, at the bases
of which are attached either pyriform oospo-
ranges, or tubular, septate trichosporanges.
Thuret states that the specimens of S. rhi-
zodes found a certain distance above low water
mark appear mostly to bear trichosporanges,
those always under water oosporanges, and
those in an intermediate position exhibit
both. The plants of the first kind are of
paler colour than those of the second.

BIBL. Harvey, Brit. Mar. Alg. p. 39.
pi. 7 C ; Greville, Alg. Brit. pi. 6 ; Thuret,
Ann. des Sc. nat. 3 ser. xiv. p. 238. pi. 38.

STING, OF INSECTS.— The well-known
sting of the female or so-called neuters of
Hymenopterous Insects, as the honey-bee,
the humble-bee, the hornet, the wasp, &c.,
appears to the naked eye to be a single,
needle-like organ; but when examined under
the microscope, it is seen to consist of three
pieces, a short, stout, cylindrico-conical
outer piece or sheath (PI. 27. fig. 14 a),
cleft throughout its length on the under
surface and obtuse at the end, within which
are partly contained two long elbowed setae
or lancets (PL 27. fig. 15, one of them),
thickened and furnished with teeth directed
backwards near the end of one margin, the
other margin sharp and cutting. These
setae play within the sheath, being partially
protrusile and retractile, as is the sheath
itself. The poison-apparatus consists of two
glandular elongated sacs, either simple (PI.
27. fig. 14 e,f), or branched as in the humble-
bee, &c., and terminating by one (fig. 14 d)
or two ducts, in a muscular reservoir (fig.
14 c), from which an excretory duct runs to
the base of the sheath of the sting.

The irritation produced by the sting of
one of these insects needs no remark. It
does not, however, serve a merely defensive
purpose, but is used also to paralyse the
prey, so that it may be kept in store for
future use.

The sting represents a modified ovipositor.

BIBL. Lacaze-Duthiers, Ann. d. Sc. nat.
3 ser. xii. xiv. ; Westwood, Introduction,,
<§-c. ; Siebold, Vergl. Anat.

STINGS, OF PLANTS.— These are epider-
mal structures, consisting of large Fig. 706.
hairs, with a bulbous base more or
less included in a cellular coat, and
attenuated upwards. In the sting
of the nettle the apex is expanded
into a little bulb, which is broken
off when the sting is lightly touched
(PL 21. fig. 8). Young stings ex-
hibit the ROTATION. Stings occur
not only in the nettles (Urtica},
but in the cultivated Loasaceae t
(Loasa,Bartonia, &c.), and of much
larger size in some exotic Urticaceae haiir of
and Euphorbiaceae. Magnified

See HAIRS, page 314. 20diams.

STOMACH.— The glands which secrete
the gastric juice are tubular glands, perpen-
dicularly placed beneath the surface of the
mucous membrane, and extending as deeply
as the muscular coat of the stomach.

They vary in length from 1-60 to 1-12",
are cylindrical, somewhat narrowed towards
the closed end, which is rounded or some-
what inflated. The lower third is wavy or

Fig. 707.

Fig. 707- Perpendicular section of the pyloric portion
of the stomach of a pig. u, glands ; b, muscular layer
of the proper mucous membrane ; c, submucous tissue
with the orifices of divided vessels ; d, transverse mus-
cular layer ; e, longitudinal ditto ; /, serous coat. Mag-
nified 30 diameters.

spiral, especially in the glands occupying the

STOMACH.

Fig. 708.

[ 619 ]
Fig. 709. •

STOMATA.

Fig. 710.

Fig. 708. Gastric gland with cylinder-epithelium, from the pylorus of a dog. a, principal cavity ; b, tubular pro-
cesses arising from it. Magnified 60 diameters.

Fig. 709. Gastric gland from the middle of the stomach, a, principal cavity ; b, primary, and c, terminal branches
arising from it. Magnified 60 diameters.

Fig. 710. Portions of a terminal branch, the upper representing a longitudinal, the lower a transverse section, a,
basement membrane ; b, large cells in close apposition with it ; c, smaller epithelial cells surrounding the cavity.
Magnified 350 diameters.

pylorus ; some of them also give off a caecal
branch.

The gastric glands consist of a delicate
basement membrane, lined in the upper
third with cylindrical epithelium, the lower
portion being filled with large, pale, poly-
gonal, finely granular cells, not arranged in
a laminated form.

In many animals the gastric glands are of
more complicated structure than in man, and
two distinct kinds exist, in one, secreting
mucus, the tubes being lined with cylin-
drical epithelium]; whilst in the other, which
secretes gastric juice, rounded epithelial cells
occur, and the walls are expanded at intervals.

Closed follicles resembling the solitary
glands of the small intestines are met with
in the stomach ; they are, however, incon-
stant and variable in number.

The stomach is lined by cylindrical epi-
thelium.

BIBL. Kolliker, MiJcrosJc. Anat. ii. 137,
and the Bibl. therein ; Todd and Bowman,
Phys. Anat., fyc.

STOMATA (plural of STOMA).— This
name is applied to the structures which
constitute the passages of communication,
through the EPIDERMIS of plants, from the
intercellular passages to the external air.
They occur almost exclusively on the green
parts of plants, and are absent from the
epidermis of roots, also on the surface of
all structures growing under water. The
lowest classes which present them are the
Liverworts and Mosses, where, however,
they are limited to a few kinds, and in the
former present a peculiar organization. In
the Ferns they are distributed just as in the
Flowering Plants, where they occur princi-
pally upon the leaves (fig. 711), especially
upon the lower face, but extend also over
the green shoots, the parts of the flower

STOMATA.

[ 620 ]

STOMATA.

(fig. 204, page 239), and even into the
interior of cavities, as on the epidermis of
the replum of Crucifera3 (wallflower), and,
still more remarkably, on the epidermis of
seeds (skin of the walnut).

In the Liverworts the stomata occur on
the fronds and recep-
tacles of certain ge-
nera (Marchantia,
Fegatella, &c., &c.).
In Marchantia (fig.
451, page 413), they
are somewhat circu-
lar orifices in the
epidermis, guarded
by cells arranged in
three or four tiers.
In the Mosses they
are met with on the
apophyses or thick-
ened summits of the
setae bearing the cap-
sules, as in Funaria
(fig. 266, page 280).
The structures here
resemble those in the
higher plants, as is surface).

the case also with Magnified 100 diameters.

those on the leaves of
the Ferns.

In the Flowering Plants the perfect sto-
mata appear as roundish or sometimes squa-
rish chasms in the epidermal layer, occurring
regularly at the meeting angles or sides of
four or more epidermal cells, the chasm
forming an orifice leading down to a sub-
epidermal, intercellular space, and guarded
a little below the upper edge, more deeply,
or even at the bottom, by (usually) two
semilunar cells, applied together by their
flat faces, but not coherent, their convex
surfaces adhering firmly to the sides of the
epidermal gap. According as the two sto-
matal-cells or "pore-cells" or "guard-cells"
are distended or collapsed, their flat faces
approach or retreat from each other, in the
latter case leaving a slit-like orifice leading
from the outer passage into the subepidermal
space. Sometimes the " guard-cells " are
four in number, in which case they either
form two tiers, as upper and lower (Prote-
acea?, e. g. Hakea, Protea, &c.), or they are
in the same line and parallel, forming inner
and outer "guard-cells" (Ficus elastica).
In certain coriaceous leaves the stomata are
placed on the sides of pits excavated beneath
the surface of the leaves, as in Dasylyrion
oblongifolium and Nerium Oleander.

A considerable difference exists between
the appearances presented by vertical sec-
tions of the epidermis of leaves made so as
to pass through the stomata. In young
leaves the guard-cells are little, if at all
below the genera] level of the epidermis, and
the same is the case with the perfect forms
in various herbaceous plants in which the
leaves are of membranous texture. In other
cases, as in the Hyacinth, Iris, Narcissus,
Equisetum, &c., the guard-cells are found at
a very early period quite beneath the layer
of epidermal cells, attached as it were under
the passage communicating with the air.
The same occurs very frequently in the
stomata of coriaceous leaves, as in Aloe (PL
39. fig. 22), Ficus, Cycas, Hakea, Protea,
&c. In other instances, also in leathery
leaves, the "guard-cells" appear more or
less elevated above the general level of the
epidermal cells, as in some species of Leu-
cadendron, Grevillca, &c. It is important to
observe, that in the cases where the " guard-
cells " are sunk in the orifice of the epi-
dermis, the upper margin of the orifice,
formed by the borders of the surrounding
epidermal cells, sometimes becomes elevated
and even converted into a kind of perforated
dome (PI. 39. fig. 22), by development of
the cuticular layers (see EPIDERMIS). This
might be mistaken for the stomate itself.
The same cuticular substance is often deve-
loped in mature leaves, not only down
over the walls of the stomatd passage, but
over the guard-cells, and from thence more
or less into contiguous intercellular passages.
This may be observed in Euphorbia Caput-
MeduscB, Helleborus niger and viridis, Betula
alba, Asphodelus luteus, and Cereus, some
Aloes, &c. Gasparrini obtained these con-
nected processes of cuticular substance, in
the form of an isolated coherent piece, by
boiling epidermis in nitric acid, which dis-
solved the adjoining cell-walls ; these he
mistook for peculiar organs, and called them
cistomes. Dr. Hooker has described a re-
markable form of stomata in the parasitical
plant Myzodendron.

In those plants in which the epidermis
becomes infiltrated with siliceous matter, the
walls of the stomatal pore and the " guard-
cells " become imbued with it, and a sili-
ceous skeleton of the structure remains after
the organic matter has been removed by
nitric acid and burning (PL 39. fig. 29).
This is readily seen in the Equisetaceae,
especially E. hyemale, also in the Grasses.

The mode of development of the stomata

STOMATA.

[ 621 ]

STRIATELLA.

appears to be uncertain. Mohl and other
authors assert that the " guard-cells " origi-
nate from one of the cells of the subepi-
dermal tissue, which is pushed up into a
vacancy formed by the separation of the
epidermal cells at certain points. This cell
is said to be next divided into two, which
become free from each other in the line of
the new partition then formed. Nageli and
others assert that the guard-cells are origin-
ally constituent cells of the epidermal layer
which become subsequently displaced down-
wards (or upwards), and undergo special
development analogous to that just described.
Dr. Garreau has recently described this mode
of development as occurring in Tradescantia.
We believe it is the correct view, at all
events in some cases, but the appearances
are certainly difficult to explain on this plan
in the Iridaceae, Equisetaceae, and some
other plants.

The stomata are generally largest upon
succulent leaves, smallest on hard and
leathery kinds ; their form and number are
most varied, both in different plants and
on different parts of the same plant. They
abound most on the lower face of leaves,
but it has been mentioned that they are not
found on submerged organs, and on floating
leaves they occur only upon the upper face.
The larger kinds are more scattered on
a given surface, the smaller occur closer
together (this depends, of course, on the
general character of the epidermal and sub-
jacent tissue). The numbers have been
estimated upon the surfaces of many leaves,
of which a few examples may be given ;
thus a square inch contains in —

Uppei

Carnation 38
Garden Flag 11
House-leek 1(
Tradescantia i
Misletoe •• ......

•surfac

!,500
,572

),7io

>,000
200
0
0
0
0

e. Lower surface.

38,500
11,572

iwk«. 6,000
;^.,.., 2,000
200
63,600
160,000
13,600
90,000

Holly

Vine •••

Laurestinus

t .

BIBL. General Works on Struct. Botany ;
Krocker, De Epidermide, Vratisvl. 1833;
Mohl, Verm. Schrift. pp. 245, 252, Bot.
Zeit. iii. p. 1 (Ann. Nat. Hist. xv. p. 217) ;
Nageli, Linneea, xvi. p. 237. 1842; Mirbel,
sur Marchantia, Mem. Acad. Roy. France,
xiii. ; Gasparrini, Nuove ric. v. strutt. d. Cis-
tomi, Naples, 1844 ; Garreau, Ann. des Sc.

nat. 4 ser. i. p. 213 ; J. D. Hooker, Flora
Antarct. i. p. 291 ; Golding Bird, Proc.
Linn. Society, i. p. 290 ; Stocks, MS.

STONES, OF FRUITS, such as cherries,
plums, &c., afford excellent materials for
sections, showing extreme development of
the woody SECONDARY DEPOSITS of vege-
table cells.

STRIARIA, Grev.— A genus of Dictyo-
siphonaceae, nearly related to Punctariaceae
(Fucoid Algae), having a branched, filiform,
tubular frond, arising from a shield-shaped,
naked disk. The walls of the tube are mem-

712.

i> ^aionabiqa

••30 d

lull 11U11U, ailMUg

3d disk. The walls
Fig.

firfV/ grfj ><>
>7/o(. *» ,cleru

Fig. 713.

gi 88 ,g.hi£lq r-xi^irf

GZ\R W&'j 3(ft

Fig. 714.

Striaria attenuata.

Fig. 712. Part of a frond. One-third of the nat. size.
Fig. 713. A fragment of the sori. Magnified 5 diams.
Fig. 714. Section of a fertile branch, with sori. Mag-
nified 25 diameters.

branous, and the cavity without septa. /S.
attenuata (fig. 712) grows from 3 to 12"
high. The branches are attenuated towards
each end, and marked with rings consisting
of clusters of oosporanges (" spores ") (fig.
713), sometimes accompanied by filaments
(fig. 714). Colour pale olive.

BIBL. Harv. Brit. Mar. Alg. p. 41. pi.
8 A ; Grev. Brit. Alg. fig. 9.

STRIATELLA, Kutz.— A genus of Dia-
tom aceae.

Char. Frustules with a stipes attached to

STRIGULA.

[ 622 ]

STYLOSPORES.

one angle, depressed, tabulate ; with longi-
tudinal, uninterrupted vittae, apparently
thickened at each end. Marine.

The vittae appear as dark lines ; no trans-
verse striae are visible under ordinary illumi-
nation.

S. unipunctata (PL 13. fig. 20). Frustules
in front view quadrangular, often broader
than long, lateral margins subalate ; valves
narrowly lanceolate ; stalk elongate, simple,
filiform and thickish. Length of frustules
1-450 to 1-280".

Compare the other genera enumerated
under Striatelleee (DIATOMACE^E, p. 205).

BIBL. Kiitzing, Eacill. 125, Sp. Alg. 114.

STRIGULA, Fries.— A genus of Lim-
borieae (Angiocarpous Lichens), containing
one British species, S. Babingtonii, growing
on the leaves of box and other evergreens ;
the thallus is subepidermal, the asci contain
eight, cymbiform, triseptate spores.

BIBL. Leighton, Brit. Angioc. Lick. p. 70.
pl.30. 4; Berkeley, Eng. .Bof.Supp. pi. 2957.

STRONTIA OR STRONTIAN.— The cry-
stals of the sulphate of this earthy base are
figured in PL 6. fig. 18, to contrast with
those of the sulphates of baryta and lime.

STRUTHIOPTE- F- 71f-

RIS,Willden.— Age-
nus of Polypodieae
(Ferns), with the
margins of the fertile
leaves rolled up so as
to conceal the sori
which are without a
true indusium. Sir.
germanica (fig. 715)
is of large size, and
the fertile fronds, di-
stinct from the sterile, _
if cursorily examined, struthiopteris germanica.
might lead to the re- Portion of a pinna wjth the

ference of this plant unrolled margins covering

to the OsmundacejB the sori.
or"Flowering-ferns." Magnified 40 diameter8'

STRYCHNINE, or STRYCHNIA. See
ALKALOIDS, p. 25.

STYLOBIBLIUM, Ehr.— A genus of
fossil Diatomaceae.

Char. Frustules circular, single, multi-
valve ; valves contiguous, in a single row,
like the leaves of a book, the inner ones with
a large median aperture (?), the outer not
being perforated, but sculptured.

The structure of the frustules of this ge-
nus requires careful examination, as does that
of many other of Ehrenberg's genera of fos-
sil Diatomaceae. It is uncertain whether the

so-called inner valves are merely hoops, or
the valves of imperfectly separated frustules;
also whether they are perforated or not, for
neither Ehrenberg nor Kiitzing can be relied on
for distinguishing a perforation, as evidenced
by their erroneous description of the struc-
ture of the valves of Pinnularia, Gramma-
tophora, and many other Diatomaceae.

Three species are described, occurring in
America and Siberia. The sculpturings upon
the outer valves consist of radiating or ex-
centric curved lines.

BIBL. Ehrenberg, Ber. d. Eerl. Akad.
1845 ; id. Mikrogeologie, &c.\ Kiitzing, Sp.
Alg. 116.

STYLONICHIA, Ehr.— A genus of In-
fusoria, of the family Oxytrichina.

Char. Body ciliated, and furnished with
styles and hooks.

In this genus, transverse and longitudinal
division, gemmation, and the encysting pro-
cess have been observed.

/S. mytilus = Kerona mytilus, D. (PL 24.
figs. 27, 28). Body white, hyaline at each
end, flat, oblong, slightly constricted in the
middle, dilated at the oblique fore-part.
Aquatic; length 1-240 to 1-100".

S. pustulata = Kerona pustul. D. (PL 24.
fig. 26). Body white, turbid, oblong, with
a median ventral band of hooks. Aquatic ;
length 1-144".

S. histrio (PL 24. fig. 29). Body white,
elliptic-oblong, hooks aggregated into an
anterior heap; no setae. Aquatic; length
1-290 to 1-220".

S. lanceolata (PL 24. fig. 30). Body lan-
ceolate, pale green, obtuse at the ends;
ventral surface flat ; hooks acervate near the
mouth ; styles none. Aquatic ; length
1-140 to 1-120".

Two other species.

BIBL. Ehrenberg, In/us. 370; Stein,
Infus. 172.

STYLOSPORES.
— Stalked spores of
Coniomycetous Fun-
gi, usually compound
or septate, then pro-
bably consisting of a
row of independent
spores connected by
an adherent parent-
sac, thus, structural-
ly, metamorphosed
asci; they are some-
times appendaged

above (fig. 716) (see Stylospores of Pestalozzia.
SPORES). Magnified 200 diameters.

Fig. 716.

STYSANUS.

[ 623 ] SUDORIPAROUS GLANDS.

STYSANUS, Corda, = CEPHALOTRI-

CHUM.

SUCCINIC ACID.— This acid, which
occurs in amber, in all fermented liquids,
and in the contents of Echinococcus cysts, is
pretty soluble in water, readily in hot but
with difficulty in cold alcohol, and but little
in aether.

The crystals belong to the oblique pris-
matic system, and are represented in PI. 7«
fig. 21.

BIBL. That of CHEMISTRY.

SUDORIPAROUS GLANDS. — These
organs secrete the perspiration.

Fig. 717.

They are found in most parts of the skin,
but in variable numbers in different locali-
ties. Thus it has been estimated that 41 7
exist in a square inch of the skin of the back
of the hand, 1093 in an inch of the outside,
and 1123 in the inside of the fore-arm, and
2736 in an inch of the palm of the hand.

Each gland consists of a long tube coiled
into a knot near the closed end, which is
situated in the subcutaneous cellular tissue,
and forms the gland proper, and a straight,
undulate, or spiral duct, which traverses the
skin perpendicularly, to terminate upon its
surface between the papillae.

Fig. 718.

Fig. 717. A sudoriparous gland, with its blood-vessels, a, proper gland ; b, duct ; c, blood-vessels of a gland.
Magnified 35 diameters.

Fig. 718. Portion of the tube forming a sudoriparous gland from the hand, a, areolar coat; b, epithelium ; c, cavity.
Magnified 350 diameters.

In the glands of the axilla, the portion
of the tube forming the gland proper is
branched, and sometimes the branches ana-
stomose.

The coiled portion or proper gland is sur-
rounded and permeated by an elegant plexus
of capillaries; and some of them are sur-
rounded by a capsule of areolar tissue with
spindle-shaped cells.

The tube of the glands exhibits two forms
of structure. In one of these there is an
outer coat of indistinctly fibrous areolar
tissue with elongated nuclei, sharply defined
internally by probably a basement mem-
brane, this being lined with one, two, or
more layers of polygonal pavement-epithelial
cells, mostly containing fat-globules and
pigment-granules.

In the other form, the fibrillation of the

areolar coat is tolerably distinct, the fibres
longitudinal, sometimes also with an inner

Fig. 719.

Portion of a tube with a muscular coat, from the scro-
tum, a, areolar tissue ; b, muscular layer ; c, epithelial
cells filling the tube, and containing yellow granules.

Magnified 350 diameters.

SUGAR.

[ 624 ]

SYNCH^TA.

delicate transverse layer, and both contain-
ing nuclear elastic fibres; and within this
coat is a layer of longitudinal, unstriped
muscular fibres.

The portion of the ducts traversing the
cuticle is spiral.

It is by no means an easy matter to ob-
tain the sudoriparous glands in the entire
state. The skin of the palm of the hand or
the paw of a dog is best for the purpose ;
and before making sections with a Valen-
tin's knife, the structure should be mace-
rated in a mixture of 1 part nitric acid and
2 of water, or in solution of carbonate of
potash.

BIBL. Kolliker, Mikrosk. Anat. ii.; Todd
and Bowman, Physiolog. Anat. fyc,

SUGAR.— The crystals of sugar of milk
are represented in PL 6. fig. 12, and those
of diabetic sugar in PI. 6. fig. 13.

BIBL. That of CHEMISTRY.

SULPHUR. See LIME, sulphate of (p.
396).

SURIRELLA, Turpin.— A genus of Dia-
tomacese.

Char. Frustules free, ovate, elliptical, ob-
long, cuneate or broadly linear in front view;
valves with a longitudinal median line or a
clear space, the margins winged, and with
transverse or slightly radiating canaliculi or
tubular striae.

It appears that in the valves the margins
of the depressions are fused together to
form tubular channels open at the ends.

Kiitzing describes fifty-six species or
forms, Smith twenty as British.

S. bifrons (Ehr. 1833 = S. biseriata, Breb.
and Smith) (PI. 13. fig. 22). Frustules in
front view broadly linear, with rounded an-
gles; valves elliptic-lanceolate, somewhat
obtuse ; alse and canaliculi distinct. Aquatic;
length 1-180 to 1-96".

S. gemma (PI. 13. fig. 21). Frustules
ovate ; valves elliptic-ovate ; canaliculi nar-
row, inequidistant. Marine; length 1-240".

S. splendida. Frustules ovato-cuneate,
ends rounded ; valves ovato-lanceolate ; alse
and canaliculi distinct. Aquatic; length
1-160".

Compare TRYBLIONELLA, and see DIA-
TOMACE^E (p. 201).

BIBL. Smith, Brit. Diatom. i. 30; Kiitz.
Bacill. 59, and Sp. Alg. 34.

SWARMING.— This term has been ap-
plied by the Germans, from comparison
with the swarming of bees, to the remark-
able oscillating crowding movements of the
zoospores of Confervae, while free in the

cavity of the parent-cell, and preparing to
break forth. The zoospores are hence often
called " swarming-spores." See HYDRO-
DICTYON.

SYMBOLOPHORA, Ehr.— A genus of
Diatomaceae.

Char. Frustules single, disk-shaped, with
incomplete septa radiating from the solid
angular centre; valves not areolar (under
ordinary illumination). Marine and fossil.

-S. Trinitatis (PI. 18. fig. 6). Valves with
a triangular umbilicus, the transparent mar-
gins of which are crenulate, the rest of the
disk covered with six bundles of very fine
radiating lines. Diameter 1-220". America.

Five other species.

BIBL. Ehrenberg, Ber. d. Eerl. Akad.
1844. 74; Kiitzing, Sp. Alg. 131.

SYMPHIOTHRIX, Kiitz. = OSCTLLA-

TORIA.

SYMPHYOSIPHON, Kiitz.— A genus of
Oscillatoriaceae (Confervoid Algae), growing
on the ground, &c. S. (Scytonema, Lyngb.)
Eangii grows among mosses ; it is of black-
ish colour, tufted and bristling, the filaments
from 1-9600 to 1-7200" in diameter.

BIBL. Kiitz. Sp. Alg. p. 324, Tab. Phyc.
ii. pi. 44. 1.

SYMPLOCA, Kiitz.— A genus of Oscilla-
toriaceae (Coufervoid Algae), perhaps not
distinct from Symphyosiphon. Kiitzing in-
cludes here S. Ralfsiana = Osc. Friesii of
British authors, S. lucifuga = Oscill. luci-
fuga, Harv., and S. hydnoides = Calothrix
hydnoides, Harvey.

BIBL, Kiitz. Sp. Alg. p. 270, Tab. Phyc.
i. pi. 74-76 ; Harvey, Brit. Alg. 1st ed.

SYNAMMIA, Presl.— A genus of Gram-
mitideae (Polypodaeous Ferns). Exotic.

SYNAPTA, Eschsch.— A genus of vermi-
form Echinodermata, of the order Apoda.

The species of Synapta, which are not
British, are of special microscopic interest,
on account of the presence in their skin of
remarkable anchor-shaped, calcareous spi-
cula, the base of which plays in a perforated
plate. These are situated upon minute pa-
pillae of the skin, and serve to aid in loco-
motion and adhesion.

These bodies have been formed into ge-
nera and species of Polygastric Infusoria by
Ehrenberg, the perforated plate constituting
a Dictyocha.

BIBL. V. d. Hoeven, Zoologie, i. 150;
Vogt, Zool. Brief e, i. 168 ; Quatrefages, Ann.
d. Sc. nat. 2 ser. xvii. 19.

SYNCH^TA, Ehr.— A genus of Rota-
toria, of the family Hydatinsea.

SYNCRYPTA.

[ 625 ] SYNOVIAL MEMBRANES.

Char. Eye single, cervical, rotatory organ
furnished with styles ; foot forked.

Jaws each with a single tooth.

Some of the species are furnished with
one or more so-called crests, which in some
appear to correspond to the calcar.

S. baltica (PL 35. fig. 26). Body ovate ;
rotatory lobes four ; styles four ; a single
median sessile crest. Marine ; length 1-108".
Phosphorescent.

Three other species.

BIBL. Ehrenberg, In/us, p. 436.

SYNCRYPTA, Ehr.— A doubtful genus
of Volvocineae (Confervoid Algae), composed
of organisms consisting of a hyaline spherical
membrane (" gelatinous envelope," Ehr.)
enclosing a number of ovate green bodies
placed at the periphery and sending out a
pair of free vibratile cilia (only one, Ehr.)
from the surface of the envelope. Green
bodies not attenuated at the posterior extre-
mity ; " no eye-spot." S. Volvox (PL 3. fig.
14 b), globe 1-576" in diameter, greed "ani-
malcules " 1-2880" long; aquatic, not ma-
rine. This object, which we have observed
in company with those represented in figs.
14 a, 31 and 32 of the same plate, is most
probably a Volvox in one of the stages of
conversion of an encysted spore (fig. 34)
into a perfect family-stock (fig. 24). See
VOLVOX.

BIBL. Ehrenberg, Infus. p. 60.

SYNCYCLIA, Ehr.— A genus of Diato-
maceae.

Char. Frustules cymbelliform, united in
circular bands, immersed in an amorphous
gelatinous substance. Marine.

The nodules appear to be the same as
those of Cymbella.

S. salpa (PL 14. fig. 14). Frustules semi-
ovate, unstriated (ord. ilium.), commonly
six together, united into a ring ; endochrome
bright green.

S. quaternaria. Frustules two or four
together; endochrome yellow or reddish;
length 1-860".

BIBL. Ehrenberg, Infus. p. 233, Ber. d.
BerL Akad. 1840. 32 ; Kiitzing, Sp. Alg. 61 .

SYNDENDRIUM, Ehr.— A genus of
Diatomaceae.

Char. Frustules single, subquadrangular,
destitute of a median umbilicus ; valves un-
equal, slightly turgid, one smooth, the other
with numerous spines or little horns branched
at the ends situated upon the median
flat portion, the margins being free from
them.

S. diadema. Frustules lanceolate ; spines

five or six, bifurcate or tufted at the end, as
long as the frustules are broad. Breadth
1-1 150''. Found in Peruvian guano.

BIBL. Ehrenberg, Ber. d. BerL Akad.
1845. 155; Kiitzing, Sp. Alg. 141.

SYNEDRA, Ehr.— A genus of Diatoma-
cea3.

Char. Frustules prismatic, rectangular, or
curved; at first attached to a gelatinous
sometimes lobed cushion, subsequently
often becoming free; valves linear or lan-
ceolate.

The valves usually exhibit a longitudinal
line, with a dilated median and two terminal
nodules; they are also generally covered
with transverse striae ; in some species the
median line and appearance of a median
nodule correspond to a clear space, free from
the transverse striae.

Kiitzing describes seventy species ; Smith
twenty-four as British.

S. splendens, K. (S. radians, Sm.) (PL 13.
fig. 23 a, b, c). Frustules elongated, in front
view dilated and truncate at the ends;
valves gradually attenuated from the middle
to the obtuse ends. Aquatic; common;
length 1-70".

Frustules radiate upon the cushion.

S.fulgens (Licmophora fulg . K.) (PL 13.
fig. 24). Frustules linear ; valves slightly
dilated in the middle and at the rounded
ends, arranged in a fan-shaped manner upon
the branched cushion. Marine; length
1-120".

S. capitata (PL 13. fig. 25). Frustules
linear, truncate, ends slightly dilated ; valves
linear, ends dilated into a triangular head.
Aquatic; length 1-60".

BIBL. Smith, Brit.Diat.i. 69; Kiitzing,
Sp. Alg. 40.

SYNOVIAL MEMBRANES.— In minute
structure these resemble serous mem-
branes.

They are sometimes furnished with appen-
dages, some of which contain fatty tissue ;
others abound in capillaries, and are met
with forming fringes where the synovial
membrane is attached to the articular carti-
lages. The latter consist of a basis of indi-
stinctly fibrous areolar tissue, covered by the
synovial epithelium, with a few fat-cells,
sometimes isolated cartilage-cells, and the
capillaries. Attached to their margins are
flattened, conical, stalked, smaller appendages
(fig. 720), seldom containing blood-vessels,
and composed of indistinctly fibrous areolar
tissue, with scattered cartilage-cells, and a
thick epithelial layer; while some of the

2 s

SYNURA.

[ 626 ]

SYZYGITES.

smaller ones consist almost entirely of epi-
thelial cells or of areolar tissue.

Fig. 720.

From the synovial membrane of a finger-joint.

A. Two appendages of the synovial processes, a, areo-
lar tissue in its axis ; b, epithelium of the free margin ;
c, that continuous with the epithelium of the processes ;
(I, cartilage-cells.

Magnified 250 diameters.

B. Four epithelial cells from the synovial membrane
of the knee-joint, one of them with two nuclei.

Magnified 350 diameters.

BIBL. Kolliker, Mikrosk. Anat. i. 322.

SYNURA, Ehr.— A supposed genus of
Volvocineae (Confervoid Algae), described as
consisting of a number of oblong corpuscles
attached together by their prolonged filiform
posterior extremities in the form of a globe,
the whole enclosed in a gelatinous sphere (or a
membrane ?) ; the corpuscles are said to have
only one " flagelliform filament" (cilium),
and no " eye-spot." In S. Uvella the cor-
puscles are yellowish, the "tails" three times
as long as the bodies. Diameter of globes
1-290 to 1-190". See VOLVOX.

BIBL. Ehrenberg, Infus. p. 6.

SYRINGIDIUM, Ehr.— A genus of Dia-
tomacese.

Char. Frustules single, cylindrical; valves
dissimilar, kept apart by a turgid ring (hoop?).
Marine.

/S. bicorne. Frustules oblong, smooth, not
striated (ord. ilium.), turgid in the middle,
one end attenuate, with two slight constric-
tions, and acuminate, the other subglobose,
turgid, and with two horns. Length 1-3/0".
Coast of Africa.

BIBL. Ehrenberg, Ber. d. Berl. Akad.
1845. 365; Kiitzing, Sp. Alg. 32.

SYSTEPHANIA, Ehr.— A genus of Dia-
tomaceae.

Char. Frustules circular; valves alike,
areolar, neither radiate nor septate, with a
crown of spines or an erect membrane on the
outer surface of each valve (not on the mar-
gin). Fossil.

Three species ; found in Bermuda.

BIBL. Ehrenberg, Ber. d. Berl. Akad.
1844. 264; Kiitzing, Sp. Alg. 126.

SYZYGITES, Ehrenberg.— A. genus of
Mucorini (Physomycetous Fungi), contain-
ing one species, a kind of mould growing
over decaying Agarics, remarkable among
all the* class to which it belongs for the oc-
currence of the phenomenon of conjugation
of its branches as a preliminary to the for-
mation of the spores. The only species is
S. megalocarpus, in which the conjugation
was discovered by Ehrenberg many years
ago. The young filaments are simple, slen-

Fig. 721.

Syzygites megalocarpus.

A branched filament, exhibiting the conjugation in
various stages.

Magnified 200 diameters.

der, rather rigid, pellucid and straight, soon
becoming forked, thickish, whitish-yellow
(somewhat olive when dry). The rudiments
of the peridioles spring out as papillae from
the branches, becoming pear-shaped, and
when two come in contact, they cohere, and
become confluent into a fusiform body. The

TABELLARIA.

[ 627 ]

T^NIA.

contents of the filaments next ascend and
accumulate in the peridiole, at length form-
ing a black globule (sporange?). While this
is ripening, the apices grow out into long
simple filaments.

BIBL. Ehrenb. Verhandl. Naturf. Freund.
Berlin, i. p. 91; Fries, Syst. Myc. iii. p.329;
Berkeley, Ann. Nat. Hist. i. p. 257.

T.

TABELLARIA, Ehr.— A genus of Diato-
maceae.

Char. Frustules tabular, attached, at
first united into a filament, subsequently
cohering only by the angles, with longitudi-
nal vittae interrupted in the middle ; valves
inflated in the middle and at each end.
Aquatic.

T.flocculosa (PL 13. fig. 27 a, b}. Vittse
alternate, middle and ends of the valves
equally inflated. Length 1-960 to 1-840".

T. ventricosa. Vittae alternate, median
inflation the largest. Length 1-960".

T. fenestrata. Frustules oblong; vittae
opposite; inflations equal. Length 1-600
to 1-290".

Five fossil species.

BIBL. Kiitzing, Sp. Alg. 1 18.

TABLE.— A table for the conversion of
foreign into English measures, is given un-
der MEASUREMENT (p. 418).

TADPOLE. See FROG (p. 273).

TJENIA (Tape-worm).— A genus of En-
tozoa, belonging to the order Cestoidea.

Char. Body elongate, compressed, jointed.
Head mostly broader than the neck, with
four suctorial depressions; and usually a
median, imperforate, retractile rostellum,
very frequently armed with one or two cir-
cles of minute recurved hooks, especially in
the young state. Genital orifices situated at
the margins of the joints, either on one side
only, or on both margins and on alternate
joints.

The Tcenia, of which the common tape-
worm may be taken as the type, are found
in vertebrate animals alone, and in these
only in the alimentary canal. They are most
common in birds, next in mammalia, then
in fishes, and lastly in reptiles.

The species are very numerous ; Rudolphi
enumerates 146, of which 53 were considered
doubtful. Dujardin admits 135 species.

T<Bnia solium, the common human English
species, varies in breadth from 1-50 to 1-40"
at the anterior part, to about 1-3" at the

middle and posterior part. At the anterior
extremity is situated a central rostellum,
which is surrounded by a crown of small
recurved hooks, as in PL 16. figs. 1 /& 10.
Behind these are four suctorial depressions,,
which are not pervious at the bottom. The
digestive system, according to Blanchard, is
represented by two tubes or lateral canals
(PL 16. fig. 145), having between them a
transverse canal at the summit of each joint.
These extend from the anterior to the pos-
terior end of the body. In the cephalic
portion, directly behind the suckers, there is
a kind of lacuna or furrow communicating
directly with these intestinal tubes ; and it
appears that the nutritive matters respired
by means of the suckers penetrate into this
lacuna, and thence into the digestive canals.
These tubes have distinct walls, and are best
seen when the animal has been macerated in
water, and is examined by transmitted light,
or after having been injected.

The vascular system, according to the
above author, consists of four longitudinal
vessels (PL 16. fig. 146) situated a little
above the intestinal tubes, and infinitely
more slender than these. They traverse the
whole length of the body, and between them
are numerous transverse vessels (PL 16.
fig. 14).

The male generative organ consists of a
slender coiled tube, extending to near the
principal ovigerous canal, where it is pre-
ceded by some very small testicular capsules
(PL 16. fig. 14 c). The slender tube termi-
nates in a duct (PL 16. fig. 14 d), which
opens into the lateral orifice, or sometimes it
projects externally in the form of a spiculum.
The ovary consists of a principal median
canal, presenting slight flexuosities, and ex-
tending nearly from one end to the other of
each joint. It presents caecal branches on
both sides, and opens by a slender oviduct
(PL 16. fig. 14 c) just within the genital
orifice.

The ova are innumerable ; one is figured
in PL 16. fig. 15. They consist of an outer
delicate membrane enclosing a gelatinous
substance containing numerous highly re-
fractive globules. Within this is another
very delicate and transparent membrane,
closely applied upon a brittle, dark-looking
(by transmitted light, but white by reflected
light), thick envelope, within which is
the yolk or embryo, according to the
state of development of the ovum. Very
frequently the hooks of the young taenia
are seen imbedded in its centre, as shown in
2s2

TJENIOPTERIS.

[ 628 ]

TARDIGRADA.

the figure. The thick brittle coat of the
ovum exhibits an appearance of radiating
fibres, and when broken the fractures are
radiant. When the middle of the outer
surface of the brittle envelope is brought
into focus, it presents a tolerably regular
appearance, as if composed of cells; this
arises, however, from the extremities of the
fibres being brought into focus.

The spermatozoa are readily found, simply
by picking any joint containing ova to pieces
with needles.

The old genera Cwnurus, Cysticercus, and
Echinococcus represent the larval or nurse-
forms of Tcenia.

See ENTOZOA.

Tcenia lata = Bothriocephalus latus.

BIBL. See that of ENTOZOA and BOTH-
RIOCEPHALUS.

T.ENIOPTERIS, Hook.— A genus of
Taenitideae (Polypodaeous Ferns). Exotic.

T^ENITIDE^E.— A subtribe of Polypo-
daeous Ferns, without an indusium, including
the following genera : —

I. PLEUROGRAMMA. Sori contiguous
on each side of the rib, parallel, linear, and
continuous.

II. POLYT^NIUM. Sori very long, con-
tinuous or interrupted, two to four between
the rib and the margin, linear, immersed,
parallel, occupying longitudinal veins. Veins
anastomosing.

III. T^ENIOPTERIS. Sori submarginal,
linear, elongated, continuous, deeply im-
bedded. Veins simple, scarcely anastomo-
sing.

IV. T^ENITIS. Sori submarginal in the
middle of the disk of the leaf, linear, elon-
gated and continuous. Veins anastomosing
more or less regularly into meshes.

V. JENKINSIA. Sori linear, elongated,
continuous. Veins anastomosing into more
or less regular meshes, with free venules.

T^ENITIS, Sw.— The typical genus of
Tsenitidese (Polypodaeous Ferns). Exotic.

TALC. See'MiCA.

TAONIA, J. Ag.— A genus of Dictyotaceae
(Fucoid Algae), containing one rare British
species, T. atomaria, which has a flat, mem-
branous, fan-shaped, deeply cleft frond,
3 to 12" high, of brownish olive colour;
marked on both faces at intervals of 1-4 to
1-2", with concentric wavy lines, formed by
rather crowded dark brown "spores," the
interspaces being dotted over with scattered
spores. The disk of attachment is covered
with woolly filaments.

Thuret has recently shown that the Dic-

tyotaceae should be separated from the Fu-
cacese, and stand between them and the
Floridese, since he has found not only that
their spores are analogous to the concepta-
cular spores of the latter, and do not pro-
duce ciliated zoospores, but that also they
produce tetraspores, and what appear to be
antheridia (Dictyota) in different individuals.

BIBL. Harvey, Brit. Mar. Alg. p. 38.
pi. 7 A; Thuret, Ann. des Sc. nat. 4 ser.
iii. p. 7.

TAPHROCAMPA, Gosse.— A genus of
Rotatoria, of the family Hydatinaea.

Char. Rotatory organs absent ; body fusi-
form, annulose, tail forked, gizzard oval.

T. annulosa. Aquatic; length 1-110".

BIBL. Gosse, Ann. Nat. Hist. 1851. viii.
199.

TAPIOCA. — A very pure fecula prepared
from the finer particles of the starch of the
Mandioc or Cassava plant (PL 36. fig. 14).
The starch-granules of tapioca of the shops
appear to have undergone the action of
heat, which disguises the characters. See
STARCH.

TARDIGRADA (Water-bears).— A family
of Arachnida, of the order Colopoda.

Char. As this is the only family, the cha-
racters are those of the order (ARACHNIDA,
p. 57).

These microscopic animals are found in
stagnant fresh water, amongst water-plants,
in patches of wet moss, in the gutters of
houses, &c.

Body soft, cylindrical, or elongate-oval in
outline, with four transverse furrows, or in-
distinct segments, and a fifth anterior, corre-
sponding to a head, short, conical, retractile,
and with indications of two or three seg-
ments ; sometimes dilated at the end to form
a sucker, or furnished with unequal, short,
palp-like processes. Eyes two.

The oral organs are represented by a tu-
bular rostrum, through the sides of which,
from without inwards, two calcareous styles
or mandibles pass, and serve to wound the
animals forming their prey. At the base of
the rostrum is a gizzard with radiating mus-
cular fibres, in Macrobiotus enclosing a kind
of framework consisting of six parallel jointed
cylinders.

The alimentary canal is straight, and fur-
nished with lateral caecal appendages. The
ovary is a simple sac, behind which is situ-
ated a seminal vesicle containing spermatozoa,
both opening into a cloaca. But few eggs
are produced at a time; they are either
smooth, rugous, or studded with points, and

TARGIONIA.

[ 629 ]

TARGIONIA.

are usually deposited during the ecdysis, the
exuviae serving as a protection to them
during the process of hatching. The young
resemble the parents.

The Tardigrada resemble some of the Ro-
tatoria in reviving after having been kept
dried for years.

Genera. Emydium, Macrobiotus, Milne-
sium (Arctiscon, doubtful).

BIBL. Doyere, Ann. des Sc. nat. 2 ser.
xiv. 269, xvii. 193, xviii. 1; Dujardin, x. 185;
Vogt. Zoolog. Brief e, i. 4P6; Kaufmann,
Siebold and Kolliker's Zeitschr. iii. 220.

TARGIONIA, Mich.— A genus of Fellies
(Hepaticaceae), characterized by the almost
sessile, globose capsule arising from the end
of the midrib of the under face of the frond,
which is somewhat fleshy, smooth, deep-
green, purplish at the edges, and forms large
patches on rather moist but exposed banks.
The frond has an epidermis on both faces,
with stomata and intermediate parenchyma;
the midrib is only apparent beneath, and
has radical hairs, with purple scales. The
perichaete originates from this rib, on the
under surface, rising to the upper side (fig.
722). When mature, it is globose, of dark

Fig. 722.

Fig. 723.

9TIOO

Fig. 724.

Fig. 725.

Targonia hypophylla.

Fig. 722. Lobe of a frond with fruit. Magnified 5
diameters.

Fig. 723. Perichsete opened, showing the globular spo-
range. Magnified 20 diameters.

Fig. 724. Vertical section of a very young sporange.
Magnified 200 diameters.

Fig. 725. A branched elater. Magnified 200 diameters.

purplish colour and firm texture, and marked

with a vertical prominent line or keel ; at
this line it ultimately splits into two valves
(fig. 723). From Hofmeister's recent ob-

Fig. 726.

Fig. 727.

Fig. 728.

Fig. 729.

Figs. 726 & 727. Groups of four spores, not quite
mature. Magnified 400 diameters.

Fig. 728. Parent-cells of spores and imperfect elaters,
from a more advanced fruit. Magnified 100 diameters.

Fig. 729. The same. Magnified 200 diameters.

Fig. 730. A single ripe spore. Magnified 400 diameters.

servations, however, this envelope grows
up after the fertilization of the archegone,
which is originally naked in its upper half;
hence it would seem to be a perigone.
Several archegones are found half-immersed
in the end of the midrib, and one of these is
converted into a fruit; the lower part be-
comes spherical, and the neck forms for a
long time a filiform point or style. This
epigone bursts irregularly and vertically.
The spherical capule emerges from it, but is
not protruded beyond the perichaete. The
globular capsule bursts irregularly at the
summit, and discharges spores and elaters
resembling those of Marchantia (figs. 728
to 730). The antheridia are imbedded in
the midrib, opening on papillae on the
lower face.

BIBL. Hook. Brit. Flor. ii. pt. 2. p. 105 ;
Corda, Sturm's Deutschl. Fl. Jungerm. pi.
30 ; Nees, Lebermoose, iv.

TARTARIC ACID.

[ 630 ]

TEETH.

TARTARIC ACID.— The crystals of this
substance, which belong to the oblique pris-
matic system, exhibit beautiful colours under
the polariscope.

TAXUS, L.— Taxus baccata is the Yew-
tree, belonging to the Coniferae. Its wood
(PI. 39. fig. 4), as also that of T. canadensis,
shows the remarkable combination of spiral
fibres with the coniferous pits. Its embryo-
logy is also interesting. See CONIFERS
and OVULE.

TAYLORIA, Hook.— A genus of Splach-
naceae (Acrocarpous operculate Mosses),
containing some of Splachna of authors.

Tayloria serrata, Br. and Sch. y tennis =
Splachnum tenue, Dicks.

TEETH.— The teeth of the Mammalia are
inserted in sockets or alveolar cavities of the
jaws.

The teeth consist of a crown, or that por-
tion which projects beyond the alveolar
cavity and the gum ; the fangs, or the por-
tions which are inserted into the bony struc-
tures ; and a neck, or narrower intermediate
portion. The crown of the tooth contains
the pulp-cavity, which is closed below, but
prolonged above through the fangs.

Fig. 731.

Molar tooth, human ; longitudinal section,
a, enamel ; b, pulp-cavity ; c, cement ; d, ivory, with
the ivory-tubes. Magnified 5 diameters.

In regard to their structure, teeth are in
part identical with bone, in part closely
allied to it ; but in respect to their develop-

ment, they must be regarded as formations
of the mucous membrane, as modified pa-
pillae.

The substance of human teeth consists of
three parts : the ivory or dentine (fig. 731 d},
which constitutes the greater portion of their
mass, and to which their form is mainly
owing; the cement, or bony portion (fig.
731 c), which forms an external covering,
principally of the fangs; and the enamel
(fig. 731 a), which covers the crown.

The ivory or dentine (fig. 731 d, 732 d) is
whitish and of a silky lustre, and, excepting

Fig. 732.

Transverse section of the same, the references as above.
Magnified 5 diameters.

a small portion at the base of the fangs,
forms the entire boundary of the cavity of
the teeth. It consists of a homogeneous
basis enveloping numerous tubes or canali-
culi, called the ' ivory-tubes ' (fig. 734 a, b).
These are very fine, and pursue an undu-
lating course, at first curving, then bifur-
cating, throughout giving off numerous fine
lateral communicating branches, which are
best seen in a horizontal section (fig. 733), and
ultimatelyramifyingand anastomosing freely.
They commence at the surface of the pulp-
cavity, in the crown following a somewhat
radiating direction from its centre (fig. 731),

Fig. 733.

Transverse section of the ivory- tubes of the fang (a, fig.
734), showing their numerous anastomoses.

Magnified 450 diameters.

whilst in the fangs their course is more ho-

TEETH.

[ 631 ]

TEETH.

rizontal. They have distinct walls, about
equal in thickness to their calibre, although

Fig. 734.

Ivory-tubes of a fang of a human tooth, a, inner
surface of the ivory, with few tubes ; b, their branches ;
c, their terminations in loops ; d, granular layer, con-
sisting of small ivory globules at the boundary of the
ivory ; e, lacunse of bone, one anastomosing with an ivory-
tube. Magnified 350 diameters.

in transverse sections (fig. 735) this thick-
ness is generally exaggerated, on account of

Fig. 735.

Transverse section of the ivory-tubes, a, closely aggre-
gated, b, wider apart. Magnified 450 diameters.

their being obliquely divided. They contain
air in the dry state, which may be displaced
by liquids. By removing the inorganic salts
from a tooth with dilute muriatic acid, and
macerating the remaining cartilage with
acids or caustic alkalies until it forms a pasty
mass, the tubes may be isolated from the
basis.

The ivory not unfrequently exhibits indi-
cations of a laminated structure, forming,
in longitudinal sections, curved lines more
or less parallel to the outline of the crown
(fig. 736), appearing as rings in transverse
sections, and called the contour-lines.

Near the enamel (fig. 736) and the cement
(fig. 734 d) also, the ivory presents one or
more irregular dark patches or bands, often
continuous with the ends of the contour-
lines, and exhibiting a coarsely cellular ap-
pearance. On careful examination, the dark
appearance is seen to result from a number
of irregular spaces filled with air (fig. 737 a)
intervening between certain globules, called
ivory-globules, the spaces being termed the
interglobular spaces. In the recent tooth,
these spaces are filled with the organic basis
of the ivory, containing tubes like the rest
of that substance, in which, however, the
inorganic matter has not been deposited;
hence this structure arises from imperfect
development.

Other ill-defined iridescent stripes, running
parallel to the pulp-cavity, are sometimes
seen ; these correspond to the primary curves
of the ivory-tubes.

The cement or bone of teeth forms the
outer coating of the fangs (figs. 731 c & 738),
sometimes cementing them together. It
commences as a very thin layer at the part
where the enamel ceases, increasing in thick-
ness towards the ends of the fangs. The

TEETH.

[ 632 ]

TEETH.

cement does not differ from bone in struc-
ture, except in rarely containing Haversian

Fig. 736.

ii: ban ,

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aftfon
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ytid

Perpendicular section of the apex of a human incisor
tooth, a, pulp cavity ; b, ivory ; c, curved contour lines
with interglobular spaces ; d, cement ; e, enamel, with
indications of the course of ,the fibres in various directions ;
/, coloured stripes of the enamel.

Magnified 7 diameters.

Fig. 737.

Portion of the ivory, with ivory globules and interglo-
tmlar spaces filled with air. Magnified 350 diameters.

canals. In the molar teeth of old persons,
these are, however, met with (fig. 738 e).

Fig. 738.

Cement and ivory of the fang of a tooth of an old
person, a, cavity ; b, ivory ; c, cement with lacunae ;
e, Haversian canal. Magnified 30 diameters.

The lacunae are frequently absent from the
thinner portion of the cement, and it some-
times contains tubes like those of the ivory.
The interlacunar substance is sometimes
striated, and exhibits a laminated struc-
ture.

The enamel (fig. 731 a) covers the ivory of
the crown of the teeth. It is thickest at the
opposing surface, decreasing towards the
neck, where it terminates. It is covered by
a very thin membrane, separable after the
action of muriatic acid, and containing cal-
careous matter ; this has been regarded as a
continuation of the cement. The enamel
has a fibrous aspect, and appears of a bluish
white colour by reflected light, and of a
greyish brown by transmitted light. It is
very brittle, and so hard as to strike fire with
steel. It consists of numerous solid fibres
or prisms (fig. 739), about 1-6000 to 1-5000"
in breadth, mostly six-sided, more or less
wavy, slightly varicose, and transversely
striped. These usually extend throughout
the thickness of the enamel, and are placed
in a direction generally perpendicular to the
surface of the portions of the ivory which
they cover (figs. 731, 736). The form of
the fibres is best seen by viewing their
ends or a transverse section (fig. 740). The

TEETH.

[ 633 J

TEETH.

prisms do not run exactly parallel with each
Fig. 739.

Enamel-fibres, isolated by the very slight action of
muriatic acid ; human. Magnified 350 diameters.

other, but are arranged in groups or zones,
the fibres of which cross each other. The
fibres are readily isolated before they have
become so developed as to be hard, and
when very slightly acted upon by muriatic

acid. Sometimes the ivory-tubes extend
into the enamel.

Two kinds of dark bands or stripes are
seen traversing the enamel (fig. 736). The
direction of one of these coincides pretty
nearly with that of the fibres, and it arises
from the crossing of the zones of fibres,
allowing more or less light to pass through,
the bands being light and dark. The other
set (fig. 736 ff) consists of arched, brownish
stripes, indicating the laminated structure of
the enamel. Under the polariscope, a third
set becomes visible, arising from the variable
inclination of the axes of the fibres to the
plane of polarization.

The enamel is often traversed by cracks,
mostly running parallel with the fibres, and
containing ail1 in dry teeth.

Chemically, teeth consist of an organic,
cartilaginous basis, agreeing in composition
with that of bone, and inorganic matter
consisting principally of phosphate of lime
with a small quantity of the carbonate.

Development. — The rudiments or germs
of the first (milk) teeth are met with in the
sixth week of fcetal life, and consist of small
papillae, one for each tooth, which become
visible in grooves of the mouth, afterwards
forming the alveolar processes. Processes
from the sides of these dental grooves are

' *i> *r *>/ ^"i'ii ^n'f

Fig. 740.

v\

Fig. 740. Surface of the enamel, with the ends of the enamel-fibres, from the tooth of a calf. Magnified 350 diameters.

Fig. 741. Diagram showing the development of a milk-tooth, and the corresponding permanent tooth, a, furrow ;
h, the same with the papilla ; c, the same closing, with the commencement of the reserve cavity ; d, the same, further
closing ; e, follicle completely formed, with the reserve cavity ; /, the reserve cavity receding ; g, the same, with
a tooth-germ ; h, the alveoli of both capsules formed, the milk-tooth being through the gum ; », the same, further
advanced, the neck of the capsule forming a solid cord.

TEETH.

[ 634 ]

TEETH.

then formed, and approaching each other,
Fig. 742.

f

Lower jaw of a human nine months' foetus, a, tongue,
turned back ; b, right half of the lower lip turned aside ;
b', left half of the lip cut off; c, outer wall of the gum ;
d, inner wall of the gum ; e,f, g> h, papillae of the teeth ;
i, fold where the sublingual duct subsequently opens.

Magnified 9 diameters.

enclose the papillae in distinct follicles, the
margins of which gradually grow over the
papillae, and uniting, convert them into
closed sacs or capsules. The pulps then
become moulded into the form of the future

Fig. 743.

Capsule of the second incisor tooth of an eight months'
human foetus, a, capsule ; b, enamel-pulp ; c, enamel-
membrane; d, enamel; /, ivory cells ; A, papilla of tooth
or pulp ; i, free margin of enamel- organ.

Magnified 7 diameters.

teeth ; the bases of the pulps dividing into
as many portions as the teeth have fangs,
and as the capsules increase at this stage
faster than the pulps, a space is left between
them, in which a gelatinous-looking sub-
stance is deposited from the wall of the
capsule forming the enamel organ.

The capsule (fig. 743 a) possesses an
areolar coat with vessels and nerves, and
from its base arises the tooth-germ or pulp
(fig. 743 h}. The pulp consists of an outer
non-vascular layer of elongated, nucleated
cells, with filiform processes, in close appo-
sition (fig. 744 a), covering the surface of

Fig. 744.

Surface of the pulp of a newly-born infant, a, wing-
cells ; b, their appendages ; c, vascular part of the pulp.

Magnified 300 diameters,

the pulp, the ivory-membrane (fig. 743 /),
not distinctly defined internally, but gradu-
ally passing into the vascular parenchyma of
the pulp. The inner part of the pulp con-
sists of indistinctly fibrous areolar tissue
with nuclei ; the vessels terminating in loops
beneath the enamel membrane (fig. 744 c).

The enamel organ (fig. 743 b} covers, byits
inner concave surface, the pulp, its outside
being in apposition with the capsule. It
forms a spongy tissue, composed of anasto-
mosing stellate cells or reticular areolar
tissue; in its inside is the enamel membrane,
consisting of cylindrical epithelium (fig.
743 c).

Ossification commences by the deposition
of calcareous matter in the cells of the ivory
membrane at the summit of the pulp ; this
is soon followed by similar deposition in the
cells of the enamel membrane. By the

TEMORA.

[ 635 ]

TEST-OBJECTS.

further formation of new cells and fresh
deposition, the structure of the teeth becomes
more and more consolidated, the spongy
tissue of the enamel gradually being ab-
sorbed.

When the entire enamel and a consider-
able portion of the ivory have been formed
in the capsules, these become too small to
contain the teeth, which then rupture them,
and continue to grow at the root, until the
crown projects above the margin of the jaw.
The remainder of the capsule then forms
the periosteum of the alveoli, and by depo-
sition from the side next the tooth, produces
the cement.

The permanent teeth are formed upon the
same plan ; — the three last molars in the
remains of the primitive dental groove ; the
others in distinct sacs, called reserve sacs,
and formed in the wall of the follicles of
the milk-teeth.

The teeth of animals present numerous
interesting varieties, to which we can but
briefly refer. Thus in the Mammalia, the
enamel is often absent; the cement fre-
quently extends over the crown ; the three
component structures are folded ; the teeth
are compound; the ivory contains Haversian
canals, and the ivory-tubes enter the enamel.
In reptiles the teeth are often anchylosed to
the jaws. In fishes the teeth are often
solid ; the ivory is furnished with Haversian
canals, sometimes isolated, and each sur-
rounded by a layer of ivory and cement, so
that the teeth appear to consist of aggrega-
tions of little teeth; the vessels often
branch and anastomose freely ; the ivory
tubes are often very large or absent, the ivory
then consisting of a finely granular base with
numerous vascular canals, true enamel ap-
pearing to be absent.

The method of making sections of teeth is
described under PREPARATION. They
should be very thin and preserved in the dry
state.

BIBL. Kb'lliker, Mikroskop. Anat. ii. 54 ;
Owen,0dontography, and Todd's Cycl. Anat.
fyc., iv. 864; Goodsir, Edinb. Med. and
Surg. Journ. 1839. i. ; Tomes, Lectures on
Dental Surgery, fyc., and Phil. Trans. 1849,
1850; Nasmyth, Researches on the Teeth-,
Retzius, Muller's Archiv, 1837. 486;
Heusinger, Histologie.

TEMORA, Baird.— A genus of Entomo-
straca, of the order Copepoda, and family
Diaptomidae.

Char, Thorax composed of five, abdomen
of three joints; lesser antenna two-branched;

first four pairs of legs each giving off a two-
jointed branch.

T. finmarchica. Found on the coast of
Ireland.

BIBL. Baird, Brit. Entomostr. 227.

TENDON. See LIGAMENTS.

TENTHREDO, Leach.— A genus of Hy-
menopterous Insects, of the order Tenthre-
dinidae (Saw-flies).

The species of Tenthredo and of the other
genera belonging to the family, both of
which are very numerous, are interesting on
account of the remarkable structure of the
ovipositor, which consists of two flattened
and curved saw-like plates. These are used
to saw the leaves of plants, for the deposi-
tion of the eggs.

The insects are found upon gooseberry-
bushes, rose-bushes, the white thorn, the
willow, alder, poplar, the plum and other
fruit-trees, cabbage, turnip, bramble, &c.
The larvae are very destructive to agricul-
tural crops.

T.nassata is represented in fig. 367 (p. 362).

BIBL. Westwood, Introduction, fyc. ii. 90,
and the Bibl. therein.

TERPSINOE, Ehr.— A genus of Diato-
maceae.

Char. Frustules tabular, obsoletely stipitate,
subsequently connected by isthmi, and with
transverse, short, interrupted, capitate vittae;
valves in side view with lateral inflations.

T. musica (PI. 14. fig. 33, side view; PI.
19. fig. 10, front view). Frustules very faintly
punctate, in front view rectangular oblong ;
side view equally inflated in the middle and
at the ends, in older specimens constricted
in the middle, inflated beyond the middle
towards both ends, the apices produced and
obtuse, the nodules separated by septa.
Length 1-180".

T. indica (Anaulus ind., E.).

BIBL. Ehrenberg, Abhand. d. Berl. Akad.
1841. 402; Kiitzing, Bacill. 128, Sp. Ala.
119.

TESSELLA, Ehr.— A genus of Diato-
maceae.

Char. Frustules broadly tabular, not con-
catenate, with crowded, longitudinal, alter-
nate vittae, interrupted in the middle ; stipes
absent (?). Marine.

T. interrupta (PL 14. fig. 35). Length of
frustules 1-580; breadth 1-560 to 1-120".
Found with Striatella.

BIBL. Ehrenberg, Infus. 202; Kutzing,
Bacill. 125, Sp. Alg. 114.

TEST-BOX. INTRODUCTION, p. xxiii.

TEST-OBJECTS.— Test- objects are mi-

TEST-OBJECTS.

[ 636 ]

TEST-OBJECTS.

croscopic objects used to determine the value
of object-glasses.

We must presume that the reader has
perused the remarks upon object-glasses in
the Introduction (p. xiv) ; also the article
ANGULAR APERTURE; otherwise the obser-
vations made here will be unintelligible.

The main points in which object-glasses
differ from each other are four ; viz. 1. their
magnifying power ; 2. their defining power ;
3. their penetrating power ; and 4. their cor-
rective adaptations.

1. The magnifying or separating power
scarcely requires notice ; it must be adapted
to the size of the objects likely to come
under examination. Usually, several object-
glasses are kept, of different powers ; at all
events, if scientific investigations are to be
pursued, a power of 400 diameters must be
accessible, and this without the use of the
highest eyepiece. The magnifying power
should be ascertained by MEASUREMENT,
and not by judging from the focal length.

2. Good defining power is the most im-
portant character of an object-glass ; and if
good in respect to this, the dark boundary
lines of the test-objects will appear clear,
black, sharp, as if engraved, and quite free
from colour. If this is ascertained to be the
case, the higher eyepieces should be put on;
and it must be observed, that although the
sharpness of the outline is somewhat dimi-
nished, all the parts are clearly distinguish-
able as before. In this examination the
light should be as direct as possible.

3. The power of displaying the minute
structural peculiarities of objects, or the pe-
netrating power, as it is called, depends upon
two distinct circumstances ; the goodness of
the defining power and the magnitude of
the angular aperture of the object-glass :
the degree of obliquity of the light is also of
great importance in connexion with the
latter.

Thus, in examining the scale of a Podura
(PI. 1. fig. 12 a, 6, c), the magnifying power
being sufficiently high, if the defining power
be good, the wedge-shaped bodies will be
clearly and sharply displayed by direct light,
and whether the angular aperture be large
or small. Now, if we examine a valve of
Gyrosigma (PI. 1. figs. 17 & 18) by direct
light, the minute structure will be invisible,
however small or large the angular aperture
may be, or however perfect the defining
power ; but if the light be thrown obliquely,
and the aperture be sufficient, the striae will
at once become evident. Hence there are

two distinct kinds of penetrating power, one
of which is the same as the defining power,
the other depending upon a different cause,
and hence the term penetration or penetra-
ting power should be laid aside, as tending to
cause confusion, the properties of object-
glasses being reducible simply to their defi-
ning power and their angular aperture.

The defining power should be tested upon
the different objects mentioned below in con-
nexion with each object-glass, and the angular
aperture should be determined by measure-
ment (ANGULAR APERTURE), for judgment
founded upon the examination of the valves
of the Diatomaceae may be very fallacious to
an unpractised observer, on account of the
influence of the obliquity of the light, and
of the correcting adjustment. If, however,
an opinion is to be formed in this way, the
valves should be examined by oblique light
thrown from all sides, as with the central
stop in the condenser, so that the dots may
be viewed; for an object-glass may show
the lines very fairly, but the dots very
badly.

4. The correcting adjustment is of im-
portance in examining very delicate objects
or structures with the high powers; it should
therefore always be present.

We subjoin, in connexion with each object-
glass, the magnitudes of the angle of aper-
ture which they usually have in this country,
and which may be regarded as standards for
comparison; also those objects which will
be found most suitable for the purpose of
testing an object-glass.

H or 2-inch object-glass. Magnifying
power 20 diameters ; angular aperture 12 to
20°.

Test-objects : the pygidium of the flea
(PL 1. fig. 13 a), in which the general out-
line and the hairs should be distinct ; the
hair of the mouse (PI. 1. fig. 3). Also, as
an opake object, a piece of an injected pre-
paration (PL 31. figs. 33-35).

\-inch or %rds-object-glass. Magnifying
power 60 diameters ; angular aperture 22
to 27°.

Tests: hair of Dermestes (PL 1. fig. 1) ;
of the bat (PL 1. fig. 2); of the mouse (PL
1. fig. 3); the pygidium of the flea, the
outline of the areolae being distinguishable
under the high eyepiece (120 to 200 dia-
meters), but not the rays. Also an injection,
as a piece of lung.

\-inch or -^ths-inch object-glass. Mag-
nifying power 100 to 120 diameters ; angu-
lar aperture 55°.

TEST-OBJECTS.

[ 637 ]

TEST-OBJECTS.

Tests : hairs (PI. 1. figs. 1, 2, 3) ; the disks
on deal (PI. 1. fig. 4) ; the coarser scales of
Lepisma (PI. 1. fig. 6 a); the pygidium of
the flea (PI. 1. fig. 13 a, b}, the entire struc-
ture visible under the high eyepiece; a
dark scale of Podura (PI. 1. fig. 126).

\-inch object-glass. Magnifying power
220 diameters ; angular aperture 75 to 140°.

Tests : hair of Dermestes ; the disks of deal;
the salivary corpuscles (PL 1. fig. 5), the
moving molecules being clearly distinguish-
able ; the smaller scales of Lepisma (PL 1.
fig. 6 «, b) ; the scales of Podura ; the fila-
ments of Didymohelix (PL 1. fig. 10 a) ;
the pygidium of the flea, and the scales of
Ponti'a brassiccB (PL 2/. fig. 24).

%-inch object-glass. Magnifying power
420 to 450 diameters; angular aperture 110
to 150°.

Tests : the paler scales of Podura', the pygi-
dium of the flea ; the scales of Pontia brassi-
c&\ the filaments of Didymohelix, showing the
component fibres ; the salivary corpuscles.

TVfA or ^-gth-inch object-glass. Magni-
fying power 600 to 650 diameters ; angular
aperture 80 to 120°.

Tests : the paler scales of Podura ; the fila-
ments of Didymohelix mounted in balsam ;
and the primitive fibrillas of muscular fibre
(PL 17. fig. 366, d).

It will be observed that we have omitted
the tests for angular aperture, which many
of our microscopists look upon as the true
tests of the value of an object-glass. Our
reasons for this are given in the INTRODUC-
TION (p. xv). Those, however, who wish
for an interesting series of difficult objects
in this respect, will find one in the valves of
Gyrosigma, Grammatophora, Fragilaria,
Rhipidophora, Amphipleura, some species of
Nitzschia, as N. tcenia, and Eerkeleyia (see
these articles). We regard large angular
aperture in an object-glass as of little im-
portance ; because it is only of service for
showing the markings upon the valves of
the Diatomaceae, and the time is probably
near at hand when the presence and size of
these will be shown to possess neither
generic nor specific importance ; moreover,
object-glasses of large aperture and high
power approach so nearly to the object, that
they are inapplicable to important physiolo-
gical investigations.

We shall now offer a few

General remarks on the application of
test-objects to the choice of an object-glass.
A great difficulty presents itself in this ques-
tion in the case of persons commencing the

use of the microscope. For on viewing
almost any object, they will see so much
that was invisible before, that they are natu-
rally led to regard an object-glass as good
which may simply possess tolerable magni-
fying power.

There is also some difficulty to an un-
practised eye in discriminating between a
well-defined margin of an object, and one
which is ill-defined. This may be overcome
by purchasing one or two test-objects from
those who mount objects for sale, and first
viewing them under their microscopes ; or
by examining some of the objects exhibited
at the evening meetings of the learned
societies.

The objects themselves are also variable,
some being much more delicate than others
even of the same kind. The best plan in
regard to this point is to select an object, as
the scale of an insect or whatever it may be,
in which the test-structure is not distin-
guishable under the next highest power, and
then to examine the same object under the
power to be tested.

The manner in which objects are mounted
is also of importance, for if they be immersed
in too much balsam or covered by too thick
a cover, no object-glass will show them well,
however good it may be. Hence the ne-
cessity of purchasing the test-objects, in the
case of an inexperienced observer. They
may be obtained from Mr. Norman, Fountain
Place, City Road ; Mr. Topping, New Win-
chester Street, Pentonville; or of Messrs.
Smith and Beck, Coleman Street, City.

A few notes upon the test-objects them-
selves may not be out of place here.

Hairs of animals (PL 1. figs. 1-3). These
should be mounted in Canada balsam. Many
of those represented in PL 22 might be used
with equal advantage.

Disks of deal (PL 1. fig. 4). Form a
good test-object on account of their freedom
from colour, whence the colours from un-
corrected chromatic aberration are easily
seen with a bad object-glass.

Salivary globules (PL 1. fig. 5 a, b, c).
Obtained from the saliva. A good test-object
for those engaged in physiological investi-
gations ; the marginal granules and the
moving molecules should be very distinct.

Scales of insects (PL 1. figs. 6 a, b, c, 12 a,
b, c; PL 27. fig. 24). These should be
mounted dry. The scales of Tinea and many
others have nothing to recommend them.
Nor do we advise the use of those scales
which exhibit the transverse striae by oblique

TEST-OBJECTS.

[ 638 ]

TETRACYCLUS.

light, as those of Morpho (PL 1. fig. 7), of
Hipparchia (PL 1. fig. 9), &c. ; as they are
easy tests even to inferior English object-
glasses of the present day. The long scales
of Pontia brassicte are, however, good.

Didymohelix (PI. 1. fig. 10 a, b, c, d).
The filaments should be mounted in solution
of chloride of calcium, or in Canada balsam.
It is very difficult to display the component
fibres of this beautiful object when in balsam.
It also forms a good test of magnifying
power.

Didymopriwn (PL 1. fig. 11). The lon-
gitudinal lines upon the cells require con-
siderable magnifying power.

The pygidium of PULEX. An excel-
lent test-object, mounted in as small a
quantity of balsam as possible. Dujardin
represents the rays upon the disks as round,
like so many beads, whereas they are wedge-
shaped with the bases outwards.

The valves of the Diatomacece. It is
a difficult matter to show the lines upon
Grammatopkora marina with an object-glass
of 110° of angular aperture, requiring ex-
tremely oblique light.

The ultimate fibrillee of muscular fibre.
Mounted in liquid. Kolliker represents
them as beaded (PL 17- fig. 36 c) ; they have
also been represented as in a ; probably both
these inaccuracies arise from imperfect ad-
justment, and from their immersion in too
much liquid. Their true structure is figured
in b, d, f.

Noberfs test-lines. These consist of
from ten to fifteen parallel bands or groups
of parallel lines scratched upon a slide with a
diamond. The bands are of equal breadth,
and the lines in each successive band are
more numerous and consequently closer than
those of the preceding. The breadth of
the intervals between the lines in the two
end bands is from 1-11,000 to 1-60,000".
The resolution of these lines forms a test for
angular aperture and oblique light; but it
can be effected by a moderately good Eng-
lish l-8th, and is much easier than that of
the markings upon the valves of many Dia-
tomaceae.

We have omitted to notice several test-
objects, as the scales of some insects, a
minute globule of mercury, &c. ; and this
advisedly, because the former have been so
obscurely described that we are unable to
comprehend in what the test-structure con-
sists ; and the test-appearances presented by
the latter viewed as an opaque object are
inappreciable to one unaccustomed to the

use of the microscope, by whom mainly are
remarks upon test-objects required.

Amici's test-object is Navicula gracilis,
the display of the lines forming the test ; it
is a test for angular aperture.

Chevalier's test-object consists of the
scales of Pontia brassicce (PL 27. fig. 24),
the granules being rendered distinct ; this is
a test for definition.

Mohl recommends the scales of Hippar-
chia janira for testing "penetrating" power;
pollen-grains, the scaly elytra of the diamond
beetle or bat's hair, for " definition."

Schacht's test-object consists of the scales
of Hipparchia janira (PL 1. fig. 9 c) (a test
for moderate angular aperture and oblique
light).

BIBL. That of the INTRODUCTION (p. xl),
and of ANGULAR APERTURE, and especially
the works of Goring and Pritchard.

TETHEA, Lam. — A genus of marine
Sponges.

BIBL. Johnston, Brit. Spong. fyc. 81.

TETMEMORUS, Ralfs.— A genus of
Desmidiaceae.

Char. Cells single, simple, elongated,
straight, cylindrical or fusiform, constricted
in the middle ; segments emarginate at the
ends.

Sporangia square or round.

T. granulatus (PL 10. figs. 33, 34). Cells
fusiform both in front and side view, ends
colourless and lip -like; dots irregular.
Length 1-130".

T. Icevis (PL 10. fig. 35, in conjugation).
Cells in front view somewhat tapering, ends
truncate ; side view fusiform ; dots none, or
very indistinct (under ord. ilium.). Length
1-350".

T. Brebissonii. Dots in longitudinal rows.

BIBL. Ralfs, Brit. Desmid. 145.

TETRAB^ENA, Duj.— Spores of a genus
of Algae, undergoing division?

BIBL. Dujardin, Infus. p. 330.

TETRACYCLUS, Ralfs.— A genus of
Diatomaceae.

Char. Frustules aggregated into a fila-
ment, in front view broadly tabular, with
longitudinal uninterrupted vittae; valves
broadly rounded at each end, and inflated
on each side in the middle.

Valves with coarse transverse striae.

T. Thienemanni, Ehr. (lacustris, Ralfs)
(PL 13. fig. 28). Length (?).

The structure of the compound (?) frus-
tules of this and many of the other tabel-
lar Diatomaceae, requires careful investiga-
tion, for the valves formed by division appear

TETRAGRAMMA.

[ 639 ]

THECAMONADINA.

to differ considerably in structure from the
parent-valves.

BIBL. Ralfs, Ann. Nat. Hist. 1843. xii.
105; Kiitzing, Sp.Alg. 118.

TETRAGRAMMA, Ehr. = Terpsinoe.

TETRANYCHUS, Duf. — A genus of
Arachnida, of the order Acarina, and family
Trombidina.

Char. Palpi incumbent upon the rostrum,
stout, short and conical; mandibles and
labium as in Raphignathus ', coxse inserted
in two groups on each side, one for the two
anterior, the other for the two posterior;
anterior legs longest, third joint (femur)
largest ; claws short and greatly curved.

Several species.

T.glaber (PL 2. fig. 32). Very minute;
eyes two, whitish, upon the antero-lateral
portion of the trunk. Under stones in damp
places.

T. lapidum (PI. 2. fig. 35). Legs slender,
anterior very long; eyes three on each side;
several rows of white points upon the back
and margins of the body. Found under
stones and upon plants.

BIBL. Duges, Ann. d. So. nat. 2 ser. i.
24, & ii. 55 ; Gervais, Walckenaer's Apteres,
iii. 165; Dufour, Ann. des Sc. nat. 1 ser.
xxv. 279 ; Koch, DeutschL Crustac.

TETRAPHIS, Hedwig.— A genus of
Mosses. See GEORGIA.

TETRAPLOA, Berk, and Br.— A genus
of Torulacei (Coniomycetous Fungi), com-
prising at present a single species, T. aris-
tata, a curious little fungus growing upon
leaves of grass, forming an olive-coloured
stratum composed of bodies consisting of
four connate quadri-articulate spores, each
terminated by a bristle.

BIBL. Berk. & Br. Ann. Nat. Hist. ser. 2.
v. p. 459. pi. 11. fig. 6.

TETRAPLODON, Br.and Sch.— A genus
of Splachnaceae (Acrocarpous operculate
Mosses), containing some of the Splachna
of authors.

Tetraplodon angustatnm, Br. and Sch. ==
Splachnum angustatum, Linn. fil.

T. mnioides, Br. and Sch. = Spl. mnioides,
Linn. fil.

TETRASPORA, Link.— A genus of Pal-
mellacese (Confervoid Algae), nearly related
to the Ulvacese ; indeed it is very difficult to
draw any very distinct line of demarcation
between Tetraspora and MONOSTROMA, the
fronds of both of which are membranous
strata formed of a single layer of cells ; the
latter, however, has its constituent cells
crowded, while in Tetraspora the green e cell-

contents' lie scattered, mostly in groups of
two or four, in the gelatinous frond. Thuret
states that the primordial utricles of the cells
possess long cilia in the stage when they are
imbedded in a continuous frond ( PI . 3 . fig. 1 0) .
The history of development of this genus is
imperfectly known at present ; the ciliated
cell-contents break out as swarming zoo-
spores, but their next following changes have
not been observed. Two recorded British
species appear to be distinct, growing in
stagnant pools (see MONOSTROMA, MERIS-
MOP.EDIA, and SARCINA).

1. T. gelatinosa (PI. 3. fig. 10). Frond
gelatinous, soft, of irregular shape and divi-
sion, pale green; cells 1-10800 to 1-4200"
in diameter (Kiitzing, Tab. Phyc. i. p. 28).

2. T. lubrica. Frond green, elongated,
mesentery-shaped, lobed and sinuated, lobes
often anastomosing; cells angulo-globose,
1-3600" in diameter (Kiitzing, I. c. pi. 30).

BIBL. Hassall, Brit. Fr. Alg. p. 300. pi.
78 ; Kiitzing, Sp. Alg. p. 225, Tab. Phyc. i. ;
Thuret, Ann. des Sc. nat. 3 ser. xiv. p. 248.
pi. 21; Nageli, Einzett. Alg. p. 71. pi. 2.

TEXTULARIA. See FORAMINIFERA
(p. 271).

THAMNOMYCES, Ehr.— A genus of
Sphaeriacei (Ascomycetous Fungi). T. hip-
potrichoides is referred by Fries to Rhizo-
morpha. It appears to require further ex-
amination.

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 284 ;
Fries, Summa Veg. 382.

THECA. — A term used very loosely in
the descriptions of Cryptogamic plants. In
the case of the Lichens and Fungi it is syn-
onymous with Ascus, a sac in which free
spores are developed ; these are called theca-
spores or ascospores in contrast with BASI-
DIOSPORES or stylospores. In the higher
Cryptogarnia, as Ferns, &c., it is used in the
sense of sporangium.

THECAMONADINA, Duj.— A family
of Infusoria (= Cryptomonadina and some
Astasiaea, E.).

Char. Usually coloured ; covered with a
non-contractile tegument, which is either
hard and brittle, or membranous ; no other
locomotive organs present than one or more
flagelliform filaments.

The organisms probably consist of Algae,
or their spores. They are minute, usually
green, but some are red ; and they often
colour stagnant water from existing in vast
numbers. They are mostly recognisable by
their rigidity and the uniformity of their
motion.

THELACTIS.

[ 640 ]

THYRSOPTERIS.

It is thus subdivided : —

A single f Body ovoid or f Tegument hard and brittle 1 . Trachelomonas.

fH pirf < globular I Tegument membranous 2. Cryptomonas.

filament 1 Bodv dePressed or / with a tail-like prolongation 3. Phacus (Euglena, pt. E.).

Lfoliaceous I without a prolongation 4. Crumenula.

Two f ^wo 8im^ar filaments 5. Diselmis (Chlamidomonas, E.).

fila t I <">ne fiaSe^orm filament, and /Body prismatic or boat-shaped 6. Pleeotia.

tone trailing retractile filament I Body ovoid or pip-shaped 7. Anisonema.

Several filaments

/rrhis.

BIBL. Dujardin, In/us. 323.

THELACTIS, Mart.— A doubtful genus
of Mucorini (Physomycetous Fungi), con-
sisting apparently of a Mucor with one or
more whorls of barren branches near the
lower part of the erect fertile Hlaments.

BIBL. Fries, Summa Veg. p. 487.

THELOTREMA, Ach.— A genus of En-
docarpese (Angiocarpous Lichens), contain-
ing two British species.

BIBL. Leighton, Brit. Angioc. Lichens,
p. 31.

THEORUS, Ehr.— A genus of Rotatoria,
of the family Hydatinaea.

Char. Eyes colourless, more than three,
cervical, in two groups; foot forked; jaws
each with a single tooth.

T. vernalis (PL 35. fig. 32). Toes small,
frontal hook absent. Aquatic; length 1-140
to 1-120".

T. uncinatus. Toes long, frontal (or ra-
ther cervical) region with hooks. Aquatic ;
length 1-240".

BIBL. Ehrenberg, Infus. 454.

THOREA, Bory. — A genus of Batra-
chospermeae (Confervoid Algae), of which
one species (T. ramosissima} occurs in Bri-
tain; its fronds are branched filaments, a
foot or more long, about as thick as a crow-
quill, with a villous surface, of olive-black

Fig. 745.

Thorea ramosissima.

Horizontal section of a filament (halved). The semi-
circular denser portion represents the axis, the loose
spreading branches, the villi. Magnified 25 diameters.

colour. The filaments are composed of ra-
diating branched cells, closely compacted

into a kind of solid axis, from which proceed
lax, radiating ramuli (forming the villous
surface). The spores (or sporangial cells)
arise from these ramules (fig. 745).

BIBL. Kiitzing, Phyc. generalis, pi. 16,
Sp. Alff. p. 534, Eng. Bot. Supp. No. 2948 ;
Hassall, Brit. Fr. Alg.p.64.

THUJA, L.— A genus of Conifers (Gym-
nospermous Plants), to which belongs the
arbor mice of gardens, Thuja occidentalism
T. orientalis is placed by some authors under
another genus, Biota. The characters of
Coniferous wood, Gymnospermous ovules,
&c., may be observed in these plants (see
CONIFERS and OVULE).

THYRSOPTERIS, Kuiize.— A genus of
Cyathaeous Ferns, with a curious structure
of the fertile fronds. Exotic (figs. 746-9).

.folido s }o bmslg fc/o-r^riJ 3nJ moil >-r>PT'??/ \

Fig. 746. Fig. 747.

Fig. 748.

Thyrsopteris elegan

Fig. 746. A fertile pinna.

Fig. 747. A pinnule converted into a cup-like sorus.
Magnified 20 diameters.

Fig. 748. Vertical section of the same, with the spo-
ranges removed from the columella.

Fig. 749. Side view of a sporange. Magn. 100 diams.

THYROID GLAND.

[ 641 ]

TINEA.

THYROID GLAND.— The thyroid gland
is one of the vascular glands, or glands with-
out ducts.

It consists of rounded, closed, glandular

.-BftiMbVl ,9 bsqfu''

Fie. 750

5 ' pflioqaoiu

[ihl B Ol£fi

Glandular vesicles from the thyroid gland of a child.
(i, intervening areolar tissue; b, basement membrane;
c, epithelium.

Magnified 250 diameters.

vesicles (fig. 750), surrounded by or imbedded
in a fibrous stroma (a), and aggregated into

Fig. 751.

Glandular vesicles with colloid matter.
Magnified 50 diameters.

roundish, elongate, or somewhat polygonal
acini or minute lobules, these being grouped
in secondary lobules, which unite to form
lobes. The vesicles are from 1-600 to 1-240"
in diameter, the acini from 1-50 to 1-24".
The stroma is condensed around the lobules,
to form a fibrous coat.

The stroma consists of ordinary interlacing
bundles of areolar tissue, with fine elastic
fibres; at its outer surface containing fat-
cells.

The vesicles consist of a basement-mem-
brane (fig. 750 b), lined by a single layer of
polygonal epithelial cells (c), and containing
a yellowish, tenacious, albuminous liquid.

The capillaries form plexuses surrounding
the vesicles.

In goitre, the vesicles become greatly en-
larged, and confluent, so as to form cysts
containing colloid matter, with fat-globules
and crystals of cholesterine. The same con-
ditions, in a minor degree, are so frequently
met with, that they can scarcely be regarded
as abnormal. The epithelium is also often
found loose in the vesicles (fig. 751). The
minute arteries and capillaries are often
found varicose,

BIBL. Kolliker, Mikrosk. Anat. ii. 327 ;
Forster, Pathol Anat. ii. 233.

THYSANURA.— An order of Insects, to
which Lepisma and Podura belong.
See INSECTS (p. 362).
TILLETIA, Tulasne.— A genus of Usti-
laginei (Coniomycetous Fungi), forming the
Bunt, a kind of blight of various corn grains,
in which the ears are attacked, and the in-
ternal substance of the grains is replaced by
a foetid, black powder, consisting of the
spores of the fungus. T. Caries ( Uredo Ca-
ries, D.C.) attacks wheat and other grain.
The interior of the ovaries of the corn is at
first occupied by an interwoven mycelium,
from which the globular spores arise on
short stalks; as the latter grow, the ears
become more or less deformed, the my-
celium disappears, and the spores are set
free as a pulverulent mass ; the spores have
a reticulated surface, and their pedicel is
often found attached. (See USTILAGINEI.)
BIBL. Berk. Brit. Flor. ii. pt. 2. p. 375 ;
Tulasne, Ann. des Sc. nat. 3 ser. vii. p. 112.
pi. 5, 4 ser. ii. p. 161.

TIMMIA, Hedw.— A genus of Mniaceous
mosses, containing one British species,
Timmia austriaca, Hedw. (megapolitana,
Hook, and Tayl.).

TINEA, Fabr. — A genus of Lepidopterous
Insects, of the family Tineidse.

TINTINNUS.

[ 642 ]

TISSUES.

The small scales from the under side of
the wings of T. pellionella (or vestianella},
the common clothes' moth, have been pro-
posed as test-objects ; but they can hardly
be regarded as such for object-glasses of the
present day. The longitudinal lines form
the test- structure.

BIBL. Westwood, Introduction, 8fc.
TINTINNUS, Schrank. — A genus of
Infusoria, of the family Ophrydina.

Char. Single ; body contained in a cylin-
drical, sessile, bellgshaped carapace, to the
bottom of which it is attached by a stalk.

Five species. In one, the carapace is co-
vered with dots, and its orifice toothed.

T. inquilinus (PI. 25. fig. 4). Body hya-
line or yellowish ; carapace cylindrical, hya-
line. Marine; length 1-240".

Dujardin unites this genus with Vaainicola,
where it properly belongs.

BIBL. Ehrenberg, In/us. 294 ; id. Ber.d.
Eerl. Akad. 1840; Dujardin, Infus. 561.

TISSUE, FIBRO-PLASTIC. — A term ap-
plied by Lebert to imperfectly developed
abnormal areolar tissue. The separate ele-
ments are often found diffused through those
of normal tissues, or products of inflamma-
tory exudation. They consist of rounded or
oblong cells, from 1-2300 to 1-1600" in dia-
meter ; in a more advanced stage becoming
fusiform or angular, and finally forming di-
stinct fibres ; hence resembling the elements
of embryonic areolar tissue (PI. 40. fig. 43).
In some instances the development is arrested
at one of the early phases, so that the tissue
consists almost exclusively of the rounded or
the fusiform cells ; and in others, the cells
enlarge and produce a number of nuclei or
secondary cells (PL 30. fig. 10 c).

Fibro-plastic tissue or its elements are
met with in inflammatory effusions upon the
serous and synovial membranes, but rarely ;
in the interstitial effusions of pneumonia,
especially when chronic ; in cirrhosis of the
liver; in the products of suppurating sur-
faces ; on the surface of chronic ulcers, and
non-malignant fungoid vegetations; in the
soft yellow vascular tissue occupying the
cancelli of ulcerated bones; in certain tu-
mours, &c. See TUMOURS.

BIBL. Lebert, Physiol. patholog. ; Wedl,
Patholog. Histolog. ; Forster, Patholog.
Anat. i.

TISSUES, ANIMAL.— The following syn~
optical arrangement of the principal animal
tissues is intended to facilitate reference to
the various articles scattered through the
work.

3. Cellular

4. Blastemic and cellular .-

A. Simple.

1. Blastemic or protoplastic. . Sarcode.

2. Membranous Basement membrane.

C Fatty tissue ; nerve-cells ;
< simple cartilage ; un-

t striated muscular fibre.

f Without secondary depo-
J sit. True cartilage.
' | With secondary deposit.

l_ Bone.

f Areolar (cellular) tissue ;

5. Fibrous •< tendon ; ligament; elas-

l. tic tissue ; muscle.

6. Fibrous and cellular Fibro-cartilage.

f Without secondary depo-

7. Tubular ..^..;wlw.. j w^ J^ deposit.

I Nerve-tubes.

B. Compound. Glands ; mucous and serous membranes ;
skin ; synovial membrane ; teeth.

TISSUES, VEGETABLE. — The tissues
composing the substance of vegetables are
all comparatively slight modifications of one
type, being composed of cellulose sacs, or
"cells" par excellence, varying only in
form and consistence and in their mode oi
union. The tissues may be divided into
groups on different principles; but for our
purpose a very simple arrangement will suf-
fice, based chiefly on the character of the
compound tissues, leaving the secondary di-
visions to be determined by the nature of the
component cells.

1. Cambium tissue, occurring in the growing
regions of all plants having stems, is com-
posed of minute cells of variable form, closelj
packed and densely filled with protoplasm
it is a transitional structure, forming the
first stage of all the rest.

2. Parenchyma, or " cellular tissue," is
composed of cells in which the diameter is nol
excessive in any one direction, and the walls
are comparatively thin. This is divided bj
authors into many sections, according to th(
form of the cells, the laxity of their cohe-
rence, &c. The only distinctions worth not(
are between —

a. Parenchyma proper, where the cell
have polygonal forms.

b. Merenchyma, where the cells are round
oval, &c.

c. Collenchyma, which is a form of cellula:
tissue where the walls are greatly thick
ened with softish secondary deposits
it occurs beneath the epidermis of man;;
herbaceous plants, in the fronds of thi
larger Algae, of Lichens, &c.

d. Sterenchyma. A name which might bi
used to distinguish the bony cellula
tissue of shells, stones of fruits, &c.

3. Prosenchyma. Cellular tissue, usuall;
forming the mass of wood and various fibrou

TMESIPTERIS.

[ 643 ]

TONGUE.

airo
TO ,

structures, where the cells are attenuated to
a point at each end, the cells, " fibres/' being
intercalated and applied side to side.

4. Tela context a. This name is used to
indicate the interwoven tissue formed by the
ramified, jointed filaments of the mycelium
of Fungi and the cottony substance in the
interior of the thallus of many Lichens.

5. Fibro-vascular tissue is composed of
vessels, ducts, and prosenchymatous cells or
"fibres" associated in various ways, forming
fibrous or fibro-vascular bundles, which
either remain distinct or cohere to form
masses of wood.

a. Fibrous bundles, occurring in liber, in
the outer part of many Monocotyledo-
nous stems, and in the stems of Mosses,
consist of cords formed of prosenchy-
matous cells, which are often of great
length.

b. Fibro-vascular bundles, composed of
vessels and ducts together with prosen-
chyma,form the "woody fibres" of every
part (except the bark) of all plants
above the Mosses.

6. Laticiferous tissue and Reservoirs for
Secretion, composed either of intercellular
passages lined by a proper coat, or of lines
of cells fused at their ends, so as to form
continuous branched canals ; they occur in
the bark, wood, and pith of the Flowering
Plants.

7. Epidermal tissue. Composed of cel-
lular tissue, forming a continuous firm layer
over the external surface of the higher plants.
It is composed usually of a single layer of
cells, and presents very varied appendages,
such as HAIRS, GLANDS, &c., and is per-
forated by STOMATES. Its outer surface is
rendered dense by the deposit of CUTICLE.
The epidermis is replaced, on stems, by the
CORK or sebaceous layer of BARK.

For further particulars see the various
heads above named.

BIBL. General Works on Botany.

TMESIPTERIS.— A genus of Psilotese
(Lycopodiaceae) (fig. f&2\ remarkable for

Fig. 752.

Tmesipteris tannensis.

the peculiar habit and the bivalved sporanges
bursting by a vertical crack.

BIBL. See LYCOPODIACE^E.

TODEA, Willdenow.— A genus of Osmun-
daeous Ferns (fig. 753-5). Exotic.

Fig. 753. Fig. 754.

Fig. 755.

Todea africana.

Sporanges closed and bursting.
Magnified 40 diameters.

TOLYPOTHRIX, Kiitz.— A genus of
Oscillatoriaceae (Confervoid Algae), appa-
rently not very satisfactorily defined. Has-
sall describes six species as British, of which
T. distorta (PI. 4. fig. 14) is said to be com-
mon, adhering to sticks, stems, &c. in stag-
nant water, forming tufts from 1-2 to 1" in
height, dark green when fresh, verdigris or
blue-green when dry; primary filaments
1-1800 to 1-1440" in diameter; joints about
as long as broad.

BIBL. Kutz. Sp. Alg. p. 312, Tab. Phyc.
ii. pis. 31-33; Hassall, Brit. Freshw. Alg.
p. 240. pis. 68 & 69.

TONGUE.— We have only space here to
notice the structure of the beautiful papill&e
of the human tongue.

The filiform or conical papillae (fig. 760)
are whitish, very numerous, and occupy the
intervals between the fungiform papillae.
The papilla of the mucous membrane at
their bases (p,p) are conical, and covered
either at the. end only, or all over the surface
with a number of smaller or secondary pa-
pillae ; the whole being coated by an epithe-
lial investment (e}, terminating in a tuft of
free filiform processes (/). The inner layers
of the epithelium agree in structure with
that of the mouth, whilst the outer layers,
and especially the epithelium of the processes,
resemble rather the scales of the epidermis,
in their hardness, small size and considerable
resistance to the action of alkalies and acids.
The papillae themselves consist of areolar
tissue, with a large number of undulating
nuclear fibres, each containing a small ar-
tery (a) and vein (b), with an intermediate
plexus of looped capillaries, and numerous
nerve-tubes.

2T2

.

*o\. .?

e--

TONGUE.

Fig. 756.

TONGUE.

Fig. 758.

Fig. 756. Fungiform papilla covered by the epithelium e on one side, and with the secondary or simple papillae p.
Magnified 35 diameters.

Fig. 757. The same, with the vessels ; the epithelium e represented in outline, a, artery ; v, vein ; d, capillary loops
of the simple papilla ; e, capillaries in the simple papillae of the mucous membrane at the base of the fungiform
papilla. Magnified 18 diameters.

Fig. 758. Perpendicular section of a human circumvallate papilla. A, proper papilla ; B, wall ; a, epithelium ; b b,
nerves of the papilla and wall ; c, secondary papillae. Magnified 10 diameters.

Fig. 759. Follicular gland from the root of the human tongue, a, epithelium ; b, papillae of the mucous membrane ;
c, areolar coat ; e, cavity ; /, epithelium lining it ; g g, follicles in the thick capsule. Magnified 30 diameters.

The fungiform or clavate papillae (fig. 756)
are reddish, distributed over the entire sur-
face of the tongue, and are very nume-
rous at its point. Each has at its base
a club-shaped mucous papilla, and is covered
all over with simple or secondary conical
papillae (p p], and a simple epithelial layer
(e), without filiform processes. The vessels
are more numerous, but otherwise resemble
those in the filiform papillae (fig. 757).

The circumvallate or lenticular papillae
(fig. 758) consist of a flattened central pa-
pilla (A), surrounded by an elevated wall or
ridge (B). The flat surface is furnished with
crowded conical secondary papillae (c), the
whole being covered with epithelium (a) free
from processes. The wall appears as a
simple fold of the mucous membrane, and
also exhibits beneath its smooth epithelial
coat numerous rows of simple, conical se-
condary papillae. In other respects these
papillae do not differ essentially in structure
from the fungiform.

In some of the papillae of the tongue axial
bodies are found resembling those in the
papillae of the skin.

The epithelial processes of the filiform
papillae are often covered by a fungus (Lep-
tothrix}, the mycelium closely surrounding
them, whilst some of the filaments project
from the surface.

The glands of the tongue consist of mucous
and follicular glands.

The mucous glands resemble those of the
mouth (MOUTH).

The follicular glands are most numerous
between the epiglottis and the circumvallate
papillae, and are so superficially situated as
to form projections of the mucous membrane.
They form lenticular or globular masses,
from 1-24 to 1-6" in diameter, imbedded in
the submucous tissue, and in the middle of
the free surface is the orifice (759 d] of a co-
nical cavity (e), formed by a depression of
the mucous membrane. Each gland forms a
thick-walled capsule, surrounded by a fibrous

TONGUE.

[ 645 ]

TORULA.

coat (c), continuous with the deeper portion
of the mucous membrane, and lined in-

Fig. 760.

Two human filiform papillae, one with epithelium.
p, p, papillae ; a, v, artery and vein, with the capillary loops ;
e, epithelial covering ; /, its processes.

Magnified 35 diameters,

ternally by a prolongation of the mucous
membrane with papillae and epithelium (a,
b) ; and between the two are closed capsules
or follicles (g), imbedded in a fibrous and
vascular basis. The follicles are from 1-120
to 1-48" in diameter, rounded or somewhat
elongate, whitish, composed of a coat of
areolar tissue without elastic fibres, and with
greyish white contents consisting of cells
1-6000 to 1-4000" in diameter and free
nuclei.

The tongues of the Mollusca have long
formed interesting microscopic objects, on
account of the elegant horny (or chitinous ?)
teeth placed upon them in numerous rows,
and in various patterns; the number and
arrangement of which are also of importance
in characterizing the families, genera, &c.

They may be easily examined in the limpet
(Patella), the whelk (Buccinum), or in the
freshwater snails, Lymnceus, Planorbis, &c.

BIBL. Kolliker, Mikrosk. Anat. ii.; Todd
and Bowman, Physiol. Anat. &c. ; Mollusca :
Woodward, On Shells ; Gray, Mic. Journal,
1853. p. 170; Siebold, Vergleich. Anat.

TONSILS.— These organs may be re-
garded as consisting of from ten to twenty
follicular glands, resembling those found at
the root of the tongue, surrounded by a
common fibrous coat or capsule.

The blood-vessels are numerous, forming
elegant networks around the follicles.

BIBL. Kolliker, Mikroskop. Anat. ii.

TOPAZ.— The crystals of this mineral
belong to the rhombic or right rhombic
prismatic system. They consist principally
of silicate of alumina, with the fluorides of
aluminium and silicium.

Sections of topaz exhibit remarkable
microscopic cavities, often of most singular
and elegant forms, frequently containing
crystals and one or two non-miscible liquids ;
the latter sometimes including bubbles of
gas, vapour or vacuities.

Sir David Brewster recommends the sphe-
rical cavities as the best objects for exami-
ning the aberrations of lenses, and as infi-
nitely preferable to the globules of mercury.

BIBL. Brewster, Edinb. Phil. Trans, x. &
xvi., Treat, on the Microscope, 186.

TORTOISE-SHELL. SeeSHELL(p.575).

TORTULA, Hedw. A genus of Mosses.
See BARBULA.

TORULA, Pcrs.— A genus of Torulacei
(Coniomycetous Fungi). The plants ordi-
narily referred here appear to be somewhat
heterogeneous in their nature. In what may
be considered as the true species, the chains
of spores form the principal bulk of the
plants, little or no filamentous mycelium
existing. Other forms very generally in-
cluded under this head agree in their cha-
racters with OIDIUM, which itself is a
doubtful genus, probably founded on the coni-
diferous states of more perfect kinds. But in
T. sacchari (or Cerevisice), the Yeast fungus,
usually referred here, we find both forms
presented; for when actively vegetating in
fermenting liquids, it presents the characters
shown in fig. 23. PL 20, while, when the
liquid becomes exhausted, portions of the
fungus float to the top, and produce a fila-
mentous structure, terminating in chains of
" spores," such as are represented in fig. 24
(PL 20), and in fig. 761. The simply beaded
form is taken as the type of a genus Cryp-

TORULA.

[ 646 ]

TORULACEI.

tococcus by some authors, of whom a part
consider it a Fungus, another part (Kiitzing

Fig. 761.

Torula sacchari (aerial form) .
Magnified 200 diameters.

especially) an Alga. The same varieties of
form occur in the Vinegar plant, and in both
cases Penicillium glaucum seems invariably
to succeed to the preceding when kept at a
moderate temperature. Thus between all
these various forms, together with Oidium
lactis, there appears to be a relation, not yet
quite clearly made out, indicating that they
probably represent different states of the same
plant growing under different conditions of
nutrition and temperature. Further remarks
on this head are made under YEAST and
VINEGAR PLANT. A growth similar to T.
sacchari presents itself sometimes in decom-
posing urine (PI. 20. fig. 7), from healthy
subjects, and indeed scarcely any decompo-
sing animal or vegetable fluid, in which
there exist fermentable elements, remain
long free from Tbrw/a-like growths, if left
exposed to the air (see FERMENTATION).

We find it impossible to give definite cha-
racters for the species that have been enu-
merated. T. herbarum may be named as a
common form growing on decaying stems of
plants ; it forms at first erect greenish tufts,
which afterward become blackish, ramify
and form a black crust, the spores readily
separating. T. Sporendonema, a form grow-
ing on decaying cheese, represents the Spo-
rendonema casei of Desmazieres. T. Fumago
is now separated with other forms under the
genus CAPNODIUM. T. alternata also is
the type of the genus ALTERNARIA.

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 359,
Ann. Nat. Hist. i. p. 263, vi. p. 439. 2nd ser.
v. p. 460, xiii. p. 460 ; Fries, Syst. Myc. iii.
499, Summa Veget. 505; Fresenius, Beitr.

z. Myc. 2nd heft. 58. pi. 6. fig. 55 ; Corda,
Icones Fungorum.

TORULACEI.— A family of Coniomyce-
tous Fungi, forming moulds and mildews on
decaying vegetable substances, or acting as
ferments in decomposing vegetable and ani-
mal fluids. They are compound microscopic,
cylindrical or beaded filaments, simple or
ramified, the joints of which (all or part) se-
parate from each other to form the " spores".
There is no definite receptacle here, the
mycelium grows as a cottony web over or in
the infected body, or forms clouds or flocks
in liquids. Much obscurity prevails respect-
ing most of the genera included below, and it
is indeed doubtful whether most of them are
independent productions. Some species of
Torula, such as T. Cerevisia (the Yeast
fungus), appear intimately connected with
certain Hyphomycetous genera, perhaps
merely representing their conidiferous forms
(see TORULA). ACHORION again seems to
be merely the spermogonous form of a Puc-
cinia. Sporendonema is founded apparently
on imperfect observation; S. muscce, the true
characters of which are given under that
head, has been renamed Empusa, and its
proper position is as yet obscure, but it would
appear to be referable to the Mucorini. Dic-
tyosporium (fig. 175, page 208), Speira (fig.

Fig. 762.

Fig. 764.

• < festn
Fig. 763.

Fig. 762. Speira toruloides. Magnified 200 diameters .
Fig. 763. Gyrocerus ammonis. Magnified 200 diams.
Fig. 764. Trimmatostroma salicis. Magnified 200
diameters.

762) and Trimmatosiroma (fig. 764) appear
to consist merely of the spores of some other
genera ; Gyrocerus (fig. 765) cannot be re-
garded as a perfect form, and indeed all the

TORULACEI.

[ 647 ]

TRACHEA.

genera require a thorough examination in a
fresh state.

Synopsis of Genera.

I. TORULA. Spores in beaded chains,
simple, readily separating, placed on a short
continuous or septate pedicel (fig. 761, PI.
20. figs. 7 & 23).

II. BISPORA. Resembling the last, but
the spores uni-septate (fig. 60, page 80).

HI. SEPTONEMA. Resembling the pre-
ceding, but having several transverse septa
in the spores (fig. 645, page 574).

IV. ALTERNARIA. Resembling the pre-
ceding, but with cellular spores connected
by a filiform isthmus (fig. 9, page 26).

V. SPORIDESMIUM. Spores in tufts,
straight, subclavate or fusiform, shortly
stalked or sessile, transversely septate or
cellular (fig. 695, page 608).

VI. TETRAPLOA. Spores sessile, quadri-
septate, coherent in bundles of four, each
spore crowned with a bristle.

VII. SPOROCHISMA. " Filaments erect,
simple, external membrane inarticulate, cell-
contents at length separating into spores,
articulated in fours, emerging."

VIII. CONIOTHECIUM. Spores without
septa, collected in heaps, finally separating
more or less into a powder.

IX. ECHINOBOTRYUM. Spores rounded-
apiculate, collected in fascicles, attached on
simple erect, annulated filaments.

X. SPILOC^EA. Spores globose, simple,
adhering firmly together and to the matrix,
forming spots laid bare by the separation of
the epidermis of the subject infected.

Doubtful and obscure Genera.

SPORENDONEMA. Described as com-
posed of erect filaments, containing single
rows of spores in the interior. -S. musca
(Empusa, Cohn) really consists of short,
tufted, erect, simple filaments, terminating
in a bell-shaped cell (spore or sporange ?),
thrown off with elasticity when mature.

ACH ORION. Mycelium somewhat ramose,
articulated, joints terminating in round, oval
or irregular spores (conidia ?).

SPEIRA. Spores connate into concentric
filaments, forming laminae resembling a
horseshoe, finally separating.

TRIMMATOSTROMA. Spores more or less
curved, multiseptate, chained in beaded
rows, finally separating.

GYROCERUS. Spores connate into spi-
rally coiled filaments, finally separating.

DICTYOSPORIUM. Spores tongue-shaped,
reticularly cellular (fig. 175, page 208).

TOURMALINE.— Sections of the crystals
of this mineral, cut parallel to the axis, were
formerly used as polarizers or analysers.
They are now mostly replaced by Nicol's
prisms (!NTR. p. xviii); crystals of the
quinine-salt (QUININE) form cheap substi-
tutes for either. The crystals of tourmaline
belong to the rhombohedric system. They
consist principally of silica with alumina,
also containing boracic acid, magnesia, iron,
&c., but their composition is not constant.

Good tourmalines are transparent, brown-
ish or pinkish ; the colourless ones do not
polarize.

BIBL. Pereira, Lectures on Polarized
Light-, Naumann, Mineralogie, 319.

TOUS-LES-MO1S.— A kind of fecula
consisting of the starch of species of Canna,
remarkable for the large size, great transpa-
rency and numerous striae of the granules
(Pi. 36. fig. 25). The mixture of any of the
common kinds of starch with Tous-les-mois
is readily detected by the microscopic exami-
nation. The granules are excellent subjects
for studying the physical characters of starch,
in particular the appearance with polarized
light (PL 31. fig. 40), &c. See STARCH.

TRACHEA. See LUNGS (p. 402).

TRACHEAE, OF INSECTS, &c. The re-
spiratory tubes of Insects and Arachnida
(ARACHNIDA).

Trachea (PI. 27. fig. 17; PI. 28. fig. 2 A)
are cylindrical tubes containing air. They
are broadest at their origin from the spira-
cles, afterwards branching freely, the minute
branches being distributed to all parts of the
body. By reflected light they appear white,
with a metallic lustre, or slightly iridescent ;
by transmitted light the smaller ones are
black, the larger usually of a violet tint.

The tracheae consist of two coats, between
which lies a spiral fibre (PL 27. fig. 17); in
the larger trunks a second external envelope
exists. The fibre becomes more slender and
indistinct in the smaller trachea! branches,
until it finally disappears. The outer mem-
brane appears to arise from the confluence
of cells, for in the tracheae of caterpillars
and other larvae of insects, the remaining
nuclei are visible (PL 28. fig. 17). The
inner coat forms a pavement epithelium.
The spiral fibre arises from the splitting up
of a homogeneous membrane deposited in
the space bounded by the confluent cells of
the outer membrane.

In many insects the tracheae are furnished

TRACHE.E.

[ 648 ]

TREBIUS.

with dilatations forming air-sacs, in which
the spiral fibre is absent.

An unsettled point in regard to the tra-
cheae is the presence of a peritracheal circu-
lation. When larvae are fed with indigo or
carmine, or when the dorsal vessel is injected
with colouring matter, the tracheae become
coloured, which some authors believe to
arise from the nutritive liquid circulating
between the membranes of the tracheae;
whilst by others this circulation, or the ex-
istence of a space bet ween the tracheal mem-
branes, is denied.

BIBL. That of INSECTS ; Newport, Phil.
Trans. 1836. 529; Platner, Miiller's Archiv,
1844. xxxviii. ; Stein, Vergleich. Anat. d.
Insekten ; Agassi/, Ann. des Sc. not. 3 ser.
xv.; Bassy, ibid.; Joly, ibid. xii. ; Blanchard,
Comptes Rendus, 1851, or Ann. Nat. Hist.
1852. ix. 74 ; Dufour, Comptes Rendus, 1851 ,
or Ann. Nat. Hist. 1852. ix. 435; Meyer,
Siebold and Kolliker's Zeitsch. i. 1 75.

TRACHEAE, OF PLANTS.— This name
was formerly applied to the unreliable SPI-
RAL VESSELS of Plants, from their resem-
blance to the tracheae of Insects.

TRACHELINA, Ehr.— A family of Infu-
soria.

Char. Carapace absent ; alimentary canal
with two distinct orifices, the anal only ter-
minal.

Locomotive organs consisting of cilia co-
vering the body in longitudinal rows, but
absent in Phialina ; those around the mouth
longer. In two genera teeth are present.
Mouth situated on the under surface of the
body.

Eight genera : Bursaria, Chilodon, Glau-
coma, Loxodes, Nassula, Phialina, Spiro-
stoma, Trachelius.

BIBL. Ehrenberg, In/us. 319.

TRACHELIUS, Schrank, Ehr.— A genus
of Infusoria, of the family Trachelina.

Char. Body covered with cilia; mouth
not spiral, without teeth; upper lip much
elongated in the form of a proboscis.

In three species the cilia have not been
detected !

T. lamella (PI. 25. fig. 5). Body depressed,
lamellar, linear -lanceolate, often truncate in
front, rounded behind. Aquatic; length
1-430 to 1-290".

Eight other species (Ehr.). Dujardin
places some of the species in the genera
Loxophyllupn and Amphileptus, and adds
three new ones.

BIBL. Ehrenberg, In/us. 320, and Ber. d.
Berl. Akad. 1840. 202 ; Dujardin, In/us. 398.

TRACHELOCERCA, Ehr.— A genus of
Infusoria, of the family Ophryocercina.

Char. Those of the family (= caudate
Lachrymarice}.

Four species.

T. olor (Lachrymaria olor, D.). Body
fusifornijwhite ; neck very long, simple, very
moveable, and the dilated end containing
the ciliated mouth. Aquatic; length 1-36".

T. mridis (PI. 24. fig. 33). Body green;
neck as in the last. Aquatic; length 1-120".

T. biceps. Neck bifid at the end.

BIBL. Ehrenberg, Infus. 341, and Ber. d.
Berl. Akad. 1840. 202.

TRACHELOMONAS, Ehr.— A genus of
Infusoria, of the family Cryptomonadina.

Char. Body enclosed in a spherical or
ovoid hard and brittle envelope, having a
small aperture, from which a long flagelliform
filament projects, but no neck (?) ; eye-spot
present.

T. volvocina (PI. 23. fig. 24 d, empty en-
velope). Spherical, green, brownish, or red ;
eye-spot red. Aquatic; length 1-865".

T. nigricans. Ovate -globose, green, black-
ish-brown or reddish; eye-spot brownish.
Aquatic; length 1-1730".

T. cylindrica. Oblong - subcylindrical ;
bright green; eye-spot red. Aquatic; length
1-1000".

The bodies represented in PI. 23. fig. 24
(btog}} and which are commonly found in
bog-water, probably belong here, with the
genera Chatoglena (a), Ch(Etotyphla (fig. 26),
and Doxococcus (fig. 47). The margins of
the red envelope appear as a bright red ring,
on account of the greater thickness traversed
by the light. They are probably spores of
Algae.

BIBL. Ehrenberg, Infus. 47.

TRADESCANTIA, L.— A genus of Com-
melynaceae ( Monocotyledons ), commonly
cultivated in gardens under the name of
* Spider-worts/ These plants are celebrated
for having served as material for some of the
most remarkable observations on the physio-
logical processes of vegetables, as the ROTA-
TION of the cell-contents, and the multipli-
cation of the cells, so well seen in the hairs
of the stamens when young (PI. 36. figs. 8 &
9). The stems, petioles, &c. afford beautiful
spiral, annular, and reticulated vessels, &c.

TREBIUS, Kroyer.— A genus of Crusta-
cea, of the order Siphonostoma, and family
Caligidae.

Char. Head in the form of a large buckler,
with the large frontal plates destitute of
sucking disks ; thorax three-jointed, seg-

TREMELLA.

[ 649 ]

TRICHIA.

ments uncovered ; legs four pairs, with long
plumose hairs, fourth pair slender, and two-
branched; antennae small, flat, and two-
jointed; second pair of foot-jaws two-jointed,
and not in the form of a sucking disk.

T. caudatus. Found upon the body of the
skate. Male much smaller than the female.

BIBL. Baird, Brit. Entomostraca, 280 ;
Thompson, Ann. Nat. Hist. 1847. xx. 248.

TREMELLA. See TREMELLINI.

TREMELLINL— A family of Hymeno-
mycetous Fungi, consisting of polymorphous,
often convoluted or lobed, more or less ge-
latinous masses, growing upon branches or
stumps of trees, in crevices of the bark, or
on the dead vrood. The hymenium extends
over the whole of the upper exposed surface,
and, from the recent researches of Tulasne,
appears to present remarkable characters.
The gelatinous substance of these Fungi is
composed of ramified filaments, with more
or less effused mucilage between them. In
Tremella a portion of the filaments termi-
nate at the surface at first in expanded glo-
bular cells, which become divided by vertical
septa into four somewhat pyriform cells
(basidid)-, from each of these arises a slender
filament (sterigma), which terminates in a
slender point tipped with a globular spore
(stylospore or basidiospore). Other filaments
coming to the surface in like manner ramify
extensively, with short divergent branches,
finally bearing numerous minute globular
bodies (spermatia), solitary or in groups of
four, which, like the basidiospores, fall off
and rest on the hymenial surface, involved
in jelly, but, unlike those, do not germinate.
The basidiospores are about 1-3000" in dia-
meter, the spermatia about 1-12000". In
Tremella mesenterica the surface coveredwith
basidiospores assumes a whitish colour ; the
layers of spermatia and the jelly are orange.
In Exidia the production of the basidio-
spores is similar, but the spores are reniform
and unilocular, about 1-2500" long and
1-5000" in diameter. Spermatia have not
been detected.

In Dacrymyces the basidia are represented
by simple clavate or bifurcated branches at
the hymenial surface, these terminating in
points bearing single reniform spores exhi-
biting three septa (quadrilocular). In ger-
mination some of these spores produce a long
filament from each loculus; others behave
differently, producing the spermatia of the
plant, each loculus sending out a short
pointed process bearing a globular cellule
exactly resembling the spermatia of Tremella.

Other examples of Dacrymyces bear a dif-
ferent kind of reproductive body, apparently
representing conidia. In these the peri-
pheral filaments terminate in a mass of
many-jointed Torula-like processes, which
ultimately break up into the separate joints.
(See DACRYMYCES and EXIDIA.)

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 215,
Ann. Nat. Hist. 2nd ser. xiii. p. 406. pi. 15.
fig. 4 ; Tulasne, Ann. des Sc. nat. 3 ser. xix.
p. 193. pis. 10-12.

TREPOMONAS, Duj.— A genus of Infu-
soria, of the family Monadina.

Char. Body compressed, thicker, and
rounded behind, twisted in front into two
narrowed lobes, which are inflexed laterally,
and each terminated by a nagelliform fila-
ment, which produces a very lively rotatory
and jerking motion.

T. agilis (PL 25. fig. 6). Body granular,
unequal. Length 1-1160". Found in de-
composing marsh-water.

BIBL. Dujardin, In/us. 294. .'IOA>I

TRIARTHRA, Ehr.-A genus of Rota-
toria, of the family Hydatinsea.

Char. Eyes two, frontal ; foot simply sty-
liform ; body with lateral cirrhi or fins.

Movement jerking. Jaws two ; each bi-
dentate.

T. longiseta (PI. 35. fig. 30). Eyes distant,
cirrhi and foot nearly three times as long as
the body. Aquatic; length 1-216".

T. mystacina. Eyes approximate ; cirrhi
and foot scarcely twice as long as the body.

T. breviseta (Gosse). Cirrhi much shorter
than the body.

BIBL. Ehrenberg, Infus. 446; Gosse,
Ann. Nat. Hist. 1851. viii. 200.

TRICERATIUM, Ehr.— A genus of Dia-
tomaceae.

Char. Frustules free; valves triangular,
areolar, each angle mostly with a minute
tooth or short horn.

Kiitzing describes fourteen species ; Smith
admits three British.

T.favus (PL 13. fig. 29). Valves plane or
convex, angles obtuse, with horn-like pro-
cesses ; areolae hexagonal. Marine ; diame-
ter 1-240".

T. alternans. Angles of valves slightly
elevated ; areola3 circular. Marine.

T. striolatum (?). Angles subacute ; areo-
lation faint. Brackish water.

BIBL. Ehrenberg, Ber. d. Berl. Akad.
1840; Smith, Brit. Diatomacete, i. 26;
Kiitzing, Bacill. 138, and Sp.Alg. 139.

TRICHIA, Hall.— A genus of Myxogas-
tres (Gasteromycetous Fungi) growing upon

TRICHINA.

[ 650 ]

TRICHINA.

Fig. 765.

rotten wood,, &c., characterized by a stalked or
sessile, simple, membranous peridium, which
bursts at the summit, whence the densely
interwoven free capillitium expands elasti-
cally, carrying with it the spores. The ca-
pillitium is composed of tubular filaments
(elaters), containing spiral-fibrous secondary
deposits, like the elaters of Marchantia (PI.
32. fig. 39). In some species the elaters bear
numerous little spinulose processes. The
genus is divisible into two groups. In the
first (Hemiarcyria) the dehiscence of the
peridium is obscurely circumscissile (fig.
765), the capillitium
dense ; these are
always stalked, usu-
ally of reddish co-
lour when young.
Some species have
the peridia fascicu-
late on a compound
peduncle (fig. 765),
others separate. In
the other division
( Goniospora), the
dehiscence of the
peridium is irregu-
lar, the capillitium
lax, the peduncle
short or absent, the
colour at first whi-
tish, changing to yellow, and the spores rather
angular. In T~ Serpula and reticulata the
sessile peridia are irregular, flexuous, ser-
pentine or annular bodies; in most of the
other species the peridia are pyriform, tur-
binate, or of some analogous form. The
elaters (PL 32. figs. 39 & 40) are interesting
objects, and form good tests for the defining
power of the microscope under very high
powers. They must be mounted in a very
thin stratum of liquid.

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 319,
Ann. Nat. Hist. vi. p. 432, ser. 2. v. p. 367;
Fries, Syst. Myc. iii. p. 182, Summa Veg.
457 ; Greville, Sc. Crypt. Fl. pi. 266, 281;
Henfrey, Linnean Traws.xxi. p. 221 ; Currey,
Microsc. Journ. iii. p. 15.

TRICHINA, Owen.— A genus of Entozoa,
of the order Coelelmintha and family Nema-
toidea.

T. spiralis (PL 16. figs. 16, 17, 18) inhabits
the human body, forming opaque white
specks, visible to the naked eye, in the vo-
luntary muscles. The worms usually exist
singly within a cyst situated between the
muscular bundles (fig. 16). At each end of
the cyst is a group of fat-cells resembling

u/IqonA

Trichia rubiformis.
Magnified 25 diameters.

those of ordinary fatty tissues. The cysts
are about 1-50'' in length, elliptical or oval,
usually narrowed and slightly produced at
the obtuse ends, and consist of numerous
structureless laminae, in which are frequently
imbedded minute granules, consisting of
fatty or calcareous matter. The worm is
cylindrical, narrowed towards the anterior
end, the posterior end being obtuse and
rounded. The integument is transversely
striated or annular, and exhibits an anterior
and a posterior longitudinal muscular band.
The mouth (fig. 17 a) is situated at the an-
terior extremity, from which a small papilla
is sometimes protruded. The first part of
the alimentary canal is very narrow, and
leads to a broader sacculated portion ; this
behind the commencement of the posterior
half of the body terminates in a funnel-
shaped expansion (fig. 18 c), the remainder
of the canal being narrow and lined with
pavement-epithelium (fig. 18 d). The man-
ner in which the posterior end of the alimen-
tary canal terminates is doubtful, — whether
directly continuous with the anal orifice, or
free in the abdominal cavity. M. Luschka
describes three valves as existing at the pos-
terior end of the body. At the commence-
ment of the funnel-shaped portion of the
alimentary canal (fig. 16 b) are two rounded
glandular sacs. The reproductive organs
are not well known. Just below the funnel-
shaped portion of the alimentary canal is the
csecal origin of a tubular sac (figs. 17 & 18 c),
containing a dark granular-looking body
(fig. \7 d; fig. 18 e) near its commencement;
this extends to the posterior end of the
worm, where it either terminates in the anus
or in the abdominal cavity. Luschka re-
gards this as the male organ, and the dark-
looking body as the testis ; but no sperma-
tozoa have been detected.

Some of the cysts and worms are found in
a state of fatty degeneration, with granules
or globules of fat, and calcareous matter.

It appears that the Trichina is derived
from the food; for M. Herbst found the
muscles of two dogs, which had been fed
upon parts of a badger containing the worms,
to be loaded with them.

Three or four other doubtful species have
been described.

BIBL. Owen, Trans. ofZool Soc. i. 315;
Luschka, Siebold fy Kolliker's Zeitschr. iii.
69 ; Bristowe and Rainey, Trans. Path. Soc.
v. 274 ; Dujardin, Hist. nat. d. Helminthes,
293 ; Herbst, Ann. des Sc. nat. ser. 3. xvii.
Kobelt, Valentin's Repertorium, 1841.

TR1CHOCEPHALUS.

[ 651 ]

TRICHODESMIUM.

TRICHOCEPHALUS, Goeze— A genus
of Entozoa, of the order Ccelelmintha, and
family Nematoidea.

Char. Body elongate, composed of two
parts, the anterior longer and capillary ; the
posterior becoming suddenly broader; spi-
culum of male simple, long, and surrounded
by a sheath.

The (ten) species occur in the large intes-
tine, principally the ca3cum of man and the
mammalia.

T. dispar (PI. 16. fig. 19, the male; fig.
21, the female, in which the narrowed por-
tion is too short).

Anterior portion of the body spiral in the
male, containing the oesophagus only, or the
first moniliform portion of the intestine;
posterior portion containing the rest of the
intestine and the reproductive organs. Anus
situated at the posterior obtuse end of the
body. Integument transversely striated,
and with a longitudinal band studded with
papillae (PL 16. fig. 20). Oviduct termi-
nating at the point of junction of the two
portions of the body ; ova (fig. 21 a) oblong,
covered by a resistent shell, with a short
neck at each end.

BIBL. Dujardin, Helminthes, 30 ; Owen,
Todd's Cycl. Anat. fy Phys., art. Entozoa ;
Wedl, Pathol. Histolog. 787.

TRICHOCOLEA, Nees. — A genus of
Jungermannise(Hepaticace8e),containingone
British species, T. (Jung.} tomentella, grow-
ing in moist places in the west and north of
England, Scotland, and Ireland. It is re-
markable for the character of the leaves,
which are cut up into compound capillary
segments, giving the plant a spongy texture.
Colour pale.

BIBL. Hook. Brit. Flor. ii. pt. 1. p. 127,
Brit. Jung. pi. 36 ; Eckart, Synops. Jung.
pi. 6. fig. 49 ; Endlicher, Gen. Plant. Supp.
1. No. 472, 15.

TRICHODA, Miill., Ehr.— A genus of
Infusoria, of the family Enchelia.

Char. Body free from hairs or cilia; teeth
absent ; mouth obliquely truncated, ciliated,
with a lip, but neck absent.

The six species are colourless.

T. pura. Body oblong, clavate, attenuate
in front. Aquatic; length 1 -720''. A spe-
cies of Dujardin' s genus Acomia.

The other species have been very imper-
fectly examined and illustrated.

Dujardin's genus, which is placed in the
family Trichodina, D., differs entirely from
that of Ehrenberg. The characters are : —
Body ovoid-oblong or pyriform, slightly

flexible in front, with a row of cilia directed
backwards, and appearing to indicate the
presence of a mouth.

T. angulata (PI. 25. fig. 7). Body oblong,
obliquely and irregularly folded or angular,
frequently with one or more superficial va-
cuoles. Aquatic; length 1-900".

T. pyrum, D. = Leucophrys carnium, E.

BIBL. Ehrenberg, Infus. 306 ; Dujardin,
In/us. 395.

TRICHODACTYLUS,Dufour.— A genus
of Arachnida, of the order Acarina, and fa-
mily Acarea.

Char. Rostrum short, with minute setae ;
fourth pair of legs shorter than the rest,
without claws, and terminated by a very
long seta.

T. osmicB. Glabrous, with two marginal
setae on each side ; pale red ; legs and pos-
terior part of the body darker. Length
1-50". P

Found upon the thorax of an Osmia (a
kind of mason-bee).

BIBL. Dufour, Ann. des Sc.nat. 2 ser. xi.
276; Gervais, Walckenaer'sApteres, iii.266.

TRICHODECTES, Nitzsch.— A genus of
Anoplurous Insects, of the family Philopte-
ridae.

Char. Antennas filiform, three-jointed;
maxillary palpi none or inconspicuous ;
mandibles two-toothed ; tarsi with one claw.

Ten species, parasitic upon quadrupeds,
viz. the dog, cat, fox, weasel and stoat, ox,
horse, sheep, the red and the fallow deer.

T. latus (PL 28. fig. 6). Abdomen pale
fulvous; head and thorax ferruginous yel-
low ; head subquadrate, with two black spots
in front, and a black lateral band on each
side ; abdomen oval.

Common upon dogs, especially puppies.

BIBL. Denny, Anoplur. Monograph. 186.

TRICHODERMA, Pers.— A genus of
Fungi placed by Fries among the Onygenei
(Ascomycetes), but apparently of doubtful
place. The plants are characterized by a
roundish peridium composed of interwoven,
ramified septate filaments, evanescent at the
summit ; the spores minute, heaped together,
at first conglobated. T. viride, growing on
fallen trees, has a white villous peridium,
and dusky green globose spores. The peri-
dia appear as scattered spots 1-20 to 1-8" or
more in diameter.

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 323;
Greville, Sc. Crypt. Fl. pi. 271; Fries, Summa
Veg. p. 417.

TRICHODESMIUM, Ehrenb.— A genus
of microscopic Algae, apparently belonging

TRICHODINA.

[ 652 ]

TRICHOMANES.

to the Nostochacese, discovered by Ehrenberg
to produce the red colour over large tracts in
the Red Sea, and found also in the Atlantic
and Pacific Oceans by Darwin and Hinds,
and in the Chinese Sea. No vesicular cells
or spermatic cells have been detected, hence
the characters are as yet imperfect. Mon-
tagne has separated the plant of Hinds from
Ehrenberg's, and Kiitzing characterizes the
two species in his Sp. Algarum, and figures
them in his Tabula Phycologicce, but neither
the figures nor the descriptions indicate any
very marked differences.

1. Tr. Ehrenbergii, Montagne. Blood-red
(at length becoming green) ; bundles widish,
confluent; filaments 1-3000" in diameter,
joints about twice as wide as long. Mon-
tagne, Ann. des Sc. nat. ser. 3. vol. ii. p. 360.
pi. 10; Kiitzing, Tab. Phyc. i. pi. 9. fig. 3.
Tr. erytkraum, Ehr., Pogg. Annalen, 1830.
p. 506. Oscillaria erythraa, Ktitz. Phyc.
oeneralis, 188. Found floating in vast strata
in the Red Sea by Ehrenberg and Dupont,
and in the Yellow Sea (China) by Mollien,
Bellot, and others.

2. Tr. Hindsii, Montagne. Blood-red,
with a strong odour ; bundles longish, slen-
derish; filaments 1-3600 to 1-2760" in dia-
meter, joints twice or thrice as broad as long,
transversely granulated. Montagne, Ann.
des Sc. nat. 3 ser. ii. p. 360. pi. 10 ; Kiitzing,
Tab. Phyc.i. pi. 91. iv.

For further information on these species,
and on the red coloration of the sea by
plants, see Montague's papers iniheAnnales
des Sc. naturelles, ser. 3. ii. p. 332, vi. p.
262; ser. 4. i. p. 81.

TRICHODINA, Duj.—A family of Infu-
soria.

Char. Body soft, flexible, more or less
variable in form, ciliated ; mouth either
visible or simply indicated by a row or fringe
of larger cilia ; no cirrhi (styles or hooks).

Genera: Acineria; Dileptus; Pelecida;
Trachelius ; Trichoda, D. (not E.).

BIBL. Dujardin, Infus. 392.

TRICHODINA, Ehr.— A genus of Infu-
soria, of the family Vorticellina.

Char. No tail, nor pedicle; cilia absent
from the surface of the conical or discoidal
body, but forming a frontal crown or a tuft;
oral orifice not spiral.

T. pediculus (Urceolaria stellina, D.) (PI.
24. fig. 16). Body discoidal, the under and
upper surfaces, each with a crown of cilia.

Parasitic upon Hydra vulgaris and viridis.
Breadth 1-575 to 1-290". On the under
surface is an annular undulatory membrane,

and within and at the base of this is a horny
ring, with an outer and inner row of teeth,
forming an organ of adhesion.

T. mitra. Parasitic upon Planaria torva.

T. arandinella and T. vorax are swarm-
germs or free gemmae of Vorticellina.

T. tentaculata. Body discoidal, cilia large,
forming a tuft; a styliform, tentacle-like
process present. Aquatic ; diameter 1-290".

BIBL. Ehrenberg, Infus. 265 ; Dujardin,
Infus. 527; Siebold, Vergl. Anat. 12, Sie-
bold and Kolliker's Zeitschr. ii. 361 ; Stein,
Infus. 174.

TRICHODISCUS, Ehr.— A genus of In-
fusoria, of the family Acinetina, E. (Actino-
phryina, D.).

Char. Body depressed, stalkless; seta-
ceous tentacles forming a simple row at the
margin of the body.

T. sol (PL 25. fig. 8). Body suborbicular,
hyaline or yellowish, tentacles variable.
Aquatic; diameter 1-432 to 1-216".

BIBL. Ehrenberg, Infus. 304.

TRICHOGASTRES (Puff-balls}.— A fa-
mily of Gasteromycetous Fungi, character-
ized by the contents of the leathery peridium
breaking up when mature into a pulverulent
mass of spores and filaments, without a
central column, the whole being expelled by
the bursting of the case (see GASTEROMY-

CETES).

BIBL. Berkeley, Ann. Nat. Hist.iv. 155;
Tulasne, L. R. and C., Ann. des Sc. nat.
s£r. 2. xvii. 1.

TRICHOMANES,Lmn.— A genus of Hy-

Fig. 766.

riswoirii

Fig. 767.

Trichomanes alatum.

Fig. 766. A pinnule. Magnified 6 diameters.

Fig. 767. Section through a sorus, showing the vein
prolonged as cplumella, and continued out beyond the
border. Magnified 25 diameters.

TRICHOMONAS.

[ 653 ]

TRICHOSPORANGE.

menophyllaceous Ferns, of elegant and deli-
cate habit.

Fig. 768.

,syrt*m ,T

10

sr

Fig. 768. A sporange, with horizontal annulus. Mag-
nified 100 diameters.

TRICHOMONAS, Duj.— A genus of In-
fusoria, of the family Monadina.

Char. Body ovoid or globular, becoming
drawn out when adherent to the slide, hence
sometimes exhibiting a tail-like prolonga-
tion; an anterior flagelliform filament present,
with a group or row of vibratile cilia.

T. vaginalis (PL 25. fig. 9). Body glu-
tinous, nodular, unequal, frequently becoming
agglutinated to other objects ; movement va-
cillating. Length 1-2500". Found in morbid
vaginal mucus.

T. limacis (PL 25. fig. 10). Body ovoid,
smooth, pointed at each end; movement
forwards, by revolution upon its axis. Length
1-1600". Found in the intestine of Limax
agrestis.

BIBL. Dujardin, In/us. 299.

TRICHOPTERIS, Presl.— A genus of
Cyathaeous Ferns. Exotic.

TRICHORMUS (Anabaina, Bory, Bre-
bisson, Kutzing. Montagne, &c.). — A genus
of Nostochaceae (Confervoid Algae), growing
on wet earth, or rising to the surface of
lakes, brackish ditches, &c., forming an in-
determinate stratum, at first nearly colour-
less and transparent, with the filaments spa-
ringly scattered through the mass ; the fila-
ments afterwards increasing rapidly in
number, causing the mass to become opake,
deep bluish-green, and occasionally mottled
with brown,especially beneath. The filaments
are mostly short, moniliform, and frequently
as much curved as in Nostoc. The cells are
more or less globular, and the spermatic
cells resemble the ordinary cells more in this
than in the allied genera. The filaments
closely resemble those of Nostoc, and some
of the floating aquatic species can only be
distinguished from that genus by the absence
of definite form or size, and of the hardened
periderm. It differs from Dolichospermum
in the globular shape of its sporangia, and
from Spharozyga and Cylindrospermum in
the arrangement of its vesicular and sper-
matic cells, which are here always separated
by ordinary cells. Mr. Ralfs enumerates
five British species. In PL 4. fig. 2, we

have represented what appears to be a new
species.

1. T. fios-aqucB (Lyngbye). Filaments
flexuose or curved, moniliform ; cells orbi-
cular, vesicular ones larger, terminal and
interstitial. Ralfs, Ann. Nat. Hist. ser. 2.
vol. v. pi. 8. fig. 2. Anabaina flos-aqua,
Kutzing, Spec. Algarum ; Trichormus incur-
vatus, Allman, Ann. Nat. Hist. xi. 163.
t. 5 (1843); Hassall, Brit. Freshw. Algts,
t. 75. fig. 1. Rising to the surface of stag-
nant pools or other still waters in gelatinous
masses of considerable size, generally of a
rich bluish-green colour.

2. T. (?) spiralis (Thompson). Filaments
coiled or spiral ; ordinary cells subquadrate
or orbicular; vesicular and spermatic cells
orbicular.— Ralfs, I. c. pi. 8. fig. 3. (?) Ana-
baina spiralis, Thompson, Ann. Nat. Hist.
vol. v. 81 ; Spirillum Thompsoni, Hassall,
Br. Fr. Alga, t. Ixxv. 7- (See SPIRULINA.)

3. T. Thwaitesii (Harvey). Filaments
moniliform, slightly flexuose ; ordinary cells
globular or nearly so ; vesicular cells larger,
globular when interstitial, ovate when ter-
minal, ciliated ; sporangia oval, catenate. —
Ralfs, I. c. pi. 8. fig. 4. Spharozyga
Thwaitesii, Harvey, Phyc. Britannica, t.
1 13 B. Salt-marshes, forming thin, gelati-
nous, dark green patches, either on damp
soil, covered at spring-tides, or at the bottom
of brackish ditches or pools, afterwards
floating in large gelatinous masses, and then
abounding in spermatic cells.

4. T. oscillarioides (Bory). Filaments
elongated, flexuose; ordinary joints sub-
quadrate, distinct ; vesicular cells barrel-
shaped or elliptic, naked; spermatic cells
oval, catenate. — Ralfs, 1. c. pi. 8. fig. 5.
Anabaina oscillarioides, Bory, Diet. d'Hist.
natur. ; Sphcerozyga oscillarioides, Kutzing,
Tabula Phycologica, pi. 96. fig. 5. In
brackish ditches, bluish-green.

5. T. rectus (Thwaites). Filaments bright
green, straight, short, slightly tapering to-
wards the extremities; ordinary cells sub-
spherical, rather shorter than wide; vesicular
cells oblong, smooth, scarcely wider than
the ordinary cells, and never terminating the
filament; spermatic cells spherical or oblong,
numerous. — Ralfs, 1. c. pi. 8. fig. 6. Pools
(near Bristol, Thwaites) ; of a beautiful green
colour.

BIBL. The works cited above.

TRICHOSPORANGE.— A term used by
Thuret in application to multiseptate fila-
ments, occurring in some of the Fucoid
Algae, producing ciliated zoospores in their

TRICHOSPORIUM.

[ 654 ]

TRIPHRAGMIUM.

Fig. 769.

joints (see MESOGLOIA). In a recent paper,
however, he has stated that the proper tri-
chosporanges and oosporanges pass into one
another by numerous intermediate forms,
and he desires to dismiss the terms in favour
of uni- and multi-locular sporanges.

BIBL. Thuret, Ann. des Sc. nat. ser. 3.
xiv. p. 235. ser. 4. iii. p. 15.

TRICHOSPORIUM, Fr.— A genus of
Mucedines (Hyphomycetous Fungi), nearly
allied to BOTRYTIS, characterized by a caes-
pitose mycelium, whence arise fertile, conti-
nuous filaments, bearing solitary, simple,
acrogenous spores. T. nigrum = Sporotri-
chum nigrum, Fries (Syst. Myc.}, Botrytis
nigra, Link.

BIBL. Fries, Summa Veg. p. 492 ; Grev.
Sc. Crypt. Fl. pi. 274.

TRICHOSTO-
MUM, Hedw. — A
genus of Pottiaceous
Mosses, so called from
thehair-likeperistome,
resembling closely that
of BARBULA (Tortu-
la), but with the teeth
straight instead of
twisted; in T. rigidu-
lum, however (fig. 769),
there exists a slight cur-
ling even in this genus.
Mr. Wilson combines

LEPTOTRICHUM with Trichostomum rigidulum.
this. TheTrichostoma Fragment of the peristome

grew on the ground with filiform teeth.
and on stones. Magnified 100 diameters.

TRICHOTHECIUM, Link. (Diplospori-
um, Ej usd . ) . — A genus of Mucedines ( Hypho-
mycetous Fungi), growing upon dead sticks,
herbaceous parts of plants, &c., forming a
caespitose, entangled mycelium, from which
arise erect fertile filaments, bearing at the
summit a few acrogenous, free, didymous
spores. These plants are nearly allied to
DACTYLIUM, under which Mr. Berkeley in-
cludes them; but apparently they may be
separated by the uniseptate, not multiseptate
spores. From some observations recently
published by Hoffmann, and confirmed by
Bail, the spores of T. roseum, when they
germinate, produce a mycelium whence
arise fertile filaments of Verticillium ru-
berrimum, the < spores ' of which they conse-
quently consider as the spermatia of this
plant. Several species are British, as T.
roseum, obovatum (Dactylium, Berk.).

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 348 ;
Ann. Nat. Hist. vi. p. 437. pi. 14; Greville,

Sc. Crypt. Fl. pi. 172; Fries, Summa Veg.
p. 492 ; Hoffmann, Botan. Zeit. xii. p. 249.
1854 ; Bail, ibid, xiii. p. 673. 1855.

TRIMMATOSTROMA, Corda (fig. 764.
page 646). — An obscure genus of Torulacei
(Coniomycetous Fungi), perhaps founded on
thesporesof aspeciesof PHRAGMOTRICHUM.
BIBL. Corda, Icon. Fung.; Fries, Summa
Veg. p. 475.

TRINEMA, Duj.— A genus of Infusoria,
of the family Rhizopoda.

Char. Carapace membranous, diaphanous,
elongate-ovoid, narrower in front, with a
large oblique lateral orifice ; expansions two
or three, filiform, very slender, as long as
the carapace.

T. acinus=Difllugia enchelys, E. (PL 25.
fig. 11, after Ehr. In Dujardin's figure the
expansions are represented as much more
slender). Aquatic.

BIBL. Dujardin, Infus. 249.
TRIOPHTHALMUS, Ehr— A genus of
Rotatoria, of the family Hydatinsea.

Char. Eyes three, red, cervical, in a trans-
verse row ; foot forked.
Jaws single-toothed.
T. dorsualis (PL 35. fig. 31). Body cry-
stalline, turgid, suddenly attenuated at the
foot which is half the length of the body.
Aquatic; length 1-48 to 1-36".
BIBL. Ehrenberg, Infus. p. 450.
TRIPHRAGMIUM, Link.— A genus of
Uredinei (Coniomycetous Fun-
gi), distinguished by their tri-
locular spores (fig. 770). T.
ulmaria (Uredo ulmaria, Brit.
Fl.), grow upon the leaves of
Spircea ulmaria, forming orange,
subsequently blackish, effused
patches, bursting from beneath
the epidermis. Tulasne has T"phragmiUm
shown that it possesses all three A pe™c"nate
forms of reproductive structure spore.
of the Uredinei, viz. 1. spermo- Magnified 350
gonia with spermalia-, 2. Uredo- diameters-
fruits, with ellipsoid or globose stylospores ;
and 3, perfect fruit, arising either among
the stylospores or in special sori, containing
stipitate, three-lobed spores (fig. 7/0), each
lobe of which is unilocular and exhibits a
single pore in its black tubercular outer coat.
The last germinate in the spring, and pro-
duce from each pore a tubular filament
which becomes divided into four or five
chambers, from three or four of which arise
single styliform processes (sterigmata), each
bearing a small smooth spherical " spori-
dium." The globular stylospores also ger-

p-

TRIPOSPORIUM.

[ 655 ]

TROMBIDIUM.

minate (in the first summer), but produce
only a long, filiform process, probably the
rudiment of a newmycelium (see UREDINEI).

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 368 ;
Tulasne, Ann. des Sc. nat. ser. 4. ii. p. 181.
pi. 10; Fries, Summa Veg. p. 513.

TRIPOSPORIUM, Corda.— A genus of
Dematiei (Hyphomycetous Fungi), charac-
terized by three lobed septate spores. T.

Fig. 771.
t

wldo aj

Triposporium elegans.
Magnified 200 diameters.

ctt/ aiiJ Wfirf gi doitf?/ iooi
elegans (fig. 771) has been found in this
country on bare oak trunks. Another spe-
cies, T. Gardneri, forms a blight on the
coffee plantations of Ceylon.

BIBL. Berk. Ann. Nat. Hist. 2 ser. vii.
p. 98 ; Hortic. Journal, iv. p. 8.

TRITON, Laur.— A genus of Reptiles.

If a male and female T. cristatus (fig.

Fig. 772.

772), one of the common water-newts, be
kept in a glass jar with healthy water-plants,
they will lay their eggs upon them. The
larvae are very beautiful microscopic objects,
for showing the circulation in the gills and
tail, the chorda dorsalis and the embryonic
tissues; they should be kept in a vessel
separate from the parents, otherwise these
will devour them.

The injected skin of T.palustris, the large
warty newt, forms a beautiful opake object ;
showing the loose capillary network, which

contrasts well with the brilliantly mottled
skin.

BIBL. Bell, British Reptiles.

TROCHILIA, Duj.— A genus of Infu-
soria, of the family Ervilina.

Char. Body irregularly oval, narrower in
front, where there are some vibratile cilia ;
carapace obliquely furrowed, slightly twisted,
and terminated behind by a moveable
pedicle ; no distinct mouth.

T. sigmoides (PI. 25. figs. 12 & 13). Body
narrowed and sinuous in front; carapace
with five or six rounded oblique ribs ;
pedicle capable of adhering to the slide.
Marine; length 1-630".

Fig. 12 represents the animal undergoing
transverse division.

TROMBIDIUM, Latr. — A genus of
Arachnida, of the family Trombidina.

Char. Palpi large, free; mandibles un-
guiculate ; body turgid, bearing the four
posterior legs, and an anterior narrow
moveable eminence, upon which the eyes,
the four anterior legs and the mouth are
situated ; anterior legs longest.

The species are numerous and not well
characterized.

T. phalangii (PL 2. fig. 37). Body sub-
triangular, angles obtuse ; of a velvety ap-
pearance, from the presence of numerous
plumose hairs ; eyes two, placed upon auri-
cular appendages.

An external parasite of Phalangium (the
harvest-spider) and insects, at least in its
early hexapodous stage.

T. elongatum. Crimson ; eyes approxi-
mate. Found under stones.

T. cinereum (PI. 2. fig. 40), (Rhyncholo-
phus ciner. Dug. Body with brown and
greyish-white spots ; hairs spathulate ; eyes
two on each side. Length 1-12". Found
in ditches amongst plants and stones.

T. autumnale (PL 2. fig. 38), (Leptus
autumn.}. The harvest-bug. This well-
known, but imperfectly examined arach-
nidan insinuates itself into the human skin
in autumn, causing troublesome irritation.
It is found on plants and the stubble of corn-
fields, and may easily be caught by tying a
white pocket-handkerchief around the legs,
and walking through stubble-fields. The
young form with six legs is most frequently
met with.

BIBL. Duges, Ann. d. Sc. nat. ser. 2. i.
36; Gervais, Walckenaer's Apteres, iii. 178;
Johnston, Transact, of Berwickshire Natu-
ralists' Club, 1847. 221 ; Koch, Deutschl
Crustac. Myriap. fyc.

TRYBLIONELLA.

[ 656 ]

TUBERCLE.

TRYBLIONELLA, Smith.— A genus of
Diatomaceae.

Char. Frustules free, linear or elliptical
in front view ; valves plane, with parallel
transverse (tubular ?) stria3, and submarginal
or obsolete alae.

In some a median line is present, in others
not. The alae are not marginal, as in Suri-
rella, but arise from the surface of the valves,
as shown by the diagram of a transverse
section in PI. 13. fig. 32.

T. scutellum (PL 13. fig. 30). Valves
elliptical, with a median longitudinal line ;
alae very short ; striae faint. Marine ; length
1-140".

T. gracilis (PL 13. fig. 31). Frustules
linear, narrowed at the ends ; valves linear,
acuminate, striae coarse; alae distinct. Fresh
and brackish water ; length 1-200".

Four other species.

BIBL. Smith, Brit. Diat. i. 35.

TUBER, Mich.— A genus of Tuberacei
(Ascomycetous Fungi), to which belongs
the common truffle (see TUBERACEI).

TUBERACEI.— A family of Ascomyce-
tous Fungi, growing underground or upon
the surface, of more or less round form,
and solid, fleshy texture, excavated with
sinuous cavities, lined by asci, containing
usually four or eight spores, elegantly reti-

T? *"-')

Fig. 7/3.

r.tdo «wi
Fig. 774.

Fig. 775.

Choiromyces Leonis.
Fig. 773, A peridium. Nat. size.
Fig. 774. An ascus with spores. Magnified 400 dia-
meters.
Fig. 775. Vertical section of a peridium.

culated or spinulose (fig. 774). The internal
substance either dries and grows hard, or
falls into a flocculent powder with age.

Tuber cibarium is the common truffle.
Sections of the marbled internal substance
show this to be composed of interlacing
branched filaments, forming fleshy convolu-
tions, between which serpentine cavities are
alternately excavated ; branches of the fila-
ments free at the surface of the lacunae bear
spherical sacs (asci), each containing four
globular spores of yellow-brown colour,
having an elegantly reticulated outer coat.
When the spores germinate, they produce a
subterraneous cottony mycelium, which after
a time presents villous nodules, in the inte-
rior of which the peridia are developed ; as
these advance, the villous coats gradually
vanish, together with the mycelial structure,
and the mature peridia appear free, either a
little beneath (Tuber cibarium}, or upon the
surface (T. album) of the soil (see also ELA-

PHOMYCES).

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 227;
Tulasne, Ann. des Sc. not. ser. 2. xvi. p. 5,
ser. 3. p. 348, Monog. Fungi Hypogcei, Paris
1851, Ann. Nat. Hist. 2 ser. viii. p. 19;
Lespiault, Ann. des Sc. nat. 3 ser. ii. p. 316;
Vittadini, Monog. Tuberacearum ; Monog.
Lycopod., Mem. Turin Acad. 2nd ser. v.
p. 145.

TUBERCLE or TUBERCULAR MATTER.
— This morbid deposit consists of three parts,
the relative proportions of which are variable;
viz. 1. an amorphous transparent basis, ren-
dered pale by, and finally soluble in acetic
acid; 2, minute granules and molecules,
some of them consisting of proteine-com-
pounds, others of fatty matter ; and 3. of a
number of nuclei, or so-called tubercle-cor-
puscles (PL 30. fig. 9 a), about 1-5000 to
1-4000" in size, of an oblong-angular form,
containing irregular granules, and unaffected
or simply rendered paler by acetic acid (PL
30. fig. 9 b).

Tubercular matter is deposited in the sub-
stance of the tissues or in the cavities of
organs (PL 30. fig. 8). The corpuscles have
been supposed to be peculiar to and charac-
teristic of tubercle ; but late researches tend
to the conclusion that they are the nuclei of
normal cells, the development of which has
been arrested.

When softening occurs, the tuberculous
matter usually undergoes fatty degeneration;
the number of free fatty granules is much
increased, and the tubercle becomes yel-

lowish.

TUBERCULARIA.

[ 657 ] TUMORS.

It sometimes becomes a question as to
whether a morbid deposit consists of tubercle
or not. The diagnosis must be founded
mainly upon negative characters : the ab-
sence of the elements of other abnormal pro-
ducts, as those of inflammation, cancer, &c.

In cretaceous tubercle, carbonate and
phosphate of lime, usually in the amorphous
state, are met with.

BIBL. Works on Medicine; Lebert, Phys.
Pathol.; Hasse,Patholog. Anatomy (Syden-
ham Soc. Vol.) ; Vogel, Pathol. Anat. (by
Day); Wedl, Path. Anat. 365; Forster,
Path. Anat. i. 312, & ii. 156; Rokitansky,
Path. Anat. i. & iii.

TUBERCULARIA, Tode.— A supposed
genus of Stilbacei (Hyphomycetous Fungi),
but apparently only preparatory forms of
Sphseriaceous Fungi. T. vulgaris is a state
of Nectria (Sphteria) cinnabarina ; it is ex-
tremely common, in autumn and winter, on
dead sticks, damp wooden palings, stumps,
&c., forming scarlet-orange rounded nodules
or irregular masses of fleshy consistence,
sometimes more or less stipitate, composed of
parenchymatous tissue, the surface at a certain
stiige exhibiting the ends of the filaments
terminating in chains of cellules breaking up
into a pulverulent substance. These cellules
are probably the conidia of the Nectria.

TUBULI URINIFERI. See KIDNEYS
(p. 373).

TUBULIPORA, Lam.— A genus of Po-
lypi, of the order Bryozoa, and family Tubu-
liporidae.

Char. Polypidoms calcareous, depressed,
orbicular, lobed, or divided dichotomously ;
the cells suberect, aggregate, long and tubu-
lar, with a round, unconstricted aperture;
polypes with an uninterrupted circle of ci-
liated tentacula. Marine.

Nine British species. Some of them are
common upon shells, sea-weeds, &c.

PL 33. fig. 30 represents a species (not
British).

BIBL. Johnston, British Zoophytes, 266.

TUBURCINIA, Fries.— An obscure genus
of microscopic Fungi, referred by Fries to
the Sepedonei (Hyphomycetous Fungi),
growing in roots and tubers, or on leaves,
forming 'scabs.' The evanescent mycelium
creeps through the tissue of the infected
organ, and produces solitary globular spores,
of cellular texture (hollow), ultimately be-
coming free. T. Scabies forms one kind of
scab on potatoes (not that in the ordinary
disease).

BIBL. Berk. Hort. Journal, i. p. 33. pi. 4.

figs. 30, 31, Ann. Nat. Hist. 2nd ser. v. p.
464 ; Fries, Summa Veg. p. 497.

TUMORS.— Under this head we shall
make a few brief remarks upon some of the
more interesting elements of certain tumors
and other morbid growths.

Cancer. — The most constantly present
elements of a cancerous growth are, — 1 . or-
ganic molecules and granules, with globules
of fat ; 2. fibres ; and 3. cells in all stages of
development. As occasional or accidental
elements, are found, — 4. fibro-plastic cells ;
5. granule-cells; 6. pigment; 7- inorganic
matters, in the form of molecules, granules,
and crystals ; and 8. the products of inflam-
mation.

The cells only require distinct notice, the
other elements resembling those usually met
with in other healthy or morbid products.
They are comparatively large, varying con-
siderably in diameter, of a rounded ob-
long or ovate form, usually arranged in no
definite order in the intervals of the fibres
(PL 30. figs. 11 & 12), although sometimes
in the meshes formed by the aggregation of
the fibres into loose bundles (fig. 17). Their
most important feature is the indication of
endogenous growth, shown by their usually
containing numerous nuclei and nucleoli, or
secondary and tertiary cells. In some of
them a tendency to the formation of fibres is
evidenced by the elongation of their ends
(fig. 21). When acted upon by acetic acid,
the primary cell becomes pale and transpa-
rent, the nuclei or inner cells remaining di-
stinct.

The interspaces of the cells and fibres are
occupied by a pale yellowish or colourless
liquid ; and the cells are so loosely imbedded
in the fibrous basis, that on scraping the
surface of a section of a cancer, numerous
cells are found in the juice thus obtained.

The number of fibres present varies ac-
cording to the form or stage of development
of the cancer. In hard or schirrous cancer,
they preponderate, the cells being few ;
whilst in soft or medullary cancer they are
scanty, the cells being very abundant ; glo-
bules of fat usually also abound in the latter
form.

Other varieties of cancer have received
special names. Thus, when the capillaries
are very numerous and distended, extrava-
sated blood being also frequently present,
we have haematoid cancer, or fungus ha3ma-
todes; when the fibres are grouped into
bundles, forming marked areolae, we have
areolar, colloid or gelatiniform cancer (PL 30.

2u

TUMORS.

[ 658 ]

TYMPANIS.

fig. 18) ; again, when the cancer-cells abound
in pigment, we have melanotic cancer, &c.

The diagnosis of a cancerous growth is of
great importance, and cannot in general be
regarded as a matter of difficulty. It can-
not, as was formerly supposed, be based
simply upon the characters of the cells ; for
cells exhibiting a marked endogenous repro-
duction, which is the most striking feature
of cancer- cells, are also met with in normal
tissues; but when these cells exhibit no
tendency to the formation of a definite tis-
sue, but retain their cell-form, and contain
or are mixed with numerous fat-globules,
the whole being loosely imbedded in a serous
liquid, the cancerous nature of the morbid
product may be considered as certain.

In regard to cells generally, an insuperable
difficulty is met with in discovering the ex-
ponent of their power, as it might be termed ;
thus, the embryonic cells or corpuscles in an
early stage are undistinguishable from each
other ; and yet some grow into areolar fibres,
others into nerve-tubes, &c. Chemistry
lends no aid here, and the difficulty will
probably ever remain.

Cancroid growths. — This term has been
applied to certain kinds of tumors or growths
which somewhat resemble cancerous growths
in their course and tendency to recur, yet
differ from them in the nature of their mor-
phological elements. They consist generally
of epithelial formations, or of some kind of
fibrous development. As instances, may be
mentioned so-called epithelial cancer, as of
the lip, and certain forms of fibroid, fibro-
plastic, or sarcomatous tumors.

In epithelial cancer, the general arrange-
ment of the elements is not strikingly altered,
but the papillae of the skin are hypertrophied,
the epithelial cells more numerous than na-
tural, sometimes containing many nuclei or
secondary cells, and the intercellular juice is
more abundant. The flattened epithelial
cells are often also arranged around the pa-
pillae in the form of concentric rings, resem-
bling fibres ; but the cell-structure is at once
rendered evident by the addition of solution
of potash.

In the fibroid or fibro-plastic tumors, the
arrest of development at the cell-stage is
often well shown by the presence of nume-
rous nuclei or secondary cells within the pri-
mary ones (PL 30. fig. 10). These brood-
cells are also met with in obstinate fungous
granulations and vegetations.

Enchondroma, cartilaginous growth or tu-
mor.— In some kinds of this, the cartilage is

indistinguishable from normal true carti-
iage j in others it exhibits the formation of
secondary deposits in the cells, as in imper-
fectly formed bone (PI. 30. fig. 19), the
cavities of the cartilage-cells being filled up
with the exception of the irregularly stellate
median portions.

In the examination of tumors and other
morbid growths, sections should be made
with a Valentin's knife, the elements being
first observed in water, and then in the na-
tural fluid. The sections and elements are
best preserved in water.

BIBL. Paget, Lectures on Tumors (1851),
and Surgical Pathology ; the Bibl. of TU-
BERCLE ; Bennett, on Cancer, and Edinb.
Monthly Journal. & viii.; Redfern, ibid, xi.;
and the Trans, of Pathol. Soc., passim.

TYMPANIS, Fr.— A genus of Phacidiacei
(Ascomycetous Fungi), consisting of horny
bodies growing on branches of trees, break-
Fig. 776.

Tympanis conspersa.

Fig. 776. A collection of perithecia, more or less ma-
ture, bursting through the bark. Magnified 1 0 diameters .

ing out through the bark. T. conspersa (fig.

776) grows upon Rosaceous trees, T. s1-™"

on the privet. In Y\V. 777.

the former the perithe-

cia are collected in

tufts; they are first

closed, afterwards

opening into cups,

the disk of which is \S /

occupied by the hy- \

menium bearing long H£ ':j

and broad asci, con- Vj$$| /

taining numerous %

spores, and, as has Vertical section through a

Messrs. Berkeley and cup-like perithecia.

Broome, sometimes Magnified 20 diameters.

also septate stylospores simultaneously. In
T. saligna the perithecia occur only two to
four together. Tulasne has shown in addi-
tion, that the plants have spermogonia, which
are oblong or conical bodies, intermixed with
the perithecia, perforated by a terminal pore
(resembling perithecia of Sphceria] ; these
are lined with delicate branched filaments

TYNDARIDEA.

[ 659 ]

ULVA.

bearing minute corpuscles (spermatia), which
when mature escape from the pore in a ten-
dril (as in Cytispora] if moistened or pressed
(see also CENANGIUM).

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 210,
Ann. Nat. Hist. 2nd ser. vii. p. 185, Hook.
Journ. of Botany, iii. p. 322 (1851); Tulasne,
Ann. des Sc. nat. 3 ser. xx. p. 143. pi. 16.
figs. 15, 16; Fries, Summa Veg. p. 399 ;
Greville, Sc. Crypt. Fl. pi. 335.

TYNDARIDEA, Bory. See ZYGNEMA.

TYPHLINA, Ehr.— An imperfectly exa-
mined genus of Rotatoria, of the family
Philodinaea.

T. viridis (PL 35. fig. 33). Found in
Egypt.

BIBL. Ehrenberg, Infus. 483.

U.

ULOTHRIX.— A genus of Confervoid
Algae, perhaps referable to the Chaetophora-
ceae, allied to Draparnaldia and Stigeoclo-
nium. They consist of unbranched filaments
adhering loosely together to form a mucous
stratum, growing upon stones, &c. in fresh
water. The filaments are composed of short
hyaline cells (PI. 5. fig. 6), the green con-
tents of which are at first granular, adhering
to the walls (a), then contracted into trans-
verse bands (b), and finally converted into
two, four, or more zoospores, with four cilia
(c). Hassall appears to have confused these
plants with the Oscillatoriaceous genus
Lyngbya ; his L. muralis is apparently the
true plant, his L. copulata perhaps a Schizo-
gonium ; the rest of his species belong here,
since, according to Kiitzing, Berkeley's
Sphceroplea crispa and punctalis belong to
this genus. There appear to be several
British species, but we give them with some
doubt.

1. U. zonata. Filaments 1-960" in dia-
meter, joints about as long (Lyngbya zonata,
Hass. pi. 59. figs. 2, 3, 6).

2. U. pectinalis. Filaments 1-1800,
1-1200, 1-960" in diameter, joints one-
half or one-fourth the length ; fertile cells
swollen (L. zonata, Hass. pi. 60. figs. 1,
4,5).

3. U. crispa. Filaments very long, 1-600"
in diameter, joints one-half or one-third as
long (Cow/, bicolor, Eng. Bot. p. 2288).

4. U. floccosa. Filaments 1-2160 to
1-1800" in diameter, joints about as long
(Lyngb. floccosa, Hass. pi. 60. figs. 1 & 2).

5. U. punctalis. Filaments 1-3000 to
1-2500" in diameter, regularly torulose;

joints two and a half times as long as broad
(Lyngb. punctalis, Hass. pi. 60. fig. 4; L.
virescens, fig. 3, and L. vermicularis, Hass.
fig. 5, are scarcely distinct from this).

6. U.speciosa. Filaments 1-780 to 1-420"
in diameter, curled ; sterile joints one-half
or one-third as long.

BIBL. Kiitzing, Sp. Alg. p. 345, Tab.
Phyc.ii.-, Hassall, Brit. Fr. Alg. p. 219;
Thuret, Ann. des Sc. nat. 3 ser. xiv. p. 222.
pi. 18.

ULVA, Linn. — A genus of Ulvacese (Con-
fervoid Algae), here taken in the sense of
Thuret. The plants are all marine, consist-
ing of broad, green, simple or lobed, mem-
branous fronds, growing upon rocks and
stones. They are distinguished from Mono-
stroma by being composed of a double plate
of cellular tissue, and from Enteromorpha
by the two plates being permanently adhe-
rent, and not separating so as to convert the
flat plate into a sac. The cells are round-
ed-angular (PI. 5. figs. 2 & 3), and are at
first filled with amorphous green colouring
matter, which subsequently becomes collected
into masses (a), ultimately converted into
numerous zoospores. Under the influence
of light, these soon " swarm" and break out
from the cells by a pore in the outer wall
(fig. 3 b}. The emptied cells give a pale co-
lour to the parts of the frond where they
are situated. The zoospores appear in two
forms, some large and bearing four cilia (fig.
3 c), others much smaller, and possessed of
only two cilia (fig. 2 b). The fronds in which
the latter occur are generally of a yellower
colour. Thuret has seen both kinds germi-
nate. As defined by that author, the British
species stand as follows : —

1. U. Lactuca, L. Frond broadly ovate
or oblong, 6 to 18" long, and several inches
wide (Engl. Bot. pi. 1551; U. latissima,
Harvey and Greville ; Phycoseris gigantea,
Kiitz.).

/3. latissima. Frond 3' or more long, 18"
or more wide ; found in the muddy water at
the entrance of harbours (Phycoseris Myrio-
trema, Kiitz. Sp. Alg.}.

2. U. Lima, L. Frond linear-lanceolate,
6 to 24" long, 1-2 to 3-2" wide. (17. Lac-
tuca, Greville, Sc. Crypt. Fl. pi. 313 ; Har-
vey, Phyc. Brit. pi. 243 = Enteromorpha
Grevillei, Thuret, olim).

BIBL. Harvey, Brit. Mar. Alg. p. 216.
pi. 25 B ; Thuret, Mem. de la Soc. de Cher-
bourg, ii. (1854), Ann. des Sc. nat. 3 ser. xiv.
p. 224. pi. 20; Greville, Harvey, Kiitzing,
I. cit. supra.

2u2

ULVACE.E.

[ 660 ]

UREDINEI.

ULVACE^.— A family of Confervoid
Algae. Marine or freshwater Algae, consist-
ing of membranous, expanded, saccate or tu-
bular, sometimes filiform fronds, composed of
spherical or polygonal cells, united together
firmly into layers, either single or double.
Reproduced by roundish spores formed from
the whole contents of cells, or by ciliated
zoospores formed in twos, fours, or many in
each cell. British genera :

I. ULVA. Frond plane, simple, or lobed,
formed of a double layer of cells closely
packed, producing zoospores.

II. ENTEROMORPHA. Frond hollow,
simple or branched, of a single layer of cells
closely packed, forming a sac or tube ; with
zoospores.

III. MONOSTROMA. Frond flat or sac-
cate, simple or lacerate-lobed, forming a
single layer of cells, which are scattered in
a homogeneous membrane ; with zoospores.

IV. PRASIOLA. Fronds membranous,
lacerate-lobed, formed of a single layer of
cells arranged in simple or compound lines,
or in groups multiple of four. Spores from
the whole contents of cells, motionless.

V. SCHIZOGONIUM. Fronds filiform,
dilated here and there into flat ribands con-
taining two or four rows of cells. Spores
formed from the whole contents, motion-
less.

ULVINA, Kiitz. — A supposed genus of
Algae, founded on the " mother" of Vinegar.
(See VINEGAR PLANT).

BIBL. Kiitz. Sp. Alg. p. 147-

UMBILICARIA, Fe'e (Gyrophora, Ach.).
— A genus of Lecidinese (Gymnocarpous Li-
chens). U. pustulata grows on rocks in
various parts of Britain. It is remarkable
for the tubercles or hollow papillae occurring
on its surface. The apothecia are flat, and
at first black, at length tuberculate. Sper-
mogonia also occur, in the form of little
tubercles containing a nucleus of densely
packed sterigmata, enclosed by a thin black
rind. The species in which the disk of the
apothecia is concentrically plicate form the
proper Gyrophorce of Ach. ; they occur on
mountain rocks.

BIBL. Hook. Brit. Flor. ii. pi. 1. p. 223;
Tulasne, Ann. des Sc. nat. 3 ser. xvii. p. 207.
pi. 5. figs. 5-12 ; Schaerer, Enum. crit. p. 25.

URATES. See URIC ACID and URATES.

URCEOLARIA, Ach.— A genus of Par-
meliaceae (Gymnocarpous Lichens), included
under Parmelia by Fries, but agreeing in
almost every particular with LECANORA.
U. scruposo, the commonest species, grows

on heaths, walls, and rocks. The disk of the
apothecia is black, and the border crenated.
The spores are cellular or multilocular (PI.
29. fig. 17). The spermogonia are scattered
over the thallus, sometimes in the outer wall
of the (thallodal) border of the apothecia ;
they are very inconspicuous, on account of
the light colour of their ostiole.

BIBL. Hook. Brit. Flor. ii. pt. 1.
p. 175; Tulasne, Ann. des Sc. nat. 3 ser.
xvii. p. 172. pi. 4. figs. 5-14 ; Schaerer, Enum.
crit. p. 85.

URCEOLARIA, Duj.— A genus of Infu-
soria, consisting of U. stellina, D. (= Tri-
chodina pediculus, E.), and three doubtful
species described by Miiller.

BIBL. Dujardin, In/us. 525.

URCEOLARINA, Duj.— A family of In-
fusoria.

Char. Body variable in form, alternately
top-shaped or hemispherical, or globular,
sometimes ciliated all over, furnished at the
upper and anterior end with a marginal row
of very large cilia, spirally arranged, and
leading to the marginal mouth ; sometimes
swimming, sometimes temporarily fixed by
means of the cilia of the posterior end.

This family includes the genera Ophrydia,
Stentor, Urceolaria, and Urocentrum.

BIBL. Dujardin, Infus. 518.

UREA. — This substance occurs normally
in the urine of man and the carnivora, in
small quantity in that of the herbivora ; also
in the amniotic liquid, and the vitreous and
aqueous humours of the eye. Pathologically,
it is found in the blood, dropsical effusions,
vomited liquids, and doubtfully in the saliva,
the bile, and perspiration.

When pure, it forms colourless four-sided
prisms, sometimes longitudinally striated,
and with one or two oblique terminal facets.
The crystals are readily soluble in water and
alcohol, but not in pure aether.

When nitric or oxalic acid is added to a
solution of urea, the nitrate or oxalate sepa-
rates in the crystalline form.

The nitrate of urea, when rapidly formed,
consists of irregularly aggregated scaly cry-
stals (PI. 9. fig. 18 c) ; when more slowly
formed, rhombic or hexagonal plates, or di-
stinct prisms (PL 9. fig. 18 «, 6). The cry-
stals of the nitrate of soda (PI. 6. fig. 19) bear
some resemblance to those of the urea salt.

The crystals of the oxalate of urea somewhat
resemble those of the nitrate, the rhombic
form being evident.

BIBL. That of CHEMISTRY, Animal.

UREDINEI.— Since the article Caeomacei

UREDINEI.

[ 661 ]

UREDINEI.

has been in print, Tulasne has published an
elaborate memoir upon the Uredinei and
Ustilaginei, which renders it necessary to
devote considerable space to the present
article, which, with that of USTILAGINEI,
must be regarded as superseding what was
stated under the head of C^BOMACEI.

Under the head of Ustikginei are placed
the various forms of bunt, caries, &c., which
affect the ovaries and anthers of Flowering
plants, growing in the interior of these or-
gans, causing them to become more or less
deformed, and finally occupying the whole
of their interior as a pulverulent substance,
commonly of a black colour, and sometimes
with a foetid odour (see USTILAGINEI).

The genus Uredo is shown by Tulasne to
have no satisfactory claim to a distinct exist-
ence, since the structures which have repre-
sented it appear to be merely a form of the
reproductive organs common to a number of
plants, which, in their most perfect state,
represent the genera Puccinia, Phragmidium,
Uromyces, &c.

Of the genus Phragmidium, P. bulbosum
(Puccinia Rubi, Schaer.) is a species com-
monly occurring on the leaves of brambles,
forming reddish, then orange, and finally
blackish rusty spots -pv 770

(fig. 778). The first
signs of reproductive
organs appear in the
middle of the spots
on the upper face of
the leaf, consisting
of a few minute
unilocular cavities
(spermogonia) exca-
vated in the leaf,
with a little flat os-
tiole ; in these occur
ovate spermatia (see
J«!CIDIUM), which
are accompanied by Leaf of bramble, with

a yellowish mUCOUS "Uredo Ruborum." Half

liquid, and are ex- the natl size'
pelled with this in the form of drops. Sub-
sequently to this, the t/recfo-fruits are de-
veloped, mostly on the lower face of the leaf,
at the back of the spermogonia, or more
rarely on the upper face, in a circle around
the latter. They are pulverulent patches
(fig. 778), solitary or a few together j and a
vertical section (fig. 779) shows them to
consist of paraphyses (fig. 780), and simple
or branched, short filaments bearing globose
stylospores (fig. 781), which soon become
detached, and in ripening acquire an echinate

Fig. 779.

Vertical section of the same Uredo-fruit, with para-
physes and imperfect stylospores. magnified 460 diams.

Fig. 780.

Fig. 781.

Fig. 780. Separate paraphyses.
Fig. 781. Detached pedicels with stylospores.
Magnified 460 diameters.

outer coat with numerous pores. When
these germinate, they produce merely a long
slightly branched filament. Finally, the
perfect fruits (spores) appear on the same or
in distinct sori (on the lower face of the leaf),
in the form represented in fig. 570 (p. 502).
The loculi of these have each three or four
pores in the upper part of the side-walls,
whence emerge in germination (in spring)
short tubular filaments, which soon divide
into four cells, from each of which arises a
minute " sporidium," borne on a pointed
sterigmatous process.

Puccinia Compositarum exhibits very si-
milar phenomena ; its J7rec?o-fruit has been
described as Uredo suaveolens. Fig. 782

Fig. 782.

Vertical section of the sorus of " Uredo sua
with immature stylospores. Magnified 460 diameters.

UREDINEI.

[ 662 ]

UREDINEI.

represents a vertical section through an im-
mature sorus of this; fig. 783 some of the

Fig. 783.

Ripe stylospores of the same, germinating.
Magnified 460 diameters.

stylospores detached and germinating; the
outer spinulose coat is here fully developed,

Fig. 784.

Fig. 785.

Deformed stylospores, with the spinulose coat developed.
Magnified 460 diameters.

and the tubular filaments are seen emerging
from the pores. The spores of the perfect
fruits of this genus differ from those of
Phragmidium in being only bilocular, or, by
abortion, unilocular (see PUCCINIA).

In JScioiuM, CYSTOPUS, and some other
genera, only spermogonia and stylosporous
fruits ( Uredo-fruits, Tulasne) have been ob-
served. In Cronartium, spermogonia are
unknown, but the Uredo-fruit exists. In
Podisoma both spermogonia and Uredo-fruits
are unknown ; in both of these genera the
perfect-fruits are placed on a fleshy columella
or ligula.

We subjoin Tulasne's synopsis of the fa-
mily ; but as his generic characters are far
too long to transcribe, we can only cite the
typical species.

1. Albuginei (white or pale yellow, hetero-

sporous).

I. CYSTOPUS, Lev. (Type, Uredo Candida,

Pers.).

2. JEcidinei (with a peridium, homceospo-

rous).

II. C^JOMA, Tul. (Type, Uredo Euonymi,
Mart.; U. pinguis, Duby).

III. jEcioiuM, Lk. (Type, JEc. Cichora-
cearum. D.C. ; JE. Tussilaginis, Pers. ; M.
Violarum, D.C.).

IV. RCESTELIA, Rebent, Fr. (Type, ^Ec.
cancellation, Pers.).

V. PERIDERMIUM, Lk. (Type, Per. Pini,
Fries).

3. Melampsorei (solid, pulvinate, biform).

VI. MELAMPSORA, Cast. (Type, Uredo
populina, Pers.; U. Caprcearum, D.C.).

VII. COLEOSPORIUM, Lev. (Type, Uredo
Rhinanthacearum, D. C. ; U. Campanula >
Pers.).

4. Phragmidiacei (pulverulent, biform, in-

fuscate; centre of the family).

VIII. PHRAGMIDIUM, Lk. (Types,
Phragm. incrassatum, bulbosum, with Uredo
Ruborum, B.C.; Puccinia Potentillce, Pers.,
with U. Potentillarum, D.C.).

IX. TRTPHRAGMIUM, Lk. (Type, T. Ul-
marice, Lk.).

X. PUCCINIA, Lk. (Type, Puce. Compo-
sitarum, Schl., with Ur. suaveolens, Pers. ;
P. graminis, Pers., with Ur. linearis. Pers.).

XI. UROMYCES, Lk. (Type, Uredo Fica-
ricB, Alb. and Schw.).

XII. PILEOLARIA, Cast. = Uromyces?
which itself may consist of species of Pucci-
nia with spores unilocular by abortion.

5. Pucciniei (fleshy, ligulate, or tremelliform,

naked and uniform in the fruits; the
largest plants of the family).

XIII. PODISOMA, Lk., Fr. (Type, P. Ju-
nip eri communis).

XIV. GYMNOSPORANGIUM, Lk., Nees,
Fr. (Type, G. Juniperinum, Fr.).

6. Cronartiei (peridiate, biform, ligulate ;

perhaps the most highly organized of
all the genera).

XV. CRONARTIUM (Type, Cr. asclepia-
deum, Fr., with Uredo Vincetoxici ; Cr. Peeo-
nice, with Ur. Pceonice, Cast.).

Genera cancelled by Tulasne : — Uredo,
Epitea, Podocystis, Trichobasis, Lecythea,
Physonema, Solenodonta.

Genera of C^EOMACEI referred to USTI-
LAGINEI : Ustilago, Tilletia, Thecaphora.
Doubtful Ustilaginei : Protomyces, Poly-
cystis, Testicularia.

BIBL. Berk. Brit. Flor. ii. pt. 2. art.
JEcid., Puce., Uredo, &c., Ann. Nat. Hist.
i. p. 264; ser. 2. v. p. 463; Tulasne, Ann.

UREDO.

[ 663 ]

URIC ACID.

des Sc. nat. 3 ser. vii. p. 12; 4 ser. p. 77 ;
Leveille, ibid. 3 ser. vhi. p. 369 ; De Bary,
Brandpilze, Berlin, 1853; Fries, Summa
Veg. p. 509; Unger, Exanthem. Plant.; and
the works cited under the Genera.

UREDO, Pers. See UREDINEI.

URIC ACID and URATES, or lithic acid
and lithates. — Uric acid may easily be pro-
cured in small quantity from human urine, by
adding a few drops of dilute muriatic acid,
and setting the liquid aside for some hours,
when it subsides in crystals. In larger
quantity it may be obtained by heating the
excrement of serpents with excess of dilute
solution of potash, until the odour of ammo-
nia has disappeared, and filtering the solution
whilst hot into dilute muriatic acid, when it
falls in a colourless state. Or the excrement
may be digested, without heat, with excess
of strong sulphuric acid, the mixture set
aside that the impurities may subside, and
subsequently poured gradually into a large
quantity of distilled water.

It exists also in the excrement of birds,
in the urine of Mollusca and insects, and of
all the Mammalia, excepting those which
are herbivorous ; it has also been found in
the human blood, of which it is probably a
normal constituent in minute quantity, al-
though mostly secreted with the urine as
soon as formed.

In the natural state of solution in the
urine, uric acid exists combined with soda
and ammonia, but it is frequently found as
an abnormal deposit in the human urine,
and is often precipitated after the secretion
has been evacuated, from the occurrence of
an acid fermentation. The crystals of the
free acid are sometimes also met with in the
urine or excrement of the lower animals, as
Insects, &c,

Uric acid is but little affected by water,
alcohol, acetic or muriatic acid ; slowly so-
luble in solution of ammonia, but readily in
solution of potash, from which it is re-pre-
cipitated by a dilute acid.

The crystals belong to the right rhombic
prismatic system.

Their various forms are represented in PI.
8. figs. 1-10, and fig. 15. Those in fig. 1
are frequently met with as natural deposits
from human urine ; although most of the
same forms, with those in fig. 15, are
also found in the artificially precipitated
acid. The most common and characteristic
form is the rhomb (a), the side view being
linear or rectangular. When the urine is
strongly acid, the crystals often appear stri-

ated from the presence of linear fissures (c,
d). Sometimes they are narrower and more
elongate, with a prismatic form (e). They
are frequently aggregated, and either fused
into twin crystals (/, g\ or form aigrettes or
tufts (k, I, m, n, o). The other forms are
noticed in the description of the plate.

The crystals forming a natural deposit are
almost invariably coloured, from combining
with the colouring matter of the urine;
sometimes their colour is very brilliant (fig.
4); they may also be coloured artificially by
precipitation from a solution of purpurate of
ammonia (fig. 3), madder, &c.

The test for uric acid is the production of
the colour of purpurate of ammonia or mu-
rexide, which may be effected by dissolving
the crystals or suspected substance in a small
quantity of dilute nitric acid, gently evapo-
rating the solution to dryness, and adding a
little ammonia to the residue, or exposing it
to the vapour of ammonia, when the red
colour becomes visible. But the rhombic
form, when present, with the action of potash
and dilute acid, would be sufficient to di-
stinguish uric acid from most substances.

The formation of the crystals of uric acid
presents an interesting object for examina-
tion. A drop or two of solution of uric acid
in potash is first placed upon a slide and
covered with thin glass; a little dilute
muriatic acid is then applied to the edge of
the liquid, or a drop of strong acetic acid
placed near its edge, so that the vapour may
be absorbed by the liquid. The latter soon
becomes turbid from the formation of a pre-
cipitate of numerous molecules and granules.
If the turbid liquid be watched under the
microscope, a minute crystal will presently
be seen to form suddenly in some part of
the field. The molecules and granules then
slowly dissolve immediately around the cry-
stal, leaving this in the middle of a clear
space. The crystal now enlarges, and the
surrounding molecules gradually disappear,
until they at last entirely vanish from the
field. By careful inspection it may easily
be seen that the crystal is not formed by the
conflux of the precipitated molecules, but is
deposited from a state of solution.

Some crystals of uric acid polarize light
splendidly, and some of the feathery crystals
(PI. 8. fig. 8 e) possess considerable analytic
power.

The forms of the crystals and crystalline
groups of the urates are represented in PI. 8.
figs. 11-14 ; they are not very characteristic,
and the aid of chemistry is required for de-

URINARY DEPOSITS.

[ 664 ]

UROCOCCUS.

termining with certainty the composition of
the respective crystals.

The urate of ammonia may be prepared
artificially by adding ammonia to a boiling
mixture of uric acid and water ; the urate of
lime by mixing urate of potash with chloride
of calcium ; the urate of soda by dissolving
uric acid in solution of soda ; and the urate
of magnesia by mixing solutions of sulphate
of magnesia and urate of potash.

See URINARY DEPOSITS.

BIBL. That of CHEMISTRY, Animal.

URINARY DEPOSITS.— We shall give
here a list of the deposits most commonly
occurring in the human urine, with the refer-
ences to the plates in which they are repre-
sented, and the articles in which they are
described.

Since the publication of the important
paper by Vigla (L' 'Experience, 1839), in
which most of these deposits were first illus-
trated, the use of the microscope has con-
stantly been called in to aid in their detec-
tion. In regard to the pathological indica-
tions afforded by their presence, upon which
we cannot enter, it may be remarked that
most of the deposits are formed after the
evacuation of the urine.

Uric acid. PL 8. figs. 1, 2 ; and Urates,
PL 8. figs. 11 c, d, e, 13 a, 14 a (URIC ACID
and URATES).

Oxalate of lime. PL 9. figs. 9, 10, 1 1 , 12
(LiME, SALTS OF). The concretionary forms
of this salt (figs. 10, 11, 12) are more slowly
acted upon by reagents than simple, crystals.

Ammonio-phosphate of magnesia. PL 9.
1, 2, 3, 4 (MAGNESIA, SALTS OF).

Carbonate of lime. PL 9. fig. 8 (LiME,
SALTS OF).

Cystic oxide. PL 9. fig. 5 (CYSTIC
OXIDE).

Blood-corpuscles. PL 40. fig. 21, espe-
cially the form fig. 21 e (BLOOD).

Mucous corpuscles. PL 1. fig. 5 (MOUTH,
p. 439).

Pus-corpuscles. PL 30. figs. 4, 5 (Pus).

Spermatozoa. PL 41. fig. 25 (SPERMA-
TOZOA). These are found in the urine of
the female for several days after connexion,
and we have detected them in the uterus
more than a fortnight after the same.

Sarcina. PL 3. fig. 5 (SARCINA).

Fungi. Penicillium (fig. 562, page 495,
PL 20. fig. 15) and Torula (PL 20. fig. 7).
The spores of Penicillium form the so-called
small organic globules.

Casts of the tubuli uriniferi. The extreme
diameter of these is rather less than that of

the tubules, but they are often much more
slender. They are cylindrical, generally
wavy, sometimes hollow, at others solid.
Some are very transparent, finely granular,
and are composed of fibrine ; others consist
entirely of, or contain imbedded in them
renal epithelial cells, with or without glo-
bules of fat, either free or within the cells ;
they sometimes also contain mucous and
pus- corpuscles, with blood-globules; some
of the epithelial cells occasionally contain
lithates. The epithelium of the bladder
agrees essentially in structure with that of
the pelvis of the kidney (KIDNEY, p. 375).

BIBL. That of CHEMISTRY, Animal;
Lehmann, Phys. Chem. ; Bird, Urinary
Deposits; Schmidt, Versuch., SfC.; Griffith,
Urinary Deposits, and Med. Gaz. 1843.

UROCENTRUM, Nitzsch, Ehr.— A genus
of Infusoria, of the family Vorticellina.

Char. Free, no pedicle ; tail awl-shaped ;
cilia absent from the body, but forming an
anterior crown ; mouth not spiral.

U. turbo (PL 25. fig. 14). Body hyaline,
ovate, trilateral, tail one-third the length of
the body. Aquatic ; length 1-430 to 1-290".

BIBL. Ehrenberg, Infus. 268.

UROCOCCUS, HassalL— A genus of
Palmellaceae (Confervoid Algse), remarkable
for the peduncular processes formed by the
gelatinous coats of the cells. The cells are
invested by a gelatinous coat or "membrane"
(like that of GL.EOCAPSA), which is origin-
ally simple, but new gelatinous layers are
successively produced on the immediate sur-
face of the cell-contents, and as each new
one is formed, the preceding layer is rup-
tured on one side and partially thrown off,
the cell with its new layer lying in the pre-
ceding layer as in a cup ; by the repetition
of this process, the cup-like exuviae accumu-
late, packed one within another so as to
form a peduncle, the structure of which may
be roughly compared to a pile of wooden
washing-bowls or tea-cups standing one in
another. When the cell-contents divide
into two portions, the peduncles bifurcate
(PL 3. fig. 7). The striae indicating the suc-
cessively shed coats are more or less distinct
in different species, and probably in different
conditions of the same. Several species are
named by Hassall, but no satisfactory di-
stinctive characters are given. The cell-con-
tents of four are blood-red. U. Hookerianus
is represented in PL 3. fig. 7 ; U. insignis is
very much larger; U. Allmanni and U. cry-
ptophila are much alike, and neither present
the striae. A green species is also described

UROGLAUCINE.

[ 665 ]

USNEA.

with the synonym (erroneous ?) of Chloro-
coccum murale, Grev.

The mode of reproduction is unknown.

BIBL. Hassall, Brit. Mar. Alg. p. 322.
pi. 80 ; A. Braun, Verjungung, &c. ( Ray Soc.
Vol. 1853, p. 178).

UROGLAUCINE. — This substance,
which was first detected by Heller, may be
obtained by evaporating human urine with
concentrated nitric acid (PI. 9. fig. 20). Its
true nature is unknown, but it is probably a
product of the decomposition of the colour-
ing matter of the urine ; it has perhaps some
relation with indigo.

BIBL. Heller, Archiv f. phys. Chemie
und Mikrosk. ; Lehmann, Physiolog. Chem. ;
Funke, Atlas, &c.

UROGLENA, Ehr.— A supposed genus
of Volvocinese (Confervoid Algre), consisting
of a family of zoospore-like individuals ar-
ranged at the periphery of a membranous
sphere, as in Volvox, but said to differ from
that genus in having only one cilium, and
also a basal prolongation or tail running
toward the centre of the sphere. U. Volvox
is described as a sphere, 1-95" in diameter,
with yellowish corpuscles 1-1728" long, ex-
clusive of the tail, which is three or four
times as long. Inhabiting bog-pools. We
very much doubt whether it is distinct from
VOLVOX.

BIBL. Ehrenb. In/us, p. 61.

UROLEPTUS, Ehr.— A genus of Infu-
soria, of the family Colpodea.

Char. Eye-spot absent ; no tongue-like
process, nor proboscis ; a tail present.

U. piscis (PL 25. fig. 15 a) = Oxytricha
caudata, Duj. Body terete, subturbinate,
gradually narrowed behind into a tail ;
internal granules green. Aquatic; length
1-288 to 1-144".

U. lamella (PI. 25. fig. 15 b). Body de-
pressed, hyaline, linear-lanceolate, flat and
very slender. Aquatic ; length 1-216".

Three other species.

BIBL. Ehrenberg, Infus. 358.

UROMYCES, Lk.— A genus of Uredinei
(Coniomycetous Fungi), perhaps not pro-
perly separated from Puccinia, but distin-
guished from the ordinary state of that
genus by the unilocular spores of the perfect
fruit (see UREDINEI and PUCCINIA). The
Uromycetes are rusts occurring upon leaves,
presenting at least two forms of fructifica-
tion (spermogonia have not yet been ob-
served), viz. 1. Uredo-fruits, consisting of
stylospores unaccompanied by paraphyses,
which have been described as species of Tri-

chobasis, Lev., and, 2. the perfect fruit,
resembling that of PUCCINIA, but with uni-
locular spores, unaccompanied by paraphyses.
Ur. Ficaria, Lev. (Uredo Ficariee, Alb. and
Schw.) is not uncommon on Ranunculaceae,
U. appendiculatus, Lk. (Uredo appendicu-
losa, Berk.) on various Leguminosse.

BIBL. Berk. Brit. Flor. ii. pt. 2. pp. 380,
382; Tulasne, Ann. des Sc. nat. ser. 4. ii.
pp. 145 & 185; Leveille, ibid. ser. 3. viii.
p. 370 ; De Bary, Brandpilze, p. 33.

URONEMA, Duj.— A genus of Infusoria,
of the family Enchelia.

Char. Body elongate, narrowed in front,
slightly curved, surrounded with radiating
cilia, and with a long straight cilium behind.

U. marina (PI. 25. fig. 16). Body colour-
less, semitransparent, nodular, and with four
or five faint longitudinal ribs. Marine;
length 1-570".

BIBL. Dujardin, Infus. 392.

UROPODA, Latr.— A genus of Arach-
nida, of the order Acarina and family Ga-
masea.

Char. Palpi and rostrum inferior ; dorsal
shield consisting of a single, broad, circular
or oval piece ; legs nearly equal ; body fre-
quently with a caducous anal peduncle.

U. vegetans (PL 2. fig. 25). Sixth joint
of legs longest. The peduncle forms a horny
filament, secreted from the anus, and serving
to attach the body to Coleopterous insects,
of which this animal is the parasite, although
it is sometimes found under stones.

Four other species, most of them doubtful.

BIBL. Duges, Ann. d. Sc. nat. ser. 2. ii.
29 ; Gervais, Walckenaer's Arachniden, iii.
220.

UROSTYLA, Ehr.— A genus of Infu-
soria, of the family Oxytricha.

Char. Body ciliated ; styles present, but
no hooks.

On the under surface of the posterior part
of the body is a small cleft with styles.

U. grandis (PL 25. fig. 17). Semicylin-
drical, subclavate, rounded at the ends, an-
terior portion slightly thickened. Aquatic ;
length 1-144 to 1-96".

BIBL. Ehrenberg, Infus. 369.

URTICA, L.— The botanical name of the
genus to which the stinging-nettle belongs
(see STINGS). The plants yielding the fibre
of Chinese grass-cloth, and Puya, are placed
by some authors under Urtica, by others
under BOEHMERIA.

USNEA, Ach.— A genus of Parmeliaceae
(Gymnocarpous Lichens), with a somewhat
crustaceous branched thallus, bearing peltate

USTILAGINEI.

[ 666 ]

USTILAGO.

apothecia, which often have a ciliated mar-
gin. U. barbata is common on park-pales
and old trees, U.jloridaanA plicata in simi-
lar situations, mostly in mountainous regions;
it is possible they are all forms of one spe-
cies. The pendulous, fibrillous thallus and
ciliated apothecia of U. barbata are very
characteristic.

BIBL. Hook. Brit. Flor. ii. pt. 1. p. 230;
Schaerer, Enum. Crit. p. 3.

USTILAGINEI.— A family of Coniomy-
cetous(?) Fungi related to the Uredinei,
generally distinguished by their growing in
the interior of the organs (especially the
ovaries and anthers) of Flowering Plants,
causing deformity, absorption of the internal
tissue, and its replacement by a pulverulent
substance consisting of the spores of the
Fungi. In the earlier stages, the infected
organ exhibits either a grumous mass, or an
interwoven filamentous mycelium from which
acrogenous spores arise; finally the myce-
lium disappears, and a dark-coloured (often
foetid) powder remains, composed entirely of
the spores, which are simple or more rarely

Fig. 786. Fig. 787.

Fig. 788.

Fig. 789.

Thecaphora deformans.

Compound spores, entire and broken up.

Magnified 460 diameters.

compound (figs. 789, 790), i. e. several co-
herent within a common coat, at length free
(figs. 786-788), smooth, or unequally echi-
nate or reticulated.

They are thus divided by Tulasne : —

1 . Ustilaginei veri :

Stroma at first mucilaginous or grumous-
mucous, entire, or soon broken up into
variously conglomerated masses, afterwards
divided into unappendaged spores; few or
no filaments persistent.

1. USTILAGO. Spores simple.

II. THECAPHORA. Spores compound.

2. Tilletiei. Stroma composed of inter-

woven fragile filaments ; spores acrogenous
on their ramules, hence often appendaged
when free.

III. TlLLETIA.

Polycystis, Lev. and Testicularia^lotsch,
are doubtful. PROTOMYCES, Unger, is ap-
parently allied to Tilletia.

The species of Ustilago are very numerous
(see USTILAGO). The Thecaphora are fewer
and more rare ; T. deformans is an Algerian
plant, infesting Medicago tribuloides. Til-
letia infests corn-grains and other grasses,
T. Caries being the Uredo Caries, D.C. and
U.fatida, Bauer, forming the foetid blight
called Bunt, or pepper-brand, of corn (see
TILLETIA).

Tulasne has observed the germination of
the spores in some Ustilagines and in Til-
letia ; they produce filamentous processes,
from which arise pedicels (basidia) bearing
minute ' sporidia,' as in the Uredinei.

BIBL. Berk. Brit. Fl. (art. Uredo); Tu-
lasne, Ann. des Sc. nat. ser. 3. vii. p. 5;
ser.4.ii. p. 157; DeBary, Brandpilze; Bauer
and Banks in Curtis's Pract. Obs. on Brit.
Grasses, London 1805; Unger, Exantliem.
Plant.

USTILAGO, Fries.— A genus of Ustila-
ginei (Coniomycetous Fungi), forming smuts,
infesting the ears of corn and other grasses,
the ovaries and anthers of other Flowering
Plants, and in some cases the leaves and
stems of plants. The interior of the organ
infested by them presents at first a grumous-

Fig. 791.

Fig. 792.

I

Fig. 791. Ustilago Carbo, on oats. Nat. size.
Fig. 792. Ustilago Carbo, on barley. Nat. size.

mucous, whitish mass, which grows at the

USTILAGO.

[ 667 ]

UTERUS.

expense of the tissue and juice of the infested
organ, and is finally converted into a pulve-
rulent mass of simple spores, mostly of deep
colour, and with a smooth, spiny or reticu-
lated surface.

The species growing upon leaves and
stems occur on grasses, e. g. U. longissima
(Uredo longissima, Sow.), U. hypodytes (Ur.
hypodytes) and U. grandis (or typhoides)-,
they form linear patches, ultimately con-
taining smooth black spores.

The greater number, however, occur in
the parts of flowers, especially of grasses;
as Ust. Carbo (Uredo segetum, Pers.), form-
ing the blight called smut of com, com-
monly infesting wheat, oats (fig. 791), barley
(fig. ^92) and other grasses, filling the ears
with a black powder of smooth spores, about
1 -5000" in diameter in corn, sometimes about

Fig. 793.

/

Portion of a spike of Maize infested with Ustilago
Maidis. Some of the lower grains perfect and mature ;
above these, female flowers with abortive ovaries. The
projecting bodies are grains which have become deformed
by the Ustilago developed within them.

twice as large in the varieties attacking
species of Bromus. The smut of maize ( U.
Maidis, fig. 793) has minutely echinate
spores, 1-2500" in diameter.

Sedges are infested by Ust. urceolarum
with dark brown, and Ust. olivacea with
olive-coloured spores ( Uredines, Brit. Flor.).
Ust. antherarum, growing in the anthers of
Caryophyllaceae, has violet-coloured spores.
Many other species are described by Tulasne,
several of which have occurred in Britain.

BIBL. Tulasne, Ann. des Sc. nat. ser. 3.
vii. p. 73; ser. 4. ii. p. 157; Berk. Brit.
Flor. art. Uredo ; Ann. Nat. Hist. ser. 2. v.
p. 463.

UTERUS.— The substance of the uterus
consists of longitudinal, transverse, and
oblique, unstriated muscular fibres, inter-
woven with imperfectly developed areolar
tissue, resembling that in the stroma of the
ovary.

Three layers of the muscular fibres are
described, but they are intimately connected.
Those in the cervix are principally trans-
verse or circular ; and imme-
diately beneath the mucous
membrane at the mouth of
the uterus, the transverse
fibres form a sphincter.

The muscular fibres are
from 1-600 to MOO" in
length, fusiform, with elon-
gate oval nuclei, and very
difficultly separable on ac-
count of the large amount of
areolar tissue intermingled
with them.

The epithelium is simple
and ciliated. The mucous
membrane of the body has
no papillae, but here and there
some folds, and contains nu-
merous tubular or uterine
glands resembling the Lie-
berkuhn's glands of the in-
testines, their csecal ends
being simple, bifurcate, or

spiral, and Consisting of a fibres, three weeks

basement-membrane with cy- after parturition,
linder-epithelmm. Sr^jOT,

In the cervix are situated y, globules of fat.
glandular depressions of the Magnified
mucous membrane, which ^**^e*T
secrete a transparent tenacious mucus ; some
of these are closed, and form the ovules of
Naboth.

The lower third or half of the canal of the
cervix contains papillae covered with ciliated
epithelium.

During pregnancy, the uterine elements,
especially the muscular fibres, as also the
vessels, and probably the nerves, become

Uterine muscular

UVELLA.

[ 668 ] VASCULAR BUNDLES.

enlarged and more numerous, from new-
formation (fig. 795).

All three of the coats of the veins of the
pregnant uterus contain muscular fibres.
After parturition, many of the muscular

Fig. 795.

Muscular elements from a uterus at five months' preg-
nancy, a, formative cells; b, young, c, fully developed
muscular fibres. Magnified 350 diameters.

fibres undergo fatty degeneration, and be-
come absorbed (fig. 794).

BIBL. Kolliker, Mikr. Anat. ii.

UVELLA, Bory, Ehr.— A genus of Infu-
soria (Algae ?), of the family Monadina.

Char. Corpuscles tailless, without an eye-
spot, moving by means of one or two flagel-
liform filaments, or an anterior circle of cilia,
and aggregated into spherical revolving
clusters.

U. virescens (PI. 25. fig. 18). Corpuscles
ovate, rounded at each end, bright green.
Aquatic ; diameter of clusters 1 -288", length
of corpuscles 1-2016".

Five other species, one green, the rest
colourless.

Dujardin regards the presence of the fla-
gelliform filament as a character of the genus.

BIBL. Ehrenberg, In/us. 19; Dujardin,
Infos. 300.

V.

VAGINICOLA, Lamarck, Ehr.— A genus
of Infusoria, of the family Ophrydina.

Char. Solitary ; body ovoid or campanu-
late, sessile, in a membranous, urceolate,'
sessile sheath.

Cilia forming an anterior circle.

V. crystallina (PI. 25. fig. 19). Sheath
crystalline, urceolate, straight, internal gra-
nules green. Aquatic; length 1-216".

Stein has observed the Acineta-form (Aci-
neta mystacina] of this animal, and the sub-
sequent development of swarm-germs within
it.

Several other species.

BIBL. Ehrenberg, In/us. 295 ; Dujardin,
Infus. 560 ; Stein, Infusoria, passim.

VALLISNERIA, Mich.— An aquatic ge-
nus of Angiospermous Flowering Plants,
belonging to the family Hydrocharidacese.
V. spiralis, a native of the South of Europe,
occurring wild also in North America, India,
&c., is commonly grown in jars for the sake
of observing the ROTATION in the leaves.
This plant is dioecious, and the specimens
ordinarily found in cultivation are the pistil-
late forms, which often produce flowers, but
the seeds, remaining unfertilized, never ripen;
the plant increases rapidly, however, by run-
ners, if in a healthy condition. We find it
thrive well in any situation indoors near a
window and not exposed to frost, but it
attains far larger size in water kept at a high
temperature, as in Victoria-tanks in Botanic
Gardens. It is necessary, when growing it
in jars, not to keep too many or too large
" snails " in the water, as they destroy the
leaves. See ROTATION.

VARIOLARIA, Pers. — A spurious genus
of Lichens, founded upon imperfect forms
of PERTUSARIA, &c.

BIBL. Hook. Brit. Flor. ii. pt. 1. p. 172;
Schaerer, Enum. Grit. p. 229.

VASCULAR BUNDLES.— This title is
applied to the fibrous cords which form the
ribs, veins, &c., of the leaves, petioles and
other appendicular organs of all plants rank-
ing above the Mosses, and which by their
confluence and more considerable develop-
ment constitute the wood of stems and
trunks. The vascular bundles of petioles
(fig. 665, page 592), &c., running into leaves
to form their ribs, and lying imbedded in
parenchyma, resemble the bundles which
form the rudiments of wood of the stem
itself. The bundles remain isolated as fibrous
cords in the stems of the herbaceous Monoco-

VASCULAR BUNDLES. [ 669 ] VASCULAR BUNDLES.

tyledons, or are only combined into a wood,
in the Palms, &c., by the lignification of the
cells of the parenchyma in which they are
imbedded (fig. 465, p. 430). In the Dicoty-
ledons, the rudimentary bundles are deve-
loped in a circle surrounding the pith (tig.
459, p. 419), and soon unite to form a tube
of wood, with an external cambium layer and
a true bark, and the cambium layer is the
seat of renewed development of the vascular
bundle in each successive year. On such
characters of growth, Schleiden founded a
division of the vascular bundles into classes,
which are convenient in reference to micro-
scopical investigations, and affixed tolerably
perfect systematic characters for the classes.
In the higher Flowerless Plants, viz.
Ferns, Equisetacese, &c., the vascular bun-
dles are composed chiefly of ducts, sur-
rounded by elongated tubular cells, almost
devoid of secondary deposits, the whole
enclosed by a layer of tolerably firm prosen-
chymatous wood-cells, especially developed

Fig. 796.

l.f

Monocotyledon.

Transverse section of a fibro- vascular bundle of a Palm;
the upper end is directed towards the centre of the stem.
w, woody fibres resembling liber in structure ; s. v, spiral
vessels ; c, cambium (vasa propria} ; d, ducts ; p, paren-
chyma ; /, liber ; /. c, laticiferous canals. Magnified 150
diameters.

in the Ferns. In the Ferns, the ducts are
mostly of the kind called scalariform (fig.
669, page 593 ; PL 39. fig. 10), in the Equi-
setacea3 annular (fig, 666, page 593), in the
Lyeopodiacese spiral (fig. 664, page 592;

PI. 39. figs. 11 & 12). They are variously
arranged in the different orders, but agree in
the mode of development, namely in grow-

Fig. 797.

Dicotyledon.

Transverse section of a fibro-Tascular bundle of a Melon
stem ; the upper end next the centre of the stem, p,
pith ; s. v, spiral vessels ; m. r, medullary rays ; w, wood ;
d, pitted ducts ; c, cambium ; /. liber ; /. c, laticiferous
canals ; c. e, cellular envelope of the bark ; e, epidermis.
Magnified 50 diameters.

ing only at the end next the punctum vege-
tationis, in proportion to the elongation of
the stem and the evolution of leaves. Hence
Schleiden calls them simultaneous bundles,
their various elements, ducts, tubular and
prosenchymatous cells, being formed simulta-
neously.

In the Monocotyledons, where the vas-
cular bundles occur isolated, they originate
in the punctum vegetationis, and are deve-
loped with the growth of the stem outwards
and upwards into the leaves, and outwards
and downwards towards the permanent cir-
cumference of the stem, old and new bundles
crossing each other in a more or less com-
plicated manner (fig. 465, page 430). Here
(fig. 796) the first trace of the vascular bundle
consists of spiral vessels, followed on the
outer side by spiral, annular or reticulated
ducts ; next comes a collection of elongated
tubular cells, of delicate structure and in the
outer part, at first a cambium region, which
is gradually converted into prosenchymatous
woody structure, having the character of
LiBER-cells. In this case, the development
is not only gradual from the punctum vege-
tationis outward, but the inner side of each
bundle is perfected first, and the conversion
of the outer part into wood occupies a whole
season of growth. Hence these are entitled

VAUCHERIA.

[ 670 ]

VAUCHERIA.

progressive bundles; but as no new develop-
ment occurs in these in successive seasons,
they are further distinguished as definite
bundles from those of the Dicotyledons. The
structure of the vascular bundles of Monoco-
tyledons is very well seen in different charac-
teristic conditions, in vertical and horizontal
sections of the stems of the white lily, of the
large grasses, rhizomes of sedges and rushes ;
affording well- developed examples in herba-
ceous structures ; of the bamboo (an arbo-
rescent grass), of the common cane or the
" partridge cane " (both species of Palms),
where the bundles are connected by lignified
parenchyma. In leaves of bulbous Monoco-
tyledons, &c., the bundles consist chiefly of
spiral vessels; in the palms, bananas, &c.,
the woody fibre extends also into the ribs of
the foliaceous organs.

In the Dicotyledons, the bundles of the
stem appear first as a circle of cords com-
posed of spiral vessels, around the pith, out-
side which larger vessels and ducts, and sub-
sequently woody fibre or wood-cells are
developed, passing into the elongated pros-
enchymatous liber (fig. 797). The develop-
ment of the successive regions is progressive
during the first season ; but here the cam-
bium layer remains capable of renewed
activity, and a new layer of wood (and of
liber) is added on the outside of the bundle
in each successive season ; hence these bun-
dles are distinguished as indefinite. These
may be observed in sections and young
shoots of any common tree (figs. 459 & 461,
page 419).

Infinite variety of modification occurs in
the character and arrangement of the vas-
cular bundles within the limits above laid
down, or very slightly overstepping them.
A few remarkable cases may be mentioned
here ; in the Orobanchacese (parasites) no
spiral vessels occur in the vascular bundles
forming the wood; in Victoria regia the
isolated bundles are composed of spiral
vessels without any prosenchymatous wood-
cells ; other peculiarities, influencing more
especially the characters of WOOD, are given
under that article. (See also CAMBIUM and
MEDULLA.)

BIBL. Works on Structural Botany.

VAUCHERIA, D.C.— A genus of Sipho-
nacea3 (Confervoid Algae), consisting of green
filamentous plants growing in fresh and salt
water, and on damp ground, characterized
by the continuity of the cavity throughout
the branched tubular filament (sometimes
several inches long) of which each plant is

composed, and by the modes of reproduction,
both by gonidia and by spores. Vaucherice
may be gathered on damp borders in
every garden, or by the sides of ditches,
where they form fine silky green tufts; they
are very variable in form and size, so that
the specific distinctions heretofore laid down
appear to be worth little. The ordinarily
occurring species presents itself as a tubular
cell, of comparatively gigantic dimensions,
containing more or less protoplasm, coloured
by chlorophyll, in the form of minute gra-
nules, applied upon th,e wall, or occupying
more or less of the cavity. The green gra-
nules may be seen to lie imbedded in a
colourless protoplasm at the inner surface
of the cellulose wall; and it is curious to
observe, when the filament is accidentally
or intentionally ruptured, that the green
granules which may escape are contained in
a mucous investment which soon rounds
itself into a globular body, of size propor-
tionate to the quantity of green granules
extruded; these globules even exhibit a
slight rolling movement sometimes, but they
appear ultimately to decay. Such globules
sometimes occur inside the filaments, when
the growth is unhealthy, and Itsigsohn calls
them spermatospheres, stating that they pro-
duce spermatozoids. This, like all this au-
thor's observations, requires confirmation.

If the Vaucheria filaments are gathered at
a favourable epoch, or if they are cultivated
in a vessel of water well exposed to light,
the blind ends of the filaments (or rather of
the ramifications of the filament) are found
very densely filled with green contents, ap-
pearing almost black ; and if these ends are
watched early in the morning, a remarkable
series of phenomena is observed in them.
The ends of the filaments about to produce
gonidia are found swollen into a slightly
clavate form; the green contents of the
"club" part from the general contents of
the filament, leaving a transparent space
(fig. 798) ; then, having as it were acquired
a definite independence, the isolated mass
returns so as to fill up the transverse light
space, but does not again coalesce with the
lower mass of contents. Next a light space
is observed between the surface of the ter-
minal body of contents and the cellulose
wall surrounding it, and the latter soon
gives way at the apex, forming a passage for
the escape of the contents. This mass of
contents is now clearly recognizable as the
gonidium or zoospore; it gradually extri-
cates itself from the tube, with a rotatory

VAUCHERIA.

[ 671 ]

VAUCHERIA.

motion around its own axis, and it exhibits
a remarkable elasticity of structure, giving

Fig. 798.

Fig. 799.

Vaucheria Ungeri.

Fig. 798. End of a filament in which a gonidium is
.
idium escaping from the

Magnified 50 diameters.

being developed.
Fig- 799- Gonidium escaping from the filament.

way and altering its form (fig. 799) to squeeze
through the narrow orifice of escape ; some-
times it becomes "pinched" in this process
into two independent gonidia of half the
usual size. As soon as it has perfectly
emerged, it assumes an elliptical form, in-
creases much in size, and is seen to be co-
vered with innumerable vibratile cilia (fig.
801), arising from its gelatinous (protoplas-
mic) coat (these are rendered much more di-
stinct by applying tincture of iodine) ; no
cellulose membrane exists at this time, and
the gonidium swims about actively in the
water, revolving on its long axis. The large
number of cilia existing on this gonidium

Fig 800 "' ™"

Vaucheria Ungeri.

Fig. 800. End of the filament from which the gonidium
has escaped. Magnified 50 diameters.

Fig. 801 . Gonidium which has been treated with iodine
and dried between two slips of glass, showing the cilia
very clearly. Magnified 110 diameters.

distinguish it remarkably from all others;
but we are inclined to believe that there is a

nearer relationship than appears at first sight.
The green substance at the surface of the
gonidium presents a peculiar granular or
globular appearance ; and it appears not far-
fetched to regard this body as composed of
a densely combined family of ordinary two-
or four-ciliated zoospores, such as would be
formed by the swarming-spores of Hydro-
dictyon if they remained in their primitive
crowded condition. This, however, is a point
requiring further examination. The end of
the tube from which the gonidium has
escaped appears as a hyaline sac (fig. 800),
which soon decays down to the point where
the contents parted, where a septum, now
closing the tube, is developed.

After swimming about for some time,
from one to several hours (usually about
two), the gonidium falls to the bottom of
the vessel, its cilia disappear, and it assumes
a spherical form, acquiring very soon a di-
stinct cellulose coat; after this it soon ger-
minates by pushing out one or more tubular
processes (tig. 802), which grow up into

Fig. 802.

Fig. 803.

Vaucheria Ungeri.

Fig. 802. Gonidia germinating. Magnified about 15
diameters.

Fig. 803. Filament with gonidia germinating in the
parent tube ; the left-hand figure, half a divided goni-
dium. Magnified 25 diameters.

filaments like the parent. Sometimes the
gonidium cannot make its escape, sometimes
half of it escapes and becomes pinched off,
the other half being left behind; in these
cases, the arrested body, or the remaining
portion of the divided one, germinates in
situ (fig. 803).

It should be mentioned, that the contents
of the vegetative filaments have a remark-
able tenacity of life ; for if the tube is slightly
injured at any point, the primordial utricle
commonly retracts from the wound, and
secretes a cellulose layer on its surface,
shutting off the injured part. Filaments are

VAUCHERIA.

[ 672 ]

VEGETABLE KINGDOM.

sometimes met with having several living re-
gions of this kind, shooting out into branches,
separated from each other by dead, empty
lengths of the filament.

Besides the vegetative reproduction above
described, the Vaucherice are reproduced by
spores formed by the concurrence of two
distinct kinds of reproductive organs. Fila-
ments growing on damp ground ordinarily
exhibit lateral organs of two kinds, associated
together, but variously grouped and collected
in varying numbers at particular points, ap-
parently according to external conditions.
The larger kind of organ appears first as a
pouch-like process, which expands into a
squat flask-shaped body, stalked or sessile,
the neck of which is gradually turned over
in the development, until it projects at one
side, the form then somewhat resembling
that of a bird's head (or a chemist's glass
retort cut off short at the neck). Near this
on the main filament, or on a common pedi-
cel with one or more of the bird's-head or-
gans, is developed another organ, at first
straight and tubular, but soon curving over
into the form of a hook or scroll, without,
however, expanding. The expanded part of
the bird's-head organ (or sporangium) be-
comes filled with dense green granular mat-
ter, and cut off by a septum from the main
filament. The upper part of the " hook" is
likewise cut off by a septum, and the con-
tents of the apical cell thus formed are of
light colour, and soon lose most of the chlo-
rophyll. From the association of these two
kinds of organ, and the production of spores
in the sporanges, it was supposed, as long
ago as in Vaucher's time, that they repre-
sented sexual organs. Vaucher thought the
" hooks" discharged a kind of pollen to fertilize
the sporanges. Other algologists, especially
Nageli, supposed or asserted that a conjuga-
tion took place between them (like that in Spi-
rogyra), a view more or less favourably re-
ceived until a few years since, when Karsten
asserted that he had actually observed it in all
its details. But Pringsheim has lately pub-
lished a very complete and certainly more
trustworthy account of the development of
these structures, in which he denies the con-
jugation, but asserts that the " hook " is an
antheridium, and that when mature it bursts
at the apex and discharges biciliated sper-
matozoids resembling those of Fucus, which
enter the simultaneously opened neck of the
sporange and fertilize its granular contents.
The contents become isolated from the wall,
secrete a proper coat, and form a free cell

(spore) lying in the sporange, its granule
matter gradually losing the green colou
and becoming brown. Two coats, at leasi
are developed, and the spore ultimate!;
escapes by the decay of the parent filamen
and sporange. According to Pringsheim
about three months elapse before germina
tion, in which process the outer spore-coa
splits, and the inner grows out into a tube
forming the basis of a new ramification o
the Fawc^ena-filament.

In the systematic works on Algology, nu
merous species of aquatic and land Vaucherit
are described ; but we agree with Thuret ii
believing that the characters by which mos
of the forms are distinguished are unessential
therefore we omit any synopsis of them
Even V. racemosa, Decaisne, appears merel;
an extreme of the kind of developmen
producing V. geminata. Thuret propose
the name V. Ungeri, to include all but V. ra
cemosa ; Hassall suppresses the name V. da
vat a, as indicating a form common to all tin
species, of which he describes a large num
ber. We do not find anything sufficiently
distinctive in the characters of the marim
species cited by Harvey.

The admirable essay of Unger should bi
consulted by those studying the gonidia
reproduction.

BIBL. Vaucher, Conferees d'eau douc*
(Ectosperma) ; Hassall, Brit. Fr. Alg.
Harvey, Brit. Mar. Alg. p. 195 ; Unger
Nova Act a, xiii. p. 11, Die Pflanze im Mom
der Thierwerdung, Vienna, 1843; Decaisne
Ann. des Sc. nut. 2 ser. xvii. p. 430; Thuret
ibid. xix. p. 266 ; Karsten, Bot. Zeitung, x
p. 85 (1852) ; Pringsheim, Ber. Berlin Akad
March 1855 ; Ann. Nat. Hist. 2nd ser. xv
p. 346 ; Alex. Braun, Verjungung (Hay Soc
Vol. 1853, passim}, Alg. unicell. (1855)
p. 8, 105; Nageli, Neuer Algensyst. p. 175
pi. 4 ; Itzigsohn, Bot. Zeit. xi. p. 225 (1853)

VEGETABLE IVORY.— This substanci
consists of the seeds of the Palm calle(
Pliytelepnas macrocarpa, composed of j
large round mass of bony ALBUMEN, in whicl
a small embryo is imbedded. Slices of thi:
ivory-like albumen, placed under the micro
scope, afford very beautiful examples of ve
getable cells with the cavities almost oblite
rated by SECONDARY DEPOSITS (PI. 38
fig. 23).

VEGETABLE KINGDOM.— The larg<
number of natural orders of Angiospermou!
Flowering Plants and the subordinate cha
racter of their diversities in microscopic
structure, lead us to depart from the plan or

VEGETABLE KINGDOM. [ 673 ]

VEINS.

AXOPHYTA OP CORMO-

wliich the synopsis of the Animal Kingdom
is given, and carry it into effect here only
in reference to the Cryptogamous plants.
For the microscopic phenomena in the Pha-
nerogamia described in this work, reference
should be made to the articles TISSUES.

Kingdom. VEGETABILIA.
1. Subkingdom.

PHYTA.

Div. 1. Phanerogamia. Flowering Plants.
Subdiv. 1. Angiospermia.

Class I. DlCOTYLEDONES.

Most common trees and herbs.

Class II. MONOCOTYLEDONES.

Grasses, rushes, most bulbous plants,
palms, &c.

Subdiv. 2. Gymnospermia.
Class III. CONIFERS
Firs, pines, yew.

IV. CYCADACE^E.
Cycas, Zamia.

Div. 2. Cryptogamia. Flowerless
with stems and leaves,

/-•I T T

Class I. LYCOPODIALES.

Pilularia, Pill-wort.
Order 2. LYCOPODIACEJS.

(flioitaqgoJoS)

;^n8 .7971BH

Club-mosses.
Class II. FILICALES.

Order 1. FILICACE.E.

Ferns.
Order 2. EQUISETACE^E.

Horse- taiJs.

Class III. MUSCALES.
Order 1. MUSCACE^.

Mosses.
Order 2. HEPATICACE^E.

Liverworts and Scale-mosses.

(Order of uncertain place, CHARACE^E.)

2. Subkingdom. THALLOPHYTA.

Class I. ALG^E.

Order 1. FLORIDE.E.

Red sea-weeds.
Order 2. FUCOIDE^E.

Olive sea-weeds.
Order 3. CONFERVOIDEJE.

Green silk-weeds, slime-weeds and
brittle-weeds (Diatoma^eae).

;

iAH

Class II. LICHENES.
Order 1. GYMNOCARPI.
Order 2. ANGIOCARPI.

Class III. FUNGI.
Order I. HYMENOMYCETES.

Mushrooms, toadstools, dry-rots.
Order 2. GASTEROMYCETES.

Puff-balls.
Order 3. CONIOMYCETES.

Blights, rusts.

Order 4. HYPHOMYCETES.

Mildews, moulds and blights.
Order 5. ASCOMYCETES.

Truffles, toadstools, rusts.
Order 6. PHYSOMYCETES.

n/r i i j -11

Moulds and mildews.

BIBL. Lindley, Vegetable Kingdom ; End-
licher, Gen. Plant. ; Hooker, British Flora -,
Fries, Summ. Veget. Scan. ; Balfour, Class-
book ; Henfrey, Sketch of Veg. Kingd. (with
atlas) 1855 ; and General Works on Botany.

VEINS, OF ANIMALS.— The walls of the
veins are thinner than those of the arteries,
which depends principally upon the less
development of the contractile and elastic
elements. The inner coat is less developed,
but otherwise agrees with that of the arteries
in structure. The middle coat is not yellow,

Fie 804
'io Jiuq bof _ _ r* ===1______

'.:{ orft

Longitudinal section of the vena cava inferior, near
the liver, a, inner coat ; b, middle coat without muscular
fibres ; c, inner layer of the outer coat ; a, its longitudinal
muscles ; 0, its transverse areolar elements ; d, outer por-
tion of the outer coat, without muscles. Magnified 30
diameters.

but greyish-red, containing more areolar
tissue and fewer elastic fibres and muscles ;

2x

VEINS.

[ 674 ]

VESSELS.

in addition to the transverse it has longitu-
dinal layers. The outer coat is usually the
thickest, agreeing in structure with that of
the arteries, except that in many veins,
especially those of the abdominal cavity, it
contains well-developed longitudinal mus-
cular fibres.

The veins of the brain and some other
parts contain no muscular fibres.

BIBL. Kolliker, Mikrosk. Anat. ii.

VEINS, OF PLANTS.— The name com-
monly applied to the ramifications of the
VASCULAR BUNDLES, forming the ribs of
leaves and similar organs.

VERMICULARIA, Fr.— A genus of
Sphseronemei (Coniomycetous Fungi), per-
haps stylosporous states of Sphseriacei, most
of the species being included under Sphceria
in the British Flora. They grow on decaying
stalks, leaves or wood. S. relicina, Dema-
tium, culmifraga, trichella and others of the
Br. Fl. belong here. Another species, V.
atramentaria, is common on decaying potato-
stems, forming black velvety patches. This
is distinguished from V. Dematium by its
straight spores. The erect black hairs of the
perithecia are characteristic.

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 274,
&c., Ann. Nat. Hist. 2nd ser. v. p. 378; Fries,
Summa Veg. p. 419.

VERMILION, or bisulphuret of mercury,
is used as a pigment for injecting. It should
be in a finely divided state, in which it is
best obtained by levigation ; and should not
exhibit any white crystalline particles when
examined as an opake object.

See INJECTION (p. 350).

VERRUCARIA, Pers.— A genus of Ver-
rucariae (Angiocarpous Lichens), containing
numerous species, having a crustaceous or
cartilagineo-membranous thallus growing
upon and adherent to bark of trees or stones ;
named from the wart-like processes corre-
sponding to the perithecia, which open by
a pore at the surface. The perithecia have
a black rind, enclosing either the whole or
the upper half of the nucleus. The spermo-
gonia much resemble the perithecia, only
they are much smaller; they occur either
scattered among the perithecia, or collected
towards the margins of the thallus.

BIBL. Hook. Brit. Flor.ii. pt. 1. p. 152;
Leighton, Brit. Angioc. Lich. p. 35; Schaerer,
Enum. crit. p. 213; Tulasne, Ann. des Sc.
nat. 3 ser. xvii. p. 215. pi. 3.

VERRUCARIEjE.— A family of Angio-
carpous or closed-fruited Lichens, charac-
terized by rounded apothecia, closed by &

special perithecium, perforated by a conti-
guous pore, and containing a somewhat hya-
line, gelatinous, dissolving nucleus.

Synopsis of British Genera.

I. SEGESTRELLA. Thallus crustaceous,
apothecia solitary; excipulum waxy-mem-
branous (coloured) ; ostiole simple, somewhat
papillate; nucleus gelatinous, somewhat
hyaline.

II. VERRUCARIA. Thallus crustaceous
or cartilagineo-membranous, spreading, ad-
nate, uniform. Apothecia hemispherical or
subglobose, innate and immersed or sessile,
excipulum horny, mostly black, with a simple,
papillary or perforated ostiole; nucleus gela-
tinous, fluid or deliquescent, subhyaline.

VERTICILLIUM, Nees. Fig. 805.
— A genus of Mucedines (Hy-
phomycetous Fungi), distin-
guished from Botrytis (under
which it is included, with

•* ,:*v< 7

Verticillium

cylindrosporum.

Magnified 200

diameters.

by the verticillate arrangement
of the sporiferous branches.
A number of species are de-
scribed ; but from the observa-
tions of Hoffmann and Bail on
the germination of Trichothe-
cium, this genus represents
only one form of the plants
belonging to other genera;
V. ruberrimum, Bonorden
(Botrytis verticilloides, Corda,
which HoflTmann regards as
identical with Acrostatagmus parasitans and
cinnabarinus), having been raised from the
spores of Trichothecium roseum, and its
"spores" being barren (see TRICHOTHE-
CIUM). Berk, and Broome describe and
figure several new species.

BIBL. Ann. Nat. Hist. ser. 2. vii. p. 101.
pi. 7. figs. 15-18 ; Fries, Summa Veg. (Bo-
trytis}, p. 491.

See also TRICHOTHECIUM.

VESPA, Linn. — Vespa vulgaris, the wasp,
and V. crabro, the hornet, are readily ac-
cessible insects for the examination of the
sting (STING).

VESSELS, OF PLANTS.— This name was
applied by the earlier observers to various
elongated tubular structures of vegetable
tissues, from a mistaken idea that they cor-
responded with the vessels of animals ; and
the name is still retained. The spiral, an-
nular, &c. vessels are described under
SPIRAL STRUCTURES. The term vessel is
now generally contrasted with DUCT, to

VIBRIO.

[ 675 ]

VIBRIONIA.

indicate a single, long, tubular cell, with
spiral deposits, in contradistinction to a canal
formed of a row of short cells of similar
character, applied end to end and confluent.
The LATICIFEROUS tubes are sometimes
called laticiferous or milk vessels.

VIBRIO, Miill.— A genus forming the
type of the family VIBRIONIA, Infusoria of
authors, but part of which we have provision-
ally placed in the Oscillatoriacese(Confervoid
Algae).

Char. Filiform, more or less distinctly
jointed from imperfect division, movement
undulatory, like that of a serpent.

These filamentous bodies are extremely
minute ; theii simple structure is best seen
when they are dried.

V. subtilis (PI. 3. fig. 18). Filaments
colourless, elongate, hyaline, straight, di-
stinctly jointed, motile vibrations very slight
and not perceptibly altering their form.
Aquatic, in pools; length reaching 1-430" ;
breadth 1-24000". Probably an Oscillatoria.

V. rugula (PI. 3. fig. 19). Filaments hya-
line, distinctly jointed, very tortuous when
in motion. In decomposing infusions; breadth
1-12000".

V. prolifer (PI. 3. fig. 20). Filaments
short, hyaline, distinctly jointed, tortuous in
their slow motion. In decomposing infu-
sions; length 1-9200 to 1-1150"; breadth
1-9200".

V. bacillus (PL 3. fig. 21). Filaments
elongate, hyaline, joints sometimes distinct
only after drying, flexuous in their slow
motion; length 1-288"; breadth 1-1700".
Probab]jAnabaina subtilissima, Kiitz., which
seems not Nostochaceous, but Oscillatoria-
ceous.

Two or three other species ; one of them,
V. ambiguus, is branched; they are still
more evidently algae.

BIBL Ehrenberg, Infus. 77 ', Dujardin,
In/us. 216.

VIBRIONIA.— A family of Infusoria, ac-
cording to the classifications of Ehrenberg
and Dujardin, but which appear at all events
in part to be Algae (OSCILLATORIACEJS).

Char. Active, filiform, extremely minute,
colourless, jointed bodies, of obscure organi-
zation, and without visible locomotive organs
(except Bacterium ?) ; straight or spirally
coiled, multiplied by division at the joints.

These organisms form some of the most
minute which the microscopist is called upon
to examine, and it is with the greatest diffi-
culty that their structure can be made out.
But although in the ordinary method of exa-

mination, structure is invisible, yet by allow-
ing them to dry spontaneously on a slide, or
adding solution of iodine to them in the wet
state or when dried, it can be distinctly seen
that they are composed of minute joints,
resembling very minute, colourless Oscillato-
riaceous Confervas. When treated with potash,
they are unacted upon, although the minute
monads with which they are invariably
accompanied are burst and dissolved. Nor
have we succeeded in colouring them by
Millon's or Pettenkofer's test, although their
minute size is such that the magnifying
power used to render them visible would so
dilute the colour, by diffusing it over a large
surface, that it is difficult to speak positively
upon this point. They are propagated by
the formation of new joints, and subsequent
separation at one of the articulations. They
are almost invariably the first organisms
found in decaying and putrefying organic
matters, especially animal. When treated
with iodine and then sulphuric acid, their
jointed structure is rendered very distinct ;
and it appears that they are composed of two
parts, an outer portion which seems pale or
but slightly coloured, and an inner which
becomes very dark ; but the tints cannot be
distinguished with certainty : they appear
purplish, reddish-purple-brown, quite dif-
ferent from the surrounding infusoria when
thus treated.

M. Pineau believes that animal matter is
directly transformed into Infusoria and
Algae ; but when tests are used in the proper
manner, this view is rendered altogether im-
probable.

Some of the Vibriones probably are but
the earlier stages of other algae, but what
these algae are is unknown.

The motion of these minute bodies would
seem to indicate that some are furnished
with cilia ; but in others it is evidently pro-
duced by general contractility. M. Dujardin
thinks, however, that he has sometimes seen
a flagelliform filament analogous to that of
the Monadina, or rather undulating helically,
and Ehrenberg describes a cilium or flagel-
liform filament in one Bacterium. Our own
repeated observations, made in such manner
(see CILIA) as will detect cilia with ease
when present, or at least in any part where
they have hitherto been found certainly,
have failed to detect them in the Vibrionia
(excluding Bacterium, which is doubtfully
referred to this family).

We have included the genera Bacterium
and Vibrio among the OSCILLATORIACE^E,
2x2

VILLI.

[ 676 ]

VILLI.

but the relations are still somewhat obscure,
and this is even more the case with Spirillum
and the rest, which are excluded there. We
think it advisable, therefore, to add here a
table of the genera according to the views of
those who regard them as Infusoria, or at
all events as a distinct family. More details
are given under the respective heads.

Filament f Inflexible 1 . Bacterium.

straight. \ Flexible like a serpent 2. Vibrio.

p;ia«,^f f Spi™1 helical 3. Spirillum

Filament! (Spirochata) .

:', [ Spiral flat, like a watch-spring 4 . Spirodiscus.

They are best preserved by allowing them
to dry spontaneously on the slide.

For Vibrio tritici see ANGUILLULA tri-
tici.

BIBL. Ehr. Infus. p. 73 ; Dujardin, In/us.
p. 209.

VILLI. — These are minute folds or pro-
longations of the mucous membrane of the
small intestines. They are most numerous
in the jejunum and ilium; in the former
conical and flattened, sometimes plate-like,

Fig. 806.

cylindrical, club-shaped or filiform; whilst
in the latter they are broader and flattened.

The villi form solid processes of the
mucous membrane, consisting of areolar
tissue without elastic elements, but abound-
ing in roundish nuclei ; containing also
blood-vessels, lacteals and unstriated mus-
cular fibres.

Their surface is covered with a basement
membrane, and a single layer of cylindrical
epithelial cells.

The villi are exceedingly vascular, and form
beautiful microscopic objects when injected ;
exhibiting a network of capillaries with
rounded or elongate meshes.

Each villus contains a lacteal, the origin of
which commences either in a single ca3cal
dilatation, or in a network of branches.

The muscular fibres form a thin layer, not
very distinct in man, surrounding the lacteals,
and capable of greatly contracting or short-
ening the villi.

The epithelial cells are intimately con-
nected with each other, but easily detached
from the villi, often in groups or rows.

Fig. 807.

6

Fig. 806. Intestinal villus of a kitten, free from epithelium, and after treatment with acetic acid, a, boundary of
villus ; b, subjacent nuclei ; c, nuclei of the muscular fibres ; d, roundish nuclei in the middle of the villus. Magnified
350 diameters.

Fig. 807- -A, magnified 75 diameters. Two villi with their epithelium, from a rabbit, a, epithelium ; b, parenchyma.
B, magnified 300 diameters. A row of detached epithelial cells, a, membrane separated by water. C, magnified 350
diameters. Detached epithelial cells, a with, b without the separated membrane ; c, surface view of some epithelial

' !

VILLI.

C 677 ]

VINE FUNGUS.

Fig. 808.

Fig. 809.

Fig. 808. Two villi from a calf without epithelium, and
containing each a lacteal vessel ; after treatment with
dilute solution of soda. Magnified 350 diameters.

Fig. 809- Two contracted villi, from a cat. Magnified
60 diameters.

; • ..• /' fj i.«BTJBqj»e snffidortm ,» .«lia j

When acted upon by water, the cell-membrane
atthe surface is separated, leaving a clearspace

between the granular cell-contents and the
former.

BIBL. Kolliker, Mikrosk. Anat. ii.

VINCA, L. — The generic name of the
garden plants called Periwinkles; interest-
ing to microscopists on account of the stri-
ated liber-fibres (PL 39. fig. 30). (See
SPIRAL STRUCTURES, p. 594.)

VINE FUNGUS. — The vine mildew,
Oidium Tuckeri, Berk., which has in recent
years caused such extensive destruction, has
formed a subject of investigation for most of
the principal mycologists ; and notwithstand-
ing that its natural history is not yet wholly
cleared up, many interesting points have
been discovered. As it ordinarily appears,
it forms a white and very delicate cottony
layer upon the leaves, young shoots, and
fruits of the vine, soon causing a production
of brown spots upon the green structures,
and subsequently a hardening and a destruc-
tion of the vitality of the surface. Under
the microscope, the white substance is seen
to be composed of delicate ramified fila-
ments, creeping horizontally over the surface,
and when the plant is much developed, form-
ing a dense interlacement. The horizontal
filaments exhibit few septa, these occurring
at the points of branching, and they do not
penetrate into the interior of the epidermal
layer; here and there, however, they are
found fixed to the epidermis by a more or
less developed organ of attachment, consist-
ing of a disk or lobed expansion (comparable
roughly to the so-called " root " of some of
the Fucoid Algae), which adheres firmly to
the cuticle, and when removed, leaves a
brownish scar behind. The destructive effect
of the Fungus seems to arise from its arrest-
ing the development of the epidermis, by
binding its structures together, and excluding
the surface from the influence of the air,
since when young berries are invaded, the
internal development proceeds, and the
sphacelated epidermis preventing the natural
expansion, the grapes burst and rot. [In
this case, species of Botrytis, &c. appear
upon the decomposing pulp, as on all similar
substances; and these must be distinguished
from the proper mildew.] When full-grown
leaves are affected to a moderate extent, the
vitality is often only partially affected, causing
a laxity of the tissue, and more or less
fading of the green colour, without inevi-
table decay.

When the mildew is observed with a low
magnifier, its surface exhibits a mealy ap-
pearance, arising from minute bead-like or

VINE FUNGUS.

[ 678 ]

VINE FUNGUS.

pearly shining bodies of oval form ; and the
application of sufficient power shows that
the horizontal filaments bear numerous erect
branches or pedicels, consisting of short-
jointed filaments (PL 20. fig. 8), the terminal
cells of which (or two last) are elliptical and
expanded. These terminal cells are soon
matured and then fall off; vast numbers of
them are produced, and are found lying
upon the surface among the creeping fila-
ments, where they quickly germinate (PL 20.
fig. 9), and produce new ramifications of
mycelium. The fungus, as thus described,
constitutes the Oidium proper, and the de-
ciduous terminal cells form the so-called
spores. But the history of the development
of the mildew does not cease here.

In the first place, the detached * spores '
do not always produce a filament as repre-
sented in fig. 9; some of them present,
while still attached, a kind of segmentation
of the protoplasmic contents (fig. 10), and
detached examples are found filled with
minute 'sporules' of elongated elliptical
form. These minute 'sporules5 are either
discharged by a dehiscence of the * spore '
(fig. 11), and then germinate, or sometimes
they germinate in situ, and send out slender
filaments through the walls of the spore.
We have found also that the large filaments
produced by the simple large ' spore ' (fig. 9),
do not always at once form a regular myce-
lium, but give rise to slender pedicels, ter-
minating in a point bearing minute solitary
corpuscles of about the size and form of the
' sporules ' above described, and resembling
the spermatia of many of the higher Fungi.

In addition to this, we have sometimes
observed those ' spores ' which produce the
* sporules ' in their interior, with their outer
membrane finely punctate, and in very rare
cases, this form of fruit was composed, not
of a single terminal cell, but presented indi-
cations of cross septa, as if two or more cells
of the summit of the pedicel were confluent
into one sac; here the punctation of the
surface was very strongly marked.

Thus far we depend upon our own obser-
vations, but Mohl, Tulasne and others de-
scribe a still more highly developed fruit
than that last noticed ; they have found the
terminal body, producing ' sporules,' with a
distinct cellular coat (PL 20. fig. 12), from
which the sporules are discharged by a ter-
minal dehiscence. Mohl found this body,
very rarely, of spherical form. We have
never seen this cellular coat; in the cases
we have met with, the coat was certainly

only punctate or tubercular; probably the
structure was not mature, nevertheless the
* sporules ' were distinctly evident.

These phenomena, exhibited by the Vine
fungus, clearly agree with those exhibited
by the Oidia always accompanying certain
ERYSIPHES, as described under that article ;
and most of the authors who have written
on this subject, therefore conclude that the
Vine fungus is really an Erysiphe, of which
the perfect, ascophorous fruit has not yet
been discovered. A comparison of the
figures marked 12 (PL 20), from the Vine,
copied from Mohl, with those of the Hop
Erysiphe under fig. 14, will show the agree-
ment of structure between the two plants.

It remains only to add a few remarks as
to the interpretation or nomenclature of the
different organs. Mohl, Tulasne, &c. have
denominated the simple ' spores ' above de-
scribed (figs. 8, 9) conidia ; but as we have
stated, the cells are convertible into what
may be called sporanges, producing * spo-
rules ' (or true spores) without alteration of
structure. When their walls become cellu-
lar (fig. 12), the sporangia! character is more
decided; but as the Erysiphes produce a
more perfect sporange, in which asci are
developed, the name of pycnidia is applied
to them. This fruit it was which gave rise
to the establishment of a supposed distinct
genus, by Cesati, under the name of Ampe-
lomyces ; while Ehrenberg, also regarding it
as a distinct plant, made it the type of a
genus called Cicinobolus, on account of the
peculiar tendril-like extrusion of the * spo-
rules' (fig. 12s). Mohl distinguishes it as
the Cicinobolus-fmit, which he, like Tulasne,
finds constantly associated with other (un-
doubted) Erysiphes (fig. 14), in very slightly
different and equally irregular forms.

There can be no doubt whatever in the
minds of those who have watched the deve-
lopment and progress of the Vine Fungus,
that it is the cause and not a consequence of
the ' murrain ;' still there are various curious
circumstances connected with it not at all
understood ; it is probable that peculiar at-
mospheric conditions induce predisposing
states of the plants; but the phenomena
are enigmatical; we have had it completely
covering a vine in a small greenhouse, de-
stroying all the fruit one year; and although
no precautions were taken (as it was desired
to study the disease), no sign of mildew ap-
peared there the next year; while on an
out-door trellis, a few yards off, the disease
reappeared in a slight form in the second

VINEGAR.

[ 679 ]

VINEGAR PLANT.

season. The application of sulphur appears
to arrest the growth.

BIBL. Berkeley, Gardener's Chron. 1847,
no. 48, &c. ; Journ. Hort. Soc. vi. p. 284,
ix. p. 61 ; Mohl, Botan. Zeit. x. p. 9, xi.
p. 585, xii. p. 137 (translated, Journ. Hort.
Soc. vii. p. 132, ix. pp. 1 & 64), and Bibl.
therein ; Montague, Butt. Soc. Centr. Agric.
ser. 2. v.; Journ. Hort. Soc. ix. p. 112;
Amici, Atti Giorgof. di Firenze, xxx. (Trans.
Journ. Hort. Soc. viii. p. 231 ; Savi, ibid.
241); Tulasne, Bot. Zeit. xi. p. 257 (1853);
Comptes rendus, xxxvii. (Oct. 1853) ; Visiani
and Zanardini, Atti Instit. Veneto, fyc. ser. 2.
iv.; Ehrenberg, Bot. Zeit. xi. p. 16; Cesati,
Klotzsch. Herb. Viv. Myc. Cent. xvii. no.
1669 b ; Bot. Zeit. x. p. 301 (1852) ; LeveiUe,
Revue horticole (June 1851).

VINEGAR, EELS IN. SeeANGuiLLULA.

VINEGAR PLANT.— Under this name
is known a remarkable vegetable production
formed in fluids rich in sugar, when under-
going fermentation at ordinary temperatures
and conversion into vinegar. As ordinarily
met with, it forms a tough gelatinous mass
floating on the surface of the liquid, its
shape (superficially) defined by that of the
vessel in which it is contained, extending
itself so as to occupy the whole surface even
in very large pans, — its depth or thickness
depending on its age and the amount of nu-
triment contained in the liquid. The gela-
tinous substance decreases in density from
above downwards, the lower part being very
lax and flocculent, the inferior surface being
in a state of continuous development. The
general mass, however, displays remarkable
tenacity, which, together with its lubricity,
renders it diificult to tear ; but if the lower
surface is examined, it is found possible to
strip off layer after layer, each a few lines
thick, to an extent depending on conditions
of growth, the lower, less dense portion
being thus distinctly stratified.

When portions are placed beneath the mi-
croscope, very varied forms of structure are
discovered in the interior. The general mass
of jelly appears structureless, as if formed by
some exudation, or solution of the organized
portion ; but the mode of origin of this jelly
is not yet ascertained. Imbedded in the
jelly are cellular structures, polymorphous
indeed, but exhibiting transitions which ren-
der it impossible to regard them as of distinct
origin. In the middle portion often occur
innumerable isolated masses of short rows
of cells, resembling the cells of YEAST when
coherent, except that they are generally el-

liptical ; some of them have short cylindrical
joints ; others short cylindrical portions ari-
sing from long tubular filaments, and termi-
nating in elliptical cells, so as to resemble
exactly OIDIUM. The diameter of all these
structures is most variable, from 1-4000 to
1-8000". In the upper part the elongated,
branched filaments more abound, the length
of the internodes and the diameter of the
tubes still varying extremely. At the lower,
laxer surface, the cellular structures are ac-
companied by less of the tough gelatinous
matrix. The lamination of the lower grow-
ing surface is very curious, but perhaps may
be accounted for by supposing that the infe-
rior growing surface of the mass, which is
certainly the mycelium of a fungus, periodi-
cally produces a crop of conidia, which be-
come detached and fall into the body of the
liquid on which the mass floats; there quickly
germinating they form a new entangled mass
of filaments and chaplets of cells, which then
acquires its gelatinous consistence, and,
buoyed up by the liquid, applies itself against
the lower surface of the parent-mass, with
which it adheres more or less on account of
the gelatinous condition. In the upper part
of old and thick masses, the layers become
inseparable, probably in some measure from
the pressure of the floating force from be-
low, together with the condensation arising
from the evaporation of the liquid of the
jelly at the upper surface.

When a vinegar plant is left upon the so-
lution after the saccharine matter is ex-
hausted, we find it always display after a
certain time patches of the ordinary fructifi-
cation ofPENICILLI-

as stated by Turpin
and others, forming
green, blue and yel-
low " mould " upon
the surface, also im-
bedded in the upper
strata, in which also
heaps of the spores
occur ; the vinegar
sometimes ultimate-
ly suffers more or less
decomposition, so
that the common
"mother" of vine-
gar, which by its
growth destroys the Peniciliium.

acidity, appears to Head of a fertile filament

be another condition bearins strinss of sP°res-
of this same organ- Magnified 250 diams.

VINEGAR PLANT.

[ 680 ]

VOLUTELLA.

ism. In some cases where we kept an ex-
hausted liquid in the dark for some months,
the acidity of the vinegar disappeared, the
gelatinous layer became greatly condensed,
and assumed a bright crimson tint ; and re-
mained as a dull red membranous film, some-
what like a smear of blood, when dried upon
paper.

From the above observations it would ap-
pear that the vinegar plant consists of the
mycelium of Penicillium glaucum, vegetating
actively and increasing also by crops of co-
nidia or gemmae. This opinion is enter-
tained by Turpin, Berkeley and other ob-
servers ; and the various genera and species
founded on the different forms of structure
occurring in it, cannot be entertained; among
these are Ulvina, Kiitz., and species of Uygro-
crocis, Leptomitus, &c. But the moniliform
growth is at the same time scarcely distin-
guishable from the Yeast plant by any satis-
factory characters, and repeated observations
strongly impress us with the idea, that these
objects are all referable to one species ; the
vinegar plant being the form of vegetative
growth taking place at low or ordinary tempe-
ratures in highly saccharine liquids, while
the true Yeast plant or Torula is formed in
the more rapid fermentation taking place at
more elevated temperatures. Another cir-
cumstance, mentioned under PENICILLIUM,
is, that we have found stale beer-grounds
kept at a rather low temperature, always
ultimately acquire a gelatinous crust, on
which Penicillium-fruit becomes developed.

In connexion with this subject may be
mentioned the objects called Cryptococcus
glutinis, Fres., and the "blood on bread,"
which appear nearly related to the red-co-
loured condition of the vinegar plant above
mentioned. These are possibly merely forms
of the same plant ; indeed we have observed
on some flour paste partially covered with
Penicillium glaucum, small circular patches
of a crimson tint, which under the micro-
scope were found to consist wholly of minute
elliptical bodies, generally exhibiting two in-
ternal granules or " nuclei," and exactly re-
sembling the articulations of some of the
moniliform structures of the vinegar plant,
which readily separate into their component
cells. All these phenomena require further
investigation, to which long-continued and
constant observation must be applied in order
to ascertain with certainty the relation the
different objects bear to each other. It is a
kind of research occupying much time and
demanding great care arid patience, but cal-

culated to repay the trouble far better than
the amassing of isolated characters of forms
seen at different periods and under special
conditions. Further particulars concerning
various points treated in this article will be
found under the heads FERMENTATION,
OIDIUM, PENICILLIUM, TORULA and
YEAST.

BIBL. Turpin, Mem. de Vlnstitut, xvii.
p. 135; Berkeley, Journ.Hort.Soc.iii. p. 91 ;
Lindley's Medic, fy Econ. Bot. p. 17; Fre-
senius, Beitr. z. Mycol. heft 2. p. 77-

VITREOUS HUMOUR OR BODY.— See
EYE (p. 255).

VITT^E, of the valves of the Diato-
maceae. These are internal projections or
inflections of the valves, forming imperfect
septa ; they appear as dark lines, visible
under ordinary illumination.

VITT^E.— See SECRETING ORGANS of
plants.

VOLUTELLA, Fr.— A genus of Stilbacei
(Hyphomycetous Fungi), comprising several
species of parasites which have been variously
distributed. The plants consist of minute
fleshy papillae (stromatd) of cellular struc-
ture, the surface of which is clothed with
elliptic, oblong or fusiform stylospores, from
between which project long jointed hairs
(fig. 811) traversing the stroma. It may be

Fig. 811.

Volutella Buxi.
Magnified 20 diams.

desirable to give the synonymy of these plants
according to Berkeley and Broome.

1. V. ciliata, Fr. (Psilonia rosea,Br. Fl.).
Whitish or rosy ; on potatoes.

2. V. Buxi, Berk, and Br. (Fusisporium
Buxi, Br. Fl.,and ChcetostromaBusci,Cord&).
White ; on dry box leaves (fig. 811).

3. V. setosa, B. and Br. (Psilonia setosa,
Br. Fl., JEgerita setosa, Greville). White, on
wood and herbaceous stems.

4. V. hyacinthorum, B. and Br. (PsiL hya-
cinthorum, Br. Fl.). White, stipitate; on
hyacinths grown in water.

5. V. melaloma, B. and Br. Orange, with
black hairs ; on sedges.

VOLVOCINE^E.

[ 681 ]

VOLVOCINE.E.

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 352-3;
Ann. Nat. Hist. 2 ser. v. p. 466. pi. 11. fig. 3 ;
Greville, Crypt. Fl. pi. 102. pi. 268. fig. 2 ;
Corda, Icon. Fung. ii. pi. 13. fig. 107 ; Fries,
Syst. Myc. iii. p. 447.

VOLVOCINE.E.— A family of microsco-
pic organisms which, in agreement with the
majority of recent writers on Algology, we
have included among the Confervoid Algae,
although they have been included until lately
among the Infusorial animalcules, among
which they form one of Ehrenberg's families.
The most striking general character of these
objects is, their composition of individual ele-
ments which exhibit in their mature and
most perfect stage of existence the characters
of the transitory ZOOSPORES of the other
Confervoids. If we exclude from this family
the genera Chlamidomonas and Gyges, which
we regard as founded upon the zoospores of
a plant quiescent in its typical form, the
PROTOCOCCUS of this work, — the Volvoci-
nese may be characterized as plants com-
posed of a number of permanently active
zoospore-like bodies associated together into
families of definite form (a kind of " polypi-
dom "), in which the members, connected or
held together in various ways by cell-mem-
branes, retain their distinct individuality
for all physiological purposes of nutrition,
growth, reproduction, &c., but represent
only one being in relation to the surrounding
objects. The best known and most beauti-
ful example of this family is the genus Vol-
vox (PI. 3. fig. 24), consisting when mature
of a spherical membranous sac, at the peri-
phery of which, within the membrane, are
arranged a large number of zoospore-like
bodies, each provided with a pair of cilia,
which pass out through the enveloping mem-
brane, and collectively form a coating all
over the external surface, by their vibration
causing a rotatory motion of the entire globe.
The foreign genus STEPHANOSPH.ERA,
Cohn, differs principally from Volvox in the
fact that the ciliated bodies are only eight in
number, and are placed in a circle at the
equator of the spherical sac. With regard
to Ehrenberg's genera Pandorina, Syn-
crypta, Uroglena, Eudorina, and Spharo-
sira, we much doubt whether they are not
founded merely on stages of development or
abnormal conditions of Volvox ; but even if
really distinct, they are probably constructed
on the same plan. Gonium however is very
distinct, and resembles Volvox only in the
essential character of the family above laid
down. It is composed of a group of usually

sixteen " zoospores," which are not enclosed
in a common sac, but each possesses a thick
gelatinous coat or membrane (appearing
like a transparent limb or border to the
green body, as in Glceocapsa, Coccochloris,
&c.), and the individuals cohere together by
a few points of the surface of this special
coat or "cell-membrane" (PL 3. fig. 11).
Ehrenberg's representation of a plate-like
continuous coat is erroneous ; our drawing
from nature exactly agrees with the older
figures, and Cohn's (see GONIUM). The re-
lations of the doubtful genera above named
to Volvox are treated under the article VOL-
VOX. It may be observed here that there
is certainly a close resemblance between the
objects termed Chlamidomonas and Gyges,
and the constituent individuals of the "fa-
mily-stocks " of Volvox, &c., and the nature
of the latter is best comprehended by con-
sidering them as representatives of the
former. But as we have said above, the active
Chlamidomonads appear to us to be only
transitory stages of a quiescent Alga; for al-
though they often propagate by division
while active when placed in the sunshine,
they ordinarily soon come to rest and
grow by a vegetative cell-division if kept in
a vessel with sloping borders, or if objects
are placed in the water, upon which the film
of quiescent Protococcus can gradually spread
itself up above the edge of the liquid.

It might be useful to observers to give the
characters of all the above genera as laid
down in Ehrenberg's work, in spite of our
disbelief in their validity, but in so doing it
would be necessary to describe them from
his drawings, as his written characters are
altogether useless, from being founded on
false analogies. The red-eye spot is certainly
found in Gonium, and probably in all ; we
doubt the statements about a single " pro-
boscis " (vibratile cilium) ; and the so-called
tail, a posterior prolongation of the body,
is an obscure character. The tabular ana-
lysis which Ehrenberg gives would not en-
able any one to distinguish the forms without
the assistance of plates. We have therefore
prepared a new table founded on his cha-
racters and drawings, marking those genera
which appear to us really distinct.

Char. Permanently active zoospore-like
bodies, ciliated (except Gyges), surrounded
by a gelatinous coat (like COCCOCHLORIS),
combined in definite groups (or solitary, Eh-
renberg), with or without a common enve-
loping membrane. Individuals pyriform, or
with the body prolonged posteriorly.

VOLVOX.

[ 682 ]

VOLVOX.

Solitary.

Without cilia Gyges.

With a pair of cilia CMumidomonus f.

Grouped.

Forming a square layer, indivi- \ Pn „.„,.. >
duals with two cilia / GoNIUM'

Forming a spherical body.
Cilium solitary.

With a " tail." $ .&.J.V.V Uroglena *.
Without a " tail."

Without an eye-spot.
Without special coats . Pandorina *.
With special coats .... Svncrvnta *.

With special coats.

With an eye-spot.

Individuals dividing \ Eudorina *
into two .......... J

__

Cilia twoT"

Without an eye-spot. . . . Synura * .
With an eye-spot.

* Probably stages of development of VOLVOX.
t Zoospores of PROTOCOCCUS?

The names in small capitals are well-esta-
blished genera.

BIBL. See the genera.

VOLVOX, L.— A genus of Volvocinese
(Confervoid Algae), of which only one species,
V. globator (PI. 3. fig. 24), seems satisfac-
torily established. This organism, occurring
not uncommonly and often in great abun-
dance in clear pools on open commons, &c.,
appears to the naked eye as a minute pale
green globule gently moving about in the
water, its dimensions variable, but generally
about 1-50" when full-grown. When placed
under a low magnifying power it is found to
be a spherical membranous sac, studded all
over with green points, the entire body rolling
over in the water with a motion which is
readily discerned to be caused by innumera-
ble cilia arranged upon the surface of the
globe. In the interior of the sac are gene-
rally seen dense globes, in summer mostly of
green colour (PL 3. fig. 24); sometimes the
cavity is wholly filled up by a number of
membranous sacs exactly resembling the pa-
rent, but deformed by mutual pressure (PL 3.
fig. 25), and inside these are seen smaller
green bodies, as in the former case. The
parent envelope is also flexible, yielding to
pressure and recovering its form, and in full-
grown specimens is generally ruptured at
one point, where the internal bodies escape,
so that the number varies; usually, how-
ever, the original number is eight.

The application of higher powers is requi-

site to discover the intimate structure of
Volvox, which, by the researches of William-
son and Busk, most of whose observations
we have verified, has been pretty clearly
made out. The outer envelope consists of
a layer of cell-membrane, in all probability
composed of a modification of cellulose, al-
though we have never succeeded in producing
more than a faint purple tinge with sulphuric
acid and iodine. By the application of a
sufficient magnifying power, the green cor-
puscles at the periphery are found to consist
of zoospore-like bodies (PL 3. fig. 28), which
are seated inside the membranous envelope,
each sending out its pair of vibratile cilia
(figs. 24-30) through separate orifices in the
external coat. The same investigation will
reveal that the green corpuscles have radia-
ting processes extending from their sides,
and running from the different centres to
meet each other in the light interspace,
forming thus a kind of delicate network be-
neath the membrane. The green corpus-
cles are pyriform, have a transparent anterior
end bearing a pair of cilia, and contain a
reddish-brown eye-spot and a contractile
vacuole, thus exactly resembling those of
Gonium, and indeed the zoospores of Con-
fervoids generally. The radiating processes
resemble those found in particular stages of
PROTOCOCCUS pluvialis, running through
the gelatinous coat, and probably may be
compared with the radiating filaments pro-
ceeding from the nucleus of SPIROGYRA'
(PL 5 fig. 26). There is somewhat more
difficulty in determining the nature of the
structure in which the green corpuscles are
enclosed. There is a layer of soft consistence
of some thickness within the external mem-
brane ; the green corpuscles are wholly im-
bedded in this, and their radiating processes
and cilia traverse the substance of it. We
are inclined to believe that this presents a
firm membranous layer again at the internal
surface, looking toward the general cavity of
the sphere. The nature of the soft layer
has been the subject of discussion ; we be-
lieve Busk's view to be correct, that it is not
formed by the collocation of distinct mem-
branous cells, like those of ordinary paren-
chymatous structures ; but by the close
juxtaposition of gelatinous envelopes of the
individual green bodies, resembling those of
Coccochloris, Glceocapsa, &c. We could
never detect a true line of demarcation half-
way between neighbouring green corpus-
cles; an appearance is indeed sometimes
presented in preparations kept in chloride

VOLVOX.

[ 683 ]

VOLVOX.

of calcium, which might lead to an error on
this point, for the outer membrane is then
sometimes swollen into papillae opposite
each corpuscle (PI. 3. fig. 30), the furrows
between which, in certain foci, give an ap-
pearance of a septum running round each
corpuscle (PL 3. fig. 29). Similar prepara-
tions also often show the green corpuscle
contracted, and leaving an empty ring round
it, separating it from the gelatinous coat
which runs undistinguishably into those of
the neighbouring corpuscles. But the
strongest fact we have observed is, that by
the application of solution of potash, the
substance surrounding the corpuscles is so
entirely dissolved, that the oily substance
extracted from the green bodies will run
freely about beneath the external membrane
(apparently confined internally by another
film), in sheets extending over considerable
segments of the sphere, yet leaving the cor-
puscles and their radiating processes intact,
or at least only shrunk and discoloured. If
a true cell-membrane existed around each
corpuscle, forming septa dividing them, the
above phenomenon could not display itself,
since the potash would not so dissolve the
structures.

The modes of reproduction of Volvox
have not yet been entirely elucidated. In
certain conditions, some of the corpuscles
appear larger than the rest, and as if under-
going division (PI. 3. fig. 28); it is possible
that some of the corpuscles, or of such
grouped corpuscles, escape into the cavity,
and there become developed into the large
green bodies (PI. 3. fig. 24), which are rudi-
mentary globes ; but Williams believes these
are detached in an earlier stage: perhaps
both modes of development take place.
Forms with the grouped corpuscles (PI. 3.
fig. 29) would appear to represent Ehren-
berg's Spharosira. Ehrenberg's genus Uro-
glena again would seem to be a Volvox
either imperfectly developed or decaying.

The deep green bodies (PI. 3. fig. 24)
seen in the cavity of the spheres, are young
Volvoces, and in an early stage they appear
as spherical cells filled with granular green
substance; the green substance divides by
segmentation (PL 3. figs. 31, 32) until it
forms a group of corpuscles, on each of
which a pair of cilia appears ; the enclosing
membrane expands, and they follow it and
remove apart, until they form a perfect Vol-
0oa?-sphere, studded with the corpuscles.
As above mentioned, a second generation is
sometimes met with in the parent-sphere

(PI. 3. fig. 25). We are uncertain whether
to regard the objects represented in PL 3.
fig. 14, as the young of Volvox ; they would
seemingly equally represent the genus Pan-
dorina, Syncrypta, or Eudorina, Ehr.

Volvoces, examined in autumn and early
winter, often either exhibit the green bodies
with a thick coat (PL 3. fig. 33), or the inner
globes are of an orange colour (PL 3. figs. 26
& 34), which appear to be successive stages
of development of a resting -spore. When
mature, this possesses at least two coats,
one immediately surrounding the granular
contents, another at some distance outside
the former, transparent, colourless, and as
it were glassy and brittle, breaking with
sharp-angled cracks when pressed (PL 3.
figs. 34 & 35). We cannot detect any in-
termediate substance or layer, which would
be required to complete the analogy with the
resting-spore of SPIROGYRA, as described
by Pringsheim (PL 5. fig. 21); perhaps it
does not exist in either case. Sometimes
the outer coat of the enclosed yellow globes
is tuberculated or covered with conical ele-
vations (PL 3. fig. 36). The form with the
smooth yellow resting-spores (PL 3. figs. 26
& 34) represents Ehrenberg's Volvox aureus,
and the form with the spines (PL 3. fig. 36)
his V. stellatus. The germination of these
spores does not appear to have been ob-
served.

A doubt remains as to the nature of the
object described as Synura Uvella ; it may
belong here, or, not improbably, to the
genus Uvella (PL 25. fig. 18), which itself
may be no more than a complex form of
the PROTOCOCCUS or Chlamidomonas (PL 3.
fig. 2; PL 23. fig. 30), which doubtless in-
cludes also Chlorogonium (PL 23. fig. 31),
Cryptoglena (PL 23. fig. 35), and Gyges
(PL 41. fig. 14), if not more, supposed In-
fusorial animalcules.

When a pool contains Volvox, the indi-
viduals are generally abundant, and may be
readily seen by the naked eye, as pale green
globules, in a phial of water held up to the
light ; but we have never found them survive
more than a week or two when kept for ob-
servation. The cilia are best seen by drying
them and wetting again, or by applying
iodine. The character of the corpuscles
alters a good deal in chloride of calcium.

BIBL. Ehrenberg, In/us.; Pritchard, In-
fus. ; Williamson, Trans. Phil. Soc. Man-
chester, vol. ix.; Trans. Micr. Soc. 2 ser. i.
p. 45 (1853); Busk, ibid. p. 31. See also
STEPHANOSPH^RA.

VORTICELLA.

[ 684 ]

WATER.

VORTICELLA, Linn.— A genus of In-
fusoria, of the family Vorticellina.

Char. Body campanulate, with an ante-
rior ring of cilia, stalked ; stalk simple, spi-
rally contractile.

These interesting Infusoria are very com-
monly met with in decomposing vegetable
infusions, as of hay, portions of dead
flowers, &c. Their curious metamorphoses
and modes of reproduction are noticed under
INFUSORIA.

Ehrenberg describes nine species.

V. nebulifera (PL 25. fig. 21). Body
conico-campanulate, colourless ; anterior
margin dilated; body without rings when
contracted. Length of body without the
stalk 1-576 to 1-288".

V. microstoma (PL 25. fig. 26, body with
gemmae). Body ovate, narrowed at the
ends, greenish white; anterior margin not
dilated, nor body ringed when contracted.
Length of body 1-2000 to 1-250".

V. convallaria. Body ovato-conical,
whitish hyaline, annulate; expanded ante-
rior margin slightly prominent. Length of
body 1-430 to l-240)r.

Dujardin unites the genera Carchesium
and Zoothamnium to his genus Vorticella.

BIBL. Ehrenberg, Infus. 269 ; Dujardin,
Infus. 546 ; Stein, Infus., passim.

VORTICELLINA.— A family of Infu-
soria.

Char. Isolated and free, or fixed and
aggregate; alimentary canal with two ori-
fices, separate, but in the same groove;
carapace none.

The characters are very vague, and the
family an unnatural one. The genera
Stentor, Trichodina and Urocentrum have
little affinity with the others. In the true
genera, the bodies are stalked, the stalk
usually branched, and the cilia form a ring
at the anterior end of the body.

.owifc ;iri «OaM'o*OOM
•'8 odd oj TUTU isdJo dbso

Body ciliated 1. Stentor.

Body smooth, cilia anterior. ... 2. Trichodina.
Tail present 3. Urocentrum.

Stalk present.
Bodies all uniform.
Stalk spirally flexible.
Stalk simple

Genera:

Stalk branched 5

Stalk inflexible 6

Bodies of two shapes.

Stalk inflexible 7

Vorticella.
Carchesium.
is.

Stalk spirally flexible 8

BIBL. Ehrenberg, Infusoria, 259.

Opercularia.
Zoothamnium.

w.

WASP.— See VESPA.

WATER.— Under this head we might
form a kind of index referring to a large
proportion of the articles of which this vo-
lume is composed, since water, existing under
different circumstances, forms one of the
most fertile sources of microscopic objects;
but as our space and plan do not admit
of such an enumeration, we must be content
to dwell shortly upon two of the most im-
portant questions in which the microscope
is applied to the examination of the contents
of water.

Ordinary examination of water. — Here it
appears merely necessary to point out that
the mode of examining the contents of sam-
ples of water, for the purpose of ascertaining
the extent to which organic beings are con-
tained in them, should be very different from
that pursued by the microscopist who is
engaged in collecting specimens. We make
this remark in consequence of the gross mis-
representations which are sometimes made
respecting the " animalcules " in water,
carried to their most absurd extreme in the
so-called "drop" of water shown by oxy-
hydrogen microscopes, where we often see
the field covered with larvae of dragon-flies,
of beetles, of gnats, &c., Entomostraca and
worms of different kinds, not only per-
ceptible without a microscope, but in the case
of the larvae, perhaps really more than an
inch long. Less violent exaggerations occur
when water which appears cloudy is selected,
allowed to stand for some time, and the
sediment examined. Very false results must
also be obtained when water is exposed to
the air for any length of time before exami-
nation, since infusoria and microscopic Algae
always appear in a short time, even in di-
stilled water, when exposed to the atmo-
sphere ; and a rain-water butt will generally
be found a very fertile source of microscopic
objects. We regard the presence of most
of those organisms which do not suffi-
ciently affect the water to render its impu-
rity discernible by the naked eye, as a mat-
ter of little consequence. Large quantities
of Entomostraca, certain Rotatoria and In-
fusoria, and Oscillatoriaceous Algae, generally
very perceptibly clouding or colouring the
water, of course indicate the presence of
much decomposing organic matter in the
water, which, however, reveals itself very
clearly in a short time, when the water is
kept, by a fcetid odour. The presence of

WATER.

[ 685 ]

WHALEBONE.

green Confervoid Algae is by no means a
sure sign of impurity (properly so called) in
water; for some will only grow in very
clear and pure water, while many of them
may be regarded as agents of purification.
The presence of Zygnemaceae, however, and
Diatomaceae is particularly objectionable, as
they become very foetid in decomposition,
which generally takes place very soon when
they are disturbed and injured. When large
quantities of the minute Algae appear in
water, discolouring it over extensive surfaces,
the microscope will enable us to detect the
nature of the object producing the appear-
ance, but will scarcely be requisite to prove
the impurity of the water.

Coloration of Water. — Under this head
we shall refer to those plants and animals
which most commonly produce such appear-
ances, premising that the commonest cases
of coloration depend upon suspended mineral
substances (mud), of different colours accord-
ing to the soils washed by the water.

1 . Producing a general green colour, or a
thick film on the surface. — PROTOCOCCUS
(Chlamidomonas^hr., Diselmis, Duj.), very
common in the spring ; and various Nosto-
chaceous Algae, as TRICHORMUS, CONIO-
PHYTON, &c. (see NOSTOCHACE^E ; many
with a bluish tinge); POLYCYSTIS, Kiitz.,
forming a granular verdigris-green layer;
various PALMELLACE^E ; EUGLENA viridis,
&c. [The DESMIDIACE^J form greenish
patches at the bottom of water or on plants,
as do certain OSCILLATORIACE.E.]

2. Producing a red colour in fresh water.
— ASTASIA Ji&matodes, Ehr., species of
DAPHNIA. Some Naidina produce a red
colour on the mud in shallow water. Red
forms of species of PROTOCOCCUS (see also
RED SNOW). — In salt water, DISELMIS
Dunalii, Duj. ; TRICHODESMIUM.

3. A brown cloudy appearance often ap-
pears in masses near the source of small
springs of water flowing out of blue clay, or
in pools on peat-bogs. This mostly consists
of peroxide of iron ; but sometimes a similar
brown appearance is produced in pools by
collections of amorphous granular decaying
organic matter, in which occur great abun-
dance of certain OSCILLATORS, DIATO-
MACE.E, INFUSORIA, and ROTATORIA.
The obscure mycelioid structure called by
Kiitzing LEPTOTHRIX ocliracea produces a
yellowish-brown tint. Diatomaceae often
form a yellowish-brown coat on mud at the
bottom of water. Many Rotatoria and larger
Infusoria (PARAMECIA, &c.), when abun-

dant, give water a slightly milky appear-
ance.

The above list is undoubtedly very imper-
fect, but may afford some useful hints.
Microscopists who meet with such colora-
tions will naturally examine them carefully ;
they will find further information under the
heads of the articles cited.

WATER-BEARS. See TARDIGRADA.

WEISSIA, Hedwig.— A genus of Pottia-
ceous Mosses, variously defined by different
authors, related to Gymnostomum. W. con-
troversa, Hedw. (W. viridula, C. Mull.) is
common. Wilson includes Blindia here,
and separates Rhabdoweissia (W.fugax and
denticulata).

WELLS, DARK. See INTRODUCTION,
p. xvi.

WHALEBONE.— In whales the teeth
are rudimentary ; and arising from a depres-
sion in the upper jaw on each side are a
number of parallel horny plates, many feet
in length, which project downwards ; these
plates, which are technically known as fins
or blades, constitute whalebone, and through
them the water containing the animals upon
which the whale lives is strained, and the
food thus obtained. These plates are situ-
ated upon a vascular membrane, folds of
which enter a cavity at their base, which is
the portion connected with the jaw.

Whalebone may be pretty easily divided
into longitudinal laminae and fibres; but
these are only secondary forms resulting
from the aggregation of a number of cells,
of which whalebone wholly consists.

On examining a transverse section of a
blade or plate of whalebone with the naked
eye, or a lens, two structures are readily
distinguishable; an inner porous-looking
medullary portion, surrounded by an outer
compact or cortical substance. A longitu-
dinal section through the plate exhibits a
number of dark lines or stripes, from about
1-100 to 1-150" in diameter, parallel to
each other and to the axis of the plate, and
corresponding to the pores seen in the trans-
verse section. These stripes, which have
been called whalebone canals, but which we
shall denominate medullary lines, are seen
to be surrounded by a paler substance.

With a higher power (£ inch), the trans-
verse section exhibits in the centre a number
of rounded apertures or circles corresponding
to the pores (PL 17. fig. 31), surrounded by
very fine, concentric, interrupted dark lines;
whilst towards the circumference these lines
run parallel to the surface of the plate. In

WHALEBONE.

[ 686 ]

WINTERED.

the longitudinal section, viewed with this
power, the medullary lines are seen to con-
sist of a number of cells (PL 17. fig. 30),
mostly arranged in single longitudinal series,
and, in dried whalebone, having a very dark
appearance by transmitted light, from the
presence within them of a large quantity of
pigment and air. These are the medullary
cells. The substance between the lines of
medullary cells exhibits very fine longitu-
dinal striae, and in parts, the ends of divided
laminae.

On macerating whalebone for twenty-four
hours in solution of caustic potash, it be-
comes soft ; and on afterwards digesting it
in water, the cortical portion resolves itself
into numerous large transparent cells, from
1-230 to 1-310" in length, and from 1-500 to
1-330" in breadth (PI. 17- fig. 33). These
contain a variable number of granules of
pigment, of a deep brown colour, also some
small globules of fat, which are especially
numerous in those portions nearest the base
of the plate. These cells in the natural
whalebone are laterally compressed or flat-
tened, and the transverse axes of those sur-
rounding the medullary lines are arranged
tangentially to the latter ; whilst in the cor-
tical portions these axes are parallel to the
surface of the plate. The concentric lines
seen in a transverse section arise principally
from the pigment-granules within those
cells which surround the medullary cells
becoming arranged in a linear series, by the
flattening of the cells enclosing them. This
may be shown by treating a transverse sec-
tion of whalebone with caustic potash, and
then adding water, and watching its resolu-
tion into cells. As these expand, the inter-
rupted lines are seen also to expand as it
were, and to become resolved into a number
of distinct pigment-granules existing within
each cell. The lines seen in a longitudinal
section arise from the unequal refraction of
light by the laminae of compressed cells
surrounding the medullary lines.

The medullary cells contain a large quan-
tity of pigment, as do also those compressed
cells which immediately surround them ; in
the former, these granules are frequently
aggregated. In the common dry whalebone
of commerce the medullary cells also con-
tain air, which has been mistaken for fat,
and hence the cells denominated fat-cells.
The air is readily displaced by liquids. Be-
tween the compressed cells minute cavities
containing air, sometimes assuming a linear
form, at others representing mere dots, are

seen both in the transverse and longitudinal
sections ; these are distinguished by the dis-
placement of their contents. Hence ordi-
nary whalebone closely resembles hair or
horn in its structure, and the fibres which
are seen projecting from the margin of the
blades as found in commerce have a remark-
able similarity to hair (PI. 17. fig. 32).
Chemically, it consists of a proteine com-
pound, and is therefore coloured by Millon's
and Pettenkofer's test-liquids.

Whalebone polarizes light like horn.

BIBL. Donders, Mulder's Physiol. Che-
mie; Lehmann, Phys. Chem.; Hunter, Phil.
Trans. 1/87.

WHEAT.— The STARCH of the grain of
wheat (Triticum vulgare and other species
and varieties) presents itself in the form of
delicate little flattish lenticular bodies, very
characteristic (PI. 36. fig. 8). Wheat is sub-
ject to various BLIGHTS, which are referred
to under that head, depending on the growth
of parasitic Fungi, especially TILLETIA,
attacking the ear, PUCCINIA attacking the
straw, &c. In other cases the ear is found
infested with a minute worm (ANGUILLULA
tritici) remarkable for its tenacity of life.

WINGS, OF INSECTS. — The arrangement
of the veins or nerves of the anterior wings
of the Hymenoptera is sometimes used to
form the basis of systematic arrangement;
and the several veins and interspaces have
received distinct names, which may be illus-
trated by means of PI. 27. fig. 11, represent-
ing the anterior wing of the humble-bee
(Bombus terrestris) (it must be remarked,
however, that in our figure, the nerves, a, dt
e, are not sufficiently distinguished) ; a, costal
nerve ; b, cubital nerve ; c, posterior margin
of wing, with the fold (n) for the attach-
ment of the hooks ; d, post-costal nerve ;
e, externo-medial ; /, anal ; the nerve be-
tween 3 and 10, the transverso-medial ; h, the
radial nerve ; k, the discoidal ; I, the sub-
discoidal ; m, m,m, transverso-cubital nerves ;
s, stigma; 1, costal cell; 2, medial cell;
3, interno-medial ; 4, anal; 5, marginal;
10, first discoidal cell; 11, second ditto;
12, third ditto ; 13, first apical cell.

See INSECTS, wings.

BIBL. That of INSECTS; Jurine, Nou-
velleMethode,&c.', Shuckard, Trans. Entom.
Soc. i.

WINTERED.— A section of the Dicoty-
ledonous family, Magnoliaceas (DRIMYS,
TASMANNIA), remarkable for the character
of the elementary structure of the wood,
approaching closely to that of the Coniferae.

WOOD.

[ 687 ]

WOOD.

It consists, as in that family, wholly of pitted
prosenchymatous cells without ducts, the
cells having two or three rows of bordered
pits, as in ARAUCARIA. A distinction exists
however in the character of the medullary
rays, which are very numerous in Wintereae,
occurring both large and small, six or seven
in the breadth of 1-12" in a vertical section
at right angles to the rays ; some of them
being thin, composed of one or two parallel
layers of cells, extending to a vertical extent
of about ten cells ; others much larger, ten
or twelve cells thick (or broad), and of a
vertical extent of eighty or a hundred cells ;
the latter are very evident on the surface of
the wood, when the bark is removed. The
medullary rays here traverse all the annual
layers of wood, which is not the case in the
Coniferae.

BTBL. Goeppert, Linnesa, xvi. p. 135
(1842), Ann. des Sc. nat. 2 ser. xviii.
p. 317.

WOOD.— The mode of origin of wood is
explained in the articles CAMBIUM, ME-
DULLA, MEDULLARY RAYS, and VASCU-
LAR BUNDLES, while the characters of the
elementary organs of which wood is com-
posed are described under the heads of CELL,
PITTED and SPIRAL -FIBROUS STRUC-
TURES, FIBRES, and SECONDARY DEPO-
SITS. Peculiar composition of the wood in
certain classes, families, or genera of plants
is also noticed under their especial heads,
which will be referred to presently. In this
article the principal kinds of modification of
the wood (taken as a whole) occurring in
these said cases, and in certain others, are
to some extent classified, in order to indi-
cate their relations, and to furnish a guide
to microscopists seeking to observe the most
remarkable varieties of structure occurring
in this substance.

The elements entering into the composi-
tion of wood are, — 1. FIBRO-VASCULAR
BUNDLES, which in their most complete
form contain SPIRAL and other VESSELS,
PITTED DUCTS, PROSENCHYMATOUS cel-
lular tissue with thickened walls (woody
fibre) ; and in the Monocotyledons, * proper
vessels,' as they are called by Mohl, viz.
elongated tubular cells of membranous struc-
ture occurring in the centre of the bundles,
apparently corresponding to the CAMBIUM
at the outer surface in Dicotyledons. —
2. MEDULLARY RAYS in the Dicotyledons,
or a generally diffused medullary parenchyma
in the Monocotyledons. — 3. Woody PA-
RENCHYMA, which is found under different

conditions and in different quantities in dif-
ferent cases.

The GYMNOSPERMS may be considered,
in the above enumeration, as agreeing with
the Dicotyledons. The less generally dif-
fused structures connected with Secretion
are here left out of view.

In classifying the kinds of wood, we may
commence with the less perfect forms.

Monocotyledons. — In our native plants of
this class the stem is mostly herbaceous,
and the woody structure then occurs simply
in the form of "fibres" (fibro-vascular bun-
dles) (fig. 460, p. 419), the structure of which
has been described elsewhere (fig. 7^6).
The same kinds of elements are arranged in
nearly the same way in most of the arbores-
cent plants of this class, such as Palms, for
example in the Cocoa-nut Palm, in the com-
mon Cane ( Calamus), or the various striped
solid canes (all Palms) used for walking-
sticks, &c. The solid woody texture depends
in these upon the interspace between the
fibro-vascular bundles being filled up with
woody parenchyma ; i. e. the general medul-
lary substance, which in such stems as that
of the White Lily is soft and spongy, in the
Palms &c. becomes solidified by the great
deposition of secondary layers upon the
walls of the cells ; thus the bundles, at first
"fibres," are bound together into a solid
wood. The thick woody walls of the hollow
Bamboo cane are constructed on the same
plan, being highly-developed and lignified
forms of the structure which is exhibited in
a soft and herbaceous condition in our com-
mon Grasses.

Certain Monocotyledons present a struc-
ture which differs from the above in the
appearance presented by transverse sections.
In the Smilacese, and some of the Diosco-
reacese, the fibro-vascular bundles are ar-
ranged in more definite order in one or two
circles, but there is no distinction of pith,
medullary rays, and bark here ; the bundles
are bound together by woody parenchyma,
and there is no cambium region be-
neath the rind. The anomalous growth
exhibited by the stems of other Monocoty-
ledons, such as Draccena, Yucca, &c., can-
not be regarded as depending on the forma-
tion of wood in the proper sense ; in them,
layers of fibrous structure are formed be-
tween the central region of the stem (con-
taining the original vascular bundles) and
the rind, which take their origin from the
ends of the vascular bundles at the periphery
of the stem beneath the rind, and extend

WOOD.

[ 688 ]

WOOD.

down in a kind of false cambium layer be-
neath the rind.

Interesting objects illustrating the above
structures are furnished by longitudinal and
transverse sections of the trunks of large
Palms and of the large woody leaf-stalks of
these, of canes of different kind, of Bamboo-
canes, the rhizome of Sarsaparilla-plants
(Smilax), Ruscus, the harder parts of the
stem often found attached to imported Pine-
apples, &c. Sections of silicified fossil
Palm-stems, prepared by the lapidary, can
also be obtained from the dealers in objects.

Dicotyledons. — In this class we meet with
a remarkable diversity in the character of
the wood, which moreover here exhibits,
from the indefinite power of growth of the
FIBRO-VASCULAR BUNDLES, a much more
extensive and perfect development than in
the Monocotyledons. In the articles ME-
DULLA (fig. 459, p. 419), MEDULLARY
RAYS (fig. 461, p. 419), and VASCULAR
BUNDLES (fig. 797, p. 669) are described the
conditions of ordinary Dicotyledonous stems
in the first year of their growth ; it is stated
in the account of the vascular bundles, that

Fig. 812.

Transverse and vertical section of a segment of a shoot
of the Maple in the early part of the second year of its
age. T, spiral vessels ; V P, pitted ducts ; F, woody
fibre ; C, cambium ; PC, cortical parenchyma ; F, liber
fibres ; PC, cellular envelope of the bark ; S, corky layer
of ditto. Magnified 60 diameters.

a new layer of wood is developed in the
cambium layer in each succeeding season
(fig. 461, p. 419). The nature of the ele-
mentary structures in such cases is illustrated
by the accompanying figures from the Maple
(Acer campestns) (812 & 813), of which

Fig. 813.

Transverse section of a Maple-wood three years old.
The figures 1, 2, 3, indicate the annual rings of wood, the
rest is bark, m, medulla ; t, spiral vessels ; v, ducts, /,
woody fibre ; c, cambium ; me, medullary parenchyma ;
/, liber. Magnified 40 diameters.

the former represents sections of a shoot at
the beginning of its second year, when the
cambium layer (c) is swelling ; the latter a
shoot of three years' growth, the portions
belonging to each year being indicated by
the figures. The only difference between
the structure developed in each succeeding
season is the absence of a layer of spiral
vessels (medullary sheath, in the first year)
at the point where each year's growth com-
mences. Here, as is seen, the body of the
wood is composed chiefly of prosenchyma-
tous cells (wood-cells or woody fibre) (/),
with a few pitted ducts (v} near the com-
mencement of each annual layer ; the me-
dullary rays are narrow in this wood. In
the Hornbeam (Carpinus Eetulus] the wood
is of very similar composition; the wood-
cells, however, are more thickened, and the
ducts exhibit a spiral marking ; the annual
layers are not very clearly defined in sections
under the microscope. This is the case,
again, with the excessively hard wood of the
box (Buxus sempervirens)., which is of analo-
gous composition. The Birch (Betula alba] has
the same structure. Other common timber
trees exhibit an additional structure in their
wood, namely masses of woody parenchyma
interspersed in various ways among the or-
dinary prosenchymatous structure of the
wood. A very small quantity of this occurs
in scattered groups in the common oak

WOOD.

[ 689 ]

WOOD.

(Quercus pedunculata) ; here also the ducts
are very large, appearing as open holes to
the naked eye in cross sections ; the larger
medullary rays are likewise very evident.
In the beech (Faaus sylvaticd) there is a
small quantity of woody parenchyma, but
greatly thickened prosenchyma prevails ;
the ducts are rather small, but the broader
medullary rays are very evident, appearing
as brown streaks to the naked eye in longi-
tudinal sections. The Chestnut (Costarica
vesca) differs from this chiefly in wanting
the broader medullary rays. In the Elm
( Ulmus campestris] the prosenchyma is in-
terposed between bands of woody parenchy-
ma and wide ducts, which renders the di-
stinction of the annual layers obscure. The
Walnut tree has no woody parenchyma;
the Apple and Pear trees have alternate
bands of prosenchyma and woody parenchy-
ma; these exist, but are narrower in the
Plum and Cherry. In the wood of most of
the Leguminosae (Robinia, Vlex, Genista,
Gleditschia, &c.) the woody parenchyma
appears in bands of considerable size, but
the walls of its cells are less thickened
than those of the prosenchymatous cells.
Woody parenchyma occurs extensively in Ma-
hogany and Rose-wood, producing a peculiar
variation of colour in the wood ; the large
holes are the orifices of the very wide ducts.
The wood of the Poplars (Populus) and
Willows (Salix] has the prosenchymatous
cells little thickened. The Hazel ( Corylus
Avellana) and the Alder (Alnus glutinosd)
present a peculiarity : the wood appears to
the naked eye to have broad medullary rays,
but under the microscope these rays are
found to be portions of the wood devoid of
ducts, intervening between segments with
closely-pitted ducts placed at particular
points in the annual rings. The Lime ( Tilia)
and the Horse-chestnut (&sculus] have wood
of soft texture, the prosenchymatous cells
being only slightly thickened; while the
ducts are large and numerous (these exhibit
a spiral band, very evident in the Lime).
The wood of the Plane (Platanus occiden-
talis] has strongly marked medullary rays ;
the prosenchymatous cells are greatly thick-
ened, and mingled with them are very nume-
rous ducts, and a small quantity of woody
parenchyma. The stem of the Vine ( Vitis
mnifera) has likewise long and broad me-
dullary rays ; the wood is composed of pros-
enchymatous cells, with a spiral-fibrous
deposit on their walls, while the cells of the
woody parenchyma are devoid of this ; the

ducts are very long, and exhibit every gra-
dation of form, from spiral, reticulated, and
scalariform to pitted ducts. The various
species of Clematis have strongly marked
medullary rays, and wood chiefly composed
of pitted ducts, as is the case also in the
common Rose.

In many of the above trees the wood ac-
quires a special peculiarity when it attains a
certain age ; the prosenchymatous cells ge-
nerally become more solid, year by year,
through the filling-up of their cavities by
the increasing thickness of the secondary
deposits on their walls: in the lighter-co-
loured and softer woods, such as the Lime,
there is no distinct line of demarcation be-
tween the older and younger part of the
trunk, the alburnum or sap-wood and the
duramen or heart-wood ; but in many cases,
as in the Ebony (Diospyros), Lignum-vitse
(Guaiacum), to a less extent in the Elm,
Oak, &c., the duramen assumes a remarkable
solidity and a deeper colour, so that after a
certain time the colours of the duramen and
alburnum are very different. This appears
to arise from a chemical alteration of the
substance of the secondary deposits of the
prosenchymatous cells.

A great degree of regularity and agree-
ment of structure exists between the woods
of the Dicotyledons above mentioned. It
remains to direct attention to various kinds
which depart more or less from the type
thus selected.

In the various parasitical Dicotyledons,
such as Lathraa, Melampyrum, Cuscuta,
&c., there is no layer of spiral vessels corre-
sponding with the medullary sheath; and in
the Misletoe (Viscum) only annular ducts
occur in this situation; the wood in the
latter is largely composed of woody paren-
chyma, the cells of which are punctated, or
possess spiral-fibrous layers (figs. 670, 67 1,
page 594). The stem of Myzodendron also
exhibits some remarkable anomalies.

In the Bombaceae (Bombax, Carolinea,
&c.) the mass of structure corresponding to
the wood is chiefly composed of membranous
parenchymatous cells, with scattered isolated
prosenchymatous cells, and large pitted
ducts. The wood of Avicennia is principally
composed of large pitted ducts, with narrow
interspaces filled up with small pitted par-
enchymatous cells.

The wood of the Cactaceae, Mammillaria,
Melocactus, is composed of dotted ducts,
together with a kind of cell, apparently re-
ferable to parenchyma, the walls of which

2 Y

WOOD.

[ 690 ]

WOOD.

have a remarkably broad spiral-fibrous band
(PI. 39. fig. 7). The wood of the Casuarinee
exhibits a curious structure ; it is composed
of long prosenchymatous cells, the walls of
which, together with those of the numerous
large ducts, have bordered pits (PI. 39. fig.2),
while concentric lines of cellular tissue ap-
pear at intervals in the cross section, con-
sisting of plates of parenchyma extending
from one medullary ray to the next, and
connecting them. The stems of some of the
Menispermacese have likewise concentric
processes of parenchymatous tissue. In the
WINTERED, a section of the Magnoliaceae,
the wood is wholly composed (with the ex-
ception of the medullary sheath) of pitted
prosenchymatous cells resembling those of
Araucaria (PI. 39. fig. 5), without any
ducts.

In certain families of Dicotyledons a re-
markable appearance arises from the ar-
rangement of the bundles in several circles,
almost as in the Monocotyledons ; but this
results in a very different kind of structure,
on account of the unlimited growth of the
cambium in Dicotyledons. Examples of
this kind of wood occur in the Chenopodia-
ceae, Nyctaginaceae, Piperacese, &c. In Pi-
sonia, which has been supposedto grow in
the same way, the result is a solid mass of
wood, composed of prosenchymatous cells
and ducts, with isolated perpendicular cords
of parenchyma (exactly the reverse of what
occurs in the Monocotyledonous stems).
The woods of Phytocrene and Nepenthes may
be further cited as offering remarkable pe-
culiarities.

It would exceed the space which we can
allow to this article to enter into a descrip-
tion of the anomalous Dicotyledonous stems
of the tropical lianes or climbing trees, of
the families Bignoniacece, Menispermacece,
MalpigMacece, &c., the irregularities of the
wood of which depend upon deviations from
the normal type arising in the course of the
growth of the steins, which, from the obser-
vations of Treviranus, Criiger, and others,
appear to be mostly regular when quite
young. Isolation of one or more fibro-vas-
cular bundles from the central cylinder of
wood, producing distinct centres of develop-
ment, is the most common cause of irregu-
larity.

The wood of Dicotyledons must be exa-
mined by transverse sections and perpendi-
cular sections parallel with and at right
angles to the medullary rays. The same
applies to the wood of Gymnosperms. The

mode of cutting these sections is stated
elsewhere.

Sections of recent woods are best pre-
served wet in chloride of calcium. Fossil
wood, if silicified, is cut (in similar direc-
tions) by the lapidary's wheel ; wood in the
state of coal in like manner, or in the way
stated under Coal (see PREPARATION,
FOSSIL WOOD, and COAL).

Gymnosperms. — In this division of the
Flowering Plants we also meet with two
types of structure.

Conifera. — Here the character of the wood
agrees in general with that of the typical
Dicotyledons, with certain distinctions ;
namely, although the medullary sheath of
spiral vessels exists, no ducts or vessels oc-
cur in the mass of wood external to this,
which is wholly composed of prosenchyma-
tous cells, with bordered pits, in single (PI.
39. fig. 6) (usually) or double or treble (Arau-
caria) rows (PI. 39. fig. 5) ; in Taxus accom-
panied in part by a spiral-fibrous band (PL
39. fig. 6). The particulars of these forms
are given under CONIFERS. It may be
mentioned, that the ' woody parenchyma' of
Dicotyledons seems to be represented here
by the cords of parenchymatous cells in some
cases traversing the prosenchyma, ultimately
filled with resinous deposits (" cords of se-
cretion cells ").

Cycadacece. — The earliest condition of the
stems here appears to resemble that in Co-
niferse, but no annual rings are formed.
Concentric layers are produced at intervals,
however, separated by parenchymatous lay-
ers. The true mode of origin of these does
not appear to be clearly made out. The
wood is composed of pitted prosenchyma-
tous cells (PI. 39. fig. 20), without vessels or
ducts, excepting in the medullary sheath of
spiral vessels.

For further details on the markings of the
ducts, &c., see PITTED and SPIRAL STRUC-
TURES.

The subject of the development of the
wood of stems has been more discussed per-
haps than any point in structural botany.
We cannot enter upon it here, beyond the
statement that the key to its comprehension
lies in the thorough appreciation of Schlei-
den's characters ofihejibro-vascular bundles
in the different classes, and of the fact that
the cambium region exists at the growing
points and all over the outer surface of the
wood in Dicotyledons ; in a conical mass at
the summit alone, of Monocotyledons ; and
in a still more limited region at the summit

WOODSIA.

[ 691 ]

WRANGELIA.

ofHhe stems of the Flowerless plants. The
researches of Trecul have furnished the
completing hand to the evidence against the
doctrines of Gaudichaud and others, and the
earlier views of the nature of cambium enjter-
tained by Mirbel.

BIBL. Lindley, Introd. to Botany, 4th ed.
i. p. 198; Link, Elem. phys. hot. i. p. 257,
Ann. des Sc. nat. 2 ser. v. p. 29 ; DeCandolle,
Organographie, i. p. 161 ; Meyen, Pflanzen-
phys. i. p. 331 ; Schleiden, Grundz. 3rd ed.
i. p. 253 (Principles, p. 56), Wiegmann's
Archiv. 1830. i. p. 220, Beitr. z. Bot. p. 29,
Mem. Acad. St. Petersb. 6 ser. iv. (1842);
Treviranus, Bot. Zeit. v. p. 3/7 (1842), Ann.
Nat. Hist. 2 ser. i. p. 124 ; Mohl, Verm.
Schrift. passim ; Miquel, Linntea, xvii. p.
465; xviii. p. 125, Ann. des Sc. nat. 2 ser.
xix. p. 164; 3 ser. v. p. 11; Goeppert, De
Struct. Conifer. Vratislav, 1841, Linncea,
xvi. p. 747; xvii. p. 135, Ann. des Sc. nat.
2 ser. xviii. pp. 1 & 317 ; Brongniart, Veget.
Fossiles, Paris, 1828, et seq., Ann. des Sc.
nat. 1 ser. xvi. p. 589 ; Jussieu, Ann. des Sc.
nat. 2 ser. xv. p. 234 ; Decaisne, ibid. xii.
p. 92, 3 ser. v. p. 247 ; Hooker, J. D. Flor.
Antarc., Ann. des Sc. nat. 3 ser. v. 193 ;
Gaudichaud, Recherches Anatom., fyc. Paris,
and Ann. des Sc. nat. 3 ser. passim,', Mene-
ghini, Richerche sulla Strutt. Monoc. ;
Schacht, Pflanzenzelle, p. 193, Das Baum.
p. 94 ; Criiger, Bot. Zeit. viii. p. 99 ; x. p.
465; Trecul, Ann. des Sc. nat. 3 ser. xviii.,
xix., xx. ; 4 ser. i., ii. iii. ; Milde, Beitr. z.
Bot. Heidelb. 1850.

Woodsia hyperborea.

A sorus and indusium with a hair- like fringe.
Magnified 50 diameters.

WOODSIA, R. Brown.— A genus of Cya-
thasous Ferns, represented by two rare indi-
genous species. The indusia are of an open
cup-shape, and bear long hairs on the mar-
gin (fig. 814).

WOODWARDIA, Smith.— A genus of
Asplenieae (Polypodaeous Ferns). Exotic.
(fig. 815).

Fig. 815.

0 ^ri.

£

oi9DfiiJoa^/>M -jAi 1
jottiu "io (iitfi'Mf*

{JIB
O'i fJ

4°l ui

Woodwardia.
A fertile pinnule. Magnified 5 diameters.

WOOL, of ANIMALS. See HAIR (p. 310).
The fibres of wool are coloured by the test-
liquids of Millon and Schultze.

WRANGELIA, Ag.— A genus of Cera-
miacea3 (Florideous Algae), differing from
Griffithsia chiefly in the scattered tetraspores.
W. multifida, the only British species, has
rose-red feathery fronds, an inch high, con-
sisting of a main filament, about as thick as
a bristle, composed of a single row of cells,
bearing long, pinnately-arranged, patent
branches, mostly branching in the same way
again. At the articulations occur two oppo-
site (or more rarely a whorl of) pinnato-
multifid or sub-dichotomous ramelli 1-12 to
to 1-6" long. The fructification consists of
— \.favellce, borne on stalks at the joints,
and surrounded by a whorl of ramelli ; and
2. elliptical tetraspores, opposite, secund
or tufted, on the lower part of the ramelli.
In some foreign species antheridia have
been observed in similar situations to the
tetraspores.

BIBL. Harvey, Brit. Mar. Alg. p. 169.
pi. 24 D., Phyc. Brit. pi. 27; Derbes and
Solier, Ann. des Sc. nat. 3 ser. xiv. p. 273
pi. 35 ; Thuret, ibid. 4 ser. iii. p. 38.
2v2

XANTHIDIA.
X.

[ 692 ]

YEAST.

XANTHTDIA. — The bodies found in
flint, and thus called, are sporangia of Des-
midiaceze (PI. 19. figs. 22-28). They have
been distributed in genera and species, the
description of the characters of which would
be useless.

XANTHIDIUM, Ehr.— A genus of Des-
midiacese.

Char. Cells single, constricted in the
middle; segments compressed, entire, spi-
nous, with a circular, usually tuberculated
projection near the centre. Spines more
than two to each segment.

X. armatum (PL 10. fig. 23 ; fig. 24, empty
cell, showing the projections). Segments
broadest at the base; spines short, stout,
tri- or multi-fid. Length 1-180".

X.fasciculatum (PL 10. fig. 25). Segments
with from four to six pairs of subulate mar-
ginal spines; central projections minute,
conical, and not beaded. Common. Length
1-400".

Four other British species.

BIBL. Ralfs, Brit. Desmid. 111.
o XANTHIOPYXIS, Ehr. — A genus of
fossil Diatomaceae, consolidated with PYXI-
DICULA. It consisted of those species, the
margins of the valves of which are fur-
nished with a dentate membrane, or the
surface covered with setae or hair-like pro-
cesses. From Bermuda.

BIBL. Ehrenberg, Ber. d. BerL Akad.
1844. 264; Kiitzing, Sp. Alg. 23.

XENODOCHUS, Schlecht.— An obscure
genus of Fungi, consisting of microscopic,
short, curved, usually shortly stipitate fila-
ments, attenuated at each end, composed of
a moniliform row (five to fifteen) of globose
cells filled with black granules ; formed in
the Uredo-frmts ofPhragmidium inerassatum,
/3 mucronatum, on Poterium. Placed among
the Puccinaei by Berkeley ; near Torula by
Fries.

BIBL. Schlechtendahl, Linncea, i. p. 237.
pi. 3. fig. 3; Fries, Summa Veg. p. 505;
Berkeley, Ann. Nat. Hist. i. p. 263.

XYLARIA, Schrank.— A genus of Sphas-
riacei (Ascomycetous Fungi), several of which
are common on rotten wood, stumps of trees,
&c. They are branched, horny or fleshy
bodies, with often clavate lobes, whitish
and mealy when young, afterwards brown
or black, with black, horny, immersed peri-
thecia all over the branches, or with the tips
barren; the perithecia have a black centre
composed of asci, each containing eight
(usually uniseptate) spores.

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 234
(Nos. 8 to 11); Fries, Summa Veg. p. 381.

Y.

YEAST (-PLANT) .—This well-known sub-
stance, which possesses the remarkable pro-
perty of resolving sugar in solution into
alcohol and carbonic acid, consists of a mi-
nute fungus, or rather of a particular condi-
tion of development of a certain fungus.

When yeast from an actively fermenting
liquid is examined with the microscope, it is
seen to consist of myriads of minute cells or
vesicles, of about 1-3000 to 1-2400" (PL 20.
fig. 23) in diameter, containing a nucleus
and some granules. During the progress of
the fermentation, these cells increase in
number, by budding, until either the sugar
or the nitrogenous matter of the fermenting
liquid is exhausted, when the cells, especially
those nearest the surface, become elongated,
remaining connected end to end, until they
reach the surface, where they produce their
fructification.

The growth of the yeast-plant has been
carefully studied by several observers. We
may describe some observations of our own,
which confirm those of Mitscherlich and
others. Some fresh wort, in which fermen-
tation had commenced, was obtained from a
brewery, and a drop of the liquid, containing
yeast-globules, placed upon a slide, and co-
vered with a piece of thin glass. After the
removal of the extraneous liquid, the upper
glass plate was cemented to the lower one ;
the slide was then placed under the micro-
scope, with the l-4th object-glass and the
micrometer eyepiece, in such a manner, that
several well-formed globules were visible,
and these were drawn on ruled paper.

At first the globules or cells enlarged until
they had attained a certain size ; then there
elapsed a short interval, during which no
change was observable. Next there took
place a projection of some point of the cell-
wall, which first appeared as a little point-
like bud, afterwards becoming larger and
larger, until at last a new cell, of the size of
the parent-cell, was formed. Within three
hours, a cell was so far developed, that a
new one was formed from it, and thus an
independent individual perfectly developed.
The rapidity of growth probably varies with
the temperature and the nature of the
process; in twenty-four hours, when the
thermometer was at about 78° in the day,
sixteen cells were developed from one ; after

YEAST.

[ 693 ]

ZOOPHYTES.

a time, the growth slackened, finally no fur-
ther increase took place, undoubtedly be-
cause all was removed from the liquid which
could serve for their growth. Growing glo-
bules from this experiment are figured in
PI. 20. fig. 23.

By the observations of numerous compe-
tent investigators, it seems certain that the
fermentation of beer, of wine, and in fact all
vinous fermentation, is effected by the growth
of this plant ; and after the evidence brought
forward in the articles FERMENTATION,
TORULA, and VINEGAR PLANT, there is
little doubt that the Vinegar plant, the
Oidium lactis, and other supposed distinct
plants, are but forms of the Yeast-plant.
Fig. 24 (PI. 20) exhibits the condition of
the Yeast- plant on the surface of exhausted
wort of malt, before the Vinegar-fungus
appears ; fig. 761, page 646, the Torula-form
at the margins of the surface of liquids.

We cannot clearly make out any difference
between the 'top-yeast' and * bottom-yeast'
(ober-hefe and unter-hefe of the Germans).
We do not believe the yeast-cells ever burst
to discharge reproductive granules. The
globular form is known by various names,
as Mycoderma cerevisia, Desm., which
agrees with Cryptococcus glutinis, Kiitz. ;
the globular form in the Vinegar-plant is
Kiitzing's Ulvina aceti; the filamentous
form with simple monilifonn fruit (fig. 761)
is Torula cerevisice, Turpin ; without fruit,
species of Hygrocrocis or Leptomitus ; the
final form being apparently Penicillium glau-
cum.

It is needless to repeat here the details
given under FERMENTATION, but it may be
added here that Turpin imagined that yeast
was formed by metamorphosis of the starch-
granules or similar bodies of vegetable cells;
and Schleiden seems to believe still (what
Kiitzing, Reissek, and others decidedly as-
sert) that the globular cells, the earliest
condition of yeast, quickly appearing in all
saccharine vegetable juices, or solutions
containing sugar and albuminous matters,
are 'autochthonous/ or rather pseudo-organ-
isms, formed by the abnormal and extra-
ordinary development of organic matters
separated from their natural position, and
capable of advancing only to a certain degree
of this false or diseased organization, when
they perish. These views are scarcely worth
notice after the numerous experiments which
have proved that no such phaenomena occur
when the germs of these certainly definitely
organized species of plants are carefully

excluded. The Yeast-plant is truly most
ubiquitous, but so are the conditions for its
growth, while its reproductive power is enor-
mous, and its small size renders it liable to
be scattered by imperceptible movements of
the air. Aspergillus glaucus is almost as
constant in its favourite nidus, cheese;
Mucor mucedo on paste, &c. ; Botrytis vul-
garis on dead leaves and stems in damp
places, &c., and all these are certainly no
pseudo-morphic productions ; and if, as we
believe, yeast is but the conidial form of
Penicillium glaucum, there has been no lack
of the spores of the latter in the air, in any
situation where we have ever exposed vege-
table substances for any length of time to a
damp atmosphere.

BIBL. Turpin, Mem. de I'lnstitut, xvii.
p. 93 (1840); Schleiden, Grundzuge der
Botanik, 3rd ed. i. p. 235 (Principles, p. 32);
and the Bibl. of FERMENTATION.

YEW. See TAXUS.

Z.

ZAMIA, Lindl. See CYCADACEJE.

ZETES, Koch.— A genus of Arachnida,
of the order Acarina, and family Oribatea.
It is consolidated with Galumna.

ZINC. — The crystals of the lactate, as
deposited from an aqueous solution, are re-
presented in PI. 7. fig. 20 ; they belong to
the right rhombic prismatic system.

The chloride of zinc is useful as a preser-
vative of animal tissues. (See PRESERVA-
TION, p. 535.)

BIBL. That of CHEMISTRY.

ZONARIA, Harvey (Aglaozonia, Zanard,
Kiitz.). — A genus of Dictyotaceae (Fucoid
Algae), of which the British species, Z. par-
vula, forms olive-green, membranous, fan-
shaped fronds, 1 " or more in diameter, grow-
ing over stones or corallines, to which it
attaches itself by whitish fibres on the lower
surface. It is scarcely marked with con-
centric lines like PADINA. The fructification
occurs in scattered sori on both surfaces,
and is apparently analogous to that of PA-
DINA, but requires further examination,
since Thuret has shown that the true Dicty-
otaceae have peculiar reproductive organs,
spores, tetraspores, and antheridia, so that
they stand between the Fucaceae and the
Florideae;

BIBL. Harvey, Brit. Mar.Alg. p. 38. pi.
6D.; Thuret, Ann. des Sc. nat. 4 ser. iii.
p. 25.

ZOOPHYTES. See POLYPI.

ZOOSPORES.

[ 694 ]

ZOOSPORES.

ZOOSPORES.— The name given to the
ciliated active gemmae or GONIDIA produced
from the contents of ordinary or special
cells of the Algae, apparently without any
previous process of fertilization. These
bodies are generally discharged from the
parent-cell in the state of PRIMORDIAL
UTRICLES, and acquire a cellulose coat
subsequently, when they cease to move,
and settle down to germinate and pro-
duce a structure resembling the parent.
In some cases (in HYDRODICTYON nor-
mally, in many other Confervoids abnormally)
they become encysted within the parent-
cell ; and it appears most probable that the
small cysts with dense (and often spinulose)
coats, such as occur in Spirogyra (PI. 5.
tigs. 24, 25) and other genera under certain
circumstances are of similar origin, but
intended to pass through a season of rest.
[In the VOLVOCINE^E, zoospore-like bodies
form the permanently active individuals of
the families.]

True zoospores occur pretty generally
throughout the Confervoid Algas (with the
exception of Oscillatoriaceae, Nostochaceae,
and perhaps Diatomaceae), and are described
under the heads of the families or genera.
A brief review may be permitted here. The
largest form is that produced in the apices
of the filaments of VAUCHERIA (fig. 801) ;
it is ciliated all over, and very unlike that of
any other genus. In CEdogonium (PL 5.
fig. 7 c & fig. 816) the zoospores are formed
out of the whole contents of a cell, and have
a crown of cilia around the transparent
'beak.' In other Confervaceae, as Clado-
phora (PI. 5. fig. 13 c, d), Conferva (PI.
5. figs. 10 b, 11 c ) ; in Chsetophora-
ceae, as in Cheetophora (PL 5. fig. 9),
Draparnaldia (fig. 183, page 216), Stigeo-
clonium (PL 5. fig. 5 c c); in Ulvaceae,
Ulva (PL 5. figs. 2b,3c, d), Enteromorpha
(Fl. 5. fig. 46), in Protococcus (PL 3. fig. 2 b),

.

Fig. 816.

b

Zoospores of CEdogonium. a have lost their cilia ; and
in b germination is more or less advanced. Magnified
200 diameters.

in ACHLYA, in Desmidiaceae (PL 6. fig. 11),
&c., as in all other cases, they are formed
either singly from the entire contents, or in
small or large number by the segmentation
of the entire contents, and mostly break out
in various ways, as pyriform bodies with two
or four cilia on the transparent beak, moving
actively for a time, and then germinating to
produce new plants. In HYDRODICTYON,
as described under that article, their history
is different, though the earlier conditions
are analogous. It has been found that zoo-
spores of two very different sizes are pro-
duced in many Confervoids ; these are called
macrogonidia and microgonidia by A. Braun
(see HYDRODICTYON), and a different func-
tion is supposed to be exercised by the lat-
ter by some authors, who. believe they are
fertilizing bodies (like SPERMATOZOIDS).

Zoospores exist in a large proportion of the
Algae usually included under the FUCOIDE^E,
but which Thuret separates under the name
of Phaeosporae, including all the families
except the FUCACE.E, DICTYOTACE^E and
Tilopterideae, which are (for the present?)
distinguished by possessing antheridia and
spores proper. The Phaeosporous families
bear organs called OOSPORANGES and TRI-
CHOSPORANGES according to their form,
(usually described in Algological works as
" spores "), from which are discharged zoo-
spores, agreeing in all essential respects with
those of the Confervoids, except that the
two cilia are often arranged fore and aft,
instead of being both in front. Examples
of these are described under ECTOCARPUS,
MYRIONEMA,CUTLERIA, LAMINARIA, &c.

It remains to direct attention to the di-
stinction between ZOOSPORES and SPER-
MATOZOIDS, which are sometimes confused
together. This confusion is rendered more
imminent by the manner in which the forms
pass one into another. The essential charac-
ter of a zoospore is, that when separated from
the parent it becomes encysted, and at once
developed into a new individual resembling
the parent (certain at present obscure excep-
tions occur, where the zoospore, after germi-
nating, at once discharges new ciliated bodies
(zoospores or spermatozoids (?)).

Spermatozoids are transitory structures;
when discharged from the parent-cell, they
either make their way to a germ-cell of a
spore, fertilize it and disappear; or if de-
barred from this, at once perish, without
germination. As stated under SPERMATO-
ZOIDS, these bodies vary much in form. In
the higher Cryptogamia they are spiral fila-

ZOOTHAMNIUM.

[ 695 ]

ZYGNEMA.

ments (PI. 32. figs. 31-4). In the Fucacea?
they are minute globular bodies with two
cilia (fore and aft) closely resembling some
zoospores ; in the Floridese they appear to
be globules without cilia ; and those recently
described as existing in VAUCHERIA, among
the Confervoids, are also biciliated globules
with the cilia fore and aft, while those in
SPH^EROPLEA resemble the microgonidia of
this family, and have then* pair of cilia on
the beak. The latter observation is in favour
of the microgonidia of Hydrodictyon, &c.
being spermatozoids.

BIBL. Thuret, Ann. des Sc. nat. 3 ser.
xiv. p. 214, xvi. p. 5, 4 ser. ii. p. 197, iii.
p. 5; A. Braun, Verjungung, fyc., Ray Soc.
Vol. 1853, and under the articles above
cited.

ZOOTHAMNIUM, Bory.— A genus of
Infusoria, of the family Vorticelhna.

Char. Those of Carchesium, the stalked
bodies being of two different kinds.

According to Stein, the remarks made
under OPERCULARIA in regard to the two
kinds of bodies, apply equally here, so that
the genus is untenable.

Ehrenberg describes two species, Stein
adds two more.

Z. arbuscula (PL 25. fig. 22). Branches
of polypidom racemose-umbellate, bodies
white, stalks very thick. Aquatic ; length
of polypidora, 1-4" ; of bodies, 1-430".

BIBL. Ehrenberg, Infus. 288; Stein,
Infus. passim.

ZOSTERA, L.— A genus of Monocotyle-
donous Flowering Plants (Nat. Ord. Zostera-
ceae), growing in sea- water ; remarkable for
the POLLEN, of which the grams are repre-
sented by tubular filaments destitute of an
outer coat and exhibiting ROTATION when
fresh.

ZYGNEMA, Agardh, in part (Tyndaridea,
Bory, Hassall). — A genus of Zygnemacese
(Confervoid Algae), consisting of filamentous
plants, with the green contents of the cells
arranged in twin, stellate or lobed masses in
each joint (fig. 137, page 166). This stellate
appearance arises from the presence of ra-
diating threads, like those from the nucleus
of SPIROGYRA; hence it cannot be well ob-
served in dried specimens. Cell-division
with previous division of the stellate masses
may be well studied in this genus. Kiitzing
separates from this genus all the forms in
which the spore is formed in the cross branch
produced in conjugation, associating them
with Zygogonium. We prefer to follow
Hassall's distribution of the forms, seeing

that Zygogonium ericetorum is a plant of very
different appearance. If the said character
is constant, this genus might be divided into
two.

Spores in one of the parent-cells.

1. Z. cruciata (fig. 137. p. 166). Fila-
ments 1-600" in diameter; joints equal or
twice as long ; spores globose (Hassall,
L c. infra, pi. 38. fig. 1 ; Kiitz. /. c. infra,
v. pi. 17. fig. 4). Z.Dillwynii and stellina
of Kiitzing appear to be only smaller states
of this ; as also Tynd. lutescens, Hassall, and
T. anomala, Ralfs.

2. Z. stagnalis. Filaments 1-2640" in
diameter, joints three or four times as long,
spores globose or oblong (Hassall, /. c.
pi. 38. figs. 9, 10). Tynd. ovalis, Hass., is
perhaps a larger form of this.

3. Z. insignis. Filaments 1-1800 to
1-1560" in diameter, joints twice as long;
spores globose (Hass. /. c. pi. 38. figs. 6,
7; Kiitz. L c. v. pi. 17- fig. 1).

4. Z. bicornis. Filaments 1-440 to 1-200"
hi diameter, joints twice as long ; spores
globose (Hass. 1. c. pi. 38. fig. 5 ; Kiitz.
L c. v. pi. 16. fig. 3).

Spores in the cross branches.

5. Z. immersa. Filaments 1-1200" in
diameter, joints about half as long again ;
transverse processes very thick, filled by the
large and globose spore (Hass. I. c. pi. 39.
fig. 3 ; Kiitz. I. c. v. pi. 12. fig. 5).

6. Z. conspicua. Filaments 1-1440 to
1-1080" in diameter, joints equal or twice as
long; transverse processes long, ventricose in
the middle, where they enclose the ovate-

flobose spore (Hass. I. c. pi. 39. figs. 1,
; Kiitz. 1. c. v. pi. 12. fig. 2).

7. Z. decussata. Filaments 1-1440" in
diameter, joints three times (more rarely five
times) as long; transverse processes short and
filled by the globose spore (Hass. /. c. pi.
39. fig. 6; Kiitz. /. c. v. pi. 11. fig. 4).

8. Z.Ralfsii. Filamentsl-1920tol-1440"
in diameter, joints three or four times as
long ; transverse processes very much
dilated in the middle, containing an
elliptical spore, with the long axis at right
angles (Hass. /. c. pi. 39. figs. 4, 5 ; Kiitz.
/. c. v. pi. 11. fig. 2).

9. Z. pectinata. Filaments 1-660" in
diameter, joints equal or a little shorter; cell-
contents transversely bipartite, more fre-
quently radiato-dentate, pectinate, dull green
(Kiitz. /. c. v. pi. 14. fig. 4 ; Etig. Bot. pi.
1611?). Possibly this is only a state of

ZYGNEMACE^E.

[ 696 ]

ZYGOSELMIS.

Z. cruciata with the spores in the transverse
processes ; if so, the subdivision above indi-
cated cannot stand.

Probably other species exist in Britain,
but we cannot satisfactorily ascertain them.

BIBL. Hassall, Brit. Fr. Alga, p. 160. pis.
38, 39 (Tyndarided) ; Kiitzing (Zygnema
and Zygogonium, in part), Tab. Phyc. v.
pis. 11-17, Spec. Alg. pp. 444, 445.

ZYGNEMACE^ (PI. 5. figs. 16-28).— A
family of Confervoid Algae, consisting of
plants composed of articulated cylindrical
filaments, the cells of which often have the
green contents arranged in elegant patterns.
The principal mode of reproduction, whence
the family takes its name, is by CONJUGA-
TION, followed by a mixture of the entire
contents of the united cells, and their con-
version into a spore. Other phenomena
occur in some instances, such as the produc-
tion of ciliated zoospores, and small spore-
like bodies with a dense spinulose coat
(asteridia), but these appearances are not yet
thoroughly understood (see SPIROGYRA and
MOUGEOTIA).

<i 80431297 (air, tR fell'

Synopsis of British Genera.

I. SPIROGYRA. Filaments simple, with
the green contents arranged in one or more
spiral bands upon the cell-wall. Conjuga-
tion normally by transverse tubular pro-
cesses ; spores formed in one of the parent-
cells (or occasionally in both).

II. ZYGNEMA. Filaments simple, with
the green contents arranged in two globular
or stellate masses in each cell. Conjugation
by transverse processes; spores formed in
one of the parent-cells, or in the cross branch.

III. ZYGOGONIUM. Filaments simple or
slightly branched, with the contents diffused
or arranged in two transverse bands. Conju-
gation by transverse processes ; spores glo-
bose, formed in the cross branches, or in
blind lateral pouches without conjugation.

IV. MESOCARPUS. Filaments simple,
with the contents diffused. Conjugation by
transverse processes, from which the fila-
ments become recurved; spores in the dilated
cross branches.

V. STAUROCARPUS. Filaments simple,
with the contents diffused (or rarely in mo-
niliform lines). Conjugation by transverse
processes, from which the filaments become
recurved ; spores (or sporanges) square or
cruciate, in the dilated cross branches.

VI. MOUGEOTIA. Filaments simple,
soon bent at intervals, contents mostly dif-
fused, sometimes in several serpentine

lines. Conjugation by the inosculation of
the filaments at the convexity of the angles ;
spores not satisfactorily known.

THWAITESIA, Montagne, resembles Zyg-
nema, in its stellate cell-contents, but the
spore (?) formed in one of the parent-cells
divides into four portions (perhaps not di-
stinct from Zygnema}.

ZYGOCEROS, Ehr.— A genus of Diato-
maceae.

Char. Frustules free, single, compressed ;
valves each with two horns. Marine.

Five species ; some of them are perhaps
isolated irustules of Biddulphia.

Z. rhombus (PI. 14. fig. 13). Frustules
turgid; valves rhomboid, angles rounded,
finely striated and granular. Length 1-288".

BIBL. Ehrenberg, Abhandl. d. Berl. Akad.
1839. 131 ; Kiitzing, Bacill. 138, and Sp.
Alg. 139.

ZYGODON, Hook, and Taylor.— A genus
of Orthotrichaceous Mosses, deriving its
name from the yoking of the teeth in pairs ;
the species are mostly found in mountainous
districts and rarely in fruit.

ZYGOGONIUM, Kiitz.— A genus of
Zygnemaceae (Confervoid Algae), consisting
of filamentous plants, growing on damp
ground or in water, green or yellowish when
fresh, purple or brownish when dry.
Kiitzing includes here all Hassall's species
of Tyndaridea (ZYGNEMA) which produce
the spore in the cross branch.

Z. ericetorum, Kiitz. Filaments 1-2160
to 1-1440" in diameter, joints as long or half
as long again ; cylindrical or torulose (fila-
ments sometimes slightly branched). Con-
jugation rare, apparently mostly * chain-like,'
from one cell to the next in the same fila-
ment. Contents green when growing in
water, purple when growing on wet heaths
(Hass. pi. 41; Greville, Sc. Crypt. Fl. pi.
261. fig. 1). Conferva ericetorum, Dillw.

See ZYGNEMA.

BIBL. Hassall, Z. c. ; Greville, /. c. ; Kiit-
zing, Sp. Alg. p. 445, Tab. Phyc. v. pi. 10,
&c. ; Eng. Bot. pi. 1553.

ZYGOSELMIS, Duj.— A genus of Infu-
soria, of the family Euglenia.

Char. Form variable ; movement effected
by two similar flagelliform filaments, inces-
santly in action.

Z. nebulosa (PI. 25. fig. 23). Body colour-
less, sometimes globular, at others variously
expanded so as to become pyriform or top-
shaped, turbid from the presence of nume-
rous granules. Aquatic; length 1-1100".

BIBL. Duj ar din, Infus. 369.

TEST OBJECTS.
__ ..... _

.1 Vv.OrifKUi.del.

DESCRIPTION OF PLATES.

The number of diameters which each object is magnified, is expressed in the Plates by small figures

placed beneath the objects.

PLATE 1.— Test-Objects.

[airs of the larva of Dermestes lardarius, viewed in balsam.

2. Hairs of the common bat (Vespertilio pipistrellus), in balsam, a b, coloured

hairs ; e, a white hair.

3. Hairs of mouse (Mus domesticus), in balsam.

4. Pits of coniferous wood, common deal (Abies excelsa), viewed dry.
f>. Mucus- (or salivary) corpuscles, seen under different powers.

6. Scales of Lepisma saccharina, dry.

7- Scale from the wing of Morpho menelaus, dry.

;$. Scale from under side of wing of common clothes-moth (Tinea vestianella), dry.

P. Scales of Hipparchia janira. a, dry, and by oblique light; b, in balsam, by
direct light ; c, dry, after Schacht.

10. Didymohelix ferruginea> under different powers ; 5, with imperfect correction

or adjustment, c with perfect correction and adjustment ; d> separate fibres.

11. Didymoprium Grevillii, empty cells.

1 2. Scales of Podura plumbed, under different powers, dry ; a, 220 diameters.

13. Pygidium of flea.

14. Frustule of Grammatophora marina (diagram). «, front view ; b, side view.

15. Frustule of Grammatophora subtilissima (diagram). «, front view ; b, side view.

16. Gyrosigma angulatum ; dry valve showing the dots.

1 7. Gyrosigma attenuatum ; dry valve showing the lines.

18. Gyrosigma elongatum\ dry valve showing the lines.

PLATE 2.— Arachnida.

Figure

1. Acarus domesticus (cheese-mite), a, labium and mandibles; b, hair; g, labium ; i, end

of leg.

2. Acarus longior. 3. Anystis ruricola. a, palp ; b, mandible.
4. Epidermis of Epeira diadema. 5. Epidermis of a Dermanyssus.

6. Mandibles of Epeira.

7. Mandibles, &c. of male Tegenaria. a, b, mandibles; c, palpi; d, maxillae; e, labium.

8. End of leg of Epeira. a, b, hairs of the same.

9. Lung-plates of Epeira.

10. Spinneret of Tegenaria domestica. a, two separate spinning- tubes, the right-hand one

from Epeira, the left-hand one from Tegenaria.

11. Portion of cobweb of .Epemz. 12. Epidermis of Arrenurus.

13. Arrenurus viridis, female, dorsal view, a, palp ; c, under view of male, showing round

mouth with hood and two first joints of palpi, the coxae, two stigmata and two gra-
nular plates, anal orifice and penis.

14. Atax histrionicus. a, mandible ; 6, palp ; c, under view, with labium, coxae, and genital

plates.

15. Hypopus muscarum. 16. Sarcoptes hominis, under view, female.
18. Psoroptes equi, under view. 19. Ixodes Dugesii, from above.

20. Ixodes Dugesii, anterior portion, from above, a, dorsal plate ; b, basilar piece of

support of rostrum ; c, palpi, between which part of mandibles is visible.

21. Ixodes Dugesii, side view of palp.

22. Ixodes Dugesii, basilar piece from above, a, dotted lines indicating first joint of man-

dibles (b) seen through support ; c, moveable toothed claw.

23. Ixodes Dugesii, sixth and seventh joints of leg, with claws and caruncle.

24. Dermanyssus avium, from beneath, a, labium of male, compressed, with palp (*) and

mandible (t) ; b, mandible of female ; c, leg.

25. Uropoda vegetans. a, mandible; b, its end more magnified; c, sixth and seventh joint

of leg in side view.

26. Gamasus coleoptratorum, from above, a, end of leg; 6, body from beneath; c, man-

dible. See PARASITE.

27. Limnochares aquatica. a, under view of labium and palpi; b, side view of labium;

c, tarsus ; d, scaly plate supporting eyes ; e, two posterior coxae of one side only ;
/, rostrum protruded, with palpi and anterior coxae, trochanters and femora of one

side only.

28. Eylais extendens. a, mouth with its hood, and first joint of palps ; b, palp ; c, end of

mandible, with hook ; d, under view of body, showing mouth, hood, and one palp, two
groups of anterior coxae with intervening genital orifice and two stigmata, posterior
coxae, anal orifice and two other stigmata.

29. Hydrachna globula, a, under view, showing rostrum and palps, coxae, heart-shaped

genital plate and anus ; b, mandible ; c, rostrum or labium, with a palp ; d, palp of
larva ; e, end of leg ; /, nymphs adherent to Nepa.

30. Diplodontus scapularis. a, labium with palp seen from beneath ; b, mandible.

31. Bdella vulgaris. b, mandible; a, end more magnified; c, mandible of Bd. carulipes.

32. Tetranychus trombidii. a, end of leg, front view, b, side view ; c, palp ; d, mandible.

33. Megamerus celer. a, labium ; b, palp ; c, mandible of Megamerus roseus.

34. Pachygnathus velutinus. a, palp ; b, end of leg ; c, mandible.

35. Raphignathus lapidum (?). a, labium of R. ruberrimus with palp and mandibles in situ ;

b, mandible of same.

36. Smaris papillosa, from above, a, mandible.

37. Trombidium phalangii. a, palpi ; b, mandible.

38. Trombidium (Leptus) autumnale, from above. 39. Pteroptus vespertilionis, from above.

40. Rhyncholophus cinereus. a, labium with a palp ; b, tarsus ; c, plume of the labium

more magnified ; d, a mandible.

41. Scirus (Bdella} elaphus, side view, a, end of mandible.

42. Demodex folliculorum, from beneath.

43. Demodex folliculorum, anterior portion from above, a, palps ; b, maxillae; c, labrum ;

d, tubercles.

ARACHNIDA

P1.2.

Lcucto

oorst 1&5S

CONFERVOID&E.

P1.3.

Ionia. Jo"ha Van Voorst .18 55.

PLATE 3.— Confervoideje.

Figure

1 . Chlorococcum vulgare, Grev. 0, groups in natural condition ; b, an isolated cell

showing the granular contents ; c, dividing cells treated with sulphuric acid
and iodine.

2. Protococcus viridis, nob. a, groups of cells, the upper one with eight in a

linear series ; those to the right with the contents dividing into numerous
gonidia (?) ; b, zoospores set free from the cells by the solution of the cellulose
membrane ; c, an isolated cell dividing and about to set free its contents as two
zoospores ; d, resting-cells with a thick coat and reddish contents ; e, a zoo-
spore with the cilia cast off; /, a zoospore with imperfect or retracted cilia;
g, remains of a zoospore left on a glass slide for twenty-four hours.

3. Palmella cruenta, R. Br. a, patch of the jelly with single cells, and dividing

and divided pairs ; b, similar cells without the gelatinous layer, the smaller
granules similar to those seen in the jelly of a ; c, cells treated with sulphuric
acid and iodine, showing the cellulose coat and granular contents ; dy diagram
indicating the relative dimensions of the cells of Palmella nivalis.

4. Glceocapsa polydermatica, Ktz. 5. a, b, Sarcina ventriculi, Goodsir.

6. Coccochloris Brebissonii, Ktz. a, group of cells, some dividing within their cell-

coat ; 5, a linear group ; c, a pair of cells conjugating ; d, conjugated cells
encysted and passing into the resting stage.

7. Urococcus HookerianuSy Berk. 8. ay 5, Hydrurus Deduzeliiy Ag.
9. Botrydina vulgaris, Ktz. a, by cy d, successive stages of growth.

10. Tetraspora gelatinosa, Ag. Four parent-cells producing bi-ciliated zoospores,

imbedded in the gelatinous frond.

1 1 . Gonium pectorale. Mull. ay perfect frond ; b, the same seen edgewise ; c, a

single zoospore.

12. Gonium tranquillum, Ehr. 13. Glceocapsa ampla, Ktz.

14. a, b, Volvox globatort, forms related to Syncrypta and Eudorina of Ehrenberg.

15. Spirulina oscillarioides (Turp. ?). 16. Spirulina Jenneri, Ktz.

17. a, Bacterium termo, Duj.; by B. catenula, D. ; cy B. punctum, Ehr. ; dy B. tri-

locularey Ehr. 18. Vibrio subtilis, Ehr.

19. Vibrio rugulay Ehr, 20. Vibrio prolifery Ehr.

21. Vibrio bacillus^ Ehr., prob. Andbaina subtilissima, Kiitz.

22. Spirochceta plicatilis, Ehr. 23. Spirillum volutansy Ehr.
24-36. Volvox globator, L. 24. A perfect family.

25. "With fully developed young within. 26. With yellow encysted (resting) spores.

27. Portion of the outer wall, with zoospores, some dividing.

28. Ditto, showing the cilia of the zoospores.

29. Ditto, a fragment after keeping some time in chloride of calcium, the portions

around each zoospore tumid.

30. The same seen obliquely, with the cilia.

31. Spore with the protoplasm dividing. 32. Ditto, more advanced.

33. An encysted spore with undivided contents.

34 . An encysted resting-spore, with yellow contents, probably a subsequent stage of 33 .

35. Ditto, ruptured by pressure.

36. A similar resting-spore with conical processes on the outer coat (characterizing

the V. stellatus, Ehr.).

PLATE 4,— Confervoidese.

Figure

1 . Aphanizomenon Flos-aquce, Morr. a, ordinary filaments ; b, filaments with

spermatic cells ; c, filament with a vesicular cell (heterocysf) .

2. Trichormus muscicola, n. sp. a, filament with vesicular cell ; b, ditto, with

adjoining spermatic cells ; c and d, fragments treated with acid to render the
membrane and contents distinct ; e and/, spermatic cells similarly treated.

3. Sphaerozyga elastica, Ag.

4. Cylindrospermum catenatum, Ralfs.

5. Spermosira littoralis, Harv.

6. Dolichospermum Ralfsii, Thwaites.

7. Nostoc commune, Vauch. a, ordinary filaments ; b> a single filament in its

gelatinous sheath ; c and d, fragments with a vesicular cell.

8. Oseillatoria autumnalis, Ag. «, fragment escaped from a sheath b.

9. Microcoleus repens, Harv.; 5, fragments showing the single sheaths ; c,c?, frag-

ments treated with sulphuric acid and iodine.

10. a, by Lyngbya muralis, Ag.

11. Dasyglcea amorpha, Berk.

12. a, b, Hassallia ocellata, Berk.

13. Stfiizosiphon Warreniee, Caspary. a, tuft of filaments; b, c, fragments; d, e,

decomposing sheaths.

14. Tolypothrix distorta, Kiitz.

15. a, Ainactis calcarea, Kiitz. ; by fragment showing the spiral sheath.

16. Euactis atra, Kiitz.

17. Schizothrix Creswellii, Harv.

18. Rivularia Boryana, Kiitz.

19. Scytonema Myochrous, Ag.

20. Arthronema cirrhosum, Hass.

21. Petalonema alatum, Berk. (Arthrosiphon Grevillii, Kiitz.). a, end of a filament ;

b, cross section.

22. a, Calothrix mirabilis, Ag. ; b, junction of filaments.

CONFERVOIDE^l.

AOienfeej- del.

loncLon: Jolm"VkrL Voorst, i855 .

ERVOTDEJE

/TT

jiuiro Jijm Van Vocrst.18 hb

PLATE 5.— Confervoidea.

Figure

1 . Monostroma bullosa, Thuret. a, fragment of frond, with some cells empty ,

b, ciliated zoospores from the cells ; c, zoospore germinating.

2. Ulva Lactuca, L. 0, fragment of frond ; b, small ciliated zoospores from ditto.

3. Ditto, a, fragment of frond ; b, ditto, with the cells nearly empty, showing the

orifices by which the zoospores escape ; c, large zoospore ; d, zoospores ger-
minating.

4. Enteromorpha clathrata, Grev. «, fragment of frond ; b, zoospores from ditto;

c, the same in germination.

5. Stiff eoclonium protensum, Kiitz. a and b, fragments of branched filaments,

b emitting zoospores, c, c ; d, germinating zoospores.

6. Vlothrix mucosa, Thur. a, 5, fragments of filaments ; c, zoospores ; d, e, ditto

germinating.

7. (Edogonium vesicatum, Link. «, fragment of a filament ; b, ditto, breaking up

and emitting a zoospore ; c, zoospore with a crown of cilia ; d, e, germinating
zoospores ; f, membrane of a zoospore which has burst by a lid and discharged
small zoospores immediately after germination ; g, fragment of a filament with
one cell containing a resting-spore ; h, fragment of a filament in an abnormal
state, containing globular bodies ; it germinated zoospore containing similar
globular bodies.

8. Chcetophora elegans, Ag.

9. A fragment of the same, emitting zoospores.

10. Conferva cerea, Dillw. «, fragment of filament, one cell of which has discharged

its contents in the form of zoospores, b.

1 1 . Conferva floccosa, Thur. a, filament breaking up ; 6, fragment of growing

filament ; c, zoospores.

12. Rhizoclonium obtusangulum, Kiitz.

13. Cladophora fflomerata, Kiitz. a, filament with one fertile branch; b, apex of a

fertile branch discharging zoospores, c.

14. Spheeroplea annulina, Kiitz. a, growing filament ; b, filament with the con-

tents converted into spores.

15. Codium tomentosum, Ag. a, apex of clavate branch, with fertile cell; b, zoo-

spores.

16. Staurocarpus gracilis, Hass. ; conjugating filaments.
17-23. Spirogyra quinina, Kiitz.; 1 7, growing filament.

18. Conjugating filaments, with spores.

19. Ditto, with the spores germinating.

20. Half- decomposed cell, with the contents converted into almost colourless bi-

ciliated zoospores.

21. Spore formed after conjugation.

22. The same shortly before germination.

23. A similar spore, with the contents converted into globular bodies.

24. a and b, Spirogyra ? with the contents converted into spiny globular

bodies.

25. Spirogyra quinina, Kiitz. ; imperfectly conjugated cells, with the contents con-

verted into globular bodies.

26. Spirogyra nitida; cell with nucleus, n.

27. Spirogyra pellucida, Kiitz.; cell with nucleus, n, and gelatinous outer coat, s.

28. Spirogyra nitida, Kiitz., half-decayed, the contents partly changed into globular

masses.

PLATE 6. — Confervoidese.— Crystals.

Figure

1. Cosmarium margaritiferumy Turp. ; conjugating pair with imperfect sporange.

2. C. Botrytis, Bory ; conjugating pair with sporange, enveloped in jelly.

3. A. Closterium acerosum, Schrank. a, 5, c, different stages of conjugation

d, frustules apparently produced from a sporange.

3. B. Closterium Lunula, Mull.; the contents converted into globular bodies.

4. Fragilaria penicillata, Lyngb. a and b> successive stages of conjugation.

5. A. Surirella bifrons, Ehr. ; conjugating pair, with intermediate large nev

frustule.

5. B. Surirella bifrons, Ehr., with the contents converted into globular bodies.

6. Eunotia turgida, Ehr. a, b, c, d, e, successive stages of conjugation producinj

pairs of new frustules.

7. Melosira (Aulacosira) crenulata, Thw. a, filament with two conjugating pair

of cells and perfect sporangial frustules ; b and c, large filaments produce<
by sporangial frustules.

8. Melosira varians, Ag. a, small filament producing sporangial frustules by con

jugation ; b, large filament developed from sporangial frustules.

9. Orthosira Dickiei, Thw. Successive stages of production of sporangial frustule

after conjugation.

10. Pinnularia viridis, W. Sm., with the contents converted into globular bodies.

11. Pediastrum granulatum, Ktz. «, a frond with most of the cells empty, thre

full, and the contents of another swarming out as zoospores ; b, c, d, swarm o
zoospores producing a new frond.

12. Crystals of sugar of milk.

13. „ diabetic sugar.

14. „ indigo, sublimed.

15. „ oxalate of soda.

16. „ sulphate of lime.

17. „ phosphate of lime.

18. „ sulphate of strontia.
1*. „ allantoin.

2*. „ antimoniate of soda.

3*. „ protoxide of antimony.

4*. „ butyrate of baryta, a, rapidly, b, slowly formed.

5*. „ hydrofluosilicate of baryta.

6*. „ sulphate of baryta, a, precipitated from concentrated, b, from ver

dilute solution.

7*. „ carbonate of potash.

CONFERVOIDEJE&.CRYSTALS

P1.6.

Trnj

CRYSTALS

*

PI 7

* * /9

^

L'mdon..John Vao Voorst. 1654.

PLATE 7.— Crystals.

Figure

1. 0, brucia; bt sulphocyanide of brucia.

2. Cinchonine.

3. Sulphocyanide of cinchonine.

4. Narcotine.

5. a, b, Strychnine.

6. Sulphocyanide of strychnine.

7. Morphia.

8. Sulphocyanide of quinine.

9. Muriate of ammonia.

10. Purpurate of ammonia (murexide).

> Nitrate of potash (analytic crystals).

13. Benzoic acid. «, crystallized from water ; b, sublimed.

14. Lithofellinic acid.

15. Margarine.

16. 0, Margaric acid ; b, stearic acid.

1 7. lodo-disulphate of quinine.

18. Hippuric acid.

1 9. Lactate of lime.

20. Lactate of zinc.

21. Succinic acid crystallized from water.

22. Creatine.

23. Creatinine.

24. Compound of creatim'ne and chloride of zinc.

PLATE 8.— Crystals from Animal Secretions,

Figure

1 . Uric acid ; human, natural. a, rhombs, front view, b, side view ; c, d, striated ;

e, rhombs with obtuse angles truncated ; ft twin crystals ; g, ditto ; h, hour-
glass crystals ; », nucleated ditto ; ky lt m, n, o (and lower h), aigrettes ; p, large
dumb-bell forms.

2. Uric acid; human, natural, a, front, 6, side view.

3. Uric acid, coloured artificially by murexide (these crystals should have been

coloured pink instead of yellow).

4. Uric acid, natural, a, front, 5, side view ; c, aigrette.

5. Uric acid, precipitated from solution in sulphuric acid by water.

6. Uric acid, rhombs, slightly acted upon with potash, showing spurious nuclei.

7. Uric acid, precipitated from gout- stones.

8. Uric acid of Boa, artificially precipitated, a — d, from solution in sulphuric acid

by water ; e — A, from solution in potash by muriatic acid.

9. Uric acid, precipitated from the excrement of the tortoise.

10. Uric acid, precipitated from the excrement of the clothes-moth.

1 1 . Urate of soda and ammonia. «, spheres with nuclei and concentric rings, arti-

ficial ; b, surface covered with radiating needles ; c, d, e, natural forms ;
/, g, artificial.

12. Urate of soda. «, artificial, deposited on cooling of an aqueous solution;

£, natural, as composing the chalky matter around gouty joints.

13. a, b, Urate of lime.

14. a, 6, Urate of magnesia.

15. Uric acid, precipitated by an acid from human urine.

CRYSTALS

PI .8

TuffaiWest. sculp.

lonSm . JoimTan V6orstB54 .

CRYSTALS

I'll

PLATE 9.— Crystals from Animal Secretions.

Figure

1 . Various prismatic forms of the ammonio-phosphate of magnesia (triple phos-

phate), naturally formed in human secretions.

2. Feathery or penniform crystals of the same salt.

3. Stellate form of the same salt.

4. Minute imperfectly formed prisms of the same.

5. Cystic oxide.

6. Carbonate of lime deposited from water by standing.

7. Carbonate of lime from the urine of the horse ; natural.

8. Carbonate of lime from the urine of man; natural.

9. Octohedra of oxalate of lime, as seen in water.

10. Octohedra of oxalate of lime, as seen when dried.

1 1 . Ellipsoidal forms of oxalate of lime ; natural.

12. Ellipsoidal constricted, or dumb-bell forms of the same ; natural.

13. Crystals of oxalate of lime, prepared with acid.

14. Modified octohedra of the same salt, formed by double decomposition.

15. Crystals of bilifulvine ; natural, human.

16. Crystals of hsematoidine.

17. Crystals of urea.

18. Nitrate of urea. ay b, slowly, c, rapidly formed.

19. Oxalate of urea.

20. Uroglaucine.

21. Cholesterine.

PLATE 10.— Desmidiacea.

Figure

1. Hyalotheca dissiliens, front view.

2. Hyalotheca dissiliens, side or end view.

3 1

4* > Hyalotheca dissiliens, conjugating cells, with sporangia.

5. Didymoprium Grevillii, front view.

6. Didymoprium Grevillii, side view.

7. Desmidium Swartzii, front view.

8. Desmidium Swartzii, side view.

9. Sphcerozosma vertebratum, front view.

10. Sphcerozosma vertebratum, side view.

1 1 . Micrasterias denticulata, cell dividing.

12. Micrasterias denticulata, sporangium.

13. Micrasterias rotata. 14. Euastrum verrucosum.
15. Euastrum oblonaum. 16. Euastrum Didelta.

17. Euastrum didelta, cell free from contents.

18. Cosmarium pyramidatum. 19'. Cosmarium pyramidatum, empty cell
20. Cosmarium crenatum. 21. Cosmarium margaritiferum.

22. Cosmarium tetraophthalmum.

23. Xanthidium armatum. 24. Xanthidium armatum, empty cell.

25. Xanthidium fasciculatum.

26. Staurastrum dejectum. 27. Arthrodesmus convergens.

28. Staurastrum margaritaceum, front view.

29. Staurastrum margaritaceum, side view.

30. Staurastrum gracile, front view. 31. Staurastrum aracile, side view.

32. Didymocladon furcigerus, front view (fig. 56, side view).

33. Tetmemorus aranulatus.

34. Tetmemorus aranulatus, empty cell.

35. Tetmemorus Icevis, in conjugation.

36. Penium Brebissonii.

37. Penium margaritaceum, empty cell.

38. Docidium truncatum.

39. Docidium baculum.

40. Closterium lunula.

41. Closterium acerosum.

42. Closterium acerosum, in conjugation.

43. Closterium moniliferum.

44. Closterium didymotocum.

45. Closterium setaceum.

46. Closterium setaceum, in conjugation.

47. Ankistrodesmus falcatus.

48. Pediastrum Boryanum.

49. Pediastrum aranulatum, empty cell.

50. Scenedesmus quadricauda.

51. Scenedesmus obliquus.

52. Aptogonum desmidium, side view (fig. 55, front view).

53. Scenedesmus obtusus, just after division.

54. Scenedesmus obtusus, ordinary state.

55. Aptogonum desmidium, front view (fig. 52, side view).

56. Didymocladon furcigerus a, side view (fig. 32, front view).

57. Closterium Grijffithii.
58.

LondoiL. Jon-n Yan ^"001-51, iSr>4

IBasire,

DIATOMACE^E

200 dum?

Lanim, John Van Voorst . 1854

PLATE 11.— Diatomacese.

[The figures represent the prepared frustules or valves, except when otherwise stated.]

1. Pinnularia nobilis, side view.

2. Pinnularia viridis, side view, with endochrome.

3. Pinnularia oblong a, side view.

4. Pinnularia radiosa, side view.

5. Pinnularia radiosa, front view.

6. Navicula cuspidata, side view.

7. Navicula cuspidata, front view.

8. Portion of the valve of a Navicula, showing the transverse rows of dots.

9. Navicula didyma, side view.

10. Gyrosigma balticum, side view.

1 1 . Hoop of the same, side view.

12. Gyrosigma strigile, side view.

13. Gyrosigma hippocampus, side view.

14. Gyrosigma acuminatum, side view.

15. Gyrosigma attenuatum, side view.

16. Gyrosigma attenuatum, front view.

17. Gyrosigma Spencerii, side view.

18. Gyrosigma lacustre, side view.

19. Gyrosigma littorale, side view:

20. Gyrosigma distortum, side view.

21. Gyrosigma fasciola, side view.

22. Gyrosigma macrum, side view.

23. Gyrosigma prolongatum, side view.

24. Gyrosigma tenuissimum, side view.

25. Gyrosigma formosum, side view.

26. Gyrosigma decorum, side view.

27. Gyrosigma obscurum, side view.

28. Gyrosigma speciosum, side view.

29. Gyrosigma strigosum, side view.

30. Gyrosigma rigidum, side view.

31. Gyrosigma elongatum, side view.

32. Gyrosigma delicatulum, side view.

33. Gyrosigma angulatum, side view, a, with endochrome ; b, variety /3 ; c, variety y,

end of.

34. Gyrosigma quadratum.

35. Gyrosigma cestuarii.

36. Gyrosigma intermedium.

37. Gyrosigma transversale.

38. Gyrosigma transversale.

39. Portion of valve of 6r. balticum.

40. Portion of valve of 6r. strigosum.

4 1 . Portion of valve of G. angulatum.

42. Portion of valve of G. littorale.

43. Stauroneis phcenicenteron, side view.

44 . Stauroneis pulchella, side view.

45. Stauroneis pulchella, front view.

46. Stauroneis pulchella, portion of valve.

47. (The fig. beneath fig. 41, erroneously numbered 43.) Portion of Isthmia enervis.

48. Portion of valve of Gyrosigma strigosum.

PLATE 12.— Diatomacese.

Figure

1 . Achnanthes longipes, the front view of the frustules is visible.

2. Achnanthes longipesy side view, upper valve.

3. Achnanthes longipesy side view, lower valve.

4. Achnanthes exilis.

5. Achnanthidium microcephalum, side and front views.

6. Achnanthidium flexellum, front and side views.

7. a, Amphipleura pelluciday side view of frustule; by Amphipleura pellucida, single

valve ; c, Amphipleura sigmoidea.

8. Amphiprora alata. a, side view ; b, front view.

9. Amphitetras antediluviana. a, frustules united ; by side view ; c, front view ;

d, perspective view.

10. Amphora ovalis, front view ; 100, transverse section.

11. Amphora membranacea ; front view of single valve.

12. Arachnoidiscus Ehrenbergiiy side view.

13. Arachnoidiscus Ehrenbergii, portion of valve from the centre to the circumference.

14. Bacillaria paradoxa. ay front view of conjointed frustules; b, side view;

c, front view of single frustule.

15. Biddulphia pulchella, front view. «, frustule dividing, front view.

16. Campylodiscus costatus, side view, b, front view.

1 7. Cocconeis pediculus.

18. Cocconeis scutellum, single valve (side view).

19. Cocconema lanceolatum.

20. Cocconema lanceolatum, single valve (side view).

21. Cyclotella operculata. a, side view; b, front view.

22. Cyclotella Kutzingianay front view.

23. Sphinctocystis solea. a, side view; b, front view.

24. Sphinctocystis ellipticay side view.

25. Denticula obtusa. b, front view ; c, side view of single frustule ; dy front view

of the same.

26. Diatoma vulgarey connected frustules. ay side view; b, front view of single

frustule.

27. Diadesmis confervacea. ay front view ; by side view.

28. Meridion constrictum. ay connected frustules forming a coil ; by front view of

single frustule.

29. Doryphora amphiceros. ay side view of frustule with endochrome ; by front

view ; c, prepared single valve.

30. Eupodiscus argus. ay side view ; b, front view.

31. Eupodiscus sculptusy side view.

32. Epithemia turgida. ay side view ; b, front view.

33. Fragilaria capucina; side view of frustule, front view of the same, and frustules

united into a filament.

34. Gomphonema acuminatum. by side view; cy front view of frustule.

35. Grammatophora marina, connected frustules. b, single frustule, front view ;

cy side view.

36. Himantidium pectinale, united frustules, front view, a, side view of single frus-

tule ; b, side view of variety @ ; c, sporangial frustule.

DIATOMACE^

PI. 12.

PLATE 13.— DiatomacesB.

Figure

1 . Hyalosira rectangula, front view of connected frustules.

2. Isthmia enervis, front view.

3. Licmophora splendida. b, side view ; c, front view of single frustule.

4. Lithodesmium undulatum. «, front view; b, side view.

5. Melosira nummuloides, front view.

6. Melosira varians, front view. «, side view.

7. Meridian circular e. 0, frustules united into a coil, front view ; b, side view of

single frustule.

8. Micromega parasitica, natural size. 5, portion of a filament containing the

frustules ; c, side view, d, front view of a frustule.

9. Nitzschia sigmoidea. «, side view ; b, front view.

10. Nitzschia lanceolata. a, front view; b, separate valve; e, side view of the same.

1 1 . Nitzschia longissima. a, side view ; b, front view.

12. Nitzschia reversa, front view of single valve.

13. Nitzschia acicularis, left-hand frustule; N. acicularisy right-hand frustule.

14. Odontidium turgidulum. a, frustules united, front view ; b, single valve, side

view.

15. Orthosira Dickieii. a, front view; b, side view.

16. Pododiscusjamaicensis. a, side view ; b, front view.

17. Podosphenia Ehrenbergii. a, front view; b, side view of single frustule.

18. Rhabdonema arcuatum. a, united frustules, front view ; b, side view of single

frustule.

19. Ehipidopteraparadoxa. b, front view of single frustule; c, side view of the same.

20. Striatella unipunctata. #, front view ; 5, the same ; c, side view.

21. Surirella gemma, a, side view ; b, front view.

22. Surirella bifrons. a, front view ; 6, side view.

23. Synedra splendens. a, attached frustules ; b, side view of prepared frustule ;

c, front view of the same.

24. Synedra fulg ens. a, side view; 5, front view of a prepared frustule.

25. Synedra capitata, side view.

26. Sphenosira catena. «, united frustules, front view; b, side view of single frustule.

27. Tabellaria Jlocculosa. a, united frustules, front view ; 5, side view of single

frustule.

28. Tetracyclus lacustris, united frustules, front view. «, side view.

29. Triceratiumfavus. a, side view ; 5, front view.

30. Tryblionella scutellum, side view.

31. Tryblionella gracilis, front view.

32. Tryblionella gracilis, diagram of transverse section.

PLATE 14. — Diatomaceae and Entomostraca.

Figure
1. Acroperus nanus. 2. Acroperus harpce.

3. Alteutha depressa. a, first pair of feet.

4. Alona reticulata. 5. Alona quadrangularis.

6. Anomalocera Patersoniiy male.

7. Anchorella uncinata. a, arms ; b, abdomen ; c, ovarian tubes.

8. Berkeley iafragilis. a, natural size ; b, portion of a branch containing frustules ;

c, side view, d, front view of a single frustule.

9. Biddulphia aurita. Frustules undergoing division: a, hoop of original frustule

to which two new halves (c) have been formed ; the hoop of the new frustules
is seen at b ; the hoop of the parent has separated from the two frustules d d,
which are perfectly formed, each with its new hoop.

10. Encyonema paradoxum. a, frustules contained in a gelatinous tube, side view ;

b, front view ; c, separate frustules, side view.

1 1 . Raphidoglcea micans. ay natural size ; b, group of frustules ; c, single frustule,

front view.

12. Schizonema Dillwynnii. a, natural size ; b, filaments containing frustules ;

c, front view, d, side view of frustule.

13. Zygoceros rhombus, a, front view ; b, side view.

14. Syncyclia salpa ; frustules immersed in a gelatinous mass.

15. Homceocladia anglica. a, portion of the natural size ; b, part of a filament con-

taining two frustules ; c, front view, d, side view of a prepared frustule.

16. Dickieia ulvoides. a, natural size ; b, portion of frond containing frustules ; c,

d, f, prepared frustules, front view ; ey side view.

17. Frustulia saxonica ; frustules immersed in a gelatinous mass.

18. Cymbosira Agardhii. a, united frustules; b, front view, c, side view of pre-

pared frustules.

19. Sphenella vulgaris. a, front view; b, side view.

20. Filaments found in a Cypris, noticed under OSTRACODA.

21. Cetochilus septentrionalis, dorsal view.

22. Notodelphys ascidicola, female. 23. Lepeophtheirus pectoralis, female.
24. Lerneonema spratta, female. 25. Macrothrix laticornis, female.
26. Moina rectirostris, female. 27. Sida crystallina.

28. Neb alia bipes. 29. Polyphemus pediculus.

30. Evadne Nordmanni.

31. Peracantha ovata. «, superior antenna.

32. Pleuroxus trigonellus.

33. Terpsinoe musica (front view, PI. 19. fig. 10).

34. Podosira hormoides, front view. 35. Tessella interrupta, front view.

36. Nicothoe astaci. a, ovaries.

37. Grammatophora marina, as seen by ordinary illumination, a, front view; b,

side view.

38. Grammatophora subtilissima, as seen by ordinary illumination. «, front view ;

bt side view.

DIATOMACH/E & ENTOMOSTRACA. ,

9

P114-.

FadA.Hfe8t.Iop.

Xaaim JofanWa Oboist .1355 .

ENTOMOSTRACA.

PI. 15.

Tuffe^/fot,

London, John Van Voorst, ]8&5.

Fcrd {.. Vest, Imp.

PLATE 15.— Entomostraca.

Figure

1 . Argulus foliaceus, seen from beneath. 0, anterior, b, posterior antennae ; c,

rostrum ; d, suckers, representing the first pair of legs ; ey second pair of
legs ; /", four posterior pairs of legs.

2. Bosmina longirostris ; 2*, the same, natural size.

3. Branchipus stagnalis. 4. Camptocercus macrourus.

5. Candona reptans ; 5 0, inferior antenna.

6. Canthocamptus minutus ; 6 0, inferior antenna ; 6 b, first pair of foot-jaws ;

6 e, second pair of foot-jaws.

7. Chydorus sphcericus.

8. Cyclops quadricornis, male, 0, b, superior antennae.

9. Cyclops quadricornis, female, a, superior, b, inferior antennas ; c, external

ovaries.

10. Cyclops quadricornis ; inferior antenna.

1 1 . Cyclops quadricornis ; mandible. 0, body ; 5, serrated seta ; c, filaments of

palp.

12. Cyclops quadricornis; first pair of foot-jaws.

13. Cyclops quadricornis', second pair of foot-jaws; 130, internal portion; 136,

external portion.

14. Cyclops quadricornis ; first pair of thoracic feet.

15. Cyclops quadricornis; fifth pair of legs.

16. Cyclops quadricornis ; recently hatched.

17. Cypris tristriata. 18. Cypris tristriata ; superior antenna.
19. Cypris tristriata ; inferior antenna. 20. Cypris tristriata ; mandible.

21. Cypris tristriata ; first pair of jaws. 0, basal plate ; 5, branchial lamina.

22. Cypris tristriata; second pair of jaws. 23. Cypris tristriata ; first pair of legs.

24. Cypris tristriata ; second pair of legs.

25. Cypris tristriata; lateral half of the abdomen.

26. Cy there inopinator. 27. Daphnella Wingii.

28. Daphnia pulex. ay superior antennae ; b, inferior antennae ; c, heart.

29. Daphnia pulex ; first pair of legs. 30. Daphnia pulex ; second pair of legs.
31. Daphnia pulex ; third pair of legs. 32. Daphnia pulex ; fourth pair of legs.
33. Daphnia pulex ; fifth pair of legs. 34. Daphnia pulex ; mandible.

35. Daphnia pulex ; lab rum. 36. Daphnia pulex ; jaw.

37. Daphnia reticulata. a, ephippium. 38. Diaptomus castor.
39. Eurycercus lamellatus.

PLATE ]6.— Entozoa.

Figure

1 . Echinococcus veterinorum (hominis) ; 1 a, in the contracted state ; 1 b, hooks ;

1 c, d, in the expanded state ; 1 e, imperfectly developed individual.

2. Echinococcus veterinorum (hominis) ; cyst reproducing by external gemmation.
3 a.Cysticercus cellulose, nat. size; 3 b, C.fasciolaris, head of.

4. Anguillula jluviatilis.

5. Anguillula aceti.

6. Anguillula tritici. a, b, ova ; c, mature individual ; d, e, imperfectly developed

individuals.

7. Anguillula glutinis.

8. Ascaris vermicularis ; 8 a, head ; 8 b, body ; d, stomach ; e, oesophagus ;

ff, anus ; h, ovaries ; k, oviduct.
90. Ascaris lumbricoides, front view of head ; 9 b, tail of male, with spicula ;

9 c, side view of head.
10. Ccenurus cerebralis ; portion of a cyst.

12. Tania solium, head of, side view; two of the suckers only are visible.

13. T&nia solium, head of, front view; all the four suckers are visible.

14. Tania solium ; a single joint, injected. a, gastric (?) canals ; b, vascular canals ;

c, testicular capsule ; dy spermatic duct ; e, oviduct ; the dark ramified organ
is the ovary.

15. Teenia solium, ovum of.

16. Trichina spiralis, lying within its cyst, imbedded in muscle.

17. Trichina spiralis, removed from its cyst.

18. Trichina spiralis ; internal organs.

19. Trichocephalus dispar, male.

20. Trichocephalus dispar ; portion of the neck.

21. Trichocephalus dispar, female; 21 a, ovum.

22. Ovum of Monostoma verrucosum.

23. Ovum of Tcenia variabilis.

25. Gregarina sipunculi.

26. Gregarina sipunculi, with two enclosed cells.

27. Caudate pseudo-navicula, from the abdominal cavity of Sipunculus nudus.

28. Gregarina Sieboldii.

29. Young pseudo-navicula-cyst of Gregarina scenuridis, from testis of Scenuris

variegata ; consisting of two loosely connected ovate cells, without an outer
envelope.

30. The same, with an outer envelope.

31. More advanced pseudo-navicula-cyst of the same Gregarina, with two cells

containing rounded pseudo-naviculse.

32. The same, with elongated pseudo-naviculae ; the cyst has three cell-like bodies

on its surface.

33. The same with a single cavity, containing elongated pseudo-naviculee.

34. Two Gregarince scenuridis, adherent by their ends.

ENTOZOA.

PL 16.

t ; :'W^f^

TaffoiWeel.se

ion&n. -Mm TfcaVooraLl3H>

FISH SCALES

PI. 17.

TufR.T, West.. :,c.

PLATE 17.— Fish-scales, etc.

Figure

1 . Scale of sturgeon, perpendicular section, a, outer spongy portion ; b, inner

laminated portion ; 1 c, transverse section of outer portion.

2. Skin of skate (Raia batis), viewed from above.

3. Large spine of skate, side view.

4. Portion of transverse section of large spine of skate (fig. 3 b).

5. Longitudinal section of tooth of a small spine of skate (fig. 2).

6. Scale of perch (Percaflumatilis).

7. Perch-scale, portion of (fig. 6 #), more magnified.

8. Perch-scale, portion of (fig. 6 6), more magnified.

9. Scale of sole (Solea vulgaris).

10. Scale of roach (Leuciscus rutilus).

11. Scale of roach (Leuciscus rutilus), portion of surface more highly magnified.

12. Scale of roach (Leuciscus rutilus), perpendicular section.

13. Scale of minnow (Leuciscus phoxinus) .

14. Feather of finch ; shaft with medullary cells.

15. Feather of goose (Anser cinereus). a, pinnae with hooks ; by pinnae with teeth ;

c, harbs.

16. Separate pinnae, a, with hooks ; b, with teeth.

,' > Feather (downy), free barbs of.

10. J

19. Skin of eel (Anguilla vulgaris), with stellate pigment-cells, and indications of

subjacent scales.

20. Scale of eel (Anguilla vulgaris). 20 a, portion more magnified.

21. Calcareous corpuscles from the same, left after red heat.

22. Scale of jack or pike (Esox lucius).

23. Scale of dace (Leuciscus vulgaris).

25. Leech (Hirudo medicinalis), anterior sucker of.

26. Leech, jaw of, side view, a b, teeth ; c, fibro-cartilaginous substance of jaw ;

£?, pigment-cells.

27. Leech, jaw of, the free margin turned towards the observer.

28. Leech, teeth of. a, side view ; b, front view.

29. Horn of cow. a, section parallel to surface ; b, cells softened by potash, d con-

taining pigment ; e, perpendicular section ; fy cracks between laminse ; g, edges
of divided laminae.

30. Whalebone, longitudinal section.

31. Whalebone, transverse section.

32. Whalebone, longitudinal section of hair of.

33. Whalebone, cells of, resolved by potash.

34. Fish, crystals from scales of.

35. Muscular fibres of lobster (Astacus marinus).

36. Muscular fibrillae, various appearances presented by.

37. Large spine of skate, outer portion of.

PLATE 18.— Foraminifera, etc.

Figure

1. Rotalia Beccarii, shell of, from sea-sand.

2. Rotalia Beccarii, shell of, dorsal view.

3. Rotalia Beccarii, shell of, antero-lateral view. The oblique dark line indicates the part

at which the anterior portion of the body protrudes.

4. Rotalia Beccarii, shell of, ventral surface.

5. Rotalia Beccarii, body freed from the shell.

6. Rotalia Beccarii, portion of shell.

7. Marginulina raphanus, shells, nat. size.

8. Marginulina raphanus, body freed from the shell.

9. Marginulina raphanus, shell, magnified.

10. Marginulina raphanus, shell, longitudinal section.

11. Orbiculina numismatis, shells, nat. size, from sea-sand.

12. Orbiculina numismatis, shell, side view.

13. Orbiculina numismatis, shell, front view, showing the apertures.

14. Orbiculina numismatis, portion of shell, with the foramina, and the numerous orifices

corresponding to the individual animals (Ehr.).

15. Orbiculina numismatis; portion of anterior margin, with the oval holes for the

protrusion of the expansions, and the transverse neck -like prolongations of the
anterior part of the body.

16. Sorites orbiculus, shells, nat. size, side- and edge-views.

17. Sorites orbiculus, shell, side view; two of the cells are broken open, others are shown

partly closed by dendritic calcareous particles.

18. Sorites orbiculus, shell, side view ; from one cell protrude eight expansions.

19. Geoponus Stella borealis, with the expansions issuing from the foramina.

20. Geoponus stella borealis, after removal of shell by acid.

21 . Rotalia perforata, living, side view.

22. Opercularia arabica, shell, side view, nat. size.

23. Opercularia arabica, shell, surface view, a, small, b, large papillae.

24. Opercularia arabica, spicula.

25. Opercularia arabica, vertical section of shell over the chambers, a, large, b, small

papillae ; c, lines of growth ; d, vertical tubes.

26. Opercularia arabica; vertical section of septum, showing, — a, intraseptal vessel;

b, septum ; c, grand channel of intercameral communication ; d, part of spicular
cord.

27. Opercularia arabica ; horizontal section of three large chambers, showing — a, cham-

bers ; b, septa ; c, intraseptal vessels ; d, branches to surfaces of septa ; e, branches
to wall of shell, &c.; f, marginal plexus ; g, terminal branches on the surface ; h, spi-
cular cord ; i, half-formed septum.

28. Opercularia arabica, perpendicular section, a, spicular cord; 'b, papillary tubes;

c, truncated vessels of marginal plexus; d, small channels of intercameral commu-
nication ; e, grand channel of the same ; f, septum.

29. Nummulites acuta, vertical section, a, spicular cord ; b, truncated vessels of marginal

plexus; c, chambers of central plane; d, vertical intraseptal vessels; e, horizontal
intraseptal vessels ; f, chambers on each side of central plane ; g, vertical tubes.

30. Eunotia tetraodon. a, side view; b, front view.

31. Cymbella Ehrenbergii. a, side view; b, front view.

32. Coscinodiscus radiatus. a, side view ; b, front view.

33. Rotalia perforata, from chalk, b, fragment.

34. Textularia striata. 35. Textularia globulosa.

36. Rosalina Icevigata, basal view. 37. Rosalina leevigata, side view.

38. Rotalia turgida, side view. 39. Textularia aspera, fragment.

40. Rotalia globulosa ; b, fragment. 41. Rotalia globulosa, chambers filled with air.

42. Lithocampe ?, fragment.

43. Actinocyclus undulatus. a, side view ; b, front view.

44. Campylodiscus ciypeus, side view.

45. Actinoptychus senarius. a, side view ; b, front view.

46. Dictyocha gracilis, a, oblique view ; b, side view ; c, front view.

TORAMINIFERA
6

lonim. Join VaJiToorst.1854.

FOSSILS.

London. John Van Voorst. 185 4.

PLATE ] 9.— Fossils.

Figure

1 . Mesocena octogona.

2. Asteromphalus Hookerii, side view.

3. Hemiaulus antarcticus, front view.

4. Heliopelta Leeuwenhoeckii, side view.

5. Asterolampra marylandica, side view.

6. Symlolophora trinitatis, side view.

7. Coscinodiscus craspedodiscus, side view.

8. Coscinodiscus craspedodiscus, half a valve.

9. Climacosphenia moniligera. a, side view ; b, front view.

10. Terpsinoe musica, front view (side view, PL 14. fig. 33).

1 1 . Amphipentas alternans, side view.

12. Bodies found in flint, nature doubtful (see PYXIDICULA).

13. Pyxidicula major, front view.

14. Agate, a, a, fibres of sponge ; b, gemraules ; c, branched fibre ; d, spicula (all

doubtful).

15. Crystalloids of chalk, a, simple rings; b, transversely striated rings; c, disks.

16. Lagena Icevis. b, section.

17. Lagena gracilis.

18. Lagena striata.

19. Entoselenia globosa. b, section.

20. Entoselenia squamosa, var. catenulata.

21. Entoselenia squamosa, var. hexagona.
22:

23.

Fossil bodies from flint, so-called Xanthidia, but consisting of the sporangia of
the Desmidiacese.

27.
28J

29. Vertical (radial) section of coal from Disco, consisting of Coniferous wood

(Pinus).

30. Transverse section of the same coal.

31. Splinter of the same.

32. Vertical section of silicified wood (Pinus) from Virginia.

33. Vertical section of silicified wood (Araucaria ?) from Australia.

PLATE 20.— Fungi.

Figure

1 . Vertical section of a leaf of black currant, infested with JEcidium Grossularice.

sp, spermagonia ; p, perithecia.

2. Sterigmata (st) and spermatia (sp) from the spermagonia of Mcidium Euphorbia.

3. Ditto, from Mcidium Berberidis.

4. Vertical section of a spermagonium of dEcidium Berberidis.

5. Botrytis infestansy young plants growing out from the stomate of a potato.

6. Full-grown plants of the same. 6 #, spore of ditto.

7. Torula ?, growing in urine (not diabetic).

8. Grape fungus, conidial form (Oidium Tuckeri) as commonly found on the leaves

and fruits.

9-11. Conidia of the same, germinating.

12. Sporiferous form (Circinobolus) .

13. Spores from the same.

14. Hop-mildew, Erysyphe (Sphcerotheca) Castagnei. a, Oidial form ; b, b, form

resembling Circinobolus ; c, d, Erysyphal form ; e, spores.

15. Fragment from the summit of a fertile filament of Penicillium glaucum.

16. Spores of ditto, a, two still united ; b, one detached.

17. Section of a conceptacle of Cenangium Fraxini, containing st, stylospores, and s,

spermatia.

18. Ergot of rye, Cordyceps purpurea, Tulasne ; fruits sprouting from the ergot.

19. Vertical section of the head of one of the fruits bearing conceptacles in its

periphery.

20. Vertical section of a conceptacle containing asci.

21. Asci removed from the same.

22. Spores from the interior of the asci.

23. Yeast fungus (Torula Cerevisiae), large form at the bottom of liquid.

24. Ditto, minute form, appearing as a white mealy substance on the surface of stale

beer.

25. Sphceria inquinans (a) with Stilbospora macrosperma (b) in the bark of an elm-

tree.

26. A portion of the common matrix separating the two, with the stylospores of
Stilbospora (b) above, and the asci of Sphceria (a) below.

27. Spore of Stilbospora macrosperma.

28. Spore of Sphceria inquinans.

PI. 20.

London-: John-Van. Voorst ,18 64.

J.Basire, sc.

HAIRS. FIBRES, & GLANDS OF PLANTS.

dd, TuffeaWest sc.

London. John Van Voorst, 1655.

Fori Ik Vfet, Imp.

PLATE 21.— Hairs, Fibres, Glands, &c. of Plants.

Figure

1. Cotton. 0, normal condition ; b, portion treated with sulphuric acid and iodine ;

c, a fragment of gun-cotton.

2. Flax, a, normal fibre ; b, portion boiled with nitric acid ; c, treated with nitric

acid, and afterwards with sulphuric acid and iodine.

3. Jute. a, normal fibre ; b, c, portions boiled with nitric acid.

4. Coir (Cocoa-nut fibre), bundle of fibres.

5. Ditto. a, by portions of fibres boiled with nitric acid.

6. Hemp. «, normal fibre ; 5, portions boiled with nitric acid.

7. Manilla hemp. «, normal fibres ; b, fragment boiled with nitric acid.

8. Sting of TJrtica urens.

9. Surface of the cuticle of Helleborusfcetidus.

10. Ditto of Cakile americana.

11. Imbedded gland of Ruta graveolens, vertical section.

12. Glands of Magnolia, seen from above.

13. Hair of Siphocampylus bicolor, the cuticle detached by sulphuric acid.

14. Glands of hop. a, side view ; b, from above.

15. Stellate body from the air-spaces in the leaf of Nuphar lutea.

16. Hair of Delphinium pinnattfidum. 17. Hair of Anchusa crispa.

18. Hair of Pelargonium. 19. Branched hair of Ferbascum Thapsus.

20. Scale-like hairs from the seed of Cobcea scandens.

21. Annulated hairs from the seed of Ruellia formosa, in water; 5, detached cell-wall.

22. Spiral-fibrous hairs from the seed of Collomia grandiflora, in water. 6, c, frag-

ments showing the cell-wall and free fibre.

23. Hair from the seed of a Salvia.

24. Hair from the seed of Acanthodium spicatum. b, a fragment of a branch.

25. Chinese grass-cloth fibre, a, normal fibre ; 6, fragments boiled with nitric acid;

c, afterwards treated with sulphuric acid and iodine.

26. Puya fibre. «, normal fibre ; b, fragments boiled with nitric acid ; c, afterwards

treated with sulphuric acid and iodine.
26*. Stellate hairs from the epidermis of Deutzia scabra.

27. Stellate hair of ivy-leaf. 28. Stellate hair of Alyssum.

29. Horizontal stalked hair of Grevillea lithidophylla.

30. T-shaped hair of garden Chrysanthemum.

31. Ramentum or scale from a germinating fern.

32. Hair from the bulbel of Achimenes.

33. Hair from the corolla of Digitalis purpurea.

34. Hair from the corolla of Antirrhinum majus,

35. Branched hair from the epidermis of Sisymbrium Sophia.

36. Forked hair from Capsella Bursa-pastoris.

37. Branched hair of Alternanthera axillaris.

38. Gland of Dictamnus Fraxinella.

39. Epidermis of Dictamnus Fraxinella. a, b, hairs ; c, gland vertically divided.

40. Glandular hair of Lysimachia vulgaris.

41. Glandular hair of Scrophularia nodosa.

42. Glandular hair of Bryonia alba.

43. Scale of Begonia platanifolia.

44. Glandular hair of Gilia tricolor.

45. Vertical section of papilla of Mesembryanthemum crystallinum.

46. Seta of a rose.

47. Tufted hairs of Marrubium creticum.

PLATE 22.— Hairs of Animals.

Figure

1 . Human whisker, white ; air partly displaced from medulla.

2. Human hair, transverse sections.

3. Human hair, foetal, with imbricated scales.

4. Monkey, Indian (Semnopithecus).

5. Lemur.

6. Bat, Indian.

7. Bat, Australian.

8. Mole (Talpa europ&a).

9. Lion (Felis Leo) ; left-hand figure by transmitted, right by reflected light.

10. Bear (Ursus Arctos).

11. Wolf (Canis Lupus).

12. Coati mondi (Nasua).

13. Seal, Falkland Island (Phocana falklandica) .

14. Horse (Equus Caballus).

15. Elephant (Elephas indicus), segment of a transverse section.

16. Pig (Sus Scrofa).

17. Cheiropotamus.

18. Camel (Camelus bactrianus).

19. Dromedary (Camelus dromedarius) .

20. Deer, moose- (Cervus Alces).

21. Deer, musk- (Moschus moschiferus) .

22. Wool, sheep (Ovis Aries).

23. Sloth (Brady pus didactylus).

24. Armadillo (Dasypus sexcinctus).

25. Beaver (Castor Fiber).

26. Shrew (Amphisorex rusticus).

27. Mouse (Mus musculus).

28. Ditto, treated with potash.

29. Guinea-pig (Cavia cobaya).

30. Squirrel (Sciurus vulgaris).

31. Rabbit (Lepus cuniculus).

32. Sable (Mustela zibellina).
33.. Mink-sable (Mustela lutreola).

34. Badger (Meles taxus).

35. Chinchilla (Chinchilla lanigera).

36. Kangaroo (Macropus).

37. Opossum (Didelphis virginiana).

38. Ornithorhynchus paradoxus. «, entire hair ; b, c, d and 38 *, portions more

magnified.

39. Crab (Cancer manas), from antenna of.

40. Spider (Lycosa saccata).

41. Spider (My gale).

42. Spider ( ?), from South America.

HAIRS
3

PI. 22.

London John Van Voorst 1854

I 'I

&^»WMb«dg

loaAsiJoTm \fcLVW 1854

PLATE 23.— Infusoria.

Figure

1. Acineria incurvata, Duj.

2. Acineria acuta, D.

3. Acomia vitrea, D.

4. Acineta tuber osa, Ehr.

ba.Podophryafixa, E. ; 5b, the same, or the Podophrya-stage of Vorticella?

6. Actinophrys viridis, E.

7a.Actinophrys Eichornii, E. ; 7 &, Actinophrys sol, E.

8. Alyscum saltans, D.

9. Amoeba diffluens, E. 9 a, expanded ; 9 6, contracted.

10. Amphileptus fasciola, E. 10 a, dorsal view ; 10 6, side view.

11. Amphimonas dispar, D.

12. Anisonema sulcata, D.

13. Anthophysa Miilleri, Bory, Duj. (Epistylis vegetans, E.) j 13 a, entire organism ; b,

single body.
l4a.Arcella vi'lgaris, E., dorsal view ; 14 b, Arcetta aculeata, E., under view ; 14 c, Arcella

dentata, E., under view.

\5a.Aspidisca lynceus, E., under view ; 15 b, Asp. denticulata, E., side view.
16. Astasia h&matodes, E. a, contracted; b, c, d, in different states of expansion.
17- Astasia limpida, D. (A. pusilla, E.). a, expanded; b, altered in shape.
ISa.Bodo grandis, E. ; 18 b, c, Bodo socialis, E.

19. Bursaria vernalis, E., under surface.

20. Carchesium polypinum, E.

21. Carchesium polypinum, E., separate body.

22. Cercomonas acuminata, D.

23. Cercomonas crassicauda, D.

24. Various forms of Trachelomonas, arranged by Ehrenberg in the genera Trachelomonas,

Cheetoglena and Doxococcus. See TRACHELOMONAS.
25a.ChfBtomonas globulus, E. ; 256, Ch. constrictus, E.

26. a, b, Chcetotyphla armata, E. ; c, Ch. aspera, E.

27. Chilodon cucullulus, E. a, under view; 6, side view.

28. Chilomonas granulosa, D.

29. Chlamidodon mnemosyne, E., ventral surface.

30. Chlamidomonas pulvisculus, E. (Diselmis viridis, D.), in various stages of development.

31. Chlorogonium euchlorum, E. (upper and lower figure), in different stages of development.

32. Colacium vesiculosum (left-hand fig.) ; C. stentorium, right-hand figure.

33. Coleps hirtus, E. (a, after Ehr., b, after Duj.).

34. Crumenula text a, D.
35a.Cryptoglena conica, E. ; 35 b, Cr. pigra, E.

36a.Cryptomonas ovata, E. ; b, C. lenticularis, E. ; c, C. fusca, E. ; d, C. globulus, D. ;

e, C. incsqualis, D.
37a.Cyclidium distortum, D. ; b, C. abscissum, D. ; c and d, C. glaucoma, E. ; c, side view;

d, dorsal view.

38. Cyphidium aureolum, E. a, dorsal view ; in b, the expansion is seen.

39. Difflugia proteiformis, E., a and 6.

40. Dileptus folium, D.

41. Dinobryon sertularia, E. 42. Dinobryon petiolatum, D.

43. Diophrys marina, D. a. under view ; 6, side view.

44. Discocephalus rotatorius, E. a, dorsal view; 6, side view.

45. Disoma vacillans, E.

46. a, Distigma proteus, E. ; 6, D. viride, E.

47. a, Doxococcus ruber, E. ; 6, D. pulvisculus, E.

48. Enchelys pupa, E. 49. Enchelys nodulosa, D.

50. Epipyxis utriculus, E.

51. a, Epistylis anastatica ; 6, single body of .E. grandis.

52. Ervilia legumen, D. (Euplotes monostylus, E.). a, under view ; 6, side view.

53. Euglypha tuberculata, D. 54. Euglypha alveolata, D.
55. Amblyophis viridis, E.

PLATE 24.— Infusoria.

Figure

1. Euglena pyrum, E.

2. Euglena viridis, E. a, b, in different states of contraction and extension.

3. Euglena longicauda, E. (Phacus longicauda, D.), with the body twisted. (Fig. 63, the

same, after Duj.j the body flat.)

4. Euglena acus, E., undergoing longitudinal division.

5. Euplotes patella, D. a, under view; b, lateral view.

6. Euplotes vannus, E., under view. 7. Gastroch&tafissa, D.
8. Glaucoma scintillans, E. 9. Peridinium cinctum, E.

100, b. Glenodinium cinctum, E.; 10 c (between figs. 49 & 50), Glenodinium apiculatum, E.
11. Peridinium fuscum, E. 12. Peridinium tripos, E.

13. Peridinium fusus, E. 14. Glenomorum ting ens, E.

15. Gromia fluviatilis, D., with its expansions extended.

16. Trichodina pediculus, E. a, side view; Z>, under view.

17. Heteronema marina, D. 18. Himantophorus charon, E., under view.
19. Himantophorus charon, E., side view. 20. Hexamita nodulosa, D.

21. Holophrya brunnea, D. 22. Holophrya ovum, E.

23. Ichthydium podura, E. 24. Chcetonotus larus, E.

25. Colpoda cucullus, E. 26. Kerona pustulata, D. (Stylonichia p., E.).

27. Kerona mytilus, D. (Stylonichia m., E.), under view.

28. Kerona mytilus, D. (Stylonichia m., E.), side view.

29. Stylonichia histrio, E., under view.

30. Stylonichia lanceolata, E. a, under view ; 6, side view.

31. Kondylostoma patens, D., under view.

32. Kondylostoma patens, D., half side view.

33. Trachelocerca viridis, E. 34. Amphileptus papillosus, E.

35. Lagenella euchlora, E. 36. Cryptomonas (Lagenella, E.) inflata, D.

37. Leucophrys striata, D.

38. Leucophrys patula, E. a, dorsal, 6, ventral surface.

39. Loxodes rostrum, E. (Pelecida rostrum, D.)

40. Loxodes dentatus, D. 41. Loxodes bursaria, E., under view.

42. Loxophyllum (Amphileptus, E.) meleagris,D. a, dorsal view ; 6, anterior portion twisted.

43. a, Microglena punctifera, E. ; 6, M. monadina, E.

44. a, Monaslens, D.; Z>, the same (?) with two anterior cilia; c, Af. attenuata, D.

45. Nassula elegans, E.; 6, teeth. 46. Nassula aurea, E.

47. Opalina (Bursaria, E.) ranarum, Purk. and Val.

48. Ophrydium versatile, E. ; portion expanded by compression.

49. Ophrydium versatile, E. ; marginal portion, in the natural state.

50. Ophrydium versatile, E. ; isolated body.

51. Ophryoglena atra, E. 5'2. Oxytricha pellionella, D.
53. Oxytricha gibba, E., side view. 54. Oxyrrhis marina, D.

55. Panophrys chrysalis, D. 56. Paramecium aurelia, E., dorsal view.

57- Paramecium aurelia, E., side view. 58. Pantotrichum lagenula, E.

59. Peranema globulosa, D. 60. Phialina vermicularis, E.

61. Phialina viridis, E. 62. Phacus (Euglena, E.) pleuronectes, D.

63. Phacus (Euglena, E.) longicauda, D. 64. Plagiotoma lumbrici, D.

65. Planariola rubra, D. 66. Pleuronema chrysalis, D.

67. Plceotia vitrea, D. 68. Polyselmis viridis, D.

69. Polytoma uvella, E. 70. Prorocentrum micans, E.

71. Prorocentrum micans, E., side view. 72. Prorodon teres, E.

73. Prorodon teres, E., teeth. 74. Scyphidia rugosa, E.

75. Spathidium hyalinum, D. (Leucophrys spathula, E.)

76. Spathidium hyalinum, D. ; anterior part twisted.
77- Spirostomum ambiguum, E.

78. Spirostomum ambiguum, E.; posterior end more magnified.

INFUSORIA.

P124

^m i

im i^m^a^^^m

m m

ixn SORIA.

['I 25

Lcmdm. John Van Toorst . 185 4 .

Forl^st.lam.

PLATE 25.— Infusoria.

Figure
1 . Tegument of Paramecium aurelia, dried, showing the depressions at different

foci, &c. (!NTR. p. xxxii.)

2a. Paramecium aurelia, with globules of sarcode ; 2 b, free globule of sarcode,
with numerous vacuoles.

3. Stentor Mulleri, E.

4. Tintinnus inquilinus, E.

5. Trachelius lamella, D., a and b.

6. Trepomonas agilis, D.

7. Trichoda angulata, D.

8. Trichodiscus sol, E.

9. Trichomonas vaginalis, D.

10. Trichomonas limacis, D.

1 1 . Trinema acinus, E.

12. Trochilia sigmoides, D., ventral view.

13. Trochilia sigmoides, D., dorsal view.

14. Urocentrum turbo, E.

15. a, Uroleptus piscis, E.; b, U. lamella, E.

16. Uronema marina, D.

1 7. Urostyla grandis, E.

18. Uvella virescens, E., « and 6.

19. Vaginicola crystallina, E.

20. Cothurnia imberbis, E.

21 a. Vorticella nebulifera, E. ; 215, body separated by division; 21 c, separate
body, a, mouth ; b, nucleus (auct. testis, E.) ; c, contractile vesicle (vesic.
seminal., E.).

22a.Zootkamnium arbuscula, E. ; 22 b, separate body.

23. Zygoselmis nebulosa, D. a, b, in different states of contraction.

24. Arcella vulgaris, E., half side view of young, with expansions extended.

25. Acineta-stage of Opercularia articulata, E. a, dendritic nucleus ; b, envelope ;

c, tentacles ; d, vacuoles ; e, group of fat-granules ; f, enlarged stalk.

26. Vorticella microstoma, E., full-grown, a, O3sophagus ; b, peristome ; c, con-

tractile vesicle ; d, nucleus ; e, gemma or bud ; f, mature bud.

27. Vorticella microstoma, E. (old), encysted upon its extended stalk, with its

nucleus, contractile vesicle, and retracted cilia.

28. Vorticella microstoma, E. (young), encysted upon its contracted stalk.

29. Vorticella microstoma, E., encysted and stalkless. a, cyst ; c, contractile

vesicle ; d, nucleus.

30. Isolated nucleus of an old Vorticella microstoma,

31 . Actinophrys-stage of Vorticella microstoma. The cyst is partly separated from

its contents ; the nucleus and contractile vesicle are visible.

32. Two of the above in conjugation.

33. Two Podophrya-stages of Vorticella microstoma in conjugation.

34. Cyst of Vorticella microstoma discharging its brood of germs, a, gelatinous

substance, containing b, the germs ; c, neck-like orifice of parent-vesicle ;

d, cyst ; e, parent-vesicle.

35. Spirochona gemmipara, Stein, a, peristome with its funnel-shaped process ;

b, nucleus ; c, gemma or bud.

36. Acineta-stage of the same, a, tentacles ; b, nucleus ; c, mature swarm -germ,

37. Paramecium chrysalis, E., undergoing longitudinal division.

38. Glaucoma scintillans, E., undergoing transverse division.

PLATE 26.— Insects.

Figure

1. Head of Blatta orientalis, from before, a, antennae, cut off; b, epicranium ; c, eyes;

d, clypeus ; e, labrum ; g, maxillae ; h, maxillary palpi ; k, labial palpi.

2. Head of Blatta orientalis, under portion, g, stipes, h, palp of maxilla ; i, palpiger,

k, palp, /, mentum, * paraglossa of labium ; m, submentum and gula ; X occiput.

3. Head of Hydrous piceus, under view, a, antennae ; c, eye ; e, labrum ; /, mandible ;

g, maxilla ; h, maxillary palp ; i, ligula ; k, labial palp ; /, mentum ; m, submentum ;
n, gula; X occiput.

4. Ocelli of Agrion fulvipes.

5. Portions of cornea of eye of Acheta domestica. a, with hexagonal, b, with quadran-

gular facets.

6. Perpendicular section of part of eye of Libellula. c, cornea; b, anterior convex margin';

d, anterior chamber ; /, crystalline lens ; g, choroid.

7. Antenna, setaceous (Achetidae, &c.).

8. Antenna, ensiform (Locustidae).

9. Antenna, filiform (Carabidae).

10. Antenna, moniliform (Tenebrionidae, &c.). a, scapus; b, pedicella; c, clavola.

11. Antenna, serrated (Elateridae). 12. Antenna, imbricated (Prionidae).
13. Antenna, pectinated (Lampyridae). 14. Antenna, bipectinated (Bombycidae).

15. Antenna, flabellate (Elateridae).

16. Antenna, clavate (Coleoptera).

17. Antenna, capitate (Coleoptera).

18. Antenna, lamellate and perfoliate (Melolontha). a, scapus ; b, pedicella ; c, clavola ;

d, lamellae.

19. Antenna of Globaria. a, scapus; b, pedicella; c, clavola; d, capitulum.

20. Antenna, plumose (Muscidae).

21. Antenna, plumose ( Culex pipiens, male).

22. Trophi of Blatta orientalis. a, labrum ; b b, mandibles ; c, maxillae (t lacinia, * galea) ;

d, internal tongue ; e, labium.

23. Tongue of cricket (Acheta domestica). a, b, c, parts of a fibre more magnified.

24. Head of mason-bee (Anthophora retusa), front view, a, antenna; b, ocelli; c, eye;

d, clypeus ; e, labrum ; /, mandible ; g, maxilla ; h, its palp ; i, palpiger or part of
the ligula ; k, labial palp ; * ligula, commonly called the tongue ; x, paraglossae.

25. Maxillae and labium of honey-bee (Apis mellifica] ; g, maxilla ; h, its palp ; k, labial

palp ; I, mentum ; * ligula, commonly called the tongue.

26. Trophi of water-scorpion (Nepa cinerea). * lingua; /, mandibles; g, maxilla; *,

labium.

27. Trophi of bug (Cimex lectularius). a, mandibles united; b, maxillae; the median organ

is the labium.

28. Antlia of red admirable butterfly (Vanessa atalanta). a, separate papilla; b, end of

antlia extended ; c, transverse section of antlia near its root ; * % tracheae, t tube ;
d, entire organ with two maxillae slightly separated at the end ; e, tooth ; f, section
near the end, showing the position of the papillae *, and the canal X .

29. Proboscis of the blow-fly (Musca vomitoria). a, maxillary palpi ; c, lobes of labium ;

29 a, portion of margin more magnified.

30. Trophi of female gnat (Culex pipiens). a, antennae; e, labrum; //, mandibles; g g,

maxillae ; d, tongue ; i, labium.

31. Setae of the same, more magnified, d, tongue ; e, labrum; f, mandible ; g, maxilla.

32. Trophi of flea (Pulex irritans). d, labrum;/, mandibles or lancets; g, maxilla; h,

maxillary palpi ; k, sheaths corresponding to labial palpi.

33. Trophi of flea more magnified, d, labrum ; /, end of mandible ; k, sheath ; /, labium ;

m, mentum.

INSECTS.

P1.26

lorli-West lay

INSECTS

3 d.

lonim. John T>&. vborst.i654.

PLATE 27.— Insects.

Figure

1 . Gizzard of cricket (Acheta domestica) .

20. Under membrane of elytrum of cockchafer (Melolontha vulgaris) ; 2 b, se-
parate hair or spiniform papilla (ELYTRA).

3. Scale of Lepisma saccharina, in liquid ; showing air-bubbles imprisoned by the

longitudinal ridges.

4. Hind leg of neuter honey-bee (Apis mellifca), with pollen-brushes on the first

joint of tarsus a ; c, tibia ; d, femur ; e, trochanter ; 4 b, outside of tibia
hollowed out.

5. Leg of middle pair of Gyrinusnatator. a, tarsus; c, tibia; d, femur; e, trochanter.

6. Anterior leg of male Dytiscus marginalia, a, tarsus, the first three joints with

the suckers ; b, one of the smaller ones more magnified ; c, tibia.

7. Leg of fly (Musca domestica) . a, tarsus ; c, tibia ; d, femur ; e, trochanter.

8. Tar sal pulvillus of blow-fly, with hair-like suckers.

9. One of the hair-like suckers of the same, more magnified.

10. Anterior wing of male cricket (Acheta domestica). a, drum; b, file (fig. 12,

the file more magnified).

11. Anterior wing of humble-bee (Bombus terrestris). n, fold over which the hooks

of the posterior wing play. (See INSECTS, wings, and WINGS.)

12. File of cricket (compare fig. 10 b).

13. Costal nerve of hind wing of humble-bee (Bombus terrestris), with the hooks.

(See INSECTS, wings.)

14. Sting and poison apparatus of mason-bee (Anthophora retusa). a, b, sheath of

sting ; c, reservoir ; d, duct ; e,f, secretory organs.

15. Single sting of wasp (Vespa vulgaris).

16. Spinning organs of silkworm (Bombyx mori).

1 7. Trachea of a caterpillar ; lower part of the branch containing air.

18. Internal reproductive organs of male mole-cricket (Gryllotalpa vulgaris) . a, testes;

b, vasa deferentia ; c, c', prostate (blind tubes) ; d, root of penis, with caeca
(Cowper's glands) at the upper part.

19. Female organs of the same, a, a, ovaries; b, b, oviducts; c, receptacle of
semen (blind sac), the very slender tube of which c' opens into the vagina d.

20. Battledore scale of Polyommatus argiolus, dry ; 20 «, a portion immersed in

water, and more magnified.

21. A scale of the same seen in Canada balsam.

22. Scale from the wing of the gnat (Culex pipiens).

23a. Scale from the wing of male Pontia rapce, dry; 23 b, portion of wing of the
same, showing the attachments of the two kinds of scales, a and b.

24. Scale from wing of male Pontia brassicce, dry.

25. Scale from under side of wing of clothes-moth (Tinea vestianella) .

26. Portion of wing of Pontia brassicce, dry, showing the imbricated arrangement

of the scales, and the wrinkling of the epidermis at their insertions.

27. Hair-like scales from clothes-moth, dry.

28«. Scale from wing of Lasiocampa quercus, dry; 286, upper portion of the
same, more magnified, dry. 29. Scale from wing of Papilio Paris, dry.

30. Scale from larva of Attagenus pellio, dry.

31. Portion of the above, more magnified.

32. End of one of the posterior legs of the larva of a Sphinx.

33. Anterior leg of the same.

34. Spiracle of Dytiscus marginalis; the appended figure represents one of the

marginal processes more magnified.

35. Portion of outer membrane of the ovum of the blow- fly (Musca vomitoria).

PLATE 28.— Insects.

Figure

1. Larva of gnat (Culex pipiens).

2. Organs of larva of Agrion puella. «, ocelli ; 6, oesophagus ; c, gizzard ; d, sto-

mach ; e, Malpighian vessels truncated ; /, intestine and rectum ; g, caudal
branchiae ; h, tracheae.

3. Clothes-louse (Pediculus vestimenti).

4. H&matopinus suis; 4*, leg more magnified.

5. Philopterus (Docophorus) communis.

6. Trichodectes latus ; 6*, labium and labial palpi.

7. Liotheum (Menopori) pallidum.

8. Gyropus ovalis.

9. Pulex felis (flea of cat), female. a, spiracles ; b, head ; cy thorax ; d, maxil-

lary palpi ; e, setae ; /, epimera; g, coxae ; h, trochanter ; i, femur ; k, tibia ;
I, tarsus ; x pygidium ; 9 a, separate antenna.

10. Part of Pulex canis (dog's flea), a, protothoracic setae; b, cephalic setae.

11. Head of flea from common bat (PULEX).

12. Antenna of flea from pigeon (PULEX).

13. Posterior end of abdomen of pigeon's flea; male (PULEX).

14. Head of larva of Dytiscus marginalia, a, eyes ; b, antennae ; c, mandibles ;

d, maxillae ; e, maxillary palpi ; f, labial palpi.

15. Pupa of Ephemera vulgata. a, abdominal branchiae.

16. Larva of Acilius sulcatus (formerly Dytiscus sulc.).

17. Pupa of Agrion puella ; the ocelli are omitted (LIBELLULID^E) ; 17*, caudal

branchial plate.

18. Lepisma saccharina.

19. Larva of Gyrinus natator.

20. Rectum of Mshna grandis ; 20*, portion more magnified (LJBELLULID.E).

21. Pupa of Calopteryx virgo.

22. End of abdomen of Libellula ferruginea.

23. Sheep-tick (Melophagus ovinus).

24. Flea from the mole (PULEX).

25. Head of a Scolopendra (one of the MYRIAPODA).

26. Head of a Lithobius (one of the MYRIAPODA).

27. Fibres of silk- worm's silk.

28. Three lobes of the fatty body of the larva (caterpillar) of Saturnia carpini.

29. End of abdomen of Mshna grandis.

30. (between 2 and 3), Epidermis of cricket (Acheta domestica).

31. Fat-body of Ichneumon-larva, developing from cells.

32. Egg of aquatic insect (?), common in bog-water.

PI. 28.

Lonim. Jotei Vac" .W st.lf 55 .

LICHENS.

PI 29.

lord 2c West

PLATE 29.— Lichens.

Figure

1. Fragment of the thallus of Parmelia parietina, Ach., with young apothecia and

spermagonia (near the edges of the lobes) .

2. Vertical section of one of the spermagonia and the part of the thallus in which

it lies. This section shows the upper and lower cortical layers of the thallus,
with the intermediate filamentous medulla and its globular gonidia.

3. Fragment from the wall of the above spermagonium, more magnified, to show

the articulated filaments (spermatophores) which bear the spermatia.

4. Spores of the same, treated with iodine ; the dark portion represents the proto-

plasmic contents.

5. A spore which has germinated.

6. Fragment of a vertical section through the apothecium of Parmelia stellaris, Fr.

The upper part is the fertile layer, or thalamium, composed of thecce with
spores and paraphyses ; this rests on the hypothecium, beneath which is a
portion of the medullary layer, with gonidia.

7. Ripe spores of the same.

8. Ripe spores, germinated and not germinated, treated with sulphuric acid, and

broken, showing the clear endospore inside the hard exospore.

9. Ripe spore of Verrucaria nitida, Fr.

10. Isolated spermatia from the spermagonia of ditto.

11. Ripe spores of Peltigera horizontal^, Hoffm.

12. Fragment of the thalamium of Sphcerophoron coralloides, Pers., with thecce in

different stages of development, and free ripe spores.

13. Vertical section of a spermagonium of Collema Jacobecefolium, D.C., with sper-

matia escaping. Imbedded in the thallus are seen the moniliform gonidial
filaments.

14. Isolated articulated filaments from the same.

15. Isolated spermatia from these filaments.

16. Vertical section of a spermagonium of Cladonia rangiferina, Hoffm., with sper-

matia escaping from its orifice.

17. Ripe spores of Urceolaria scruposa, Ach., seen in water.

18. Fully developed spores of Umbilicaria pustulata, Hoffm.

19. Ripe spores of Lecanora parella, Ach.

PLATE 30.— Morbid products, human.

Figure

1. Aphtha, a, spores of fungus (OIDIUM) ; b, fibres ; c and f. Bacterium termo ;

d, e, epithelial scales ; gt early state of Bacterium.

2. Areolar tissue, with formative cells and homogeneous basis ; from a fibroid

tumour of the upper jaw.

3. Cells of fatty tissue in degeneration, a, fat ; b, nucleus ; c, cell with thickened

walls.

4. Corpuscles of pus.

5. Corpuscles of pus, treated with acetic acid. «, nuclei with object-glass slightly

raised ; 5, the same when this is depressed.

6. Pyoid corpuscles, of Lebert.

7. Granule-cells and loose fat-globules ; some of the former with distinct cell- wall

and nucleus, in the lowest these are absent ; from a cutaneous cancer.

8. Tubercle in lung ; showing pulmonary fibres, tubercle-corpuscles and fat-granules.

9. Tubercle-corpuscles more magnified. «, seen in water; b, treated with acetic

acid. .

10. Fibro-plastic cells from a sarcomatous tumour of the thigh. «, loose secondary

cells ; b, fusiform cells ; c, parent-cells ; d, cell forming fibres.

11. Cancerous tissue from a medullary cancer, containing but few and pale fibres.

«, free nucleus ; 5, nucleus within a cell.

12. Cancerous tissue from a schirrhous cancer ; the fibres numerous, but delicate

and not arranged in bundles.

13. Capillary vessel in a state of fatty degeneration ; showing the oblong nuclei, and

the minute fat-globules in the substance of the wall of the vessel.

14. «, Fatty degeneration of the muscular bundles of the heart; the transverse striae

are absent, and globules of fat are disseminated through the substance ; b,
from muscle of the thigh, showing collapse of sarcolemma and partial absorp-
tion of muscular substance, with globules of fat in the remainder.

15. Intercellular fatty degeneration of encysted cutaneous tumour (cholesteatoma).

16. Tissue of medullary cancer of ovary. «, granule-cells ; b, cancer-cells; the fibres

are very few and slender.

17. Tissue of cancer of the oesophagus. «, cancer-cells ; b, their nuclei (secondary

cells) ; c, nucleoli (tertiary cells) ; d, cancer-cells with highly developed
nuclei ; e, granule-cells ; f, fibres and fusiform cells.

18. Colloid or alveolar cancer of the peritoneum, #, nuclei or secondary cells, the

walls of the two parent-cells are seen at b ; c, nuclei of areolar tissue ; the
contents of the cells are of gelatinous consistence.

19. Portion of an enchondroma, showing cells imbedded in a homogeneous basis.

«, cell with nucleus (secondary cell) and nucleolus (tertiary cell) ; c, secondary
cell with processes ; b, secondary cell from which the primary has disappeared.

20 1

' > Cancer-cells from medullary cancer.

22. Colloid corpuscles. «, simple ; b, c, concentric or laminated corpuscles from
hypertrophied heart ; d, f, laminated corpuscles from the prostate containing
calcareous matter ; e, concentric corpuscle from a cyst in an atrophied kidney.

MORBID PRODUCTS.

2

3

EL 30.

Ionian. John 1?kn."V"oarst.l855

ORNQIIK ^POLARIZING OBJKOT.S

PLATE 31. — Opake and Polarizing Objects.

Figure

1 . Two rhombs of selenite as seen under different relative positions of the polarizer

and analyser.

2. Crystals of acetate of copper (ACETIC ACID, DICHROISM).

3. Crystals of uric acid under polarized light, natural and artificial (compare PL 8).

4. Prisms of ammonio-phosphate of magnesia under polarized light.

5. Ellipsoidal-constricted, or dumb-bell crystals of oxalate of lime, under polarized

light.

6. Crystals of oxalate of soda, under polarized light.

7. Crystals of oxalate of ammonia, under polarized light.

8. Crystals of oxalate of chromium and ammonia, under polarized light.

9. Crystal of salicine, under polarized light.

10. Crystals of sulphate of cadmium, under polarized light.

1 1 . Crystals of oxalurate of ammonia, under polarized light.

12. Crystal of oxalurate of ammonia, under polarized light, with a plate of selenite.

13. Elytrum of Curculio imperialis, as an opake object.

14. Seeds of white poppy (Papaver somniferum), opake object.

15. Seed of sweet-william (Dianthusfasciculatus), opake object.

r' > Seeds of Silene gallica, opake objects.

18. Seeds of foxglove (Digitalis purpurea), opake objects.

19. Egg of puss-moth (Cerura vinula), opake object.

20. Eggs of bug (Cimex lectularius), opake objects ; the lids are removed.

21. Eggs of Pontia rapa, opake objects.

22. Skin and scales of sole (Solea vulgaris), opake objects.

23. Rhopalocanium ornatum.

24. Stephanastrum rhombus.

25. Eucertydium ampulla, front view.

26. Eucertydium ampulla, under view.

27. Podocyrtis Schomburgkii.

POLYCYSTINA. Opake objects.

28. Anthocyrtis mespilus.

29. Astromma Aristotelis.

30. Lychnocanium lucerna.

3 1 . Haliomma Humboldtii.

32. Eggs of Pontia brassicce, opake objects.

33. Portion of liver of cat ; the porta injected with red, the branches of the vena

cava with yellow ; opake object.

34. Portion of lung of toad ; opake object.

35. Kidney of pig; arteries and Malpighian bodies red, urinary tubules white ; opake

object.

36. Spiracle of Bombyx, opake object.

37 1

oo* > Sections of Rhinoceros's horn ; by polarized light.

39. White hairs of horse, interlaced; by polarized light.

40. Tous-les-mois starch, by polarized light, with plate of selenite.

PLATE 32.— Pollen, etc.

Figure

1 . a and b, spiral tissue of lining of anther from wallflower (Cheiranthus Cheiri).

2. Ditto, from London Pride (Saxifraga umbrosa).

3. Ditto, from Lupinus nanus.

4. Ditto, from a cactus (Cereus speciosus). a, side view; b, from above.

5. Ditto, from daisy (Bellis perennis) .

6. Pollen of Viola odorata. a, side view ; b, end view ; c, in water.

7. Pollen of Apocynum Fenetum.

8. Pollen of daisy (Bellis perennis).

9. Pollen of Mesembryanthemum.

10. Pollen of Alisma plantago.

1 1 . Pollen of Lupinus nanus.

12. Pollen of garden geranium (Pelargonium speciosum). a, front view ; b, side

view.

13. Pollen of passion-flower (Passiflora ccerulea). a, perfect grain ; b, grain with

the lid of a pore opening.

14. Pollen of Epilobium montanum.

15. Pollen of Periploca graeca.

16. Pollen of Scorzonera hispanica.

1 7. Pollen of Erica multiflora.

18. Pollen of Sherardia arvensis. a, side view ; b, end view ; c, ditto in water.

19. Pollen ofSasella alba.

20. Pollen ofPassiflora aguilegiaefolia. a, side view ; b, end view ; e, ditto in water.

21. Pollen of Impatiens noli me-tang ere.

22. Pollen of Cucurbita Pepo, in water.

23. Pollen of Ruellia formosa.

24. Pollen of musk-plant (Mimulus moschatus).

25. Compound pollen of Acacia laxa.

26. Pollen of Hibiscus Trionum.

27. Pollen of chicory (Cichorium Intybus).

28. Pollen of Sonchus palustris, side and end views.

29. Pollen of Statice linifolia, end and side view.

30. Pollen-grain with tube upon the stigmatic papillae, from Lathraa squamaria.

31. Spermatozoid from the globule of Charaf raff His.

32. Spermatozoids from the antheridium of Marchantia polymorpha.

33. Spermatozoids from the antheridium of Polytrichum commune.

34. Spermatozoids from the antheridium of a Fern (Gymnogramma).

35. Spiral fibrous cells of the sporange of Marchantia polymorpha.

36. Elater of Marchantia polymorpha.

37. Fragments of ditto. «, from the middle; 5, one end.

38. Elater of Frullania dilatata.

39. Elaters (a) and spores (b) of Trichia.

40. Fragment of the same elater showing the three internal spiral fibres.

POLLED ETC.

t 3

PL 32.

London.: Jakn/Van "Voorst iS54.

J.Busire sc.

PLATE 34.— Rotatoria.

Figure

1. Actinurus Neptunius, E., swimming, a, orifice of intestine.

2. Gizzard, with teeth of the same.

3. Head of the same, while crawling.

4. Albertia vermiculus, D. ; 40, teeth.

5. Anurcea curvicornis, E., dorsal view.

6. Anurcea curvicornis, E., half side view.

7. Asplanchna priodonta ; b, jaws and teeth.

8. Brachionus amphiceros.

9. Brachionus rubens, jaws of.

10. Callidina elegans.

1 1 . Callidina elegans, jaws.

12. Colurus defiexus, dorsal view.

13. Colurus deflexus, under view.

14. Colurus deflexus, teeth.

i r s* T .T -il'l

15. Conochtlus volvox, isolated animal.

16. Conochilus volvox, spherical group.

17. Conochilus volvox, jaws of.

18. Cycloglena lupus. «, tremulous bodies; b, contractile sac.

19. Cyphonautes compressus, side view, a, pharynx; b, nervous ganglion ; dt intestine.

20. Cyphonautes compressust end view.

21. Diglena lacustris.

22. Diglena lacustris, jaws.

23. Dinocharis teiractis.

r>A n- i • >j, ^ t

24. Dinocharis pocillum, teeth of.

25. Distemma forficula.

26. Distemma forficula, jaws of.

27. Enteroplea hydatina.

28. Eosphora digit at a.

29. Eosphora digit at a, jaws of.

30. Euchlanis triquetra. 31. Euchlanis triquetra, jaws of.

32. Floscularia ornata.

_. _

33. f losculana proboscidea, jaws ot.

34. Furcularia Reinhardtii.

35. Furcularia Reinhardtii, jaws of.

36. Glenophora trochus.

37. Hydatina senta.

38. Hydatina senta, jaws of.

39. flyrfriflw cornigera.

40. Lindia torulosa.

T> -,. 7 1

41. Lindia torulosa, teeth of.

42. Plagiognatha hyptopus, D. (Notommata hyp., E.).

43. Lepadella emarginata. 44. Lepadella ovalis, jaws of.
45. Limnias ceratophylli. 46. Mastigocerca carinata.

ROTATORIA.

PI 34

7 a

ROTATORLV

MfenWest. sculp

londoa. Join 7aa"%orrt 165 4.

PLATE 35.— Rotatoria.

Figure

1. Megalotrocha flavicans.

2. Megalotrocha Jlavicans, jaws.

3. Melicerta ringens.

4. Melicerta ringens, removed from its sheath, a, rotatory lobes; b, lips; c,

accessory ciliated lobe ; d, tentacular processes ; e, pharynx or oesophagus
and jaws ; f, g, upper and lower stomach ; h, anus ; k, ovary ; I, oviduct ;
n, tail ; o, disk ; p, sarcodic globules ; q, ovum.

5. Melicerta ringens, tentacular process of. a, setae ; b, conical body ; c, muscle.

6. Melicerta ringens, jaws of.

7. Metopidia triptera. a, contractile sac.

8. Microcodon clavus.

9. Monocerca rattus. a, contractile sac ; b, muscle.

10. Monolabis gracilis.

n *f j. j j - j j. j.

1 1 . Monostyla quadndentata.

9 2

12. Monura dulcis.

13. Noteus quadricornis.

14. Notommata centrura.

15. Notommata centrura, jaws of.

16. (Ecistes crystallinus.

17. Philodina erythrophthalma.

i o r>7 j. i -n

18. Pleurotrocha gibba.

-n , T , !° '• •&£

1 9 . Polyarthra platyptera.

20. Pterodina patina.

21. Ptygura melicerta.

22. Rattulus lunaris.

23. Rotifer vulgaris. a, contractile sac.

24. Salpina redunca, dorsal view.

25. Stephanoceros Eichornii. a, tremulous bodies.

<•»/? C* T. 11*-

26. bynchceta baltica.

y

27. Scandium longicaudum.

28. Stephanops cirratus.

29. Squamella oblonga.

30. Triarthra longiseta.

31. Triophthalmus dorsualis.

32. Theorus vernalis.

33. Typhlina viridis.

•

PLATE 36.— Starch.

4 1 H Oft)

Figure

1 . Section of a cell of the albumen of a young maize seed, showing the nascent

starch-grains imbedded in protoplasm.

2. The same, somewhat older ; most of the starch-grains exhibit a central point or

"hilum."

3. Section of a cell from the outer horny part of the albumen of maize ; the starch-

grains completely fill the cell, and by their crowded condition have compressed
each other into polygonal form.

4. Part of a similar section treated with iodine, a, starch-grain cut across (with a

central cavity) ; b, intervening protoplasm.

5. Free starch-grains of maize from the cells of the centre of the seed.

6. Young starch-grains of ditto.

7. Compound starch-grains and separated granules, from the corm of the crocus.

8. Lenticular starch-grains of wheat. «, seen in face; 6, seen edgewise.

9. Biscuit-shaped starch-grains of barley, a a, front view ; b, edgewise.

10. Compound starch-grains and separated granules of oats.

11. Compound grains and separated granules of Portland arrow root (Arum maculatum) .

12. Part of a section of a cell of the grain of rice, exhibiting very minute starch-

grains, firmly compacted as in maize.

13. A portion of the same, more magnified.

14. Starch-grains of Cassava (Jatropha Manihot)*.

15. Young starch-grains from the cells of the prothallium of a fern (Gymnogramma).

16. Compound starch-grains and separated granules of the bread-fruit (Artocarpus

incisa)*.

17. Starch-grains of Cycas circinalis*.

18. Starch-grains of the arrowroot (Maranta arundinacea), from Singapore*.

19. Starch-grains of an East Indian arrow root obtained from a species of Curcuma*.

20. Cell of a potato, showing the loosely-packed starch-grains.

21. Isolated starch-grains of the potato.

22. Starch-grains of Tacca pinnatifida, from Tahiti*.

23. Starch-grains of sago (from a Sagusl)*.

24. Starch from plantain-meal (Musa). a, front view; b, edgewise*.

25. Starch of Tous-les-mois (Canna). a, front view ; b, edgewise*.

26. Section of a cell of the cotyledon of a haricot-bean, a, starch-grains ; b, the

pitted secondary layers of amyloid upon the cell- wall.

27. An isolated starch-grain from the same.

28. Part of a cell of the stem of the white lily (Lilium candidum), showing nascent

starch-grains. «, forming in cavities of the protoplasm c ; £, nucleus.

* The figures to which this asterisk is appended, were taken from specimens with which we were
favoured from the Museum of Economic Botany at Kew.

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SHELL

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Ford iWest,

PLATE 37.— Shell, etc.

Figure
1 . Calcareous corpuscles of common-star-fish (Asterias ( Uraster) rubens), a, b, c, d,

e ; /, the same from an Ophiura ; g, calcareous disk from an Echinus ; h, i, k,

I, m, from an Ophiura (ECHINODERMATA).
2*. Spine of an Ophiura ; 2, portion of the same more magnified.

3. A pedicellaria of the common star-fish (Asterias rubens) ; on the right hand is

a portion of the margin more magnified to show the teeth.

4. Shell of Pinna, section parallel to the surface.

5. Shell of Pinna, section perpendicular to the surface.

6. Spine of an Echinus, transverse section. 6 a, segment of the same, more magnified.

7. Sections of shell of a Terebratula ; a, perpendicular to, b, parallel with the

surface.

8. Portion of a sponge, with the spicula projecting from its surface.

9. Shell of oyster, a, b, sections parallel to surface.

10. Shell of oyster, showing the rhomboidal crystals of carbonate of lime,

1 1 . Shell of oyster, showing the cellular appearance ; a, parallel with, b, perpendicular

to the surface.

12. Shell of hen's egg ; from a " soft " egg.

13. Shell of hen's egg, perfectly formed.

14. Shell of egg of ostrich ; section parallel to surface.

15. Shell of egg of ostrich ; section perpendicular to surface.

16. Shell of lobster ; section perpendicular to surface.

19. Anchor-shaped spicular hooks of Synapta (ECHINODERMATA).
™ . . r • m, • i V

The remaining figures represent the spicula of sponges.

a. Elongato-fusiform, tubercular.

b. Acicular, acute at both ends.

b*. Subulato-acicular, base trifid, rays shortly bifid.

c. Subulato-acicular.

d. Subulato-acicular, base swollen.

e. Arcuato-acicular, acute at both ends.

f. Shortly cylindrical, ends doubly trifid.

g. Subulato-acicular, base turbinate.
h. Subulato-acicular, base capitate.
i. Subulato-fusiform.

k. Elongato-subulate, base capitate.
I. Terete, geniculate.
m. Filiform, ends capitate.
n. Acicular, ends bifurcate.
o. Acicular, ends trifurcate.
p. Subulato-acicular, base tnradiate.

q. Acicular, base tri-retro-cuspid. r. Uncinato-filiform.

s. Bacilliform, ends tri-retro-cuspid.

t. Arcuate, ends uncinate. u. Stellato-triradiate.

v. Geminate, arms subulato-filiform, geniculate.

w. Stellato-quadriradiate. x. Stellato-quinquiradiate.

y. Stellato-multiradiate, ends capitate.

a. Subulate, tuberculate. /3. Arcuate, spinulose, ends clavate.

y. Stellate, insequiradiate.

5. Bacilliform, spinulose, with dentate, discoid, rotate ends,
e. Globular, with subulate spines.

£. Oblong, with irregularly stellate ends, the rays capitate; * side view, X end view.
rj. Bacilliform, with stellate, rotate ends.

PLATE 38.— Vegetable Tissues.

1 J • 11 /• ^ 7 •

1. Embryo-sac and supporting cells, of Orchis mono.

2. The same, more advanced.

3. The same, with a germinal vesicle at its apex.

4. The same, with three germinal vesicles, just before impregnation.

5. The same, after the pollen-tube (p f) has reached it ; one of the germinal vesicles

(e) already being developed to form the embryo.

6. The same, more advanced, showing the first cell of the suspensor (s) at the upper

end.

7. Embryo-sac of Lathraa Squamaria before the origin of the germinal vesicles ;

p, amorphous protoplasm ; e, protoplasm in course of development into endo-
sperm-cells.

8. 9. Apices of very young hairs of the filaments of Tradescantia virginica ; n, n,

nuclei, containing nucleoli ; p, protoplasm.

1 0. Cylindrical cell from which are formed the parent-cells of the spores of Marchantia
polymorpha ; p, primordial utricles of the parent-cells.

11. The same, converted into a string of cells.

12. One of the parent-cells isolated, with four primordial utricles of the spores.

13. The four spores free.

14. Transverse section of pith and internal wood of elder ; e?, porous duct.

15. Epidermis of the leaf of the pine-apple, seen from above.

16. Vertical section of cork.

17. Transverse section of ditto.

18. Transverse section of stellate parenchyma of rush-pith,

19. Cellular tissue (parenchymatous) of the leaf of Orthotrichum pulchellum.

20. Cellular tissue (prosenchymatous) of the leaf of Hypnum decipiens.

21. Section of the albumen of the seed of Areca Catechu.

22. The same, after treatment with sulphuric acid and iodine.

23. Section of the bony albumen of vegetable ivory, a, cells and pits filled with air;

c, cells filled up with Canada balsam.

24. Cell-membrane of Hydrodictyon utriculatum. m, the laminae of the cellulose

coat ; p, protoplasm.

25. Vertical section of the epidermis of a misletoe-branch several years old.

26. The same, after boiling in solution of potash and treatment with iodine.

27. Transverse section of a liber-cell of the oak, after long boiling in nitric acid and

treatment with iodine.

28. Vertical section of the upper face of the leaf of Cycas revoluta. a, cuticle,

extending over the epidermal cells, which, like the deeper-seated cells, have
pitted secondary deposits.

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PLATE 39.— Vegetable Tissues.

Figure

1 . Wood of Pinus sylvestris. a, radial vertical section ; b, tangental section of

the walls of two contiguous pitted wood-cells.

2. Tangental section of the wood of Casuarina equisetifolia. a, pitted wood-cells ;

b, duct ; c, cells of a true medullary ray ; d, cells of one of the concentric
medullary layers.

3. Vertical section of wood-cells of box.

4. Vertical (radial) section of wood- cells of the yew.

5. Vertical (radial) section of wood-cells of Araucaria imbricata.

6. Spiral-fibrous cells from the roots of Dendrobium alatum.

7. Wood-cells of Mammillaria, with broad spiral bands.

8. Spiral and annular vessel of Rhubarb.

9. Reticulated duct from the same.
Scalariform duct of a tree-fern.

End of a spiral vessel of the white lily.
Fragment of a larger and looser one.
Pitted duct of the lime (Tilia parvifolia).

14. Wall of a pitted duct of Cassyta glabella.

15. Wall of pitted ducts of Bombax pentandra. a, next another duct ; b, next cells.

16. Wall of a pitted duct of Laurus Sassafras.

17. Wall of a pitted duct of Chilianthus arboreus.

18. Wall of pitted ducts of Clematis (Clematis Vitalba).

19. End of a spiral-fibrous duct of Daphne Mezereon.

20. Walls of pitted wood-cells of Cycas.

21. Fragment of the wall of a large pitted duct of Eryngium maritimum.

22. Vertical section through the stomate of Aloe ferox. The darkly shaded part

represents the cuticular layer.

23. Fragment of a latex-duct of Euphorbia antiquorum ; the latex containing starch-

grains of peculiar shape.

. - , i - i -, /v. i., />

24. Epidermis of the petal ot the daffodil, from above.

25. Fragment of the leaf of Sphagnum cymbiforme. a> empty cells with spiral fibre;

b, interstitial cells with chlorophyll.

26. Vertical section of the upper face of the leaf of Parietaria officinalis, with a

cystolithe. Magnified 100 diameters.

27. A similar section from the leaf of Ficus elastica. Magnified 100 diameters.

28. a and b, Sections of the cellular tissue of onion-bulb, containing raphides.

29. Stomate and epidermis of Equisetum ; the siliceous coat remaining after the

destruction of the organic matter.

30. End of a liber-fibre of the periwinkle (Vinca major), with fine spiral striae.

31. Branched liber-cell of the radicle of Rhizophora Mangle.

32. Siliceous cast of the inside of a duct of unknown fossil wood ; the peculiar con-

centric concretions of the silica imitate to a certain extent the so-called glan-
dular markings of Coniferse.

PLATE 40.— Various Objects,

Figure

1. Mixtures of oil and water (!NTR. p. xxxii). a, water in oil; b, c, oil in water.

2. Oceania cruciata (ACALEPH.E), epidermis of.

3. Oceania cruciata. a, b, stinging capsules with filament included ; c, d, with

filament expelled.

4. Diphyes Kochii (ACALEPHJE) ; organs of adhesion upon tentacles.

5. Oceania cruciata, portion of margin of disk slightly magnified, a, ovary ;

b, muscular bundles ; c, transverse vessel coming from the stomach ; d, mar-
ginal vessel; e,f, tentacular filaments; g, auditory organs. Fig. 5* sperma-
tozoa.

6. Infusorial embryos of Ac ALE PH^E.

7. 8, 9, 10. The same, further developed.

11. Epidermis of Triton cristatus (water-newt).

12. Ciliated epithelium from frog's throat.

13. apiculosa *") Alder's animalcules, considerably magnified (ALDERIA).

14. ovata j> This generic name being already in use, cannot be re-

15. pyriformisj tained.

16. Htemocharis, epidermis of. ~|

1 7. Hamocharis ; transverse section of muscular fibres.

18. Htemocharis, muscular fibre, showing the sarcolemma. >(ANNULATA.)

19. Hcemocharis ; margin of cephalic disk, with branching mus-

cular fibres c ; and a, b, d, glands and ducts.

20. Aphrodita aculeata, hair of, treated with potash.

21. Blood-corpuscles, human. #, d, surface view at different foci ; c, side or edge

view ; 6, colourless or lymph-corpuscle ; ey coloured corpuscles altered, either
spontaneously or by mixture with foreign matters, as urine, &c.

22. Blood-corpuscles of the goat (Capra hircus).

23. „ „ whale (Balcena).

24. „ „ ostrich (Struthio).

25. „ „ pigeon (Columba).

26. „ „ stickleback (Gasterosteus aculeatus).

27. „ „ loach (Cobitis fossilis) ; b, colourless corpuscle.

28. „ >, frog (Rana temporaria) ; 6, colourless corpuscle ; c, d,

the same, altered by water.

29. „ „ triton (Triton cristatus) ; b, colourless corpuscle ; c, dy

e, f3 altered coloured corpuscles.

30. „ Siren ; b, colourless corpuscle.

crab (Carcinus).

spider (Teaenaria domestica).

cockroach (Blatta orientalis).

worm (Lumbricus terrestris). a, corpuscle partly drawn

31.
32.
33.
34.

out, as occurs with the bodies of some Infusoria.

35. „ „ garden-snail (Helix aspersa).

36. „ „ human, coloured, undergoing division.

37. Blood, human, in coagulation ; b, colourless corpuscle.

38. Cartilage of the ear of a mouse ; the fat is partly removed from the cells.

39. Cartilage of human rib.

40. Cartilage of human epiglottis.

41. Areolar tissue, human, with fat-cells.
43. Formation of areolar tissue from cells.

VARIOUS OBJECTS.

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